In the Linux kernel, the following vulnerability has been resolved: soc: qcom: pdr: protect locator_addr with the main mutex If the service locator server is restarted fast enough, the PDR can rewrite locator_addr fields concurrently. Protect them by placing modification of those fields under the main pdr->lock.

In the Linux kernel, the following vulnerability has been resolved: drm/vmwgfx: Fix a deadlock in dma buf fence polling Introduce a version of the fence ops that on release doesn't remove the fence from the pending list, and thus doesn't require a lock to fix poll->fence wait->fence unref deadlocks. vmwgfx overwrites the wait callback to iterate over the list of all fences and update their status, to do that it holds a lock to prevent the list modifcations from other threads. The fence destroy callback both deletes the fence and removes it from the list of pending fences, for which it holds a lock. dma buf polling cb unrefs a fence after it's been signaled: so the poll calls the wait, which signals the fences, which are being destroyed. The destruction tries to acquire the lock on the pending fences list which it can never get because it's held by the wait from which it was called. Old bug, but not a lot of userspace apps were using dma-buf polling interfaces. Fix those, in particular this fixes KDE stalls/deadlock.

In the Linux kernel, the following vulnerability has been resolved: bpf: Fail bpf_timer_cancel when callback is being cancelled Given a schedule: timer1 cb timer2 cb bpf_timer_cancel(timer2); bpf_timer_cancel(timer1); Both bpf_timer_cancel calls would wait for the other callback to finish executing, introducing a lockup. Add an atomic_t count named 'cancelling' in bpf_hrtimer. This keeps track of all in-flight cancellation requests for a given BPF timer. Whenever cancelling a BPF timer, we must check if we have outstanding cancellation requests, and if so, we must fail the operation with an error (-EDEADLK) since cancellation is synchronous and waits for the callback to finish executing. This implies that we can enter a deadlock situation involving two or more timer callbacks executing in parallel and attempting to cancel one another. Note that we avoid incrementing the cancelling counter for the target timer (the one being cancelled) if bpf_timer_cancel is not invoked from a callback, to avoid spurious errors. The whole point of detecting cur->cancelling and returning -EDEADLK is to not enter a busy wait loop (which may or may not lead to a lockup). This does not apply in case the caller is in a non-callback context, the other side can continue to cancel as it sees fit without running into errors. Background on prior attempts: Earlier versions of this patch used a bool 'cancelling' bit and used the following pattern under timer->lock to publish cancellation status. lock(t->lock); t->cancelling = true; mb(); if (cur->cancelling) return -EDEADLK; unlock(t->lock); hrtimer_cancel(t->timer); t->cancelling = false; The store outside the critical section could overwrite a parallel requests t->cancelling assignment to true, to ensure the parallely executing callback observes its cancellation status. It would be necessary to clear this cancelling bit once hrtimer_cancel is done, but lack of serialization introduced races. Another option was explored where bpf_timer_start would clear the bit when (re)starting the timer under timer->lock. This would ensure serialized access to the cancelling bit, but may allow it to be cleared before in-flight hrtimer_cancel has finished executing, such that lockups can occur again. Thus, we choose an atomic counter to keep track of all outstanding cancellation requests and use it to prevent lockups in case callbacks attempt to cancel each other while executing in parallel.

In the Linux kernel, the following vulnerability has been resolved: cachefiles: add missing lock protection when polling Add missing lock protection in poll routine when iterating xarray, otherwise: Even with RCU read lock held, only the slot of the radix tree is ensured to be pinned there, while the data structure (e.g. struct cachefiles_req) stored in the slot has no such guarantee. The poll routine will iterate the radix tree and dereference cachefiles_req accordingly. Thus RCU read lock is not adequate in this case and spinlock is needed here.

In the Linux kernel, the following vulnerability has been resolved: exfat: fix potential deadlock on __exfat_get_dentry_set When accessing a file with more entries than ES_MAX_ENTRY_NUM, the bh-array is allocated in __exfat_get_entry_set. The problem is that the bh-array is allocated with GFP_KERNEL. It does not make sense. In the following cases, a deadlock for sbi->s_lock between the two processes may occur. CPU0 CPU1 ---- ---- kswapd balance_pgdat lock(fs_reclaim) exfat_iterate lock(&sbi->s_lock) exfat_readdir exfat_get_uniname_from_ext_entry exfat_get_dentry_set __exfat_get_dentry_set kmalloc_array ... lock(fs_reclaim) ... evict exfat_evict_inode lock(&sbi->s_lock) To fix this, let's allocate bh-array with GFP_NOFS.

In the Linux kernel, the following vulnerability has been resolved: net, neigh: Do not trigger immediate probes on NUD_FAILED from neigh_managed_work syzkaller was able to trigger a deadlock for NTF_MANAGED entries [0]: kworker/0:16/14617 is trying to acquire lock: ffffffff8d4dd370 (&tbl->lock){++-.}-{2:2}, at: ___neigh_create+0x9e1/0x2990 net/core/neighbour.c:652 [...] but task is already holding lock: ffffffff8d4dd370 (&tbl->lock){++-.}-{2:2}, at: neigh_managed_work+0x35/0x250 net/core/neighbour.c:1572 The neighbor entry turned to NUD_FAILED state, where __neigh_event_send() triggered an immediate probe as per commit cd28ca0a3dd1 ("neigh: reduce arp latency") via neigh_probe() given table lock was held. One option to fix this situation is to defer the neigh_probe() back to the neigh_timer_handler() similarly as pre cd28ca0a3dd1. For the case of NTF_MANAGED, this deferral is acceptable given this only happens on actual failure state and regular / expected state is NUD_VALID with the entry already present. The fix adds a parameter to __neigh_event_send() in order to communicate whether immediate probe is allowed or disallowed. Existing call-sites of neigh_event_send() default as-is to immediate probe. However, the neigh_managed_work() disables it via use of neigh_event_send_probe(). [0] <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_deadlock_bug kernel/locking/lockdep.c:2956 [inline] check_deadlock kernel/locking/lockdep.c:2999 [inline] validate_chain kernel/locking/lockdep.c:3788 [inline] __lock_acquire.cold+0x149/0x3ab kernel/locking/lockdep.c:5027 lock_acquire kernel/locking/lockdep.c:5639 [inline] lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5604 __raw_write_lock_bh include/linux/rwlock_api_smp.h:202 [inline] _raw_write_lock_bh+0x2f/0x40 kernel/locking/spinlock.c:334 ___neigh_create+0x9e1/0x2990 net/core/neighbour.c:652 ip6_finish_output2+0x1070/0x14f0 net/ipv6/ip6_output.c:123 __ip6_finish_output net/ipv6/ip6_output.c:191 [inline] __ip6_finish_output+0x61e/0xe90 net/ipv6/ip6_output.c:170 ip6_finish_output+0x32/0x200 net/ipv6/ip6_output.c:201 NF_HOOK_COND include/linux/netfilter.h:296 [inline] ip6_output+0x1e4/0x530 net/ipv6/ip6_output.c:224 dst_output include/net/dst.h:451 [inline] NF_HOOK include/linux/netfilter.h:307 [inline] ndisc_send_skb+0xa99/0x17f0 net/ipv6/ndisc.c:508 ndisc_send_ns+0x3a9/0x840 net/ipv6/ndisc.c:650 ndisc_solicit+0x2cd/0x4f0 net/ipv6/ndisc.c:742 neigh_probe+0xc2/0x110 net/core/neighbour.c:1040 __neigh_event_send+0x37d/0x1570 net/core/neighbour.c:1201 neigh_event_send include/net/neighbour.h:470 [inline] neigh_managed_work+0x162/0x250 net/core/neighbour.c:1574 process_one_work+0x9ac/0x1650 kernel/workqueue.c:2307 worker_thread+0x657/0x1110 kernel/workqueue.c:2454 kthread+0x2e9/0x3a0 kernel/kthread.c:377 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 </TASK>

In the Linux kernel, the following vulnerability has been resolved: i3c: Use i3cdev->desc->info instead of calling i3c_device_get_info() to avoid deadlock A deadlock may happen since the i3c_master_register() acquires &i3cbus->lock twice. See the log below. Use i3cdev->desc->info instead of calling i3c_device_info() to avoid acquiring the lock twice. v2: - Modified the title and commit message ============================================ WARNING: possible recursive locking detected 6.11.0-mainline -------------------------------------------- init/1 is trying to acquire lock: f1ffff80a6a40dc0 (&i3cbus->lock){++++}-{3:3}, at: i3c_bus_normaluse_lock but task is already holding lock: f1ffff80a6a40dc0 (&i3cbus->lock){++++}-{3:3}, at: i3c_master_register other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&i3cbus->lock); lock(&i3cbus->lock); *** DEADLOCK *** May be due to missing lock nesting notation 2 locks held by init/1: #0: fcffff809b6798f8 (&dev->mutex){....}-{3:3}, at: __driver_attach #1: f1ffff80a6a40dc0 (&i3cbus->lock){++++}-{3:3}, at: i3c_master_register stack backtrace: CPU: 6 UID: 0 PID: 1 Comm: init Call trace: dump_backtrace+0xfc/0x17c show_stack+0x18/0x28 dump_stack_lvl+0x40/0xc0 dump_stack+0x18/0x24 print_deadlock_bug+0x388/0x390 __lock_acquire+0x18bc/0x32ec lock_acquire+0x134/0x2b0 down_read+0x50/0x19c i3c_bus_normaluse_lock+0x14/0x24 i3c_device_get_info+0x24/0x58 i3c_device_uevent+0x34/0xa4 dev_uevent+0x310/0x384 kobject_uevent_env+0x244/0x414 kobject_uevent+0x14/0x20 device_add+0x278/0x460 device_register+0x20/0x34 i3c_master_register_new_i3c_devs+0x78/0x154 i3c_master_register+0x6a0/0x6d4 mtk_i3c_master_probe+0x3b8/0x4d8 platform_probe+0xa0/0xe0 really_probe+0x114/0x454 __driver_probe_device+0xa0/0x15c driver_probe_device+0x3c/0x1ac __driver_attach+0xc4/0x1f0 bus_for_each_dev+0x104/0x160 driver_attach+0x24/0x34 bus_add_driver+0x14c/0x294 driver_register+0x68/0x104 __platform_driver_register+0x20/0x30 init_module+0x20/0xfe4 do_one_initcall+0x184/0x464 do_init_module+0x58/0x1ec load_module+0xefc/0x10c8 __arm64_sys_finit_module+0x238/0x33c invoke_syscall+0x58/0x10c el0_svc_common+0xa8/0xdc do_el0_svc+0x1c/0x28 el0_svc+0x50/0xac el0t_64_sync_handler+0x70/0xbc el0t_64_sync+0x1a8/0x1ac

In the Linux kernel, the following vulnerability has been resolved: gpio: pca953x: fix pca953x_irq_bus_sync_unlock race Ensure that `i2c_lock' is held when setting interrupt latch and mask in pca953x_irq_bus_sync_unlock() in order to avoid races. The other (non-probe) call site pca953x_gpio_set_multiple() ensures the lock is held before calling pca953x_write_regs(). The problem occurred when a request raced against irq_bus_sync_unlock() approximately once per thousand reboots on an i.MX8MP based system. * Normal case 0-0022: write register AI|3a {03,02,00,00,01} Input latch P0 0-0022: write register AI|49 {fc,fd,ff,ff,fe} Interrupt mask P0 0-0022: write register AI|08 {ff,00,00,00,00} Output P3 0-0022: write register AI|12 {fc,00,00,00,00} Config P3 * Race case 0-0022: write register AI|08 {ff,00,00,00,00} Output P3 0-0022: write register AI|08 {03,02,00,00,01} *** Wrong register *** 0-0022: write register AI|12 {fc,00,00,00,00} Config P3 0-0022: write register AI|49 {fc,fd,ff,ff,fe} Interrupt mask P0

In the Linux kernel, the following vulnerability has been resolved: wifi: mt76: mt7921s: fix potential hung tasks during chip recovery During chip recovery (e.g. chip reset), there is a possible situation that kernel worker reset_work is holding the lock and waiting for kernel thread stat_worker to be parked, while stat_worker is waiting for the release of the same lock. It causes a deadlock resulting in the dumping of hung tasks messages and possible rebooting of the device. This patch prevents the execution of stat_worker during the chip recovery.

In the Linux kernel, the following vulnerability has been resolved: serial: imx: Introduce timeout when waiting on transmitter empty By waiting at most 1 second for USR2_TXDC to be set, we avoid a potential deadlock. In case of the timeout, there is not much we can do, so we simply ignore the transmitter state and optimistically try to continue.

In the Linux kernel, the following vulnerability has been resolved: wifi: cfg80211: restrict NL80211_ATTR_TXQ_QUANTUM values syzbot is able to trigger softlockups, setting NL80211_ATTR_TXQ_QUANTUM to 2^31. We had a similar issue in sch_fq, fixed with commit d9e15a273306 ("pkt_sched: fq: do not accept silly TCA_FQ_QUANTUM") watchdog: BUG: soft lockup - CPU#1 stuck for 26s! [kworker/1:0:24] Modules linked in: irq event stamp: 131135 hardirqs last enabled at (131134): [<ffff80008ae8778c>] __exit_to_kernel_mode arch/arm64/kernel/entry-common.c:85 [inline] hardirqs last enabled at (131134): [<ffff80008ae8778c>] exit_to_kernel_mode+0xdc/0x10c arch/arm64/kernel/entry-common.c:95 hardirqs last disabled at (131135): [<ffff80008ae85378>] __el1_irq arch/arm64/kernel/entry-common.c:533 [inline] hardirqs last disabled at (131135): [<ffff80008ae85378>] el1_interrupt+0x24/0x68 arch/arm64/kernel/entry-common.c:551 softirqs last enabled at (125892): [<ffff80008907e82c>] neigh_hh_init net/core/neighbour.c:1538 [inline] softirqs last enabled at (125892): [<ffff80008907e82c>] neigh_resolve_output+0x268/0x658 net/core/neighbour.c:1553 softirqs last disabled at (125896): [<ffff80008904166c>] local_bh_disable+0x10/0x34 include/linux/bottom_half.h:19 CPU: 1 PID: 24 Comm: kworker/1:0 Not tainted 6.9.0-rc7-syzkaller-gfda5695d692c #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 Workqueue: mld mld_ifc_work pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : __list_del include/linux/list.h:195 [inline] pc : __list_del_entry include/linux/list.h:218 [inline] pc : list_move_tail include/linux/list.h:310 [inline] pc : fq_tin_dequeue include/net/fq_impl.h:112 [inline] pc : ieee80211_tx_dequeue+0x6b8/0x3b4c net/mac80211/tx.c:3854 lr : __list_del_entry include/linux/list.h:218 [inline] lr : list_move_tail include/linux/list.h:310 [inline] lr : fq_tin_dequeue include/net/fq_impl.h:112 [inline] lr : ieee80211_tx_dequeue+0x67c/0x3b4c net/mac80211/tx.c:3854 sp : ffff800093d36700 x29: ffff800093d36a60 x28: ffff800093d36960 x27: dfff800000000000 x26: ffff0000d800ad50 x25: ffff0000d800abe0 x24: ffff0000d800abf0 x23: ffff0000e0032468 x22: ffff0000e00324d4 x21: ffff0000d800abf0 x20: ffff0000d800abf8 x19: ffff0000d800abf0 x18: ffff800093d363c0 x17: 000000000000d476 x16: ffff8000805519dc x15: ffff7000127a6cc8 x14: 1ffff000127a6cc8 x13: 0000000000000004 x12: ffffffffffffffff x11: ffff7000127a6cc8 x10: 0000000000ff0100 x9 : 0000000000000000 x8 : 0000000000000000 x7 : 0000000000000000 x6 : 0000000000000000 x5 : ffff80009287aa08 x4 : 0000000000000008 x3 : ffff80008034c7fc x2 : ffff0000e0032468 x1 : 00000000da0e46b8 x0 : ffff0000e0032470 Call trace: __list_del include/linux/list.h:195 [inline] __list_del_entry include/linux/list.h:218 [inline] list_move_tail include/linux/list.h:310 [inline] fq_tin_dequeue include/net/fq_impl.h:112 [inline] ieee80211_tx_dequeue+0x6b8/0x3b4c net/mac80211/tx.c:3854 wake_tx_push_queue net/mac80211/util.c:294 [inline] ieee80211_handle_wake_tx_queue+0x118/0x274 net/mac80211/util.c:315 drv_wake_tx_queue net/mac80211/driver-ops.h:1350 [inline] schedule_and_wake_txq net/mac80211/driver-ops.h:1357 [inline] ieee80211_queue_skb+0x18e8/0x2244 net/mac80211/tx.c:1664 ieee80211_tx+0x260/0x400 net/mac80211/tx.c:1966 ieee80211_xmit+0x278/0x354 net/mac80211/tx.c:2062 __ieee80211_subif_start_xmit+0xab8/0x122c net/mac80211/tx.c:4338 ieee80211_subif_start_xmit+0xe0/0x438 net/mac80211/tx.c:4532 __netdev_start_xmit include/linux/netdevice.h:4903 [inline] netdev_start_xmit include/linux/netdevice.h:4917 [inline] xmit_one net/core/dev.c:3531 [inline] dev_hard_start_xmit+0x27c/0x938 net/core/dev.c:3547 __dev_queue_xmit+0x1678/0x33fc net/core/dev.c:4341 dev_queue_xmit include/linux/netdevice.h:3091 [inline] neigh_resolve_output+0x558/0x658 net/core/neighbour.c:1563 neigh_output include/net/neighbour.h:542 [inline] ip6_fini ---truncated---

In the Linux kernel, the following vulnerability has been resolved: f2fs: don't set RO when shutting down f2fs Shutdown does not check the error of thaw_super due to readonly, which causes a deadlock like below. f2fs_ioc_shutdown(F2FS_GOING_DOWN_FULLSYNC) issue_discard_thread - bdev_freeze - freeze_super - f2fs_stop_checkpoint() - f2fs_handle_critical_error - sb_start_write - set RO - waiting - bdev_thaw - thaw_super_locked - return -EINVAL, if sb_rdonly() - f2fs_stop_discard_thread -> wait for kthread_stop(discard_thread);

In the Linux kernel, the following vulnerability has been resolved: io_uring: fix possible deadlock in io_register_iowq_max_workers() The io_register_iowq_max_workers() function calls io_put_sq_data(), which acquires the sqd->lock without releasing the uring_lock. Similar to the commit 009ad9f0c6ee ("io_uring: drop ctx->uring_lock before acquiring sqd->lock"), this can lead to a potential deadlock situation. To resolve this issue, the uring_lock is released before calling io_put_sq_data(), and then it is re-acquired after the function call. This change ensures that the locks are acquired in the correct order, preventing the possibility of a deadlock.

In the Linux kernel, the following vulnerability has been resolved: pinctrl: fix deadlock in create_pinctrl() when handling -EPROBE_DEFER In create_pinctrl(), pinctrl_maps_mutex is acquired before calling add_setting(). If add_setting() returns -EPROBE_DEFER, create_pinctrl() calls pinctrl_free(). However, pinctrl_free() attempts to acquire pinctrl_maps_mutex, which is already held by create_pinctrl(), leading to a potential deadlock. This patch resolves the issue by releasing pinctrl_maps_mutex before calling pinctrl_free(), preventing the deadlock. This bug was discovered and resolved using Coverity Static Analysis Security Testing (SAST) by Synopsys, Inc.

In the Linux kernel, the following vulnerability has been resolved: ext4: do not create EA inode under buffer lock ext4_xattr_set_entry() creates new EA inodes while holding buffer lock on the external xattr block. This is problematic as it nests all the allocation locking (which acquires locks on other buffers) under the buffer lock. This can even deadlock when the filesystem is corrupted and e.g. quota file is setup to contain xattr block as data block. Move the allocation of EA inode out of ext4_xattr_set_entry() into the callers.

In the Linux kernel, the following vulnerability has been resolved: i2c: pnx: Fix potential deadlock warning from del_timer_sync() call in isr When del_timer_sync() is called in an interrupt context it throws a warning because of potential deadlock. The timer is used only to exit from wait_for_completion() after a timeout so replacing the call with wait_for_completion_timeout() allows to remove the problematic timer and its related functions altogether.

In the Linux kernel, the following vulnerability has been resolved: io_uring/rsrc: don't lock while !TASK_RUNNING There is a report of io_rsrc_ref_quiesce() locking a mutex while not TASK_RUNNING, which is due to forgetting restoring the state back after io_run_task_work_sig() and attempts to break out of the waiting loop. do not call blocking ops when !TASK_RUNNING; state=1 set at [<ffffffff815d2494>] prepare_to_wait+0xa4/0x380 kernel/sched/wait.c:237 WARNING: CPU: 2 PID: 397056 at kernel/sched/core.c:10099 __might_sleep+0x114/0x160 kernel/sched/core.c:10099 RIP: 0010:__might_sleep+0x114/0x160 kernel/sched/core.c:10099 Call Trace: <TASK> __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0xb4/0x940 kernel/locking/mutex.c:752 io_rsrc_ref_quiesce+0x590/0x940 io_uring/rsrc.c:253 io_sqe_buffers_unregister+0xa2/0x340 io_uring/rsrc.c:799 __io_uring_register io_uring/register.c:424 [inline] __do_sys_io_uring_register+0x5b9/0x2400 io_uring/register.c:613 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xd8/0x270 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x6f/0x77

In the Linux kernel, the following vulnerability has been resolved: i2c: lpi2c: Avoid calling clk_get_rate during transfer Instead of repeatedly calling clk_get_rate for each transfer, lock the clock rate and cache the value. A deadlock has been observed while adding tlv320aic32x4 audio codec to the system. When this clock provider adds its clock, the clk mutex is locked already, it needs to access i2c, which in return needs the mutex for clk_get_rate as well.

In the Linux kernel, the following vulnerability has been resolved: riscv: rewrite __kernel_map_pages() to fix sleeping in invalid context __kernel_map_pages() is a debug function which clears the valid bit in page table entry for deallocated pages to detect illegal memory accesses to freed pages. This function set/clear the valid bit using __set_memory(). __set_memory() acquires init_mm's semaphore, and this operation may sleep. This is problematic, because __kernel_map_pages() can be called in atomic context, and thus is illegal to sleep. An example warning that this causes: BUG: sleeping function called from invalid context at kernel/locking/rwsem.c:1578 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 2, name: kthreadd preempt_count: 2, expected: 0 CPU: 0 PID: 2 Comm: kthreadd Not tainted 6.9.0-g1d4c6d784ef6 #37 Hardware name: riscv-virtio,qemu (DT) Call Trace: [<ffffffff800060dc>] dump_backtrace+0x1c/0x24 [<ffffffff8091ef6e>] show_stack+0x2c/0x38 [<ffffffff8092baf8>] dump_stack_lvl+0x5a/0x72 [<ffffffff8092bb24>] dump_stack+0x14/0x1c [<ffffffff8003b7ac>] __might_resched+0x104/0x10e [<ffffffff8003b7f4>] __might_sleep+0x3e/0x62 [<ffffffff8093276a>] down_write+0x20/0x72 [<ffffffff8000cf00>] __set_memory+0x82/0x2fa [<ffffffff8000d324>] __kernel_map_pages+0x5a/0xd4 [<ffffffff80196cca>] __alloc_pages_bulk+0x3b2/0x43a [<ffffffff8018ee82>] __vmalloc_node_range+0x196/0x6ba [<ffffffff80011904>] copy_process+0x72c/0x17ec [<ffffffff80012ab4>] kernel_clone+0x60/0x2fe [<ffffffff80012f62>] kernel_thread+0x82/0xa0 [<ffffffff8003552c>] kthreadd+0x14a/0x1be [<ffffffff809357de>] ret_from_fork+0xe/0x1c Rewrite this function with apply_to_existing_page_range(). It is fine to not have any locking, because __kernel_map_pages() works with pages being allocated/deallocated and those pages are not changed by anyone else in the meantime.

In the Linux kernel, the following vulnerability has been resolved: wifi: mac80211: Fix deadlock in ieee80211_sta_ps_deliver_wakeup() The ieee80211_sta_ps_deliver_wakeup() function takes sta->ps_lock to synchronizes with ieee80211_tx_h_unicast_ps_buf() which is called from softirq context. However using only spin_lock() to get sta->ps_lock in ieee80211_sta_ps_deliver_wakeup() does not prevent softirq to execute on this same CPU, to run ieee80211_tx_h_unicast_ps_buf() and try to take this same lock ending in deadlock. Below is an example of rcu stall that arises in such situation. rcu: INFO: rcu_sched self-detected stall on CPU rcu: 2-....: (42413413 ticks this GP) idle=b154/1/0x4000000000000000 softirq=1763/1765 fqs=21206996 rcu: (t=42586894 jiffies g=2057 q=362405 ncpus=4) CPU: 2 PID: 719 Comm: wpa_supplicant Tainted: G W 6.4.0-02158-g1b062f552873 #742 Hardware name: RPT (r1) (DT) pstate: 00000005 (nzcv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : queued_spin_lock_slowpath+0x58/0x2d0 lr : invoke_tx_handlers_early+0x5b4/0x5c0 sp : ffff00001ef64660 x29: ffff00001ef64660 x28: ffff000009bc1070 x27: ffff000009bc0ad8 x26: ffff000009bc0900 x25: ffff00001ef647a8 x24: 0000000000000000 x23: ffff000009bc0900 x22: ffff000009bc0900 x21: ffff00000ac0e000 x20: ffff00000a279e00 x19: ffff00001ef646e8 x18: 0000000000000000 x17: ffff800016468000 x16: ffff00001ef608c0 x15: 0010533c93f64f80 x14: 0010395c9faa3946 x13: 0000000000000000 x12: 00000000fa83b2da x11: 000000012edeceea x10: ffff0000010fbe00 x9 : 0000000000895440 x8 : 000000000010533c x7 : ffff00000ad8b740 x6 : ffff00000c350880 x5 : 0000000000000007 x4 : 0000000000000001 x3 : 0000000000000000 x2 : 0000000000000000 x1 : 0000000000000001 x0 : ffff00000ac0e0e8 Call trace: queued_spin_lock_slowpath+0x58/0x2d0 ieee80211_tx+0x80/0x12c ieee80211_tx_pending+0x110/0x278 tasklet_action_common.constprop.0+0x10c/0x144 tasklet_action+0x20/0x28 _stext+0x11c/0x284 ____do_softirq+0xc/0x14 call_on_irq_stack+0x24/0x34 do_softirq_own_stack+0x18/0x20 do_softirq+0x74/0x7c __local_bh_enable_ip+0xa0/0xa4 _ieee80211_wake_txqs+0x3b0/0x4b8 __ieee80211_wake_queue+0x12c/0x168 ieee80211_add_pending_skbs+0xec/0x138 ieee80211_sta_ps_deliver_wakeup+0x2a4/0x480 ieee80211_mps_sta_status_update.part.0+0xd8/0x11c ieee80211_mps_sta_status_update+0x18/0x24 sta_apply_parameters+0x3bc/0x4c0 ieee80211_change_station+0x1b8/0x2dc nl80211_set_station+0x444/0x49c genl_family_rcv_msg_doit.isra.0+0xa4/0xfc genl_rcv_msg+0x1b0/0x244 netlink_rcv_skb+0x38/0x10c genl_rcv+0x34/0x48 netlink_unicast+0x254/0x2bc netlink_sendmsg+0x190/0x3b4 ____sys_sendmsg+0x1e8/0x218 ___sys_sendmsg+0x68/0x8c __sys_sendmsg+0x44/0x84 __arm64_sys_sendmsg+0x20/0x28 do_el0_svc+0x6c/0xe8 el0_svc+0x14/0x48 el0t_64_sync_handler+0xb0/0xb4 el0t_64_sync+0x14c/0x150 Using spin_lock_bh()/spin_unlock_bh() instead prevents softirq to raise on the same CPU that is holding the lock.

In the Linux kernel, the following vulnerability has been resolved: md/raid5: fix deadlock that raid5d() wait for itself to clear MD_SB_CHANGE_PENDING Xiao reported that lvm2 test lvconvert-raid-takeover.sh can hang with small possibility, the root cause is exactly the same as commit bed9e27baf52 ("Revert "md/raid5: Wait for MD_SB_CHANGE_PENDING in raid5d"") However, Dan reported another hang after that, and junxiao investigated the problem and found out that this is caused by plugged bio can't issue from raid5d(). Current implementation in raid5d() has a weird dependence: 1) md_check_recovery() from raid5d() must hold 'reconfig_mutex' to clear MD_SB_CHANGE_PENDING; 2) raid5d() handles IO in a deadloop, until all IO are issued; 3) IO from raid5d() must wait for MD_SB_CHANGE_PENDING to be cleared; This behaviour is introduce before v2.6, and for consequence, if other context hold 'reconfig_mutex', and md_check_recovery() can't update super_block, then raid5d() will waste one cpu 100% by the deadloop, until 'reconfig_mutex' is released. Refer to the implementation from raid1 and raid10, fix this problem by skipping issue IO if MD_SB_CHANGE_PENDING is still set after md_check_recovery(), daemon thread will be woken up when 'reconfig_mutex' is released. Meanwhile, the hang problem will be fixed as well.

In the Linux kernel, the following vulnerability has been resolved: drm: zynqmp_dpsub: Always register bridge We must always register the DRM bridge, since zynqmp_dp_hpd_work_func calls drm_bridge_hpd_notify, which in turn expects hpd_mutex to be initialized. We do this before zynqmp_dpsub_drm_init since that calls drm_bridge_attach. This fixes the following lockdep warning: [ 19.217084] ------------[ cut here ]------------ [ 19.227530] DEBUG_LOCKS_WARN_ON(lock->magic != lock) [ 19.227768] WARNING: CPU: 0 PID: 140 at kernel/locking/mutex.c:582 __mutex_lock+0x4bc/0x550 [ 19.241696] Modules linked in: [ 19.244937] CPU: 0 PID: 140 Comm: kworker/0:4 Not tainted 6.6.20+ #96 [ 19.252046] Hardware name: xlnx,zynqmp (DT) [ 19.256421] Workqueue: events zynqmp_dp_hpd_work_func [ 19.261795] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 19.269104] pc : __mutex_lock+0x4bc/0x550 [ 19.273364] lr : __mutex_lock+0x4bc/0x550 [ 19.277592] sp : ffffffc085c5bbe0 [ 19.281066] x29: ffffffc085c5bbe0 x28: 0000000000000000 x27: ffffff88009417f8 [ 19.288624] x26: ffffff8800941788 x25: ffffff8800020008 x24: ffffffc082aa3000 [ 19.296227] x23: ffffffc080d90e3c x22: 0000000000000002 x21: 0000000000000000 [ 19.303744] x20: 0000000000000000 x19: ffffff88002f5210 x18: 0000000000000000 [ 19.311295] x17: 6c707369642e3030 x16: 3030613464662072 x15: 0720072007200720 [ 19.318922] x14: 0000000000000000 x13: 284e4f5f4e524157 x12: 0000000000000001 [ 19.326442] x11: 0001ffc085c5b940 x10: 0001ff88003f388b x9 : 0001ff88003f3888 [ 19.334003] x8 : 0001ff88003f3888 x7 : 0000000000000000 x6 : 0000000000000000 [ 19.341537] x5 : 0000000000000000 x4 : 0000000000001668 x3 : 0000000000000000 [ 19.349054] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffffff88003f3880 [ 19.356581] Call trace: [ 19.359160] __mutex_lock+0x4bc/0x550 [ 19.363032] mutex_lock_nested+0x24/0x30 [ 19.367187] drm_bridge_hpd_notify+0x2c/0x6c [ 19.371698] zynqmp_dp_hpd_work_func+0x44/0x54 [ 19.376364] process_one_work+0x3ac/0x988 [ 19.380660] worker_thread+0x398/0x694 [ 19.384736] kthread+0x1bc/0x1c0 [ 19.388241] ret_from_fork+0x10/0x20 [ 19.392031] irq event stamp: 183 [ 19.395450] hardirqs last enabled at (183): [<ffffffc0800b9278>] finish_task_switch.isra.0+0xa8/0x2d4 [ 19.405140] hardirqs last disabled at (182): [<ffffffc081ad3754>] __schedule+0x714/0xd04 [ 19.413612] softirqs last enabled at (114): [<ffffffc080133de8>] srcu_invoke_callbacks+0x158/0x23c [ 19.423128] softirqs last disabled at (110): [<ffffffc080133de8>] srcu_invoke_callbacks+0x158/0x23c [ 19.432614] ---[ end trace 0000000000000000 ]--- (cherry picked from commit 61ba791c4a7a09a370c45b70a81b8c7d4cf6b2ae)

In the Linux kernel, the following vulnerability has been resolved: net: phy: transfer phy_config_inband() locking responsibility to phylink Problem description =================== Lockdep reports a possible circular locking dependency (AB/BA) between &pl->state_mutex and &phy->lock, as follows. phylink_resolve() // acquires &pl->state_mutex -> phylink_major_config() -> phy_config_inband() // acquires &pl->phydev->lock whereas all the other call sites where &pl->state_mutex and &pl->phydev->lock have the locking scheme reversed. Everywhere else, &pl->phydev->lock is acquired at the top level, and &pl->state_mutex at the lower level. A clear example is phylink_bringup_phy(). The outlier is the newly introduced phy_config_inband() and the existing lock order is the correct one. To understand why it cannot be the other way around, it is sufficient to consider phylink_phy_change(), phylink's callback from the PHY device's phy->phy_link_change() virtual method, invoked by the PHY state machine. phy_link_up() and phy_link_down(), the (indirect) callers of phylink_phy_change(), are called with &phydev->lock acquired. Then phylink_phy_change() acquires its own &pl->state_mutex, to serialize changes made to its pl->phy_state and pl->link_config. So all other instances of &pl->state_mutex and &phydev->lock must be consistent with this order. Problem impact ============== I think the kernel runs a serious deadlock risk if an existing phylink_resolve() thread, which results in a phy_config_inband() call, is concurrent with a phy_link_up() or phy_link_down() call, which will deadlock on &pl->state_mutex in phylink_phy_change(). Practically speaking, the impact may be limited by the slow speed of the medium auto-negotiation protocol, which makes it unlikely for the current state to still be unresolved when a new one is detected, but I think the problem is there. Nonetheless, the problem was discovered using lockdep. Proposed solution ================= Practically speaking, the phy_config_inband() requirement of having phydev->lock acquired must transfer to the caller (phylink is the only caller). There, it must bubble up until immediately before &pl->state_mutex is acquired, for the cases where that takes place. Solution details, considerations, notes ======================================= This is the phy_config_inband() call graph: sfp_upstream_ops :: connect_phy() | v phylink_sfp_connect_phy() | v phylink_sfp_config_phy() | | sfp_upstream_ops :: module_insert() | | | v | phylink_sfp_module_insert() | | | | sfp_upstream_ops :: module_start() | | | | | v | | phylink_sfp_module_start() | | | | v v | phylink_sfp_config_optical() phylink_start() | | | phylink_resume() v v | | phylink_sfp_set_config() | | | v v v phylink_mac_initial_config() | phylink_resolve() | | phylink_ethtool_ksettings_set() v v v phylink_major_config() | v phy_config_inband() phylink_major_config() caller #1, phylink_mac_initial_config(), does not acquire &pl->state_mutex nor do its callers. It must acquire &pl->phydev->lock prior to calling phylink_major_config(). phylink_major_config() caller #2, phylink_resolve() acquires &pl->state_mutex, thus also needs to acquire &pl->phydev->lock. phylink_major_config() caller #3, phylink_ethtool_ksettings_set(), is completely uninteresting, because it only call ---truncated---

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix deadlock in smb2_find_smb_tcon() Unlock cifs_tcp_ses_lock before calling cifs_put_smb_ses() to avoid such deadlock.

In the Linux kernel, the following vulnerability has been resolved: dma-buf/sw-sync: don't enable IRQ from sync_print_obj() Since commit a6aa8fca4d79 ("dma-buf/sw-sync: Reduce irqsave/irqrestore from known context") by error replaced spin_unlock_irqrestore() with spin_unlock_irq() for both sync_debugfs_show() and sync_print_obj() despite sync_print_obj() is called from sync_debugfs_show(), lockdep complains inconsistent lock state warning. Use plain spin_{lock,unlock}() for sync_print_obj(), for sync_debugfs_show() is already using spin_{lock,unlock}_irq().

In the Linux kernel, the following vulnerability has been resolved: net/mlx5: Reload only IB representors upon lag disable/enable On lag disable, the bond IB device along with all of its representors are destroyed, and then the slaves' representors get reloaded. In case the slave IB representor load fails, the eswitch error flow unloads all representors, including ethernet representors, where the netdevs get detached and removed from lag bond. Such flow is inaccurate as the lag driver is not responsible for loading/unloading ethernet representors. Furthermore, the flow described above begins by holding lag lock to prevent bond changes during disable flow. However, when reaching the ethernet representors detachment from lag, the lag lock is required again, triggering the following deadlock: Call trace: __switch_to+0xf4/0x148 __schedule+0x2c8/0x7d0 schedule+0x50/0xe0 schedule_preempt_disabled+0x18/0x28 __mutex_lock.isra.13+0x2b8/0x570 __mutex_lock_slowpath+0x1c/0x28 mutex_lock+0x4c/0x68 mlx5_lag_remove_netdev+0x3c/0x1a0 [mlx5_core] mlx5e_uplink_rep_disable+0x70/0xa0 [mlx5_core] mlx5e_detach_netdev+0x6c/0xb0 [mlx5_core] mlx5e_netdev_change_profile+0x44/0x138 [mlx5_core] mlx5e_netdev_attach_nic_profile+0x28/0x38 [mlx5_core] mlx5e_vport_rep_unload+0x184/0x1b8 [mlx5_core] mlx5_esw_offloads_rep_load+0xd8/0xe0 [mlx5_core] mlx5_eswitch_reload_reps+0x74/0xd0 [mlx5_core] mlx5_disable_lag+0x130/0x138 [mlx5_core] mlx5_lag_disable_change+0x6c/0x70 [mlx5_core] // hold ldev->lock mlx5_devlink_eswitch_mode_set+0xc0/0x410 [mlx5_core] devlink_nl_cmd_eswitch_set_doit+0xdc/0x180 genl_family_rcv_msg_doit.isra.17+0xe8/0x138 genl_rcv_msg+0xe4/0x220 netlink_rcv_skb+0x44/0x108 genl_rcv+0x40/0x58 netlink_unicast+0x198/0x268 netlink_sendmsg+0x1d4/0x418 sock_sendmsg+0x54/0x60 __sys_sendto+0xf4/0x120 __arm64_sys_sendto+0x30/0x40 el0_svc_common+0x8c/0x120 do_el0_svc+0x30/0xa0 el0_svc+0x20/0x30 el0_sync_handler+0x90/0xb8 el0_sync+0x160/0x180 Thus, upon lag enable/disable, load and unload only the IB representors of the slaves preventing the deadlock mentioned above. While at it, refactor the mlx5_esw_offloads_rep_load() function to have a static helper method for its internal logic, in symmetry with the representor unload design.

In the Linux kernel, the following vulnerability has been resolved: smb/server: avoid deadlock when linking with ReplaceIfExists If smb2_create_link() is called with ReplaceIfExists set and the name does exist then a deadlock will happen. ksmbd_vfs_kern_path_locked() will return with success and the parent directory will be locked. ksmbd_vfs_remove_file() will then remove the file. ksmbd_vfs_link() will then be called while the parent is still locked. It will try to lock the same parent and will deadlock. This patch moves the ksmbd_vfs_kern_path_unlock() call to *before* ksmbd_vfs_link() and then simplifies the code, removing the file_present flag variable.

In the Linux kernel, the following vulnerability has been resolved: RDMA/hns: Fix deadlock on SRQ async events. xa_lock for SRQ table may be required in AEQ. Use xa_store_irq()/ xa_erase_irq() to avoid deadlock.

In the Linux kernel, the following vulnerability has been resolved: dm: dm-crypt: Do not partially accept write BIOs with zoned targets Read and write operations issued to a dm-crypt target may be split according to the dm-crypt internal limits defined by the max_read_size and max_write_size module parameters (default is 128 KB). The intent is to improve processing time of large BIOs by splitting them into smaller operations that can be parallelized on different CPUs. For zoned dm-crypt targets, this BIO splitting is still done but without the parallel execution to ensure that the issuing order of write operations to the underlying devices remains sequential. However, the splitting itself causes other problems: 1) Since dm-crypt relies on the block layer zone write plugging to handle zone append emulation using regular write operations, the reminder of a split write BIO will always be plugged into the target zone write plugged. Once the on-going write BIO finishes, this reminder BIO is unplugged and issued from the zone write plug work. If this reminder BIO itself needs to be split, the reminder will be re-issued and plugged again, but that causes a call to a blk_queue_enter(), which may block if a queue freeze operation was initiated. This results in a deadlock as DM submission still holds BIOs that the queue freeze side is waiting for. 2) dm-crypt relies on the emulation done by the block layer using regular write operations for processing zone append operations. This still requires to properly return the written sector as the BIO sector of the original BIO. However, this can be done correctly only and only if there is a single clone BIO used for processing the original zone append operation issued by the user. If the size of a zone append operation is larger than dm-crypt max_write_size, then the orginal BIO will be split and processed as a chain of regular write operations. Such chaining result in an incorrect written sector being returned to the zone append issuer using the original BIO sector. This in turn results in file system data corruptions using xfs or btrfs. Fix this by modifying get_max_request_size() to always return the size of the BIO to avoid it being split with dm_accpet_partial_bio() in crypt_map(). get_max_request_size() is renamed to get_max_request_sectors() to clarify the unit of the value returned and its interface is changed to take a struct dm_target pointer and a pointer to the struct bio being processed. In addition to this change, to ensure that crypt_alloc_buffer() works correctly, set the dm-crypt device max_hw_sectors limit to be at most BIO_MAX_VECS << PAGE_SECTORS_SHIFT (1 MB with a 4KB page architecture). This forces DM core to split write BIOs before passing them to crypt_map(), and thus guaranteeing that dm-crypt can always accept an entire write BIO without needing to split it. This change does not have any effect on the read path of dm-crypt. Read operations can still be split and the BIO fragments processed in parallel. There is also no impact on the performance of the write path given that all zone write BIOs were already processed inline instead of in parallel. This change also does not affect in any way regular dm-crypt block devices.

In the Linux kernel, the following vulnerability has been resolved: jbd2: prevent softlockup in jbd2_log_do_checkpoint() Both jbd2_log_do_checkpoint() and jbd2_journal_shrink_checkpoint_list() periodically release j_list_lock after processing a batch of buffers to avoid long hold times on the j_list_lock. However, since both functions contend for j_list_lock, the combined time spent waiting and processing can be significant. jbd2_journal_shrink_checkpoint_list() explicitly calls cond_resched() when need_resched() is true to avoid softlockups during prolonged operations. But jbd2_log_do_checkpoint() only exits its loop when need_resched() is true, relying on potentially sleeping functions like __flush_batch() or wait_on_buffer() to trigger rescheduling. If those functions do not sleep, the kernel may hit a softlockup. watchdog: BUG: soft lockup - CPU#3 stuck for 156s! [kworker/u129:2:373] CPU: 3 PID: 373 Comm: kworker/u129:2 Kdump: loaded Not tainted 6.6.0+ #10 Hardware name: Huawei TaiShan 2280 /BC11SPCD, BIOS 1.27 06/13/2017 Workqueue: writeback wb_workfn (flush-7:2) pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : native_queued_spin_lock_slowpath+0x358/0x418 lr : jbd2_log_do_checkpoint+0x31c/0x438 [jbd2] Call trace: native_queued_spin_lock_slowpath+0x358/0x418 jbd2_log_do_checkpoint+0x31c/0x438 [jbd2] __jbd2_log_wait_for_space+0xfc/0x2f8 [jbd2] add_transaction_credits+0x3bc/0x418 [jbd2] start_this_handle+0xf8/0x560 [jbd2] jbd2__journal_start+0x118/0x228 [jbd2] __ext4_journal_start_sb+0x110/0x188 [ext4] ext4_do_writepages+0x3dc/0x740 [ext4] ext4_writepages+0xa4/0x190 [ext4] do_writepages+0x94/0x228 __writeback_single_inode+0x48/0x318 writeback_sb_inodes+0x204/0x590 __writeback_inodes_wb+0x54/0xf8 wb_writeback+0x2cc/0x3d8 wb_do_writeback+0x2e0/0x2f8 wb_workfn+0x80/0x2a8 process_one_work+0x178/0x3e8 worker_thread+0x234/0x3b8 kthread+0xf0/0x108 ret_from_fork+0x10/0x20 So explicitly call cond_resched() in jbd2_log_do_checkpoint() to avoid softlockup.

In the Linux kernel, the following vulnerability has been resolved: md: fix resync softlockup when bitmap size is less than array size Is is reported that for dm-raid10, lvextend + lvchange --syncaction will trigger following softlockup: kernel:watchdog: BUG: soft lockup - CPU#3 stuck for 26s! [mdX_resync:6976] CPU: 7 PID: 3588 Comm: mdX_resync Kdump: loaded Not tainted 6.9.0-rc4-next-20240419 #1 RIP: 0010:_raw_spin_unlock_irq+0x13/0x30 Call Trace: <TASK> md_bitmap_start_sync+0x6b/0xf0 raid10_sync_request+0x25c/0x1b40 [raid10] md_do_sync+0x64b/0x1020 md_thread+0xa7/0x170 kthread+0xcf/0x100 ret_from_fork+0x30/0x50 ret_from_fork_asm+0x1a/0x30 And the detailed process is as follows: md_do_sync j = mddev->resync_min while (j < max_sectors) sectors = raid10_sync_request(mddev, j, &skipped) if (!md_bitmap_start_sync(..., &sync_blocks)) // md_bitmap_start_sync set sync_blocks to 0 return sync_blocks + sectors_skippe; // sectors = 0; j += sectors; // j never change Root cause is that commit 301867b1c168 ("md/raid10: check slab-out-of-bounds in md_bitmap_get_counter") return early from md_bitmap_get_counter(), without setting returned blocks. Fix this problem by always set returned blocks from md_bitmap_get_counter"(), as it used to be. Noted that this patch just fix the softlockup problem in kernel, the case that bitmap size doesn't match array size still need to be fixed.

In the Linux kernel, the following vulnerability has been resolved: media: mt9m114: Fix deadlock in get_frame_interval/set_frame_interval Getting / Setting the frame interval using the V4L2 subdev pad ops get_frame_interval/set_frame_interval causes a deadlock, as the subdev state is locked in the [1] but also in the driver itself. In [2] it's described that the caller is responsible to acquire and release the lock in this case. Therefore, acquiring the lock in the driver is wrong. Remove the lock acquisitions/releases from mt9m114_ifp_get_frame_interval() and mt9m114_ifp_set_frame_interval(). [1] drivers/media/v4l2-core/v4l2-subdev.c - line 1129 [2] Documentation/driver-api/media/v4l2-subdev.rst

In the Linux kernel, the following vulnerability has been resolved: mm/kmemleak: avoid deadlock by moving pr_warn() outside kmemleak_lock When netpoll is enabled, calling pr_warn_once() while holding kmemleak_lock in mem_pool_alloc() can cause a deadlock due to lock inversion with the netconsole subsystem. This occurs because pr_warn_once() may trigger netpoll, which eventually leads to __alloc_skb() and back into kmemleak code, attempting to reacquire kmemleak_lock. This is the path for the deadlock. mem_pool_alloc() -> raw_spin_lock_irqsave(&kmemleak_lock, flags); -> pr_warn_once() -> netconsole subsystem -> netpoll -> __alloc_skb -> __create_object -> raw_spin_lock_irqsave(&kmemleak_lock, flags); Fix this by setting a flag and issuing the pr_warn_once() after kmemleak_lock is released.

In the Linux kernel, the following vulnerability has been resolved: net: hibmcge: fix rtnl deadlock issue Currently, the hibmcge netdev acquires the rtnl_lock in pci_error_handlers.reset_prepare() and releases it in pci_error_handlers.reset_done(). However, in the PCI framework: pci_reset_bus - __pci_reset_slot - pci_slot_save_and_disable_locked - pci_dev_save_and_disable - err_handler->reset_prepare(dev); In pci_slot_save_and_disable_locked(): list_for_each_entry(dev, &slot->bus->devices, bus_list) { if (!dev->slot || dev->slot!= slot) continue; pci_dev_save_and_disable(dev); if (dev->subordinate) pci_bus_save_and_disable_locked(dev->subordinate); } This will iterate through all devices under the current bus and execute err_handler->reset_prepare(), causing two devices of the hibmcge driver to sequentially request the rtnl_lock, leading to a deadlock. Since the driver now executes netif_device_detach() before the reset process, it will not concurrently with other netdev APIs, so there is no need to hold the rtnl_lock now. Therefore, this patch removes the rtnl_lock during the reset process and adjusts the position of HBG_NIC_STATE_RESETTING to ensure that multiple resets are not executed concurrently.

In the Linux kernel, the following vulnerability has been resolved: LoongArch: Optimize module load time by optimizing PLT/GOT counting When enabling CONFIG_KASAN, CONFIG_PREEMPT_VOLUNTARY_BUILD and CONFIG_PREEMPT_VOLUNTARY at the same time, there will be soft deadlock, the relevant logs are as follows: rcu: INFO: rcu_sched self-detected stall on CPU ... Call Trace: [<900000000024f9e4>] show_stack+0x5c/0x180 [<90000000002482f4>] dump_stack_lvl+0x94/0xbc [<9000000000224544>] rcu_dump_cpu_stacks+0x1fc/0x280 [<900000000037ac80>] rcu_sched_clock_irq+0x720/0xf88 [<9000000000396c34>] update_process_times+0xb4/0x150 [<90000000003b2474>] tick_nohz_handler+0xf4/0x250 [<9000000000397e28>] __hrtimer_run_queues+0x1d0/0x428 [<9000000000399b2c>] hrtimer_interrupt+0x214/0x538 [<9000000000253634>] constant_timer_interrupt+0x64/0x80 [<9000000000349938>] __handle_irq_event_percpu+0x78/0x1a0 [<9000000000349a78>] handle_irq_event_percpu+0x18/0x88 [<9000000000354c00>] handle_percpu_irq+0x90/0xf0 [<9000000000348c74>] handle_irq_desc+0x94/0xb8 [<9000000001012b28>] handle_cpu_irq+0x68/0xa0 [<9000000001def8c0>] handle_loongarch_irq+0x30/0x48 [<9000000001def958>] do_vint+0x80/0xd0 [<9000000000268a0c>] kasan_mem_to_shadow.part.0+0x2c/0x2a0 [<90000000006344f4>] __asan_load8+0x4c/0x120 [<900000000025c0d0>] module_frob_arch_sections+0x5c8/0x6b8 [<90000000003895f0>] load_module+0x9e0/0x2958 [<900000000038b770>] __do_sys_init_module+0x208/0x2d0 [<9000000001df0c34>] do_syscall+0x94/0x190 [<900000000024d6fc>] handle_syscall+0xbc/0x158 After analysis, this is because the slow speed of loading the amdgpu module leads to the long time occupation of the cpu and then the soft deadlock. When loading a module, module_frob_arch_sections() tries to figure out the number of PLTs/GOTs that will be needed to handle all the RELAs. It will call the count_max_entries() to find in an out-of-order date which counting algorithm has O(n^2) complexity. To make it faster, we sort the relocation list by info and addend. That way, to check for a duplicate relocation, it just needs to compare with the previous entry. This reduces the complexity of the algorithm to O(n log n), as done in commit d4e0340919fb ("arm64/module: Optimize module load time by optimizing PLT counting"). This gives sinificant reduction in module load time for modules with large number of relocations. After applying this patch, the soft deadlock problem has been solved, and the kernel starts normally without "Call Trace". Using the default configuration to test some modules, the results are as follows: Module Size ip_tables 36K fat 143K radeon 2.5MB amdgpu 16MB Without this patch: Module Module load time (ms) Count(PLTs/GOTs) ip_tables 18 59/6 fat 0 162/14 radeon 54 1221/84 amdgpu 1411 4525/1098 With this patch: Module Module load time (ms) Count(PLTs/GOTs) ip_tables 18 59/6 fat 0 162/14 radeon 22 1221/84 amdgpu 45 4525/1098

In the Linux kernel, the following vulnerability has been resolved: btrfs: fix subvolume deletion lockup caused by inodes xarray race There is a race condition between inode eviction and inode caching that can cause a live struct btrfs_inode to be missing from the root->inodes xarray. Specifically, there is a window during evict() between the inode being unhashed and deleted from the xarray. If btrfs_iget() is called for the same inode in that window, it will be recreated and inserted into the xarray, but then eviction will delete the new entry, leaving nothing in the xarray: Thread 1 Thread 2 --------------------------------------------------------------- evict() remove_inode_hash() btrfs_iget_path() btrfs_iget_locked() btrfs_read_locked_inode() btrfs_add_inode_to_root() destroy_inode() btrfs_destroy_inode() btrfs_del_inode_from_root() __xa_erase In turn, this can cause issues for subvolume deletion. Specifically, if an inode is in this lost state, and all other inodes are evicted, then btrfs_del_inode_from_root() will call btrfs_add_dead_root() prematurely. If the lost inode has a delayed_node attached to it, then when btrfs_clean_one_deleted_snapshot() calls btrfs_kill_all_delayed_nodes(), it will loop forever because the delayed_nodes xarray will never become empty (unless memory pressure forces the inode out). We saw this manifest as soft lockups in production. Fix it by only deleting the xarray entry if it matches the given inode (using __xa_cmpxchg()).

In the Linux kernel, the following vulnerability has been resolved: net/mlx5: Fix lockdep assertion on sync reset unload event Fix lockdep assertion triggered during sync reset unload event. When the sync reset flow is initiated using the devlink reload fw_activate option, the PF already holds the devlink lock while handling unload event. In this case, delegate sync reset unload event handling back to the devlink callback process to avoid double-locking and resolve the lockdep warning. Kernel log: WARNING: CPU: 9 PID: 1578 at devl_assert_locked+0x31/0x40 [...] Call Trace: <TASK> mlx5_unload_one_devl_locked+0x2c/0xc0 [mlx5_core] mlx5_sync_reset_unload_event+0xaf/0x2f0 [mlx5_core] process_one_work+0x222/0x640 worker_thread+0x199/0x350 kthread+0x10b/0x230 ? __pfx_worker_thread+0x10/0x10 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x8e/0x100 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1a/0x30 </TASK>

In the Linux kernel, the following vulnerability has been resolved: hfsplus: remove mutex_lock check in hfsplus_free_extents Syzbot reported an issue in hfsplus filesystem: ------------[ cut here ]------------ WARNING: CPU: 0 PID: 4400 at fs/hfsplus/extents.c:346 hfsplus_free_extents+0x700/0xad0 Call Trace: <TASK> hfsplus_file_truncate+0x768/0xbb0 fs/hfsplus/extents.c:606 hfsplus_write_begin+0xc2/0xd0 fs/hfsplus/inode.c:56 cont_expand_zero fs/buffer.c:2383 [inline] cont_write_begin+0x2cf/0x860 fs/buffer.c:2446 hfsplus_write_begin+0x86/0xd0 fs/hfsplus/inode.c:52 generic_cont_expand_simple+0x151/0x250 fs/buffer.c:2347 hfsplus_setattr+0x168/0x280 fs/hfsplus/inode.c:263 notify_change+0xe38/0x10f0 fs/attr.c:420 do_truncate+0x1fb/0x2e0 fs/open.c:65 do_sys_ftruncate+0x2eb/0x380 fs/open.c:193 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd To avoid deadlock, Commit 31651c607151 ("hfsplus: avoid deadlock on file truncation") unlock extree before hfsplus_free_extents(), and add check wheather extree is locked in hfsplus_free_extents(). However, when operations such as hfsplus_file_release, hfsplus_setattr, hfsplus_unlink, and hfsplus_get_block are executed concurrently in different files, it is very likely to trigger the WARN_ON, which will lead syzbot and xfstest to consider it as an abnormality. The comment above this warning also describes one of the easy triggering situations, which can easily trigger and cause xfstest&syzbot to report errors. [task A] [task B] ->hfsplus_file_release ->hfsplus_file_truncate ->hfs_find_init ->mutex_lock ->mutex_unlock ->hfsplus_write_begin ->hfsplus_get_block ->hfsplus_file_extend ->hfsplus_ext_read_extent ->hfs_find_init ->mutex_lock ->hfsplus_free_extents WARN_ON(mutex_is_locked) !!! Several threads could try to lock the shared extents tree. And warning can be triggered in one thread when another thread has locked the tree. This is the wrong behavior of the code and we need to remove the warning.

In the Linux kernel, the following vulnerability has been resolved: mm: slub: avoid wake up kswapd in set_track_prepare set_track_prepare() can incur lock recursion. The issue is that it is called from hrtimer_start_range_ns holding the per_cpu(hrtimer_bases)[n].lock, but when enabled CONFIG_DEBUG_OBJECTS_TIMERS, may wake up kswapd in set_track_prepare, and try to hold the per_cpu(hrtimer_bases)[n].lock. Avoid deadlock caused by implicitly waking up kswapd by passing in allocation flags, which do not contain __GFP_KSWAPD_RECLAIM in the debug_objects_fill_pool() case. Inside stack depot they are processed by gfp_nested_mask(). Since ___slab_alloc() has preemption disabled, we mask out __GFP_DIRECT_RECLAIM from the flags there. The oops looks something like: BUG: spinlock recursion on CPU#3, swapper/3/0 lock: 0xffffff8a4bf29c80, .magic: dead4ead, .owner: swapper/3/0, .owner_cpu: 3 Hardware name: Qualcomm Technologies, Inc. Popsicle based on SM8850 (DT) Call trace: spin_bug+0x0 _raw_spin_lock_irqsave+0x80 hrtimer_try_to_cancel+0x94 task_contending+0x10c enqueue_dl_entity+0x2a4 dl_server_start+0x74 enqueue_task_fair+0x568 enqueue_task+0xac do_activate_task+0x14c ttwu_do_activate+0xcc try_to_wake_up+0x6c8 default_wake_function+0x20 autoremove_wake_function+0x1c __wake_up+0xac wakeup_kswapd+0x19c wake_all_kswapds+0x78 __alloc_pages_slowpath+0x1ac __alloc_pages_noprof+0x298 stack_depot_save_flags+0x6b0 stack_depot_save+0x14 set_track_prepare+0x5c ___slab_alloc+0xccc __kmalloc_cache_noprof+0x470 __set_page_owner+0x2bc post_alloc_hook[jt]+0x1b8 prep_new_page+0x28 get_page_from_freelist+0x1edc __alloc_pages_noprof+0x13c alloc_slab_page+0x244 allocate_slab+0x7c ___slab_alloc+0x8e8 kmem_cache_alloc_noprof+0x450 debug_objects_fill_pool+0x22c debug_object_activate+0x40 enqueue_hrtimer[jt]+0xdc hrtimer_start_range_ns+0x5f8 ...

In the Linux kernel, the following vulnerability has been resolved: e1000: Move cancel_work_sync to avoid deadlock Previously, e1000_down called cancel_work_sync for the e1000 reset task (via e1000_down_and_stop), which takes RTNL. As reported by users and syzbot, a deadlock is possible in the following scenario: CPU 0: - RTNL is held - e1000_close - e1000_down - cancel_work_sync (cancel / wait for e1000_reset_task()) CPU 1: - process_one_work - e1000_reset_task - take RTNL To remedy this, avoid calling cancel_work_sync from e1000_down (e1000_reset_task does nothing if the device is down anyway). Instead, call cancel_work_sync for e1000_reset_task when the device is being removed.

In the Linux kernel, the following vulnerability has been resolved: PCI: pciehp: Avoid unnecessary device replacement check Hot-removal of nested PCI hotplug ports suffers from a long-standing race condition which can lead to a deadlock: A parent hotplug port acquires pci_lock_rescan_remove(), then waits for pciehp to unbind from a child hotplug port. Meanwhile that child hotplug port tries to acquire pci_lock_rescan_remove() as well in order to remove its own children. The deadlock only occurs if the parent acquires pci_lock_rescan_remove() first, not if the child happens to acquire it first. Several workarounds to avoid the issue have been proposed and discarded over the years, e.g.: https://lore.kernel.org/r/4c882e25194ba8282b78fe963fec8faae7cf23eb.1529173804.git.lukas@wunner.de/ A proper fix is being worked on, but needs more time as it is nontrivial and necessarily intrusive. Recent commit 9d573d19547b ("PCI: pciehp: Detect device replacement during system sleep") provokes more frequent occurrence of the deadlock when removing more than one Thunderbolt device during system sleep. The commit sought to detect device replacement, but also triggered on device removal. Differentiating reliably between replacement and removal is impossible because pci_get_dsn() returns 0 both if the device was removed, as well as if it was replaced with one lacking a Device Serial Number. Avoid the more frequent occurrence of the deadlock by checking whether the hotplug port itself was hot-removed. If so, there's no sense in checking whether its child device was replaced. This works because the ->resume_noirq() callback is invoked in top-down order for the entire hierarchy: A parent hotplug port detecting device replacement (or removal) marks all children as removed using pci_dev_set_disconnected() and a child hotplug port can then reliably detect being removed.

In the Linux kernel, the following vulnerability has been resolved: KVM: Allow CPU to reschedule while setting per-page memory attributes When running an SEV-SNP guest with a sufficiently large amount of memory (1TB+), the host can experience CPU soft lockups when running an operation in kvm_vm_set_mem_attributes() to set memory attributes on the whole range of guest memory. watchdog: BUG: soft lockup - CPU#8 stuck for 26s! [qemu-kvm:6372] CPU: 8 UID: 0 PID: 6372 Comm: qemu-kvm Kdump: loaded Not tainted 6.15.0-rc7.20250520.el9uek.rc1.x86_64 #1 PREEMPT(voluntary) Hardware name: Oracle Corporation ORACLE SERVER E4-2c/Asm,MB Tray,2U,E4-2c, BIOS 78016600 11/13/2024 RIP: 0010:xas_create+0x78/0x1f0 Code: 00 00 00 41 80 fc 01 0f 84 82 00 00 00 ba 06 00 00 00 bd 06 00 00 00 49 8b 45 08 4d 8d 65 08 41 39 d6 73 20 83 ed 06 48 85 c0 <74> 67 48 89 c2 83 e2 03 48 83 fa 02 75 0c 48 3d 00 10 00 00 0f 87 RSP: 0018:ffffad890a34b940 EFLAGS: 00000286 RAX: ffff96f30b261daa RBX: ffffad890a34b9c8 RCX: 0000000000000000 RDX: 000000000000001e RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000018 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffffad890a356868 R13: ffffad890a356860 R14: 0000000000000000 R15: ffffad890a356868 FS: 00007f5578a2a400(0000) GS:ffff97ed317e1000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f015c70fb18 CR3: 00000001109fd006 CR4: 0000000000f70ef0 PKRU: 55555554 Call Trace: <TASK> xas_store+0x58/0x630 __xa_store+0xa5/0x130 xa_store+0x2c/0x50 kvm_vm_set_mem_attributes+0x343/0x710 [kvm] kvm_vm_ioctl+0x796/0xab0 [kvm] __x64_sys_ioctl+0xa3/0xd0 do_syscall_64+0x8c/0x7a0 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7f5578d031bb Code: ff ff ff 85 c0 79 9b 49 c7 c4 ff ff ff ff 5b 5d 4c 89 e0 41 5c c3 66 0f 1f 84 00 00 00 00 00 f3 0f 1e fa b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 2d 4c 0f 00 f7 d8 64 89 01 48 RSP: 002b:00007ffe0a742b88 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000004020aed2 RCX: 00007f5578d031bb RDX: 00007ffe0a742c80 RSI: 000000004020aed2 RDI: 000000000000000b RBP: 0000010000000000 R08: 0000010000000000 R09: 0000017680000000 R10: 0000000000000080 R11: 0000000000000246 R12: 00005575e5f95120 R13: 00007ffe0a742c80 R14: 0000000000000008 R15: 00005575e5f961e0 While looping through the range of memory setting the attributes, call cond_resched() to give the scheduler a chance to run a higher priority task on the runqueue if necessary and avoid staying in kernel mode long enough to trigger the lockup.

In the Linux kernel, the following vulnerability has been resolved: virtio-net: fix recursived rtnl_lock() during probe() The deadlock appears in a stack trace like: virtnet_probe() rtnl_lock() virtio_config_changed_work() netdev_notify_peers() rtnl_lock() It happens if the VMM sends a VIRTIO_NET_S_ANNOUNCE request while the virtio-net driver is still probing. The config_work in probe() will get scheduled until virtnet_open() enables the config change notification via virtio_config_driver_enable().

In the Linux kernel, the following vulnerability has been resolved: af_packet: move notifier's packet_dev_mc out of rcu critical section Syzkaller reports the following issue: BUG: sleeping function called from invalid context at kernel/locking/mutex.c:578 __mutex_lock+0x106/0xe80 kernel/locking/mutex.c:746 team_change_rx_flags+0x38/0x220 drivers/net/team/team_core.c:1781 dev_change_rx_flags net/core/dev.c:9145 [inline] __dev_set_promiscuity+0x3f8/0x590 net/core/dev.c:9189 netif_set_promiscuity+0x50/0xe0 net/core/dev.c:9201 dev_set_promiscuity+0x126/0x260 net/core/dev_api.c:286 packet_dev_mc net/packet/af_packet.c:3698 [inline] packet_dev_mclist_delete net/packet/af_packet.c:3722 [inline] packet_notifier+0x292/0xa60 net/packet/af_packet.c:4247 notifier_call_chain+0x1b3/0x3e0 kernel/notifier.c:85 call_netdevice_notifiers_extack net/core/dev.c:2214 [inline] call_netdevice_notifiers net/core/dev.c:2228 [inline] unregister_netdevice_many_notify+0x15d8/0x2330 net/core/dev.c:11972 rtnl_delete_link net/core/rtnetlink.c:3522 [inline] rtnl_dellink+0x488/0x710 net/core/rtnetlink.c:3564 rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6955 netlink_rcv_skb+0x219/0x490 net/netlink/af_netlink.c:2534 Calling `PACKET_ADD_MEMBERSHIP` on an ops-locked device can trigger the `NETDEV_UNREGISTER` notifier, which may require disabling promiscuous and/or allmulti mode. Both of these operations require acquiring the netdev instance lock. Move the call to `packet_dev_mc` outside of the RCU critical section. The `mclist` modifications (add, del, flush, unregister) are protected by the RTNL, not the RCU. The RCU only protects the `sklist` and its associated `sks`. The delayed operation on the `mclist` entry remains within the RTNL.

In the Linux kernel, the following vulnerability has been resolved: iio: light: opt3001: fix deadlock due to concurrent flag access The threaded IRQ function in this driver is reading the flag twice: once to lock a mutex and once to unlock it. Even though the code setting the flag is designed to prevent it, there are subtle cases where the flag could be true at the mutex_lock stage and false at the mutex_unlock stage. This results in the mutex not being unlocked, resulting in a deadlock. Fix it by making the opt3001_irq() code generally more robust, reading the flag into a variable and using the variable value at both stages.

In the Linux kernel, the following vulnerability has been resolved: PM: hibernate: Avoid deadlock in hibernate_compressor_param_set() syzbot reported a deadlock in lock_system_sleep() (see below). The write operation to "/sys/module/hibernate/parameters/compressor" conflicts with the registration of ieee80211 device, resulting in a deadlock when attempting to acquire system_transition_mutex under param_lock. To avoid this deadlock, change hibernate_compressor_param_set() to use mutex_trylock() for attempting to acquire system_transition_mutex and return -EBUSY when it fails. Task flags need not be saved or adjusted before calling mutex_trylock(&system_transition_mutex) because the caller is not going to end up waiting for this mutex and if it runs concurrently with system suspend in progress, it will be frozen properly when it returns to user space. syzbot report: syz-executor895/5833 is trying to acquire lock: ffffffff8e0828c8 (system_transition_mutex){+.+.}-{4:4}, at: lock_system_sleep+0x87/0xa0 kernel/power/main.c:56 but task is already holding lock: ffffffff8e07dc68 (param_lock){+.+.}-{4:4}, at: kernel_param_lock kernel/params.c:607 [inline] ffffffff8e07dc68 (param_lock){+.+.}-{4:4}, at: param_attr_store+0xe6/0x300 kernel/params.c:586 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (param_lock){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0x19b/0xb10 kernel/locking/mutex.c:730 ieee80211_rate_control_ops_get net/mac80211/rate.c:220 [inline] rate_control_alloc net/mac80211/rate.c:266 [inline] ieee80211_init_rate_ctrl_alg+0x18d/0x6b0 net/mac80211/rate.c:1015 ieee80211_register_hw+0x20cd/0x4060 net/mac80211/main.c:1531 mac80211_hwsim_new_radio+0x304e/0x54e0 drivers/net/wireless/virtual/mac80211_hwsim.c:5558 init_mac80211_hwsim+0x432/0x8c0 drivers/net/wireless/virtual/mac80211_hwsim.c:6910 do_one_initcall+0x128/0x700 init/main.c:1257 do_initcall_level init/main.c:1319 [inline] do_initcalls init/main.c:1335 [inline] do_basic_setup init/main.c:1354 [inline] kernel_init_freeable+0x5c7/0x900 init/main.c:1568 kernel_init+0x1c/0x2b0 init/main.c:1457 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 -> #2 (rtnl_mutex){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0x19b/0xb10 kernel/locking/mutex.c:730 wg_pm_notification drivers/net/wireguard/device.c:80 [inline] wg_pm_notification+0x49/0x180 drivers/net/wireguard/device.c:64 notifier_call_chain+0xb7/0x410 kernel/notifier.c:85 notifier_call_chain_robust kernel/notifier.c:120 [inline] blocking_notifier_call_chain_robust kernel/notifier.c:345 [inline] blocking_notifier_call_chain_robust+0xc9/0x170 kernel/notifier.c:333 pm_notifier_call_chain_robust+0x27/0x60 kernel/power/main.c:102 snapshot_open+0x189/0x2b0 kernel/power/user.c:77 misc_open+0x35a/0x420 drivers/char/misc.c:179 chrdev_open+0x237/0x6a0 fs/char_dev.c:414 do_dentry_open+0x735/0x1c40 fs/open.c:956 vfs_open+0x82/0x3f0 fs/open.c:1086 do_open fs/namei.c:3830 [inline] path_openat+0x1e88/0x2d80 fs/namei.c:3989 do_filp_open+0x20c/0x470 fs/namei.c:4016 do_sys_openat2+0x17a/0x1e0 fs/open.c:1428 do_sys_open fs/open.c:1443 [inline] __do_sys_openat fs/open.c:1459 [inline] __se_sys_openat fs/open.c:1454 [inline] __x64_sys_openat+0x175/0x210 fs/open.c:1454 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 ((pm_chain_head).rwsem){++++}-{4:4}: down_read+0x9a/0x330 kernel/locking/rwsem.c:1524 blocking_notifier_call_chain_robust kerne ---truncated---

In the Linux kernel, the following vulnerability has been resolved: jfs: Prevent copying of nlink with value 0 from disk inode syzbot report a deadlock in diFree. [1] When calling "ioctl$LOOP_SET_STATUS64", the offset value passed in is 4, which does not match the mounted loop device, causing the mapping of the mounted loop device to be invalidated. When creating the directory and creating the inode of iag in diReadSpecial(), read the page of fixed disk inode (AIT) in raw mode in read_metapage(), the metapage data it returns is corrupted, which causes the nlink value of 0 to be assigned to the iag inode when executing copy_from_dinode(), which ultimately causes a deadlock when entering diFree(). To avoid this, first check the nlink value of dinode before setting iag inode. [1] WARNING: possible recursive locking detected 6.12.0-rc7-syzkaller-00212-g4a5df3796467 #0 Not tainted -------------------------------------------- syz-executor301/5309 is trying to acquire lock: ffff888044548920 (&(imap->im_aglock[index])){+.+.}-{3:3}, at: diFree+0x37c/0x2fb0 fs/jfs/jfs_imap.c:889 but task is already holding lock: ffff888044548920 (&(imap->im_aglock[index])){+.+.}-{3:3}, at: diAlloc+0x1b6/0x1630 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&(imap->im_aglock[index])); lock(&(imap->im_aglock[index])); *** DEADLOCK *** May be due to missing lock nesting notation 5 locks held by syz-executor301/5309: #0: ffff8880422a4420 (sb_writers#9){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:515 #1: ffff88804755b390 (&type->i_mutex_dir_key#6/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:850 [inline] #1: ffff88804755b390 (&type->i_mutex_dir_key#6/1){+.+.}-{3:3}, at: filename_create+0x260/0x540 fs/namei.c:4026 #2: ffff888044548920 (&(imap->im_aglock[index])){+.+.}-{3:3}, at: diAlloc+0x1b6/0x1630 #3: ffff888044548890 (&imap->im_freelock){+.+.}-{3:3}, at: diNewIAG fs/jfs/jfs_imap.c:2460 [inline] #3: ffff888044548890 (&imap->im_freelock){+.+.}-{3:3}, at: diAllocExt fs/jfs/jfs_imap.c:1905 [inline] #3: ffff888044548890 (&imap->im_freelock){+.+.}-{3:3}, at: diAllocAG+0x4b7/0x1e50 fs/jfs/jfs_imap.c:1669 #4: ffff88804755a618 (&jfs_ip->rdwrlock/1){++++}-{3:3}, at: diNewIAG fs/jfs/jfs_imap.c:2477 [inline] #4: ffff88804755a618 (&jfs_ip->rdwrlock/1){++++}-{3:3}, at: diAllocExt fs/jfs/jfs_imap.c:1905 [inline] #4: ffff88804755a618 (&jfs_ip->rdwrlock/1){++++}-{3:3}, at: diAllocAG+0x869/0x1e50 fs/jfs/jfs_imap.c:1669 stack backtrace: CPU: 0 UID: 0 PID: 5309 Comm: syz-executor301 Not tainted 6.12.0-rc7-syzkaller-00212-g4a5df3796467 #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_deadlock_bug+0x483/0x620 kernel/locking/lockdep.c:3037 check_deadlock kernel/locking/lockdep.c:3089 [inline] validate_chain+0x15e2/0x5920 kernel/locking/lockdep.c:3891 __lock_acquire+0x1384/0x2050 kernel/locking/lockdep.c:5202 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:608 [inline] __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752 diFree+0x37c/0x2fb0 fs/jfs/jfs_imap.c:889 jfs_evict_inode+0x32d/0x440 fs/jfs/inode.c:156 evict+0x4e8/0x9b0 fs/inode.c:725 diFreeSpecial fs/jfs/jfs_imap.c:552 [inline] duplicateIXtree+0x3c6/0x550 fs/jfs/jfs_imap.c:3022 diNewIAG fs/jfs/jfs_imap.c:2597 [inline] diAllocExt fs/jfs/jfs_imap.c:1905 [inline] diAllocAG+0x17dc/0x1e50 fs/jfs/jfs_imap.c:1669 diAlloc+0x1d2/0x1630 fs/jfs/jfs_imap.c:1590 ialloc+0x8f/0x900 fs/jfs/jfs_inode.c:56 jfs_mkdir+0x1c5/0xba0 fs/jfs/namei.c:225 vfs_mkdir+0x2f9/0x4f0 fs/namei.c:4257 do_mkdirat+0x264/0x3a0 fs/namei.c:4280 __do_sys_mkdirat fs/namei.c:4295 [inline] __se_sys_mkdirat fs/namei.c:4293 [inline] __x64_sys_mkdirat+0x87/0xa0 fs/namei.c:4293 do_syscall_x64 arch/x86/en ---truncated---

An issue was discovered in the Linux kernel through 5.6.11. btree_gc_coalesce in drivers/md/bcache/btree.c has a deadlock if a coalescing operation fails.

In the Linux kernel, the following vulnerability has been resolved: mm/shmem, swap: fix softlockup with mTHP swapin Following softlockup can be easily reproduced on my test machine with: echo always > /sys/kernel/mm/transparent_hugepage/hugepages-64kB/enabled swapon /dev/zram0 # zram0 is a 48G swap device mkdir -p /sys/fs/cgroup/memory/test echo 1G > /sys/fs/cgroup/test/memory.max echo $BASHPID > /sys/fs/cgroup/test/cgroup.procs while true; do dd if=/dev/zero of=/tmp/test.img bs=1M count=5120 cat /tmp/test.img > /dev/null rm /tmp/test.img done Then after a while: watchdog: BUG: soft lockup - CPU#0 stuck for 763s! [cat:5787] Modules linked in: zram virtiofs CPU: 0 UID: 0 PID: 5787 Comm: cat Kdump: loaded Tainted: G L 6.15.0.orig-gf3021d9246bc-dirty #118 PREEMPT(voluntary)· Tainted: [L]=SOFTLOCKUP Hardware name: Red Hat KVM/RHEL-AV, BIOS 0.0.0 02/06/2015 RIP: 0010:mpol_shared_policy_lookup+0xd/0x70 Code: e9 b8 b4 ff ff 31 c0 c3 cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 66 0f 1f 00 0f 1f 44 00 00 41 54 55 53 <48> 8b 1f 48 85 db 74 41 4c 8d 67 08 48 89 fb 48 89 f5 4c 89 e7 e8 RSP: 0018:ffffc90002b1fc28 EFLAGS: 00000202 RAX: 00000000001c20ca RBX: 0000000000724e1e RCX: 0000000000000001 RDX: ffff888118e214c8 RSI: 0000000000057d42 RDI: ffff888118e21518 RBP: 000000000002bec8 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000bf4 R11: 0000000000000000 R12: 0000000000000001 R13: 00000000001c20ca R14: 00000000001c20ca R15: 0000000000000000 FS: 00007f03f995c740(0000) GS:ffff88a07ad9a000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f03f98f1000 CR3: 0000000144626004 CR4: 0000000000770eb0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: <TASK> shmem_alloc_folio+0x31/0xc0 shmem_swapin_folio+0x309/0xcf0 ? filemap_get_entry+0x117/0x1e0 ? xas_load+0xd/0xb0 ? filemap_get_entry+0x101/0x1e0 shmem_get_folio_gfp+0x2ed/0x5b0 shmem_file_read_iter+0x7f/0x2e0 vfs_read+0x252/0x330 ksys_read+0x68/0xf0 do_syscall_64+0x4c/0x1c0 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7f03f9a46991 Code: 00 48 8b 15 81 14 10 00 f7 d8 64 89 02 b8 ff ff ff ff eb bd e8 20 ad 01 00 f3 0f 1e fa 80 3d 35 97 10 00 00 74 13 31 c0 0f 05 <48> 3d 00 f0 ff ff 77 4f c3 66 0f 1f 44 00 00 55 48 89 e5 48 83 ec RSP: 002b:00007fff3c52bd28 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 0000000000040000 RCX: 00007f03f9a46991 RDX: 0000000000040000 RSI: 00007f03f98ba000 RDI: 0000000000000003 RBP: 00007fff3c52bd50 R08: 0000000000000000 R09: 00007f03f9b9a380 R10: 0000000000000022 R11: 0000000000000246 R12: 0000000000040000 R13: 00007f03f98ba000 R14: 0000000000000003 R15: 0000000000000000 </TASK> The reason is simple, readahead brought some order 0 folio in swap cache, and the swapin mTHP folio being allocated is in conflict with it, so swapcache_prepare fails and causes shmem_swap_alloc_folio to return -EEXIST, and shmem simply retries again and again causing this loop. Fix it by applying a similar fix for anon mTHP swapin. The performance change is very slight, time of swapin 10g zero folios with shmem (test for 12 times): Before: 2.47s After: 2.48s [kasong@tencent.com: add comment]

In the Linux kernel, the following vulnerability has been resolved: accel/ivpu: Fix deadlock in ivpu_ms_cleanup() Fix deadlock in ivpu_ms_cleanup() by preventing runtime resume after file_priv->ms_lock is acquired. During a failure in runtime resume, a cold boot is executed, which calls ivpu_ms_cleanup_all(). This function calls ivpu_ms_cleanup() that acquires file_priv->ms_lock and causes the deadlock.