In the Linux kernel, the following vulnerability has been resolved: btrfs: fix deadlock when aborting transaction during relocation with scrub Before relocating a block group we pause scrub, then do the relocation and then unpause scrub. The relocation process requires starting and committing a transaction, and if we have a failure in the critical section of the transaction commit path (transaction state >= TRANS_STATE_COMMIT_START), we will deadlock if there is a paused scrub. That results in stack traces like the following: [42.479] BTRFS info (device sdc): relocating block group 53876686848 flags metadata|raid6 [42.936] BTRFS warning (device sdc): Skipping commit of aborted transaction. [42.936] ------------[ cut here ]------------ [42.936] BTRFS: Transaction aborted (error -28) [42.936] WARNING: CPU: 11 PID: 346822 at fs/btrfs/transaction.c:1977 btrfs_commit_transaction+0xcc8/0xeb0 [btrfs] [42.936] Modules linked in: dm_flakey dm_mod loop btrfs (...) [42.936] CPU: 11 PID: 346822 Comm: btrfs Tainted: G W 6.3.0-rc2-btrfs-next-127+ #1 [42.936] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 [42.936] RIP: 0010:btrfs_commit_transaction+0xcc8/0xeb0 [btrfs] [42.936] Code: ff ff 45 8b (...) [42.936] RSP: 0018:ffffb58649633b48 EFLAGS: 00010282 [42.936] RAX: 0000000000000000 RBX: ffff8be6ef4d5bd8 RCX: 0000000000000000 [42.936] RDX: 0000000000000002 RSI: ffffffffb35e7782 RDI: 00000000ffffffff [42.936] RBP: ffff8be6ef4d5c98 R08: 0000000000000000 R09: ffffb586496339e8 [42.936] R10: 0000000000000001 R11: 0000000000000001 R12: ffff8be6d38c7c00 [42.936] R13: 00000000ffffffe4 R14: ffff8be6c268c000 R15: ffff8be6ef4d5cf0 [42.936] FS: 00007f381a82b340(0000) GS:ffff8beddfcc0000(0000) knlGS:0000000000000000 [42.936] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [42.936] CR2: 00007f1e35fb7638 CR3: 0000000117680006 CR4: 0000000000370ee0 [42.936] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [42.936] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [42.936] Call Trace: [42.936] <TASK> [42.936] ? start_transaction+0xcb/0x610 [btrfs] [42.936] prepare_to_relocate+0x111/0x1a0 [btrfs] [42.936] relocate_block_group+0x57/0x5d0 [btrfs] [42.936] ? btrfs_wait_nocow_writers+0x25/0xb0 [btrfs] [42.936] btrfs_relocate_block_group+0x248/0x3c0 [btrfs] [42.936] ? __pfx_autoremove_wake_function+0x10/0x10 [42.936] btrfs_relocate_chunk+0x3b/0x150 [btrfs] [42.936] btrfs_balance+0x8ff/0x11d0 [btrfs] [42.936] ? __kmem_cache_alloc_node+0x14a/0x410 [42.936] btrfs_ioctl+0x2334/0x32c0 [btrfs] [42.937] ? mod_objcg_state+0xd2/0x360 [42.937] ? refill_obj_stock+0xb0/0x160 [42.937] ? seq_release+0x25/0x30 [42.937] ? __rseq_handle_notify_resume+0x3b5/0x4b0 [42.937] ? percpu_counter_add_batch+0x2e/0xa0 [42.937] ? __x64_sys_ioctl+0x88/0xc0 [42.937] __x64_sys_ioctl+0x88/0xc0 [42.937] do_syscall_64+0x38/0x90 [42.937] entry_SYSCALL_64_after_hwframe+0x72/0xdc [42.937] RIP: 0033:0x7f381a6ffe9b [42.937] Code: 00 48 89 44 24 (...) [42.937] RSP: 002b:00007ffd45ecf060 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [42.937] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f381a6ffe9b [42.937] RDX: 00007ffd45ecf150 RSI: 00000000c4009420 RDI: 0000000000000003 [42.937] RBP: 0000000000000003 R08: 0000000000000013 R09: 0000000000000000 [42.937] R10: 00007f381a60c878 R11: 0000000000000246 R12: 00007ffd45ed0423 [42.937] R13: 00007ffd45ecf150 R14: 0000000000000000 R15: 00007ffd45ecf148 [42.937] </TASK> [42.937] ---[ end trace 0000000000000000 ]--- [42.937] BTRFS: error (device sdc: state A) in cleanup_transaction:1977: errno=-28 No space left [59.196] INFO: task btrfs:346772 blocked for more than 120 seconds. [59.196] Tainted: G W 6.3.0-rc2-btrfs-next-127+ #1 [59.196] "echo 0 > /proc/sys/kernel/hung_ ---truncated---

In the Linux kernel, the following vulnerability has been resolved: drivers: staging: rtl8723bs: Fix locking in _rtw_join_timeout_handler() Commit 041879b12ddb ("drivers: staging: rtl8192bs: Fix deadlock in rtw_joinbss_event_prehandle()") besides fixing the deadlock also modified _rtw_join_timeout_handler() to use spin_[un]lock_irq() instead of spin_[un]lock_bh(). _rtw_join_timeout_handler() calls rtw_do_join() which takes pmlmepriv->scanned_queue.lock using spin_[un]lock_bh(). This spin_unlock_bh() call re-enables softirqs which triggers an oops in kernel/softirq.c: __local_bh_enable_ip() when it calls lockdep_assert_irqs_enabled(): [ 244.506087] WARNING: CPU: 2 PID: 0 at kernel/softirq.c:376 __local_bh_enable_ip+0xa6/0x100 ... [ 244.509022] Call Trace: [ 244.509048] <IRQ> [ 244.509100] _rtw_join_timeout_handler+0x134/0x170 [r8723bs] [ 244.509468] ? __pfx__rtw_join_timeout_handler+0x10/0x10 [r8723bs] [ 244.509772] ? __pfx__rtw_join_timeout_handler+0x10/0x10 [r8723bs] [ 244.510076] call_timer_fn+0x95/0x2a0 [ 244.510200] __run_timers.part.0+0x1da/0x2d0 This oops is causd by the switch to spin_[un]lock_irq() which disables the IRQs for the entire duration of _rtw_join_timeout_handler(). Disabling the IRQs is not necessary since all code taking this lock runs from either user contexts or from softirqs, switch back to spin_[un]lock_bh() to fix this.

In the Linux kernel, the following vulnerability has been resolved: sctp: add a refcnt in sctp_stream_priorities to avoid a nested loop With this refcnt added in sctp_stream_priorities, we don't need to traverse all streams to check if the prio is used by other streams when freeing one stream's prio in sctp_sched_prio_free_sid(). This can avoid a nested loop (up to 65535 * 65535), which may cause a stuck as Ying reported: watchdog: BUG: soft lockup - CPU#23 stuck for 26s! [ksoftirqd/23:136] Call Trace: <TASK> sctp_sched_prio_free_sid+0xab/0x100 [sctp] sctp_stream_free_ext+0x64/0xa0 [sctp] sctp_stream_free+0x31/0x50 [sctp] sctp_association_free+0xa5/0x200 [sctp] Note that it doesn't need to use refcount_t type for this counter, as its accessing is always protected under the sock lock. v1->v2: - add a check in sctp_sched_prio_set to avoid the possible prio_head refcnt overflow.

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/swapfile: add cond_resched() in get_swap_pages() The softlockup still occurs in get_swap_pages() under memory pressure. 64 CPU cores, 64GB memory, and 28 zram devices, the disksize of each zram device is 50MB with same priority as si. Use the stress-ng tool to increase memory pressure, causing the system to oom frequently. The plist_for_each_entry_safe() loops in get_swap_pages() could reach tens of thousands of times to find available space (extreme case: cond_resched() is not called in scan_swap_map_slots()). Let's add cond_resched() into get_swap_pages() when failed to find available space to avoid softlockup.

In the Linux kernel, the following vulnerability has been resolved: io_uring: lock overflowing for IOPOLL syzbot reports an issue with overflow filling for IOPOLL: WARNING: CPU: 0 PID: 28 at io_uring/io_uring.c:734 io_cqring_event_overflow+0x1c0/0x230 io_uring/io_uring.c:734 CPU: 0 PID: 28 Comm: kworker/u4:1 Not tainted 6.2.0-rc3-syzkaller-16369-g358a161a6a9e #0 Workqueue: events_unbound io_ring_exit_work Call trace:  io_cqring_event_overflow+0x1c0/0x230 io_uring/io_uring.c:734  io_req_cqe_overflow+0x5c/0x70 io_uring/io_uring.c:773  io_fill_cqe_req io_uring/io_uring.h:168 [inline]  io_do_iopoll+0x474/0x62c io_uring/rw.c:1065  io_iopoll_try_reap_events+0x6c/0x108 io_uring/io_uring.c:1513  io_uring_try_cancel_requests+0x13c/0x258 io_uring/io_uring.c:3056  io_ring_exit_work+0xec/0x390 io_uring/io_uring.c:2869  process_one_work+0x2d8/0x504 kernel/workqueue.c:2289  worker_thread+0x340/0x610 kernel/workqueue.c:2436  kthread+0x12c/0x158 kernel/kthread.c:376  ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:863 There is no real problem for normal IOPOLL as flush is also called with uring_lock taken, but it's getting more complicated for IOPOLL|SQPOLL, for which __io_cqring_overflow_flush() happens from the CQ waiting path.

In the Linux kernel, the following vulnerability has been resolved: btrfs: zoned: fix lock ordering in btrfs_zone_activate() The btrfs CI reported a lockdep warning as follows by running generic generic/129. WARNING: possible circular locking dependency detected 6.7.0-rc5+ #1 Not tainted ------------------------------------------------------ kworker/u5:5/793427 is trying to acquire lock: ffff88813256d028 (&cache->lock){+.+.}-{2:2}, at: btrfs_zone_finish_one_bg+0x5e/0x130 but task is already holding lock: ffff88810a23a318 (&fs_info->zone_active_bgs_lock){+.+.}-{2:2}, at: btrfs_zone_finish_one_bg+0x34/0x130 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&fs_info->zone_active_bgs_lock){+.+.}-{2:2}: ... -> #0 (&cache->lock){+.+.}-{2:2}: ... This is because we take fs_info->zone_active_bgs_lock after a block_group's lock in btrfs_zone_activate() while doing the opposite in other places. Fix the issue by expanding the fs_info->zone_active_bgs_lock's critical section and taking it before a block_group's lock.

In the Linux kernel, the following vulnerability has been resolved: ALSA: scarlett2: Add missing mutex lock around get meter levels As scarlett2_meter_ctl_get() uses meter_level_map[], the data_mutex should be locked while accessing it.

In the Linux kernel, the following vulnerability has been resolved: drm: Don't unref the same fb many times by mistake due to deadlock handling If we get a deadlock after the fb lookup in drm_mode_page_flip_ioctl() we proceed to unref the fb and then retry the whole thing from the top. But we forget to reset the fb pointer back to NULL, and so if we then get another error during the retry, before the fb lookup, we proceed the unref the same fb again without having gotten another reference. The end result is that the fb will (eventually) end up being freed while it's still in use. Reset fb to NULL once we've unreffed it to avoid doing it again until we've done another fb lookup. This turned out to be pretty easy to hit on a DG2 when doing async flips (and CONFIG_DEBUG_WW_MUTEX_SLOWPATH=y). The first symptom I saw that drm_closefb() simply got stuck in a busy loop while walking the framebuffer list. Fortunately I was able to convince it to oops instead, and from there it was easier to track down the culprit.

In the Linux kernel, the following vulnerability has been resolved: PM: sleep: Fix possible deadlocks in core system-wide PM code It is reported that in low-memory situations the system-wide resume core code deadlocks, because async_schedule_dev() executes its argument function synchronously if it cannot allocate memory (and not only in that case) and that function attempts to acquire a mutex that is already held. Executing the argument function synchronously from within dpm_async_fn() may also be problematic for ordering reasons (it may cause a consumer device's resume callback to be invoked before a requisite supplier device's one, for example). Address this by changing the code in question to use async_schedule_dev_nocall() for scheduling the asynchronous execution of device suspend and resume functions and to directly run them synchronously if async_schedule_dev_nocall() returns false.

In the Linux kernel, the following vulnerability has been resolved: can: j1939: prevent deadlock by changing j1939_socks_lock to rwlock The following 3 locks would race against each other, causing the deadlock situation in the Syzbot bug report: - j1939_socks_lock - active_session_list_lock - sk_session_queue_lock A reasonable fix is to change j1939_socks_lock to an rwlock, since in the rare situations where a write lock is required for the linked list that j1939_socks_lock is protecting, the code does not attempt to acquire any more locks. This would break the circular lock dependency, where, for example, the current thread already locks j1939_socks_lock and attempts to acquire sk_session_queue_lock, and at the same time, another thread attempts to acquire j1939_socks_lock while holding sk_session_queue_lock. NOTE: This patch along does not fix the unregister_netdevice bug reported by Syzbot; instead, it solves a deadlock situation to prepare for one or more further patches to actually fix the Syzbot bug, which appears to be a reference counting problem within the j1939 codebase. [mkl: remove unrelated newline change]

A vulnerability was found due to missing lock for IOPOLL flaw in io_cqring_event_overflow() in io_uring.c in Linux Kernel. This flaw allows a local attacker with user privilege to trigger a Denial of Service threat.

In the Linux kernel, the following vulnerability has been resolved: block: don't use submit_bio_noacct_nocheck in blk_zone_wplug_bio_work Bios queued up in the zone write plug have already gone through all all preparation in the submit_bio path, including the freeze protection. Submitting them through submit_bio_noacct_nocheck duplicates the work and can can cause deadlocks when freezing a queue with pending bio write plugs. Go straight to ->submit_bio or blk_mq_submit_bio to bypass the superfluous extra freeze protection and checks.

In the Linux kernel, the following vulnerability has been resolved: nilfs2: fix potential deadlock with newly created symlinks Syzbot reported that page_symlink(), called by nilfs_symlink(), triggers memory reclamation involving the filesystem layer, which can result in circular lock dependencies among the reader/writer semaphore nilfs->ns_segctor_sem, s_writers percpu_rwsem (intwrite) and the fs_reclaim pseudo lock. This is because after commit 21fc61c73c39 ("don't put symlink bodies in pagecache into highmem"), the gfp flags of the page cache for symbolic links are overwritten to GFP_KERNEL via inode_nohighmem(). This is not a problem for symlinks read from the backing device, because the __GFP_FS flag is dropped after inode_nohighmem() is called. However, when a new symlink is created with nilfs_symlink(), the gfp flags remain overwritten to GFP_KERNEL. Then, memory allocation called from page_symlink() etc. triggers memory reclamation including the FS layer, which may call nilfs_evict_inode() or nilfs_dirty_inode(). And these can cause a deadlock if they are called while nilfs->ns_segctor_sem is held: Fix this issue by dropping the __GFP_FS flag from the page cache GFP flags of newly created symlinks in the same way that nilfs_new_inode() and __nilfs_read_inode() do, as a workaround until we adopt nofs allocation scope consistently or improve the locking constraints.

In the Linux kernel, the following vulnerability has been resolved: net/mlx5e: Fix deadlock in tc route query code Cited commit causes ABBA deadlock[0] when peer flows are created while holding the devcom rw semaphore. Due to peer flows offload implementation the lock is taken much higher up the call chain and there is no obvious way to easily fix the deadlock. Instead, since tc route query code needs the peer eswitch structure only to perform a lookup in xarray and doesn't perform any sleeping operations with it, refactor the code for lockless execution in following ways: - RCUify the devcom 'data' pointer. When resetting the pointer synchronously wait for RCU grace period before returning. This is fine since devcom is currently only used for synchronization of pairing/unpairing of eswitches which is rare and already expensive as-is. - Wrap all usages of 'paired' boolean in {READ|WRITE}_ONCE(). The flag has already been used in some unlocked contexts without proper annotations (e.g. users of mlx5_devcom_is_paired() function), but it wasn't an issue since all relevant code paths checked it again after obtaining the devcom semaphore. Now it is also used by mlx5_devcom_get_peer_data_rcu() as "best effort" check to return NULL when devcom is being unpaired. Note that while RCU read lock doesn't prevent the unpaired flag from being changed concurrently it still guarantees that reader can continue to use 'data'. - Refactor mlx5e_tc_query_route_vport() function to use new mlx5_devcom_get_peer_data_rcu() API which fixes the deadlock. [0]: [ 164.599612] ====================================================== [ 164.600142] WARNING: possible circular locking dependency detected [ 164.600667] 6.3.0-rc3+ #1 Not tainted [ 164.601021] ------------------------------------------------------ [ 164.601557] handler1/3456 is trying to acquire lock: [ 164.601998] ffff88811f1714b0 (&esw->offloads.encap_tbl_lock){+.+.}-{3:3}, at: mlx5e_attach_encap+0xd8/0x8b0 [mlx5_core] [ 164.603078] but task is already holding lock: [ 164.603617] ffff88810137fc98 (&comp->sem){++++}-{3:3}, at: mlx5_devcom_get_peer_data+0x37/0x80 [mlx5_core] [ 164.604459] which lock already depends on the new lock. [ 164.605190] the existing dependency chain (in reverse order) is: [ 164.605848] -> #1 (&comp->sem){++++}-{3:3}: [ 164.606380] down_read+0x39/0x50 [ 164.606772] mlx5_devcom_get_peer_data+0x37/0x80 [mlx5_core] [ 164.607336] mlx5e_tc_query_route_vport+0x86/0xc0 [mlx5_core] [ 164.607914] mlx5e_tc_tun_route_lookup+0x1a4/0x1d0 [mlx5_core] [ 164.608495] mlx5e_attach_decap_route+0xc6/0x1e0 [mlx5_core] [ 164.609063] mlx5e_tc_add_fdb_flow+0x1ea/0x360 [mlx5_core] [ 164.609627] __mlx5e_add_fdb_flow+0x2d2/0x430 [mlx5_core] [ 164.610175] mlx5e_configure_flower+0x952/0x1a20 [mlx5_core] [ 164.610741] tc_setup_cb_add+0xd4/0x200 [ 164.611146] fl_hw_replace_filter+0x14c/0x1f0 [cls_flower] [ 164.611661] fl_change+0xc95/0x18a0 [cls_flower] [ 164.612116] tc_new_tfilter+0x3fc/0xd20 [ 164.612516] rtnetlink_rcv_msg+0x418/0x5b0 [ 164.612936] netlink_rcv_skb+0x54/0x100 [ 164.613339] netlink_unicast+0x190/0x250 [ 164.613746] netlink_sendmsg+0x245/0x4a0 [ 164.614150] sock_sendmsg+0x38/0x60 [ 164.614522] ____sys_sendmsg+0x1d0/0x1e0 [ 164.614934] ___sys_sendmsg+0x80/0xc0 [ 164.615320] __sys_sendmsg+0x51/0x90 [ 164.615701] do_syscall_64+0x3d/0x90 [ 164.616083] entry_SYSCALL_64_after_hwframe+0x46/0xb0 [ 164.616568] -> #0 (&esw->offloads.encap_tbl_lock){+.+.}-{3:3}: [ 164.617210] __lock_acquire+0x159e/0x26e0 [ 164.617638] lock_acquire+0xc2/0x2a0 [ 164.618018] __mutex_lock+0x92/0xcd0 [ 164.618401] mlx5e_attach_encap+0xd8/0x8b0 [mlx5_core] [ 164.618943] post_process_attr+0x153/0x2d0 [ ---truncated---

In the Linux kernel, the following vulnerability has been resolved: usb: typec: displayport: Fix potential deadlock The deadlock can occur due to a recursive lock acquisition of `cros_typec_altmode_data::mutex`. The call chain is as follows: 1. cros_typec_altmode_work() acquires the mutex 2. typec_altmode_vdm() -> dp_altmode_vdm() -> 3. typec_altmode_exit() -> cros_typec_altmode_exit() 4. cros_typec_altmode_exit() attempts to acquire the mutex again To prevent this, defer the `typec_altmode_exit()` call by scheduling it rather than calling it directly from within the mutex-protected context.

In the Linux kernel, the following vulnerability has been resolved: net/sched: Restrict conditions for adding duplicating netems to qdisc tree netem_enqueue's duplication prevention logic breaks when a netem resides in a qdisc tree with other netems - this can lead to a soft lockup and OOM loop in netem_dequeue, as seen in [1]. Ensure that a duplicating netem cannot exist in a tree with other netems. Previous approaches suggested in discussions in chronological order: 1) Track duplication status or ttl in the sk_buff struct. Considered too specific a use case to extend such a struct, though this would be a resilient fix and address other previous and potential future DOS bugs like the one described in loopy fun [2]. 2) Restrict netem_enqueue recursion depth like in act_mirred with a per cpu variable. However, netem_dequeue can call enqueue on its child, and the depth restriction could be bypassed if the child is a netem. 3) Use the same approach as in 2, but add metadata in netem_skb_cb to handle the netem_dequeue case and track a packet's involvement in duplication. This is an overly complex approach, and Jamal notes that the skb cb can be overwritten to circumvent this safeguard. 4) Prevent the addition of a netem to a qdisc tree if its ancestral path contains a netem. However, filters and actions can cause a packet to change paths when re-enqueued to the root from netem duplication, leading us to the current solution: prevent a duplicating netem from inhabiting the same tree as other netems. [1] https://lore.kernel.org/netdev/8DuRWwfqjoRDLDmBMlIfbrsZg9Gx50DHJc1ilxsEBNe2D6NMoigR_eIRIG0LOjMc3r10nUUZtArXx4oZBIdUfZQrwjcQhdinnMis_0G7VEk=@willsroot.io/ [2] https://lwn.net/Articles/719297/

In the Linux kernel, the following vulnerability has been resolved: xen: privcmd: Switch from mutex to spinlock for irqfds irqfd_wakeup() gets EPOLLHUP, when it is called by eventfd_release() by way of wake_up_poll(&ctx->wqh, EPOLLHUP), which gets called under spin_lock_irqsave(). We can't use a mutex here as it will lead to a deadlock. Fix it by switching over to a spin lock.

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: 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().

A deadlock flaw was found in the Linux kernel’s BPF subsystem. This flaw allows a local user to potentially crash the system.

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: When HCI work queue is drained, only queue chained work The HCI command, event, and data packet processing workqueue is drained to avoid deadlock in commit 76727c02c1e1 ("Bluetooth: Call drain_workqueue() before resetting state"). There is another delayed work, which will queue command to this drained workqueue. Which results in the following error report: Bluetooth: hci2: command 0x040f tx timeout WARNING: CPU: 1 PID: 18374 at kernel/workqueue.c:1438 __queue_work+0xdad/0x1140 Workqueue: events hci_cmd_timeout RIP: 0010:__queue_work+0xdad/0x1140 RSP: 0000:ffffc90002cffc60 EFLAGS: 00010093 RAX: 0000000000000000 RBX: ffff8880b9d3ec00 RCX: 0000000000000000 RDX: ffff888024ba0000 RSI: ffffffff814e048d RDI: ffff8880b9d3ec08 RBP: 0000000000000008 R08: 0000000000000000 R09: 00000000b9d39700 R10: ffffffff814f73c6 R11: 0000000000000000 R12: ffff88807cce4c60 R13: 0000000000000000 R14: ffff8880796d8800 R15: ffff8880796d8800 FS: 0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000c0174b4000 CR3: 000000007cae9000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> ? queue_work_on+0xcb/0x110 ? lockdep_hardirqs_off+0x90/0xd0 queue_work_on+0xee/0x110 process_one_work+0x996/0x1610 ? pwq_dec_nr_in_flight+0x2a0/0x2a0 ? rwlock_bug.part.0+0x90/0x90 ? _raw_spin_lock_irq+0x41/0x50 worker_thread+0x665/0x1080 ? process_one_work+0x1610/0x1610 kthread+0x2e9/0x3a0 ? kthread_complete_and_exit+0x40/0x40 ret_from_fork+0x1f/0x30 </TASK> To fix this, we can add a new HCI_DRAIN_WQ flag, and don't queue the timeout workqueue while command workqueue is draining.

In the Linux kernel, the following vulnerability has been resolved: net: hinic: avoid kernel hung in hinic_get_stats64() When using hinic device as a bond slave device, and reading device stats of master bond device, the kernel may hung. The kernel panic calltrace as follows: Kernel panic - not syncing: softlockup: hung tasks Call trace: native_queued_spin_lock_slowpath+0x1ec/0x31c dev_get_stats+0x60/0xcc dev_seq_printf_stats+0x40/0x120 dev_seq_show+0x1c/0x40 seq_read_iter+0x3c8/0x4dc seq_read+0xe0/0x130 proc_reg_read+0xa8/0xe0 vfs_read+0xb0/0x1d4 ksys_read+0x70/0xfc __arm64_sys_read+0x20/0x30 el0_svc_common+0x88/0x234 do_el0_svc+0x2c/0x90 el0_svc+0x1c/0x30 el0_sync_handler+0xa8/0xb0 el0_sync+0x148/0x180 And the calltrace of task that actually caused kernel hungs as follows: __switch_to+124 __schedule+548 schedule+72 schedule_timeout+348 __down_common+188 __down+24 down+104 hinic_get_stats64+44 [hinic] dev_get_stats+92 bond_get_stats+172 [bonding] dev_get_stats+92 dev_seq_printf_stats+60 dev_seq_show+24 seq_read_iter+964 seq_read+220 proc_reg_read+164 vfs_read+172 ksys_read+108 __arm64_sys_read+28 el0_svc_common+132 do_el0_svc+40 el0_svc+24 el0_sync_handler+164 el0_sync+324 When getting device stats from bond, kernel will call bond_get_stats(). It first holds the spinlock bond->stats_lock, and then call hinic_get_stats64() to collect hinic device's stats. However, hinic_get_stats64() calls `down(&nic_dev->mgmt_lock)` to protect its critical section, which may schedule current task out. And if system is under high pressure, the task cannot be woken up immediately, which eventually triggers kernel hung panic. Since previous patch has replaced hinic_dev.tx_stats/rx_stats with local variable in hinic_get_stats64(), there is nothing need to be protected by lock, so just removing down()/up() is ok.

In the Linux kernel, the following vulnerability has been resolved: padata: Always leave BHs disabled when running ->parallel() A deadlock can happen when an overloaded system runs ->parallel() in the context of the current task: padata_do_parallel ->parallel() pcrypt_aead_enc/dec padata_do_serial spin_lock(&reorder->lock) // BHs still enabled <interrupt> ... __do_softirq ... padata_do_serial spin_lock(&reorder->lock) It's a bug for BHs to be on in _do_serial as Steffen points out, so ensure they're off in the "current task" case like they are in padata_parallel_worker to avoid this situation.

In the Linux kernel, the following vulnerability has been resolved: dm thin: Fix ABBA deadlock between shrink_slab and dm_pool_abort_metadata Following concurrent processes: P1(drop cache) P2(kworker) drop_caches_sysctl_handler drop_slab shrink_slab down_read(&shrinker_rwsem) - LOCK A do_shrink_slab super_cache_scan prune_icache_sb dispose_list evict ext4_evict_inode ext4_clear_inode ext4_discard_preallocations ext4_mb_load_buddy_gfp ext4_mb_init_cache ext4_read_block_bitmap_nowait ext4_read_bh_nowait submit_bh dm_submit_bio do_worker process_deferred_bios commit metadata_operation_failed dm_pool_abort_metadata down_write(&pmd->root_lock) - LOCK B __destroy_persistent_data_objects dm_block_manager_destroy dm_bufio_client_destroy unregister_shrinker down_write(&shrinker_rwsem) thin_map | dm_thin_find_block ↓ down_read(&pmd->root_lock) --> ABBA deadlock , which triggers hung task: [ 76.974820] INFO: task kworker/u4:3:63 blocked for more than 15 seconds. [ 76.976019] Not tainted 6.1.0-rc4-00011-g8f17dd350364-dirty #910 [ 76.978521] task:kworker/u4:3 state:D stack:0 pid:63 ppid:2 [ 76.978534] Workqueue: dm-thin do_worker [ 76.978552] Call Trace: [ 76.978564] __schedule+0x6ba/0x10f0 [ 76.978582] schedule+0x9d/0x1e0 [ 76.978588] rwsem_down_write_slowpath+0x587/0xdf0 [ 76.978600] down_write+0xec/0x110 [ 76.978607] unregister_shrinker+0x2c/0xf0 [ 76.978616] dm_bufio_client_destroy+0x116/0x3d0 [ 76.978625] dm_block_manager_destroy+0x19/0x40 [ 76.978629] __destroy_persistent_data_objects+0x5e/0x70 [ 76.978636] dm_pool_abort_metadata+0x8e/0x100 [ 76.978643] metadata_operation_failed+0x86/0x110 [ 76.978649] commit+0x6a/0x230 [ 76.978655] do_worker+0xc6e/0xd90 [ 76.978702] process_one_work+0x269/0x630 [ 76.978714] worker_thread+0x266/0x630 [ 76.978730] kthread+0x151/0x1b0 [ 76.978772] INFO: task test.sh:2646 blocked for more than 15 seconds. [ 76.979756] Not tainted 6.1.0-rc4-00011-g8f17dd350364-dirty #910 [ 76.982111] task:test.sh state:D stack:0 pid:2646 ppid:2459 [ 76.982128] Call Trace: [ 76.982139] __schedule+0x6ba/0x10f0 [ 76.982155] schedule+0x9d/0x1e0 [ 76.982159] rwsem_down_read_slowpath+0x4f4/0x910 [ 76.982173] down_read+0x84/0x170 [ 76.982177] dm_thin_find_block+0x4c/0xd0 [ 76.982183] thin_map+0x201/0x3d0 [ 76.982188] __map_bio+0x5b/0x350 [ 76.982195] dm_submit_bio+0x2b6/0x930 [ 76.982202] __submit_bio+0x123/0x2d0 [ 76.982209] submit_bio_noacct_nocheck+0x101/0x3e0 [ 76.982222] submit_bio_noacct+0x389/0x770 [ 76.982227] submit_bio+0x50/0xc0 [ 76.982232] submit_bh_wbc+0x15e/0x230 [ 76.982238] submit_bh+0x14/0x20 [ 76.982241] ext4_read_bh_nowait+0xc5/0x130 [ 76.982247] ext4_read_block_bitmap_nowait+0x340/0xc60 [ 76.982254] ext4_mb_init_cache+0x1ce/0xdc0 [ 76.982259] ext4_mb_load_buddy_gfp+0x987/0xfa0 [ 76.982263] ext4_discard_preallocations+0x45d/0x830 [ 76.982274] ext4_clear_inode+0x48/0xf0 [ 76.982280] ext4_evict_inode+0xcf/0xc70 [ 76.982285] evict+0x119/0x2b0 [ 76.982290] dispose_list+0x43/0xa0 [ 76.982294] prune_icache_sb+0x64/0x90 [ 76.982298] super_cache_scan+0x155/0x210 [ 76.982303] do_shrink_slab+0x19e/0x4e0 [ 76.982310] shrink_slab+0x2bd/0x450 [ 76.982317] drop_slab+0xcc/0x1a0 [ 76.982323] drop_caches_sysctl_handler+0xb7/0xe0 [ 76.982327] proc_sys_call_handler+0x1bc/0x300 [ 76.982331] proc_sys_write+0x17/0x20 [ 76.982334] vfs_write+0x3d3/0x570 [ 76.982342] ksys_write+0x73/0x160 [ 76.982347] __x64_sys_write+0x1e/0x30 [ 76.982352] do_syscall_64+0x35/0x80 [ 76.982357] entry_SYSCALL_64_after_hwframe+0x63/0xcd Funct ---truncated---

In the Linux kernel, the following vulnerability has been resolved: riscv:uprobe fix SR_SPIE set/clear handling In riscv the process of uprobe going to clear spie before exec the origin insn,and set spie after that.But When access the page which origin insn has been placed a page fault may happen and irq was disabled in arch_uprobe_pre_xol function,It cause a WARN as follows. There is no need to clear/set spie in arch_uprobe_pre/post/abort_xol. We can just remove it. [ 31.684157] BUG: sleeping function called from invalid context at kernel/locking/rwsem.c:1488 [ 31.684677] in_atomic(): 0, irqs_disabled(): 1, non_block: 0, pid: 76, name: work [ 31.684929] preempt_count: 0, expected: 0 [ 31.685969] CPU: 2 PID: 76 Comm: work Tainted: G [ 31.686542] Hardware name: riscv-virtio,qemu (DT) [ 31.686797] Call Trace: [ 31.687053] [<ffffffff80006442>] dump_backtrace+0x30/0x38 [ 31.687699] [<ffffffff80812118>] show_stack+0x40/0x4c [ 31.688141] [<ffffffff8081817a>] dump_stack_lvl+0x44/0x5c [ 31.688396] [<ffffffff808181aa>] dump_stack+0x18/0x20 [ 31.688653] [<ffffffff8003e454>] __might_resched+0x114/0x122 [ 31.688948] [<ffffffff8003e4b2>] __might_sleep+0x50/0x7a [ 31.689435] [<ffffffff80822676>] down_read+0x30/0x130 [ 31.689728] [<ffffffff8000b650>] do_page_fault+0x166/x446 [ 31.689997] [<ffffffff80003c0c>] ret_from_exception+0x0/0xc

In the Linux kernel, the following vulnerability has been resolved: tty: fix deadlock caused by calling printk() under tty_port->lock pty_write() invokes kmalloc() which may invoke a normal printk() to print failure message. This can cause a deadlock in the scenario reported by syz-bot below: CPU0 CPU1 CPU2 ---- ---- ---- lock(console_owner); lock(&port_lock_key); lock(&port->lock); lock(&port_lock_key); lock(&port->lock); lock(console_owner); As commit dbdda842fe96 ("printk: Add console owner and waiter logic to load balance console writes") said, such deadlock can be prevented by using printk_deferred() in kmalloc() (which is invoked in the section guarded by the port->lock). But there are too many printk() on the kmalloc() path, and kmalloc() can be called from anywhere, so changing printk() to printk_deferred() is too complicated and inelegant. Therefore, this patch chooses to specify __GFP_NOWARN to kmalloc(), so that printk() will not be called, and this deadlock problem can be avoided. Syzbot reported the following lockdep error: ====================================================== WARNING: possible circular locking dependency detected 5.4.143-00237-g08ccc19a-dirty #10 Not tainted ------------------------------------------------------ syz-executor.4/29420 is trying to acquire lock: ffffffff8aedb2a0 (console_owner){....}-{0:0}, at: console_trylock_spinning kernel/printk/printk.c:1752 [inline] ffffffff8aedb2a0 (console_owner){....}-{0:0}, at: vprintk_emit+0x2ca/0x470 kernel/printk/printk.c:2023 but task is already holding lock: ffff8880119c9158 (&port->lock){-.-.}-{2:2}, at: pty_write+0xf4/0x1f0 drivers/tty/pty.c:120 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&port->lock){-.-.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x35/0x50 kernel/locking/spinlock.c:159 tty_port_tty_get drivers/tty/tty_port.c:288 [inline] <-- lock(&port->lock); tty_port_default_wakeup+0x1d/0xb0 drivers/tty/tty_port.c:47 serial8250_tx_chars+0x530/0xa80 drivers/tty/serial/8250/8250_port.c:1767 serial8250_handle_irq.part.0+0x31f/0x3d0 drivers/tty/serial/8250/8250_port.c:1854 serial8250_handle_irq drivers/tty/serial/8250/8250_port.c:1827 [inline] <-- lock(&port_lock_key); serial8250_default_handle_irq+0xb2/0x220 drivers/tty/serial/8250/8250_port.c:1870 serial8250_interrupt+0xfd/0x200 drivers/tty/serial/8250/8250_core.c:126 __handle_irq_event_percpu+0x109/0xa50 kernel/irq/handle.c:156 [...] -> #1 (&port_lock_key){-.-.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x35/0x50 kernel/locking/spinlock.c:159 serial8250_console_write+0x184/0xa40 drivers/tty/serial/8250/8250_port.c:3198 <-- lock(&port_lock_key); call_console_drivers kernel/printk/printk.c:1819 [inline] console_unlock+0x8cb/0xd00 kernel/printk/printk.c:2504 vprintk_emit+0x1b5/0x470 kernel/printk/printk.c:2024 <-- lock(console_owner); vprintk_func+0x8d/0x250 kernel/printk/printk_safe.c:394 printk+0xba/0xed kernel/printk/printk.c:2084 register_console+0x8b3/0xc10 kernel/printk/printk.c:2829 univ8250_console_init+0x3a/0x46 drivers/tty/serial/8250/8250_core.c:681 console_init+0x49d/0x6d3 kernel/printk/printk.c:2915 start_kernel+0x5e9/0x879 init/main.c:713 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:241 -> #0 (console_owner){....}-{0:0}: [...] lock_acquire+0x127/0x340 kernel/locking/lockdep.c:4734 console_trylock_spinning kernel/printk/printk.c:1773 ---truncated---

In the Linux kernel, the following vulnerability has been resolved: ALSA: pcm: Fix potential AB/BA lock with buffer_mutex and mmap_lock syzbot caught a potential deadlock between the PCM runtime->buffer_mutex and the mm->mmap_lock. It was brought by the recent fix to cover the racy read/write and other ioctls, and in that commit, I overlooked a (hopefully only) corner case that may take the revert lock, namely, the OSS mmap. The OSS mmap operation exceptionally allows to re-configure the parameters inside the OSS mmap syscall, where mm->mmap_mutex is already held. Meanwhile, the copy_from/to_user calls at read/write operations also take the mm->mmap_lock internally, hence it may lead to a AB/BA deadlock. A similar problem was already seen in the past and we fixed it with a refcount (in commit b248371628aa). The former fix covered only the call paths with OSS read/write and OSS ioctls, while we need to cover the concurrent access via both ALSA and OSS APIs now. This patch addresses the problem above by replacing the buffer_mutex lock in the read/write operations with a refcount similar as we've used for OSS. The new field, runtime->buffer_accessing, keeps the number of concurrent read/write operations. Unlike the former buffer_mutex protection, this protects only around the copy_from/to_user() calls; the other codes are basically protected by the PCM stream lock. The refcount can be a negative, meaning blocked by the ioctls. If a negative value is seen, the read/write aborts with -EBUSY. In the ioctl side, OTOH, they check this refcount, too, and set to a negative value for blocking unless it's already being accessed.

In the Linux kernel, the following vulnerability has been resolved: drivers: staging: rtl8192u: Fix deadlock in ieee80211_beacons_stop() There is a deadlock in ieee80211_beacons_stop(), which is shown below: (Thread 1) | (Thread 2) | ieee80211_send_beacon() ieee80211_beacons_stop() | mod_timer() spin_lock_irqsave() //(1) | (wait a time) ... | ieee80211_send_beacon_cb() del_timer_sync() | spin_lock_irqsave() //(2) (wait timer to stop) | ... We hold ieee->beacon_lock in position (1) of thread 1 and use del_timer_sync() to wait timer to stop, but timer handler also need ieee->beacon_lock in position (2) of thread 2. As a result, ieee80211_beacons_stop() will block forever. This patch extracts del_timer_sync() from the protection of spin_lock_irqsave(), which could let timer handler to obtain the needed lock.

In the Linux kernel, the following vulnerability has been resolved: drivers: usb: host: Fix deadlock in oxu_bus_suspend() There is a deadlock in oxu_bus_suspend(), which is shown below: (Thread 1) | (Thread 2) | timer_action() oxu_bus_suspend() | mod_timer() spin_lock_irq() //(1) | (wait a time) ... | oxu_watchdog() del_timer_sync() | spin_lock_irq() //(2) (wait timer to stop) | ... We hold oxu->lock in position (1) of thread 1, and use del_timer_sync() to wait timer to stop, but timer handler also need oxu->lock in position (2) of thread 2. As a result, oxu_bus_suspend() will block forever. This patch extracts del_timer_sync() from the protection of spin_lock_irq(), which could let timer handler to obtain the needed lock.

In the Linux kernel, the following vulnerability has been resolved: drivers: staging: rtl8192e: Fix deadlock in rtllib_beacons_stop() There is a deadlock in rtllib_beacons_stop(), which is shown below: (Thread 1) | (Thread 2) | rtllib_send_beacon() rtllib_beacons_stop() | mod_timer() spin_lock_irqsave() //(1) | (wait a time) ... | rtllib_send_beacon_cb() del_timer_sync() | spin_lock_irqsave() //(2) (wait timer to stop) | ... We hold ieee->beacon_lock in position (1) of thread 1 and use del_timer_sync() to wait timer to stop, but timer handler also need ieee->beacon_lock in position (2) of thread 2. As a result, rtllib_beacons_stop() will block forever. This patch extracts del_timer_sync() from the protection of spin_lock_irqsave(), which could let timer handler to obtain the needed lock.

In the Linux kernel, the following vulnerability has been resolved: driver core: fix deadlock in __device_attach In __device_attach function, The lock holding logic is as follows: ... __device_attach device_lock(dev) // get lock dev async_schedule_dev(__device_attach_async_helper, dev); // func async_schedule_node async_schedule_node_domain(func) entry = kzalloc(sizeof(struct async_entry), GFP_ATOMIC); /* when fail or work limit, sync to execute func, but __device_attach_async_helper will get lock dev as well, which will lead to A-A deadlock. */ if (!entry || atomic_read(&entry_count) > MAX_WORK) { func; else queue_work_node(node, system_unbound_wq, &entry->work) device_unlock(dev) As shown above, when it is allowed to do async probes, because of out of memory or work limit, async work is not allowed, to do sync execute instead. it will lead to A-A deadlock because of __device_attach_async_helper getting lock dev. To fix the deadlock, move the async_schedule_dev outside device_lock, as we can see, in async_schedule_node_domain, the parameter of queue_work_node is system_unbound_wq, so it can accept concurrent operations. which will also not change the code logic, and will not lead to deadlock.

In the Linux kernel, the following vulnerability has been resolved: PCI: Avoid pci_dev_lock() AB/BA deadlock with sriov_numvfs_store() The sysfs sriov_numvfs_store() path acquires the device lock before the config space access lock: sriov_numvfs_store device_lock # A (1) acquire device lock sriov_configure vfio_pci_sriov_configure # (for example) vfio_pci_core_sriov_configure pci_disable_sriov sriov_disable pci_cfg_access_lock pci_wait_cfg # B (4) wait for dev->block_cfg_access == 0 Previously, pci_dev_lock() acquired the config space access lock before the device lock: pci_dev_lock pci_cfg_access_lock dev->block_cfg_access = 1 # B (2) set dev->block_cfg_access = 1 device_lock # A (3) wait for device lock Any path that uses pci_dev_lock(), e.g., pci_reset_function(), may deadlock with sriov_numvfs_store() if the operations occur in the sequence (1) (2) (3) (4). Avoid the deadlock by reversing the order in pci_dev_lock() so it acquires the device lock before the config space access lock, the same as the sriov_numvfs_store() path. [bhelgaas: combined and adapted commit log from Jay Zhou's independent subsequent posting: https://lore.kernel.org/r/20220404062539.1710-1-jianjay.zhou@huawei.com]

In the Linux kernel, the following vulnerability has been resolved: nvdimm: Fix firmware activation deadlock scenarios Lockdep reports the following deadlock scenarios for CXL root device power-management, device_prepare(), operations, and device_shutdown() operations for 'nd_region' devices: Chain exists of: &nvdimm_region_key --> &nvdimm_bus->reconfig_mutex --> system_transition_mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(system_transition_mutex); lock(&nvdimm_bus->reconfig_mutex); lock(system_transition_mutex); lock(&nvdimm_region_key); Chain exists of: &cxl_nvdimm_bridge_key --> acpi_scan_lock --> &cxl_root_key Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&cxl_root_key); lock(acpi_scan_lock); lock(&cxl_root_key); lock(&cxl_nvdimm_bridge_key); These stem from holding nvdimm_bus_lock() over hibernate_quiet_exec() which walks the entire system device topology taking device_lock() along the way. The nvdimm_bus_lock() is protecting against unregistration, multiple simultaneous ops callers, and preventing activate_show() from racing activate_store(). For the first 2, the lock is redundant. Unregistration already flushes all ops users, and sysfs already prevents multiple threads to be active in an ops handler at the same time. For the last userspace should already be waiting for its last activate_store() to complete, and does not need activate_show() to flush the write side, so this lock usage can be deleted in these attributes.

In the Linux kernel, the following vulnerability has been resolved: media: mediatek: vcodec: prevent kernel crash when rmmod mtk-vcodec-dec.ko If the driver support subdev mode, the parameter "dev->pm.dev" will be NULL in mtk_vcodec_dec_remove. Kernel will crash when try to rmmod mtk-vcodec-dec.ko. [ 4380.702726] pc : do_raw_spin_trylock+0x4/0x80 [ 4380.707075] lr : _raw_spin_lock_irq+0x90/0x14c [ 4380.711509] sp : ffff80000819bc10 [ 4380.714811] x29: ffff80000819bc10 x28: ffff3600c03e4000 x27: 0000000000000000 [ 4380.721934] x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000000000 [ 4380.729057] x23: ffff3600c0f34930 x22: ffffd5e923549000 x21: 0000000000000220 [ 4380.736179] x20: 0000000000000208 x19: ffffd5e9213e8ebc x18: 0000000000000020 [ 4380.743298] x17: 0000002000000000 x16: ffffd5e9213e8e90 x15: 696c346f65646976 [ 4380.750420] x14: 0000000000000000 x13: 0000000000000001 x12: 0000000000000040 [ 4380.757542] x11: 0000000000000000 x10: 0000000000000000 x9 : 0000000000000000 [ 4380.764664] x8 : 0000000000000000 x7 : ffff3600c7273ae8 x6 : ffffd5e9213e8ebc [ 4380.771786] x5 : 0000000000000000 x4 : 0000000000000001 x3 : 0000000000000000 [ 4380.778908] x2 : 0000000000000000 x1 : ffff3600c03e4000 x0 : 0000000000000208 [ 4380.786031] Call trace: [ 4380.788465] do_raw_spin_trylock+0x4/0x80 [ 4380.792462] __pm_runtime_disable+0x2c/0x1b0 [ 4380.796723] mtk_vcodec_dec_remove+0x5c/0xa0 [mtk_vcodec_dec] [ 4380.802466] platform_remove+0x2c/0x60 [ 4380.806204] __device_release_driver+0x194/0x250 [ 4380.810810] driver_detach+0xc8/0x15c [ 4380.814462] bus_remove_driver+0x5c/0xb0 [ 4380.818375] driver_unregister+0x34/0x64 [ 4380.822288] platform_driver_unregister+0x18/0x24 [ 4380.826979] mtk_vcodec_dec_driver_exit+0x1c/0x888 [mtk_vcodec_dec] [ 4380.833240] __arm64_sys_delete_module+0x190/0x224 [ 4380.838020] invoke_syscall+0x48/0x114 [ 4380.841760] el0_svc_common.constprop.0+0x60/0x11c [ 4380.846540] do_el0_svc+0x28/0x90 [ 4380.849844] el0_svc+0x4c/0x100 [ 4380.852975] el0t_64_sync_handler+0xec/0xf0 [ 4380.857148] el0t_64_sync+0x190/0x194 [ 4380.860801] Code: 94431515 17ffffca d503201f d503245f (b9400004)

In the Linux kernel, the following vulnerability has been resolved: loop: implement ->free_disk Ensure that the lo_device which is stored in the gendisk private data is valid until the gendisk is freed. Currently the loop driver uses a lot of effort to make sure a device is not freed when it is still in use, but to to fix a potential deadlock this will be relaxed a bit soon.

In the Linux kernel, the following vulnerability has been resolved: scsi: lpfc: Fix SCSI I/O completion and abort handler deadlock During stress I/O tests with 500+ vports, hard LOCKUP call traces are observed. CPU A: native_queued_spin_lock_slowpath+0x192 _raw_spin_lock_irqsave+0x32 lpfc_handle_fcp_err+0x4c6 lpfc_fcp_io_cmd_wqe_cmpl+0x964 lpfc_sli4_fp_handle_cqe+0x266 __lpfc_sli4_process_cq+0x105 __lpfc_sli4_hba_process_cq+0x3c lpfc_cq_poll_hdler+0x16 irq_poll_softirq+0x76 __softirqentry_text_start+0xe4 irq_exit+0xf7 do_IRQ+0x7f CPU B: native_queued_spin_lock_slowpath+0x5b _raw_spin_lock+0x1c lpfc_abort_handler+0x13e scmd_eh_abort_handler+0x85 process_one_work+0x1a7 worker_thread+0x30 kthread+0x112 ret_from_fork+0x1f Diagram of lockup: CPUA CPUB ---- ---- lpfc_cmd->buf_lock phba->hbalock lpfc_cmd->buf_lock phba->hbalock Fix by reordering the taking of the lpfc_cmd->buf_lock and phba->hbalock in lpfc_abort_handler routine so that it tries to take the lpfc_cmd->buf_lock first before phba->hbalock.

In the Linux kernel, the following vulnerability has been resolved: scsi: lpfc: Move cfg_log_verbose check before calling lpfc_dmp_dbg() In an attempt to log message 0126 with LOG_TRACE_EVENT, the following hard lockup call trace hangs the system. Call Trace: _raw_spin_lock_irqsave+0x32/0x40 lpfc_dmp_dbg.part.32+0x28/0x220 [lpfc] lpfc_cmpl_els_fdisc+0x145/0x460 [lpfc] lpfc_sli_cancel_jobs+0x92/0xd0 [lpfc] lpfc_els_flush_cmd+0x43c/0x670 [lpfc] lpfc_els_flush_all_cmd+0x37/0x60 [lpfc] lpfc_sli4_async_event_proc+0x956/0x1720 [lpfc] lpfc_do_work+0x1485/0x1d70 [lpfc] kthread+0x112/0x130 ret_from_fork+0x1f/0x40 Kernel panic - not syncing: Hard LOCKUP The same CPU tries to claim the phba->port_list_lock twice. Move the cfg_log_verbose checks as part of the lpfc_printf_vlog() and lpfc_printf_log() macros before calling lpfc_dmp_dbg(). There is no need to take the phba->port_list_lock within lpfc_dmp_dbg().

In the Linux kernel, the following vulnerability has been resolved: btrfs: fix deadlock between concurrent dio writes when low on free data space When reserving data space for a direct IO write we can end up deadlocking if we have multiple tasks attempting a write to the same file range, there are multiple extents covered by that file range, we are low on available space for data and the writes don't expand the inode's i_size. The deadlock can happen like this: 1) We have a file with an i_size of 1M, at offset 0 it has an extent with a size of 128K and at offset 128K it has another extent also with a size of 128K; 2) Task A does a direct IO write against file range [0, 256K), and because the write is within the i_size boundary, it takes the inode's lock (VFS level) in shared mode; 3) Task A locks the file range [0, 256K) at btrfs_dio_iomap_begin(), and then gets the extent map for the extent covering the range [0, 128K). At btrfs_get_blocks_direct_write(), it creates an ordered extent for that file range ([0, 128K)); 4) Before returning from btrfs_dio_iomap_begin(), it unlocks the file range [0, 256K); 5) Task A executes btrfs_dio_iomap_begin() again, this time for the file range [128K, 256K), and locks the file range [128K, 256K); 6) Task B starts a direct IO write against file range [0, 256K) as well. It also locks the inode in shared mode, as it's within the i_size limit, and then tries to lock file range [0, 256K). It is able to lock the subrange [0, 128K) but then blocks waiting for the range [128K, 256K), as it is currently locked by task A; 7) Task A enters btrfs_get_blocks_direct_write() and tries to reserve data space. Because we are low on available free space, it triggers the async data reclaim task, and waits for it to reserve data space; 8) The async reclaim task decides to wait for all existing ordered extents to complete (through btrfs_wait_ordered_roots()). It finds the ordered extent previously created by task A for the file range [0, 128K) and waits for it to complete; 9) The ordered extent for the file range [0, 128K) can not complete because it blocks at btrfs_finish_ordered_io() when trying to lock the file range [0, 128K). This results in a deadlock, because: - task B is holding the file range [0, 128K) locked, waiting for the range [128K, 256K) to be unlocked by task A; - task A is holding the file range [128K, 256K) locked and it's waiting for the async data reclaim task to satisfy its space reservation request; - the async data reclaim task is waiting for ordered extent [0, 128K) to complete, but the ordered extent can not complete because the file range [0, 128K) is currently locked by task B, which is waiting on task A to unlock file range [128K, 256K) and task A waiting on the async data reclaim task. This results in a deadlock between 4 task: task A, task B, the async data reclaim task and the task doing ordered extent completion (a work queue task). This type of deadlock can sporadically be triggered by the test case generic/300 from fstests, and results in a stack trace like the following: [12084.033689] INFO: task kworker/u16:7:123749 blocked for more than 241 seconds. [12084.034877] Not tainted 5.18.0-rc2-btrfs-next-115 #1 [12084.035562] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [12084.036548] task:kworker/u16:7 state:D stack: 0 pid:123749 ppid: 2 flags:0x00004000 [12084.036554] Workqueue: btrfs-flush_delalloc btrfs_work_helper [btrfs] [12084.036599] Call Trace: [12084.036601] <TASK> [12084.036606] __schedule+0x3cb/0xed0 [12084.036616] schedule+0x4e/0xb0 [12084.036620] btrfs_start_ordered_extent+0x109/0x1c0 [btrfs] [12084.036651] ? prepare_to_wait_exclusive+0xc0/0xc0 [12084.036659] btrfs_run_ordered_extent_work+0x1a/0x30 [btrfs] [12084.036688] btrfs_work_helper+0xf8/0x400 [btrfs] [12084.0367 ---truncated---

In the Linux kernel, the following vulnerability has been resolved: ixgbe: Add locking to prevent panic when setting sriov_numvfs to zero It is possible to disable VFs while the PF driver is processing requests from the VF driver. This can result in a panic. BUG: unable to handle kernel paging request at 000000000000106c PGD 0 P4D 0 Oops: 0000 [#1] SMP NOPTI CPU: 8 PID: 0 Comm: swapper/8 Kdump: loaded Tainted: G I --------- - Hardware name: Dell Inc. PowerEdge R740/06WXJT, BIOS 2.8.2 08/27/2020 RIP: 0010:ixgbe_msg_task+0x4c8/0x1690 [ixgbe] Code: 00 00 48 8d 04 40 48 c1 e0 05 89 7c 24 24 89 fd 48 89 44 24 10 83 ff 01 0f 84 b8 04 00 00 4c 8b 64 24 10 4d 03 a5 48 22 00 00 <41> 80 7c 24 4c 00 0f 84 8a 03 00 00 0f b7 c7 83 f8 08 0f 84 8f 0a RSP: 0018:ffffb337869f8df8 EFLAGS: 00010002 RAX: 0000000000001020 RBX: 0000000000000000 RCX: 000000000000002b RDX: 0000000000000002 RSI: 0000000000000008 RDI: 0000000000000006 RBP: 0000000000000006 R08: 0000000000000002 R09: 0000000000029780 R10: 00006957d8f42832 R11: 0000000000000000 R12: 0000000000001020 R13: ffff8a00e8978ac0 R14: 000000000000002b R15: ffff8a00e8979c80 FS: 0000000000000000(0000) GS:ffff8a07dfd00000(0000) knlGS:00000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000000106c CR3: 0000000063e10004 CR4: 00000000007726e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: <IRQ> ? ttwu_do_wakeup+0x19/0x140 ? try_to_wake_up+0x1cd/0x550 ? ixgbevf_update_xcast_mode+0x71/0xc0 [ixgbevf] ixgbe_msix_other+0x17e/0x310 [ixgbe] __handle_irq_event_percpu+0x40/0x180 handle_irq_event_percpu+0x30/0x80 handle_irq_event+0x36/0x53 handle_edge_irq+0x82/0x190 handle_irq+0x1c/0x30 do_IRQ+0x49/0xd0 common_interrupt+0xf/0xf This can be eventually be reproduced with the following script: while : do echo 63 > /sys/class/net/<devname>/device/sriov_numvfs sleep 1 echo 0 > /sys/class/net/<devname>/device/sriov_numvfs sleep 1 done Add lock when disabling SR-IOV to prevent process VF mailbox communication.

In the Linux kernel, the following vulnerability has been resolved: RDMA/irdma: Fix sleep from invalid context BUG Taking the qos_mutex to process RoCEv2 QP's on netdev events causes a kernel splat. Fix this by removing the handling for RoCEv2 in irdma_cm_teardown_connections that uses the mutex. This handling is only needed for iWARP to avoid having connections established while the link is down or having connections remain functional after the IP address is removed. BUG: sleeping function called from invalid context at kernel/locking/mutex. Call Trace: kernel: dump_stack+0x66/0x90 kernel: ___might_sleep.cold.92+0x8d/0x9a kernel: mutex_lock+0x1c/0x40 kernel: irdma_cm_teardown_connections+0x28e/0x4d0 [irdma] kernel: ? check_preempt_curr+0x7a/0x90 kernel: ? select_idle_sibling+0x22/0x3c0 kernel: ? select_task_rq_fair+0x94c/0xc90 kernel: ? irdma_exec_cqp_cmd+0xc27/0x17c0 [irdma] kernel: ? __wake_up_common+0x7a/0x190 kernel: irdma_if_notify+0x3cc/0x450 [irdma] kernel: ? sched_clock_cpu+0xc/0xb0 kernel: irdma_inet6addr_event+0xc6/0x150 [irdma]

In the Linux kernel, the following vulnerability has been resolved: VMCI: Use threaded irqs instead of tasklets The vmci_dispatch_dgs() tasklet function calls vmci_read_data() which uses wait_event() resulting in invalid sleep in an atomic context (and therefore potentially in a deadlock). Use threaded irqs to fix this issue and completely remove usage of tasklets. [ 20.264639] BUG: sleeping function called from invalid context at drivers/misc/vmw_vmci/vmci_guest.c:145 [ 20.264643] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 762, name: vmtoolsd [ 20.264645] preempt_count: 101, expected: 0 [ 20.264646] RCU nest depth: 0, expected: 0 [ 20.264647] 1 lock held by vmtoolsd/762: [ 20.264648] #0: ffff0000874ae440 (sk_lock-AF_VSOCK){+.+.}-{0:0}, at: vsock_connect+0x60/0x330 [vsock] [ 20.264658] Preemption disabled at: [ 20.264659] [<ffff80000151d7d8>] vmci_send_datagram+0x44/0xa0 [vmw_vmci] [ 20.264665] CPU: 0 PID: 762 Comm: vmtoolsd Not tainted 5.19.0-0.rc8.20220727git39c3c396f813.60.fc37.aarch64 #1 [ 20.264667] Hardware name: VMware, Inc. VBSA/VBSA, BIOS VEFI 12/31/2020 [ 20.264668] Call trace: [ 20.264669] dump_backtrace+0xc4/0x130 [ 20.264672] show_stack+0x24/0x80 [ 20.264673] dump_stack_lvl+0x88/0xb4 [ 20.264676] dump_stack+0x18/0x34 [ 20.264677] __might_resched+0x1a0/0x280 [ 20.264679] __might_sleep+0x58/0x90 [ 20.264681] vmci_read_data+0x74/0x120 [vmw_vmci] [ 20.264683] vmci_dispatch_dgs+0x64/0x204 [vmw_vmci] [ 20.264686] tasklet_action_common.constprop.0+0x13c/0x150 [ 20.264688] tasklet_action+0x40/0x50 [ 20.264689] __do_softirq+0x23c/0x6b4 [ 20.264690] __irq_exit_rcu+0x104/0x214 [ 20.264691] irq_exit_rcu+0x1c/0x50 [ 20.264693] el1_interrupt+0x38/0x6c [ 20.264695] el1h_64_irq_handler+0x18/0x24 [ 20.264696] el1h_64_irq+0x68/0x6c [ 20.264697] preempt_count_sub+0xa4/0xe0 [ 20.264698] _raw_spin_unlock_irqrestore+0x64/0xb0 [ 20.264701] vmci_send_datagram+0x7c/0xa0 [vmw_vmci] [ 20.264703] vmci_datagram_dispatch+0x84/0x100 [vmw_vmci] [ 20.264706] vmci_datagram_send+0x2c/0x40 [vmw_vmci] [ 20.264709] vmci_transport_send_control_pkt+0xb8/0x120 [vmw_vsock_vmci_transport] [ 20.264711] vmci_transport_connect+0x40/0x7c [vmw_vsock_vmci_transport] [ 20.264713] vsock_connect+0x278/0x330 [vsock] [ 20.264715] __sys_connect_file+0x8c/0xc0 [ 20.264718] __sys_connect+0x84/0xb4 [ 20.264720] __arm64_sys_connect+0x2c/0x3c [ 20.264721] invoke_syscall+0x78/0x100 [ 20.264723] el0_svc_common.constprop.0+0x68/0x124 [ 20.264724] do_el0_svc+0x38/0x4c [ 20.264725] el0_svc+0x60/0x180 [ 20.264726] el0t_64_sync_handler+0x11c/0x150 [ 20.264728] el0t_64_sync+0x190/0x194

In the Linux kernel, the following vulnerability has been resolved: 9p: trans_fd/p9_conn_cancel: drop client lock earlier syzbot reported a double-lock here and we no longer need this lock after requests have been moved off to local list: just drop the lock earlier.

In the Linux kernel, the following vulnerability has been resolved: USB: gadget: Fix obscure lockdep violation for udc_mutex A recent commit expanding the scope of the udc_lock mutex in the gadget core managed to cause an obscure and slightly bizarre lockdep violation. In abbreviated form: ====================================================== WARNING: possible circular locking dependency detected 5.19.0-rc7+ #12510 Not tainted ------------------------------------------------------ udevadm/312 is trying to acquire lock: ffff80000aae1058 (udc_lock){+.+.}-{3:3}, at: usb_udc_uevent+0x54/0xe0 but task is already holding lock: ffff000002277548 (kn->active#4){++++}-{0:0}, at: kernfs_seq_start+0x34/0xe0 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (kn->active#4){++++}-{0:0}:        lock_acquire+0x68/0x84        __kernfs_remove+0x268/0x380        kernfs_remove_by_name_ns+0x58/0xac        sysfs_remove_file_ns+0x18/0x24        device_del+0x15c/0x440 -> #2 (device_links_lock){+.+.}-{3:3}:        lock_acquire+0x68/0x84        __mutex_lock+0x9c/0x430        mutex_lock_nested+0x38/0x64        device_link_remove+0x3c/0xa0        _regulator_put.part.0+0x168/0x190        regulator_put+0x3c/0x54        devm_regulator_release+0x14/0x20 -> #1 (regulator_list_mutex){+.+.}-{3:3}:        lock_acquire+0x68/0x84        __mutex_lock+0x9c/0x430        mutex_lock_nested+0x38/0x64        regulator_lock_dependent+0x54/0x284        regulator_enable+0x34/0x80        phy_power_on+0x24/0x130        __dwc2_lowlevel_hw_enable+0x100/0x130        dwc2_lowlevel_hw_enable+0x18/0x40        dwc2_hsotg_udc_start+0x6c/0x2f0        gadget_bind_driver+0x124/0x1f4 -> #0 (udc_lock){+.+.}-{3:3}:        __lock_acquire+0x1298/0x20cc        lock_acquire.part.0+0xe0/0x230        lock_acquire+0x68/0x84        __mutex_lock+0x9c/0x430        mutex_lock_nested+0x38/0x64        usb_udc_uevent+0x54/0xe0 Evidently this was caused by the scope of udc_mutex being too large. The mutex is only meant to protect udc->driver along with a few other things. As far as I can tell, there's no reason for the mutex to be held while the gadget core calls a gadget driver's ->bind or ->unbind routine, or while a UDC is being started or stopped. (This accounts for link #1 in the chain above, where the mutex is held while the dwc2_hsotg_udc is started as part of driver probing.) Gadget drivers' ->disconnect callbacks are problematic. Even though usb_gadget_disconnect() will now acquire the udc_mutex, there's a window in usb_gadget_bind_driver() between the times when the mutex is released and the ->bind callback is invoked. If a disconnect occurred during that window, we could call the driver's ->disconnect routine before its ->bind routine. To prevent this from happening, it will be necessary to prevent a UDC from connecting while it has no gadget driver. This should be done already but it doesn't seem to be; currently usb_gadget_connect() has no check for this. Such a check will have to be added later. Some degree of mutual exclusion is required in soft_connect_store(), which can dereference udc->driver at arbitrary times since it is a sysfs callback. The solution here is to acquire the gadget's device lock rather than the udc_mutex. Since the driver core guarantees that the device lock is always held during driver binding and unbinding, this will make the accesses in soft_connect_store() mutually exclusive with any changes to udc->driver. Lastly, it turns out there is one place which should hold the udc_mutex but currently does not: The function_show() routine needs protection while it dereferences udc->driver. The missing lock and unlock calls are added.

In the Linux kernel, the following vulnerability has been resolved: powerpc/pci: Fix get_phb_number() locking The recent change to get_phb_number() causes a DEBUG_ATOMIC_SLEEP warning on some systems: BUG: sleeping function called from invalid context at kernel/locking/mutex.c:580 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 1, name: swapper preempt_count: 1, expected: 0 RCU nest depth: 0, expected: 0 1 lock held by swapper/1: #0: c157efb0 (hose_spinlock){+.+.}-{2:2}, at: pcibios_alloc_controller+0x64/0x220 Preemption disabled at: [<00000000>] 0x0 CPU: 0 PID: 1 Comm: swapper Not tainted 5.19.0-yocto-standard+ #1 Call Trace: [d101dc90] [c073b264] dump_stack_lvl+0x50/0x8c (unreliable) [d101dcb0] [c0093b70] __might_resched+0x258/0x2a8 [d101dcd0] [c0d3e634] __mutex_lock+0x6c/0x6ec [d101dd50] [c0a84174] of_alias_get_id+0x50/0xf4 [d101dd80] [c002ec78] pcibios_alloc_controller+0x1b8/0x220 [d101ddd0] [c140c9dc] pmac_pci_init+0x198/0x784 [d101de50] [c140852c] discover_phbs+0x30/0x4c [d101de60] [c0007fd4] do_one_initcall+0x94/0x344 [d101ded0] [c1403b40] kernel_init_freeable+0x1a8/0x22c [d101df10] [c00086e0] kernel_init+0x34/0x160 [d101df30] [c001b334] ret_from_kernel_thread+0x5c/0x64 This is because pcibios_alloc_controller() holds hose_spinlock but of_alias_get_id() takes of_mutex which can sleep. The hose_spinlock protects the phb_bitmap, and also the hose_list, but it doesn't need to be held while get_phb_number() calls the OF routines, because those are only looking up information in the device tree. So fix it by having get_phb_number() take the hose_spinlock itself, only where required, and then dropping the lock before returning. pcibios_alloc_controller() then needs to take the lock again before the list_add() but that's safe, the order of the list is not important.

In the Linux kernel, the following vulnerability has been resolved: f2fs: initialize locks earlier in f2fs_fill_super() syzbot is reporting lockdep warning at f2fs_handle_error() [1], for spin_lock(&sbi->error_lock) is called before spin_lock_init() is called. For safe locking in error handling, move initialization of locks (and obvious structures) in f2fs_fill_super() to immediately after memory allocation.

In the Linux kernel, the following vulnerability has been resolved: drivers: staging: rtl8192eu: Fix deadlock in rtw_joinbss_event_prehandle There is a deadlock in rtw_joinbss_event_prehandle(), which is shown below: (Thread 1) | (Thread 2) | _set_timer() rtw_joinbss_event_prehandle()| mod_timer() spin_lock_bh() //(1) | (wait a time) ... | rtw_join_timeout_handler() | _rtw_join_timeout_handler() del_timer_sync() | spin_lock_bh() //(2) (wait timer to stop) | ... We hold pmlmepriv->lock in position (1) of thread 1 and use del_timer_sync() to wait timer to stop, but timer handler also need pmlmepriv->lock in position (2) of thread 2. As a result, rtw_joinbss_event_prehandle() will block forever. This patch extracts del_timer_sync() from the protection of spin_lock_bh(), which could let timer handler to obtain the needed lock. What`s more, we change spin_lock_bh() to spin_lock_irq() in _rtw_join_timeout_handler() in order to prevent deadlock.

In the Linux kernel, the following vulnerability has been resolved: drivers: staging: rtl8192bs: Fix deadlock in rtw_joinbss_event_prehandle() There is a deadlock in rtw_joinbss_event_prehandle(), which is shown below: (Thread 1) | (Thread 2) | _set_timer() rtw_joinbss_event_prehandle()| mod_timer() spin_lock_bh() //(1) | (wait a time) ... | _rtw_join_timeout_handler() del_timer_sync() | spin_lock_bh() //(2) (wait timer to stop) | ... We hold pmlmepriv->lock in position (1) of thread 1 and use del_timer_sync() to wait timer to stop, but timer handler also need pmlmepriv->lock in position (2) of thread 2. As a result, rtw_joinbss_event_prehandle() will block forever. This patch extracts del_timer_sync() from the protection of spin_lock_bh(), which could let timer handler to obtain the needed lock. What`s more, we change spin_lock_bh() to spin_lock_irq() in _rtw_join_timeout_handler() in order to prevent deadlock.

In the Linux kernel, the following vulnerability has been resolved: net/9p: use a dedicated spinlock for trans_fd Shamelessly copying the explanation from Tetsuo Handa's suggested patch[1] (slightly reworded): syzbot is reporting inconsistent lock state in p9_req_put()[2], for p9_tag_remove() from p9_req_put() from IRQ context is using spin_lock_irqsave() on "struct p9_client"->lock but trans_fd (not from IRQ context) is using spin_lock(). Since the locks actually protect different things in client.c and in trans_fd.c, just replace trans_fd.c's lock by a new one specific to the transport (client.c's protect the idr for fid/tag allocations, while trans_fd.c's protects its own req list and request status field that acts as the transport's state machine)

In the Linux kernel, the following vulnerability has been resolved: NFSv4: Don't hold the layoutget locks across multiple RPC calls When doing layoutget as part of the open() compound, we have to be careful to release the layout locks before we can call any further RPC calls, such as setattr(). The reason is that those calls could trigger a recall, which could deadlock.