In the Linux kernel, the following vulnerability has been resolved: nbd: call genl_unregister_family() first in nbd_cleanup() Otherwise there may be race between module removal and the handling of netlink command, which can lead to the oops as shown below: BUG: kernel NULL pointer dereference, address: 0000000000000098 Oops: 0002 [#1] SMP PTI CPU: 1 PID: 31299 Comm: nbd-client Tainted: G E 5.14.0-rc4 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) RIP: 0010:down_write+0x1a/0x50 Call Trace: start_creating+0x89/0x130 debugfs_create_dir+0x1b/0x130 nbd_start_device+0x13d/0x390 [nbd] nbd_genl_connect+0x42f/0x748 [nbd] genl_family_rcv_msg_doit.isra.0+0xec/0x150 genl_rcv_msg+0xe5/0x1e0 netlink_rcv_skb+0x55/0x100 genl_rcv+0x29/0x40 netlink_unicast+0x1a8/0x250 netlink_sendmsg+0x21b/0x430 ____sys_sendmsg+0x2a4/0x2d0 ___sys_sendmsg+0x81/0xc0 __sys_sendmsg+0x62/0xb0 __x64_sys_sendmsg+0x1f/0x30 do_syscall_64+0x3b/0xc0 entry_SYSCALL_64_after_hwframe+0x44/0xae Modules linked in: nbd(E-)

In the Linux kernel, the following vulnerability has been resolved: rxrpc: Fix call timer start racing with call destruction The rxrpc_call struct has a timer used to handle various timed events relating to a call. This timer can get started from the packet input routines that are run in softirq mode with just the RCU read lock held. Unfortunately, because only the RCU read lock is held - and neither ref or other lock is taken - the call can start getting destroyed at the same time a packet comes in addressed to that call. This causes the timer - which was already stopped - to get restarted. Later, the timer dispatch code may then oops if the timer got deallocated first. Fix this by trying to take a ref on the rxrpc_call struct and, if successful, passing that ref along to the timer. If the timer was already running, the ref is discarded. The timer completion routine can then pass the ref along to the call's work item when it queues it. If the timer or work item where already queued/running, the extra ref is discarded.

In the Linux kernel, the following vulnerability has been resolved: ice: fix concurrent reset and removal of VFs Commit c503e63200c6 ("ice: Stop processing VF messages during teardown") introduced a driver state flag, ICE_VF_DEINIT_IN_PROGRESS, which is intended to prevent some issues with concurrently handling messages from VFs while tearing down the VFs. This change was motivated by crashes caused while tearing down and bringing up VFs in rapid succession. It turns out that the fix actually introduces issues with the VF driver caused because the PF no longer responds to any messages sent by the VF during its .remove routine. This results in the VF potentially removing its DMA memory before the PF has shut down the device queues. Additionally, the fix doesn't actually resolve concurrency issues within the ice driver. It is possible for a VF to initiate a reset just prior to the ice driver removing VFs. This can result in the remove task concurrently operating while the VF is being reset. This results in similar memory corruption and panics purportedly fixed by that commit. Fix this concurrency at its root by protecting both the reset and removal flows using the existing VF cfg_lock. This ensures that we cannot remove the VF while any outstanding critical tasks such as a virtchnl message or a reset are occurring. This locking change also fixes the root cause originally fixed by commit c503e63200c6 ("ice: Stop processing VF messages during teardown"), so we can simply revert it. Note that I kept these two changes together because simply reverting the original commit alone would leave the driver vulnerable to worse race conditions.

In the Linux kernel, the following vulnerability has been resolved: net/smc: Transitional solution for clcsock race issue We encountered a crash in smc_setsockopt() and it is caused by accessing smc->clcsock after clcsock was released. BUG: kernel NULL pointer dereference, address: 0000000000000020 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP PTI CPU: 1 PID: 50309 Comm: nginx Kdump: loaded Tainted: G E 5.16.0-rc4+ #53 RIP: 0010:smc_setsockopt+0x59/0x280 [smc] Call Trace: <TASK> __sys_setsockopt+0xfc/0x190 __x64_sys_setsockopt+0x20/0x30 do_syscall_64+0x34/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f16ba83918e </TASK> This patch tries to fix it by holding clcsock_release_lock and checking whether clcsock has already been released before access. In case that a crash of the same reason happens in smc_getsockopt() or smc_switch_to_fallback(), this patch also checkes smc->clcsock in them too. And the caller of smc_switch_to_fallback() will identify whether fallback succeeds according to the return value.

In the Linux kernel, the following vulnerability has been resolved: xsk: Fix race at socket teardown Fix a race in the xsk socket teardown code that can lead to a NULL pointer dereference splat. The current xsk unbind code in xsk_unbind_dev() starts by setting xs->state to XSK_UNBOUND, sets xs->dev to NULL and then waits for any NAPI processing to terminate using synchronize_net(). After that, the release code starts to tear down the socket state and free allocated memory. BUG: kernel NULL pointer dereference, address: 00000000000000c0 PGD 8000000932469067 P4D 8000000932469067 PUD 0 Oops: 0000 [#1] PREEMPT SMP PTI CPU: 25 PID: 69132 Comm: grpcpp_sync_ser Tainted: G I 5.16.0+ #2 Hardware name: Dell Inc. PowerEdge R730/0599V5, BIOS 1.2.10 03/09/2015 RIP: 0010:__xsk_sendmsg+0x2c/0x690 [...] RSP: 0018:ffffa2348bd13d50 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000040 RCX: ffff8d5fc632d258 RDX: 0000000000400000 RSI: ffffa2348bd13e10 RDI: ffff8d5fc5489800 RBP: ffffa2348bd13db0 R08: 0000000000000000 R09: 00007ffffffff000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff8d5fc5489800 R13: ffff8d5fcb0f5140 R14: ffff8d5fcb0f5140 R15: 0000000000000000 FS: 00007f991cff9400(0000) GS:ffff8d6f1f700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000000000c0 CR3: 0000000114888005 CR4: 00000000001706e0 Call Trace: <TASK> ? aa_sk_perm+0x43/0x1b0 xsk_sendmsg+0xf0/0x110 sock_sendmsg+0x65/0x70 __sys_sendto+0x113/0x190 ? debug_smp_processor_id+0x17/0x20 ? fpregs_assert_state_consistent+0x23/0x50 ? exit_to_user_mode_prepare+0xa5/0x1d0 __x64_sys_sendto+0x29/0x30 do_syscall_64+0x3b/0xc0 entry_SYSCALL_64_after_hwframe+0x44/0xae There are two problems with the current code. First, setting xs->dev to NULL before waiting for all users to stop using the socket is not correct. The entry to the data plane functions xsk_poll(), xsk_sendmsg(), and xsk_recvmsg() are all guarded by a test that xs->state is in the state XSK_BOUND and if not, it returns right away. But one process might have passed this test but still have not gotten to the point in which it uses xs->dev in the code. In this interim, a second process executing xsk_unbind_dev() might have set xs->dev to NULL which will lead to a crash for the first process. The solution here is just to get rid of this NULL assignment since it is not used anymore. Before commit 42fddcc7c64b ("xsk: use state member for socket synchronization"), xs->dev was the gatekeeper to admit processes into the data plane functions, but it was replaced with the state variable xs->state in the aforementioned commit. The second problem is that synchronize_net() does not wait for any process in xsk_poll(), xsk_sendmsg(), or xsk_recvmsg() to complete, which means that the state they rely on might be cleaned up prematurely. This can happen when the notifier gets called (at driver unload for example) as it uses xsk_unbind_dev(). Solve this by extending the RCU critical region from just the ndo_xsk_wakeup to the whole functions mentioned above, so that both the test of xs->state == XSK_BOUND and the last use of any member of xs is covered by the RCU critical section. This will guarantee that when synchronize_net() completes, there will be no processes left executing xsk_poll(), xsk_sendmsg(), or xsk_recvmsg() and state can be cleaned up safely. Note that we need to drop the RCU lock for the skb xmit path as it uses functions that might sleep. Due to this, we have to retest the xs->state after we grab the mutex that protects the skb xmit code from, among a number of things, an xsk_unbind_dev() being executed from the notifier at the same time.

In the Linux kernel, the following vulnerability has been resolved: XArray: Fix xas_create_range() when multi-order entry present If there is already an entry present that is of order >= XA_CHUNK_SHIFT when we call xas_create_range(), xas_create_range() will misinterpret that entry as a node and dereference xa_node->parent, generally leading to a crash that looks something like this: general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f] CPU: 0 PID: 32 Comm: khugepaged Not tainted 5.17.0-rc8-syzkaller-00003-g56e337f2cf13 #0 RIP: 0010:xa_parent_locked include/linux/xarray.h:1207 [inline] RIP: 0010:xas_create_range+0x2d9/0x6e0 lib/xarray.c:725 It's deterministically reproducable once you know what the problem is, but producing it in a live kernel requires khugepaged to hit a race. While the problem has been present since xas_create_range() was introduced, I'm not aware of a way to hit it before the page cache was converted to use multi-index entries.

In the Linux kernel, the following vulnerability has been resolved: drm/msm/dp: do not complete dp_aux_cmd_fifo_tx() if irq is not for aux transfer There are 3 possible interrupt sources are handled by DP controller, HPDstatus, Controller state changes and Aux read/write transaction. At every irq, DP controller have to check isr status of every interrupt sources and service the interrupt if its isr status bits shows interrupts are pending. There is potential race condition may happen at current aux isr handler implementation since it is always complete dp_aux_cmd_fifo_tx() even irq is not for aux read or write transaction. This may cause aux read transaction return premature if host aux data read is in the middle of waiting for sink to complete transferring data to host while irq happen. This will cause host's receiving buffer contains unexpected data. This patch fixes this problem by checking aux isr and return immediately at aux isr handler if there are no any isr status bits set. Current there is a bug report regrading eDP edid corruption happen during system booting up. After lengthy debugging to found that VIDEO_READY interrupt was continuously firing during system booting up which cause dp_aux_isr() to complete dp_aux_cmd_fifo_tx() prematurely to retrieve data from aux hardware buffer which is not yet contains complete data transfer from sink. This cause edid corruption. Follows are the signature at kernel logs when problem happen, EDID has corrupt header panel-simple-dp-aux aux-aea0000.edp: Couldn't identify panel via EDID Changes in v2: -- do complete if (ret == IRQ_HANDLED) ay dp-aux_isr() -- add more commit text Changes in v3: -- add Stephen suggested -- dp_aux_isr() return IRQ_XXX back to caller -- dp_ctrl_isr() return IRQ_XXX back to caller Changes in v4: -- split into two patches Changes in v5: -- delete empty line between tags Changes in v6: -- remove extra "that" and fixed line more than 75 char at commit text Patchwork: https://patchwork.freedesktop.org/patch/516121/

In the Linux kernel, the following vulnerability has been resolved: net/mlx5: Use del_timer_sync in fw reset flow of halting poll Substitute del_timer() with del_timer_sync() in fw reset polling deactivation flow, in order to prevent a race condition which occurs when del_timer() is called and timer is deactivated while another process is handling the timer interrupt. A situation that led to the following call trace: RIP: 0010:run_timer_softirq+0x137/0x420 <IRQ> recalibrate_cpu_khz+0x10/0x10 ktime_get+0x3e/0xa0 ? sched_clock_cpu+0xb/0xc0 __do_softirq+0xf5/0x2ea irq_exit_rcu+0xc1/0xf0 sysvec_apic_timer_interrupt+0x9e/0xc0 asm_sysvec_apic_timer_interrupt+0x12/0x20 </IRQ>

In the Linux kernel, the following vulnerability has been resolved: tpm: use try_get_ops() in tpm-space.c As part of the series conversion to remove nested TPM operations: https://lore.kernel.org/all/20190205224723.19671-1-jarkko.sakkinen@linux.intel.com/ exposure of the chip->tpm_mutex was removed from much of the upper level code. In this conversion, tpm2_del_space() was missed. This didn't matter much because it's usually called closely after a converted operation, so there's only a very tiny race window where the chip can be removed before the space flushing is done which causes a NULL deref on the mutex. However, there are reports of this window being hit in practice, so fix this by converting tpm2_del_space() to use tpm_try_get_ops(), which performs all the teardown checks before acquring the mutex.

In the Linux kernel, the following vulnerability has been resolved: IB/rdmavt: add lock to call to rvt_error_qp to prevent a race condition The documentation of the function rvt_error_qp says both r_lock and s_lock need to be held when calling that function. It also asserts using lockdep that both of those locks are held. However, the commit I referenced in Fixes accidentally makes the call to rvt_error_qp in rvt_ruc_loopback no longer covered by r_lock. This results in the lockdep assertion failing and also possibly in a race condition.

Race condition in the ioctl_send_fib function in drivers/scsi/aacraid/commctrl.c in the Linux kernel through 4.7 allows local users to cause a denial of service (out-of-bounds access or system crash) by changing a certain size value, aka a "double fetch" vulnerability.

In the Linux kernel, the following vulnerability has been resolved: media: i2c: tc358743: Fix crash in the probe error path when using polling If an error occurs in the probe() function, we should remove the polling timer that was alarmed earlier, otherwise the timer is called with arguments that are already freed, which results in a crash. ------------[ cut here ]------------ WARNING: CPU: 3 PID: 0 at kernel/time/timer.c:1830 __run_timers+0x244/0x268 Modules linked in: CPU: 3 UID: 0 PID: 0 Comm: swapper/3 Not tainted 6.11.0 #226 Hardware name: Diasom DS-RK3568-SOM-EVB (DT) pstate: 804000c9 (Nzcv daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : __run_timers+0x244/0x268 lr : __run_timers+0x1d4/0x268 sp : ffffff80eff2baf0 x29: ffffff80eff2bb50 x28: 7fffffffffffffff x27: ffffff80eff2bb00 x26: ffffffc080f669c0 x25: ffffff80efef6bf0 x24: ffffff80eff2bb00 x23: 0000000000000000 x22: dead000000000122 x21: 0000000000000000 x20: ffffff80efef6b80 x19: ffffff80041c8bf8 x18: ffffffffffffffff x17: ffffffc06f146000 x16: ffffff80eff27dc0 x15: 000000000000003e x14: 0000000000000000 x13: 00000000000054da x12: 0000000000000000 x11: 00000000000639c0 x10: 000000000000000c x9 : 0000000000000009 x8 : ffffff80eff2cb40 x7 : ffffff80eff2cb40 x6 : ffffff8002bee480 x5 : ffffffc080cb2220 x4 : ffffffc080cb2150 x3 : 00000000000f4240 x2 : 0000000000000102 x1 : ffffff80eff2bb00 x0 : ffffff80041c8bf0 Call trace:  __run_timers+0x244/0x268  timer_expire_remote+0x50/0x68  tmigr_handle_remote+0x388/0x39c  run_timer_softirq+0x38/0x44  handle_softirqs+0x138/0x298  __do_softirq+0x14/0x20  ____do_softirq+0x10/0x1c  call_on_irq_stack+0x24/0x4c  do_softirq_own_stack+0x1c/0x2c  irq_exit_rcu+0x9c/0xcc  el1_interrupt+0x48/0xc0  el1h_64_irq_handler+0x18/0x24  el1h_64_irq+0x7c/0x80  default_idle_call+0x34/0x68  do_idle+0x23c/0x294  cpu_startup_entry+0x38/0x3c  secondary_start_kernel+0x128/0x160  __secondary_switched+0xb8/0xbc ---[ end trace 0000000000000000 ]---

An issue was discovered in the Linux kernel through 6.0.9. drivers/media/usb/ttusb-dec/ttusb_dec.c has a memory leak because of the lack of a dvb_frontend_detach call.

The netfilter subsystem in the Linux kernel through 4.15.7 mishandles the case of a rule blob that contains a jump but lacks a user-defined chain, which allows local users to cause a denial of service (NULL pointer dereference) by leveraging the CAP_NET_RAW or CAP_NET_ADMIN capability, related to arpt_do_table in net/ipv4/netfilter/arp_tables.c, ipt_do_table in net/ipv4/netfilter/ip_tables.c, and ip6t_do_table in net/ipv6/netfilter/ip6_tables.c.

In the Linux kernel, the following vulnerability has been resolved: perf/x86/amd: Fix crash due to race between amd_pmu_enable_all, perf NMI and throttling amd_pmu_enable_all() does: if (!test_bit(idx, cpuc->active_mask)) continue; amd_pmu_enable_event(cpuc->events[idx]); A perf NMI of another event can come between these two steps. Perf NMI handler internally disables and enables _all_ events, including the one which nmi-intercepted amd_pmu_enable_all() was in process of enabling. If that unintentionally enabled event has very low sampling period and causes immediate successive NMI, causing the event to be throttled, cpuc->events[idx] and cpuc->active_mask gets cleared by x86_pmu_stop(). This will result in amd_pmu_enable_event() getting called with event=NULL when amd_pmu_enable_all() resumes after handling the NMIs. This causes a kernel crash: BUG: kernel NULL pointer dereference, address: 0000000000000198 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page [...] Call Trace: <TASK> amd_pmu_enable_all+0x68/0xb0 ctx_resched+0xd9/0x150 event_function+0xb8/0x130 ? hrtimer_start_range_ns+0x141/0x4a0 ? perf_duration_warn+0x30/0x30 remote_function+0x4d/0x60 __flush_smp_call_function_queue+0xc4/0x500 flush_smp_call_function_queue+0x11d/0x1b0 do_idle+0x18f/0x2d0 cpu_startup_entry+0x19/0x20 start_secondary+0x121/0x160 secondary_startup_64_no_verify+0xe5/0xeb </TASK> amd_pmu_disable_all()/amd_pmu_enable_all() calls inside perf NMI handler were recently added as part of BRS enablement but I'm not sure whether we really need them. We can just disable BRS in the beginning and enable it back while returning from NMI. This will solve the issue by not enabling those events whose active_masks are set but are not yet enabled in hw pmu.

In the Linux kernel, the following vulnerability has been resolved: rcu-tasks: Fix race in schedule and flush work While booting secondary CPUs, cpus_read_[lock/unlock] is not keeping online cpumask stable. The transient online mask results in below calltrace. [ 0.324121] CPU1: Booted secondary processor 0x0000000001 [0x410fd083] [ 0.346652] Detected PIPT I-cache on CPU2 [ 0.347212] CPU2: Booted secondary processor 0x0000000002 [0x410fd083] [ 0.377255] Detected PIPT I-cache on CPU3 [ 0.377823] CPU3: Booted secondary processor 0x0000000003 [0x410fd083] [ 0.379040] ------------[ cut here ]------------ [ 0.383662] WARNING: CPU: 0 PID: 10 at kernel/workqueue.c:3084 __flush_work+0x12c/0x138 [ 0.384850] Modules linked in: [ 0.385403] CPU: 0 PID: 10 Comm: rcu_tasks_rude_ Not tainted 5.17.0-rc3-v8+ #13 [ 0.386473] Hardware name: Raspberry Pi 4 Model B Rev 1.4 (DT) [ 0.387289] pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 0.388308] pc : __flush_work+0x12c/0x138 [ 0.388970] lr : __flush_work+0x80/0x138 [ 0.389620] sp : ffffffc00aaf3c60 [ 0.390139] x29: ffffffc00aaf3d20 x28: ffffffc009c16af0 x27: ffffff80f761df48 [ 0.391316] x26: 0000000000000004 x25: 0000000000000003 x24: 0000000000000100 [ 0.392493] x23: ffffffffffffffff x22: ffffffc009c16b10 x21: ffffffc009c16b28 [ 0.393668] x20: ffffffc009e53861 x19: ffffff80f77fbf40 x18: 00000000d744fcc9 [ 0.394842] x17: 000000000000000b x16: 00000000000001c2 x15: ffffffc009e57550 [ 0.396016] x14: 0000000000000000 x13: ffffffffffffffff x12: 0000000100000000 [ 0.397190] x11: 0000000000000462 x10: ffffff8040258008 x9 : 0000000100000000 [ 0.398364] x8 : 0000000000000000 x7 : ffffffc0093c8bf4 x6 : 0000000000000000 [ 0.399538] x5 : 0000000000000000 x4 : ffffffc00a976e40 x3 : ffffffc00810444c [ 0.400711] x2 : 0000000000000004 x1 : 0000000000000000 x0 : 0000000000000000 [ 0.401886] Call trace: [ 0.402309] __flush_work+0x12c/0x138 [ 0.402941] schedule_on_each_cpu+0x228/0x278 [ 0.403693] rcu_tasks_rude_wait_gp+0x130/0x144 [ 0.404502] rcu_tasks_kthread+0x220/0x254 [ 0.405264] kthread+0x174/0x1ac [ 0.405837] ret_from_fork+0x10/0x20 [ 0.406456] irq event stamp: 102 [ 0.406966] hardirqs last enabled at (101): [<ffffffc0093c8468>] _raw_spin_unlock_irq+0x78/0xb4 [ 0.408304] hardirqs last disabled at (102): [<ffffffc0093b8270>] el1_dbg+0x24/0x5c [ 0.409410] softirqs last enabled at (54): [<ffffffc0081b80c8>] local_bh_enable+0xc/0x2c [ 0.410645] softirqs last disabled at (50): [<ffffffc0081b809c>] local_bh_disable+0xc/0x2c [ 0.411890] ---[ end trace 0000000000000000 ]--- [ 0.413000] smp: Brought up 1 node, 4 CPUs [ 0.413762] SMP: Total of 4 processors activated. [ 0.414566] CPU features: detected: 32-bit EL0 Support [ 0.415414] CPU features: detected: 32-bit EL1 Support [ 0.416278] CPU features: detected: CRC32 instructions [ 0.447021] Callback from call_rcu_tasks_rude() invoked. [ 0.506693] Callback from call_rcu_tasks() invoked. This commit therefore fixes this issue by applying a single-CPU optimization to the RCU Tasks Rude grace-period process. The key point here is that the purpose of this RCU flavor is to force a schedule on each online CPU since some past event. But the rcu_tasks_rude_wait_gp() function runs in the context of the RCU Tasks Rude's grace-period kthread, so there must already have been a context switch on the current CPU since the call to either synchronize_rcu_tasks_rude() or call_rcu_tasks_rude(). So if there is only a single CPU online, RCU Tasks Rude's grace-period kthread does not need to anything at all. It turns out that the rcu_tasks_rude_wait_gp() function's call to schedule_on_each_cpu() causes problems during early boot. During that time, there is only one online CPU, namely the boot CPU. Therefore, applying this single-CPU optimization fixes early-boot instances of this problem.

In the Linux kernel, the following vulnerability has been resolved: tcp: Fix data-races around sysctl_tcp_migrate_req. While reading sysctl_tcp_migrate_req, it can be changed concurrently. Thus, we need to add READ_ONCE() to its readers.

In the Linux kernel, the following vulnerability has been resolved: ip: Fix data-races around sysctl_ip_fwd_use_pmtu. While reading sysctl_ip_fwd_use_pmtu, it can be changed concurrently. Thus, we need to add READ_ONCE() to its readers.

In the Linux kernel, the following vulnerability has been resolved: tcp/dccp: Fix a data-race around sysctl_tcp_fwmark_accept. While reading sysctl_tcp_fwmark_accept, it can be changed concurrently. Thus, we need to add READ_ONCE() to its reader.

In the Linux kernel, the following vulnerability has been resolved: ip: Fix data-races around sysctl_ip_fwd_update_priority. While reading sysctl_ip_fwd_update_priority, it can be changed concurrently. Thus, we need to add READ_ONCE() to its readers.

In the Linux kernel, the following vulnerability has been resolved: bpf, sockmap: fix race in sock_map_free() sock_map_free() calls release_sock(sk) without owning a reference on the socket. This can cause use-after-free as syzbot found [1] Jakub Sitnicki already took care of a similar issue in sock_hash_free() in commit 75e68e5bf2c7 ("bpf, sockhash: Synchronize delete from bucket list on map free") [1] refcount_t: decrement hit 0; leaking memory. WARNING: CPU: 0 PID: 3785 at lib/refcount.c:31 refcount_warn_saturate+0x17c/0x1a0 lib/refcount.c:31 Modules linked in: CPU: 0 PID: 3785 Comm: kworker/u4:6 Not tainted 6.1.0-rc7-syzkaller-00103-gef4d3ea40565 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 Workqueue: events_unbound bpf_map_free_deferred RIP: 0010:refcount_warn_saturate+0x17c/0x1a0 lib/refcount.c:31 Code: 68 8b 31 c0 e8 75 71 15 fd 0f 0b e9 64 ff ff ff e8 d9 6e 4e fd c6 05 62 9c 3d 0a 01 48 c7 c7 80 bb 68 8b 31 c0 e8 54 71 15 fd <0f> 0b e9 43 ff ff ff 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c a2 fe ff RSP: 0018:ffffc9000456fb60 EFLAGS: 00010246 RAX: eae59bab72dcd700 RBX: 0000000000000004 RCX: ffff8880207057c0 RDX: 0000000000000000 RSI: 0000000000000201 RDI: 0000000000000000 RBP: 0000000000000004 R08: ffffffff816fdabd R09: fffff520008adee5 R10: fffff520008adee5 R11: 1ffff920008adee4 R12: 0000000000000004 R13: dffffc0000000000 R14: ffff88807b1c6c00 R15: 1ffff1100f638dcf FS: 0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b30c30000 CR3: 000000000d08e000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> __refcount_dec include/linux/refcount.h:344 [inline] refcount_dec include/linux/refcount.h:359 [inline] __sock_put include/net/sock.h:779 [inline] tcp_release_cb+0x2d0/0x360 net/ipv4/tcp_output.c:1092 release_sock+0xaf/0x1c0 net/core/sock.c:3468 sock_map_free+0x219/0x2c0 net/core/sock_map.c:356 process_one_work+0x81c/0xd10 kernel/workqueue.c:2289 worker_thread+0xb14/0x1330 kernel/workqueue.c:2436 kthread+0x266/0x300 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 </TASK>

In the Linux kernel, the following vulnerability has been resolved: tcp: Fix data-races around sysctl_tcp_fastopen_blackhole_timeout. While reading sysctl_tcp_fastopen_blackhole_timeout, it can be changed concurrently. Thus, we need to add READ_ONCE() to its readers.

roccat_report_event in drivers/hid/hid-roccat.c in the Linux kernel through 5.19.12 has a race condition and resultant use-after-free in certain situations where a report is received while copying a report->value is in progress.

In the Linux kernel, the following vulnerability has been resolved: fscache: Fix oops due to race with cookie_lru and use_cookie If a cookie expires from the LRU and the LRU_DISCARD flag is set, but the state machine has not run yet, it's possible another thread can call fscache_use_cookie and begin to use it. When the cookie_worker finally runs, it will see the LRU_DISCARD flag set, transition the cookie->state to LRU_DISCARDING, which will then withdraw the cookie. Once the cookie is withdrawn the object is removed the below oops will occur because the object associated with the cookie is now NULL. Fix the oops by clearing the LRU_DISCARD bit if another thread uses the cookie before the cookie_worker runs. BUG: kernel NULL pointer dereference, address: 0000000000000008 ... CPU: 31 PID: 44773 Comm: kworker/u130:1 Tainted: G E 6.0.0-5.dneg.x86_64 #1 Hardware name: Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022 Workqueue: events_unbound netfs_rreq_write_to_cache_work [netfs] RIP: 0010:cachefiles_prepare_write+0x28/0x90 [cachefiles] ... Call Trace: netfs_rreq_write_to_cache_work+0x11c/0x320 [netfs] process_one_work+0x217/0x3e0 worker_thread+0x4a/0x3b0 kthread+0xd6/0x100

In the Linux kernel, the following vulnerability has been resolved: cfg80211: fix race in netlink owner interface destruction My previous fix here to fix the deadlock left a race where the exact same deadlock (see the original commit referenced below) can still happen if cfg80211_destroy_ifaces() already runs while nl80211_netlink_notify() is still marking some interfaces as nl_owner_dead. The race happens because we have two loops here - first we dev_close() all the netdevs, and then we destroy them. If we also have two netdevs (first one need only be a wdev though) then we can find one during the first iteration, close it, and go to the second iteration -- but then find two, and try to destroy also the one we didn't close yet. Fix this by only iterating once.

In the Linux kernel, the following vulnerability has been resolved: spi: tegra210-quad: Protect curr_xfer check in IRQ handler Now that all other accesses to curr_xfer are done under the lock, protect the curr_xfer NULL check in tegra_qspi_isr_thread() with the spinlock. Without this protection, the following race can occur: CPU0 (ISR thread) CPU1 (timeout path) ---------------- ------------------- if (!tqspi->curr_xfer) // sees non-NULL spin_lock() tqspi->curr_xfer = NULL spin_unlock() handle_*_xfer() spin_lock() t = tqspi->curr_xfer // NULL! ... t->len ... // NULL dereference! With this patch, all curr_xfer accesses are now properly synchronized. Although all accesses to curr_xfer are done under the lock, in tegra_qspi_isr_thread() it checks for NULL, releases the lock and reacquires it later in handle_cpu_based_xfer()/handle_dma_based_xfer(). There is a potential for an update in between, which could cause a NULL pointer dereference. To handle this, add a NULL check inside the handlers after acquiring the lock. This ensures that if the timeout path has already cleared curr_xfer, the handler will safely return without dereferencing the NULL pointer.

In the Linux kernel, the following vulnerability has been resolved: configfs: fix a race in configfs_{,un}register_subsystem() When configfs_register_subsystem() or configfs_unregister_subsystem() is executing link_group() or unlink_group(), it is possible that two processes add or delete list concurrently. Some unfortunate interleavings of them can cause kernel panic. One of cases is: A --> B --> C --> D A <-- B <-- C <-- D delete list_head *B | delete list_head *C --------------------------------|----------------------------------- configfs_unregister_subsystem | configfs_unregister_subsystem unlink_group | unlink_group unlink_obj | unlink_obj list_del_init | list_del_init __list_del_entry | __list_del_entry __list_del | __list_del // next == C | next->prev = prev | | next->prev = prev prev->next = next | | // prev == B | prev->next = next Fix this by adding mutex when calling link_group() or unlink_group(), but parent configfs_subsystem is NULL when config_item is root. So I create a mutex configfs_subsystem_mutex.

In the Linux kernel, the following vulnerability has been resolved: ibmvnic: fix race between xmit and reset There is a race between reset and the transmit paths that can lead to ibmvnic_xmit() accessing an scrq after it has been freed in the reset path. It can result in a crash like: Kernel attempted to read user page (0) - exploit attempt? (uid: 0) BUG: Kernel NULL pointer dereference on read at 0x00000000 Faulting instruction address: 0xc0080000016189f8 Oops: Kernel access of bad area, sig: 11 [#1] ... NIP [c0080000016189f8] ibmvnic_xmit+0x60/0xb60 [ibmvnic] LR [c000000000c0046c] dev_hard_start_xmit+0x11c/0x280 Call Trace: [c008000001618f08] ibmvnic_xmit+0x570/0xb60 [ibmvnic] (unreliable) [c000000000c0046c] dev_hard_start_xmit+0x11c/0x280 [c000000000c9cfcc] sch_direct_xmit+0xec/0x330 [c000000000bfe640] __dev_xmit_skb+0x3a0/0x9d0 [c000000000c00ad4] __dev_queue_xmit+0x394/0x730 [c008000002db813c] __bond_start_xmit+0x254/0x450 [bonding] [c008000002db8378] bond_start_xmit+0x40/0xc0 [bonding] [c000000000c0046c] dev_hard_start_xmit+0x11c/0x280 [c000000000c00ca4] __dev_queue_xmit+0x564/0x730 [c000000000cf97e0] neigh_hh_output+0xd0/0x180 [c000000000cfa69c] ip_finish_output2+0x31c/0x5c0 [c000000000cfd244] __ip_queue_xmit+0x194/0x4f0 [c000000000d2a3c4] __tcp_transmit_skb+0x434/0x9b0 [c000000000d2d1e0] __tcp_retransmit_skb+0x1d0/0x6a0 [c000000000d2d984] tcp_retransmit_skb+0x34/0x130 [c000000000d310e8] tcp_retransmit_timer+0x388/0x6d0 [c000000000d315ec] tcp_write_timer_handler+0x1bc/0x330 [c000000000d317bc] tcp_write_timer+0x5c/0x200 [c000000000243270] call_timer_fn+0x50/0x1c0 [c000000000243704] __run_timers.part.0+0x324/0x460 [c000000000243894] run_timer_softirq+0x54/0xa0 [c000000000ea713c] __do_softirq+0x15c/0x3e0 [c000000000166258] __irq_exit_rcu+0x158/0x190 [c000000000166420] irq_exit+0x20/0x40 [c00000000002853c] timer_interrupt+0x14c/0x2b0 [c000000000009a00] decrementer_common_virt+0x210/0x220 --- interrupt: 900 at plpar_hcall_norets_notrace+0x18/0x2c The immediate cause of the crash is the access of tx_scrq in the following snippet during a reset, where the tx_scrq can be either NULL or an address that will soon be invalid: ibmvnic_xmit() { ... tx_scrq = adapter->tx_scrq[queue_num]; txq = netdev_get_tx_queue(netdev, queue_num); ind_bufp = &tx_scrq->ind_buf; if (test_bit(0, &adapter->resetting)) { ... } But beyond that, the call to ibmvnic_xmit() itself is not safe during a reset and the reset path attempts to avoid this by stopping the queue in ibmvnic_cleanup(). However just after the queue was stopped, an in-flight ibmvnic_complete_tx() could have restarted the queue even as the reset is progressing. Since the queue was restarted we could get a call to ibmvnic_xmit() which can then access the bad tx_scrq (or other fields). We cannot however simply have ibmvnic_complete_tx() check the ->resetting bit and skip starting the queue. This can race at the "back-end" of a good reset which just restarted the queue but has not cleared the ->resetting bit yet. If we skip restarting the queue due to ->resetting being true, the queue would remain stopped indefinitely potentially leading to transmit timeouts. IOW ->resetting is too broad for this purpose. Instead use a new flag that indicates whether or not the queues are active. Only the open/ reset paths control when the queues are active. ibmvnic_complete_tx() and others wake up the queue only if the queue is marked active. So we will have: A. reset/open thread in ibmvnic_cleanup() and __ibmvnic_open() ->resetting = true ->tx_queues_active = false disable tx queues ... ->tx_queues_active = true start tx queues B. Tx interrupt in ibmvnic_complete_tx(): if (->tx_queues_active) netif_wake_subqueue(); To ensure that ->tx_queues_active and state of the queues are consistent, we need a lock which: - must also be taken in the interrupt path (ibmvnic_complete_tx()) - shared across the multiple ---truncated---

In the Linux kernel, the following vulnerability has been resolved: can: isotp: fix potential CAN frame reception race in isotp_rcv() When receiving a CAN frame the current code logic does not consider concurrently receiving processes which do not show up in real world usage. Ziyang Xuan writes: The following syz problem is one of the scenarios. so->rx.len is changed by isotp_rcv_ff() during isotp_rcv_cf(), so->rx.len equals 0 before alloc_skb() and equals 4096 after alloc_skb(). That will trigger skb_over_panic() in skb_put(). ======================================================= CPU: 1 PID: 19 Comm: ksoftirqd/1 Not tainted 5.16.0-rc8-syzkaller #0 RIP: 0010:skb_panic+0x16c/0x16e net/core/skbuff.c:113 Call Trace: <TASK> skb_over_panic net/core/skbuff.c:118 [inline] skb_put.cold+0x24/0x24 net/core/skbuff.c:1990 isotp_rcv_cf net/can/isotp.c:570 [inline] isotp_rcv+0xa38/0x1e30 net/can/isotp.c:668 deliver net/can/af_can.c:574 [inline] can_rcv_filter+0x445/0x8d0 net/can/af_can.c:635 can_receive+0x31d/0x580 net/can/af_can.c:665 can_rcv+0x120/0x1c0 net/can/af_can.c:696 __netif_receive_skb_one_core+0x114/0x180 net/core/dev.c:5465 __netif_receive_skb+0x24/0x1b0 net/core/dev.c:5579 Therefore we make sure the state changes and data structures stay consistent at CAN frame reception time by adding a spin_lock in isotp_rcv(). This fixes the issue reported by syzkaller but does not affect real world operation.

An issue was discovered in include/asm-generic/tlb.h in the Linux kernel before 5.19. Because of a race condition (unmap_mapping_range versus munmap), a device driver can free a page while it still has stale TLB entries. This only occurs in situations with VM_PFNMAP VMAs.

In the Linux kernel, the following vulnerability has been resolved: udp: Deal with race between UDP socket address change and rehash If a UDP socket changes its local address while it's receiving datagrams, as a result of connect(), there is a period during which a lookup operation might fail to find it, after the address is changed but before the secondary hash (port and address) and the four-tuple hash (local and remote ports and addresses) are updated. Secondary hash chains were introduced by commit 30fff9231fad ("udp: bind() optimisation") and, as a result, a rehash operation became needed to make a bound socket reachable again after a connect(). This operation was introduced by commit 719f835853a9 ("udp: add rehash on connect()") which isn't however a complete fix: the socket will be found once the rehashing completes, but not while it's pending. This is noticeable with a socat(1) server in UDP4-LISTEN mode, and a client sending datagrams to it. After the server receives the first datagram (cf. _xioopen_ipdgram_listen()), it issues a connect() to the address of the sender, in order to set up a directed flow. Now, if the client, running on a different CPU thread, happens to send a (subsequent) datagram while the server's socket changes its address, but is not rehashed yet, this will result in a failed lookup and a port unreachable error delivered to the client, as apparent from the following reproducer: LEN=$(($(cat /proc/sys/net/core/wmem_default) / 4)) dd if=/dev/urandom bs=1 count=${LEN} of=tmp.in while :; do taskset -c 1 socat UDP4-LISTEN:1337,null-eof OPEN:tmp.out,create,trunc & sleep 0.1 || sleep 1 taskset -c 2 socat OPEN:tmp.in UDP4:localhost:1337,shut-null wait done where the client will eventually get ECONNREFUSED on a write() (typically the second or third one of a given iteration): 2024/11/13 21:28:23 socat[46901] E write(6, 0x556db2e3c000, 8192): Connection refused This issue was first observed as a seldom failure in Podman's tests checking UDP functionality while using pasta(1) to connect the container's network namespace, which leads us to a reproducer with the lookup error resulting in an ICMP packet on a tap device: LOCAL_ADDR="$(ip -j -4 addr show|jq -rM '.[] | .addr_info[0] | select(.scope == "global").local')" while :; do ./pasta --config-net -p pasta.pcap -u 1337 socat UDP4-LISTEN:1337,null-eof OPEN:tmp.out,create,trunc & sleep 0.2 || sleep 1 socat OPEN:tmp.in UDP4:${LOCAL_ADDR}:1337,shut-null wait cmp tmp.in tmp.out done Once this fails: tmp.in tmp.out differ: char 8193, line 29 we can finally have a look at what's going on: $ tshark -r pasta.pcap 1 0.000000 :: ? ff02::16 ICMPv6 110 Multicast Listener Report Message v2 2 0.168690 88.198.0.161 ? 88.198.0.164 UDP 8234 60260 ? 1337 Len=8192 3 0.168767 88.198.0.161 ? 88.198.0.164 UDP 8234 60260 ? 1337 Len=8192 4 0.168806 88.198.0.161 ? 88.198.0.164 UDP 8234 60260 ? 1337 Len=8192 5 0.168827 c6:47:05:8d:dc:04 ? Broadcast ARP 42 Who has 88.198.0.161? Tell 88.198.0.164 6 0.168851 9a:55:9a:55:9a:55 ? c6:47:05:8d:dc:04 ARP 42 88.198.0.161 is at 9a:55:9a:55:9a:55 7 0.168875 88.198.0.161 ? 88.198.0.164 UDP 8234 60260 ? 1337 Len=8192 8 0.168896 88.198.0.164 ? 88.198.0.161 ICMP 590 Destination unreachable (Port unreachable) 9 0.168926 88.198.0.161 ? 88.198.0.164 UDP 8234 60260 ? 1337 Len=8192 10 0.168959 88.198.0.161 ? 88.198.0.164 UDP 8234 60260 ? 1337 Len=8192 11 0.168989 88.198.0.161 ? 88.198.0.164 UDP 4138 60260 ? 1337 Len=4096 12 0.169010 88.198.0.161 ? 88.198.0.164 UDP 42 60260 ? 1337 Len=0 On the third datagram received, the network namespace of the container initiates an ARP lookup to deliver the ICMP message. In another variant of this reproducer, starting the client with: strace -f pasta --config-net -u 1337 socat UDP4-LISTEN:1337,null-eof OPEN:tmp.out,create,tru ---truncated---

In the Linux kernel, the following vulnerability has been resolved: af_unix: Fix a data-race in unix_dgram_peer_wake_me(). unix_dgram_poll() calls unix_dgram_peer_wake_me() without `other`'s lock held and check if its receive queue is full. Here we need to use unix_recvq_full_lockless() instead of unix_recvq_full(), otherwise KCSAN will report a data-race.

In the Linux kernel, the following vulnerability has been resolved: nbd: fix race between nbd_alloc_config() and module removal When nbd module is being removing, nbd_alloc_config() may be called concurrently by nbd_genl_connect(), although try_module_get() will return false, but nbd_alloc_config() doesn't handle it. The race may lead to the leak of nbd_config and its related resources (e.g, recv_workq) and oops in nbd_read_stat() due to the unload of nbd module as shown below: BUG: kernel NULL pointer dereference, address: 0000000000000040 Oops: 0000 [#1] SMP PTI CPU: 5 PID: 13840 Comm: kworker/u17:33 Not tainted 5.14.0+ #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) Workqueue: knbd16-recv recv_work [nbd] RIP: 0010:nbd_read_stat.cold+0x130/0x1a4 [nbd] Call Trace: recv_work+0x3b/0xb0 [nbd] process_one_work+0x1ed/0x390 worker_thread+0x4a/0x3d0 kthread+0x12a/0x150 ret_from_fork+0x22/0x30 Fixing it by checking the return value of try_module_get() in nbd_alloc_config(). As nbd_alloc_config() may return ERR_PTR(-ENODEV), assign nbd->config only when nbd_alloc_config() succeeds to ensure the value of nbd->config is binary (valid or NULL). Also adding a debug message to check the reference counter of nbd_config during module removal.

In the Linux kernel, the following vulnerability has been resolved: fgraph: Add READ_ONCE() when accessing fgraph_array[] In __ftrace_return_to_handler(), a loop iterates over the fgraph_array[] elements, which are fgraph_ops. The loop checks if an element is a fgraph_stub to prevent using a fgraph_stub afterward. However, if the compiler reloads fgraph_array[] after this check, it might race with an update to fgraph_array[] that introduces a fgraph_stub. This could result in the stub being processed, but the stub contains a null "func_hash" field, leading to a NULL pointer dereference. To ensure that the gops compared against the fgraph_stub matches the gops processed later, add a READ_ONCE(). A similar patch appears in commit 63a8dfb ("function_graph: Add READ_ONCE() when accessing fgraph_array[]").

In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_fs: Remove WARN_ON in functionfs_bind This commit addresses an issue related to below kernel panic where panic_on_warn is enabled. It is caused by the unnecessary use of WARN_ON in functionsfs_bind, which easily leads to the following scenarios. 1.adb_write in adbd 2. UDC write via configfs ================= ===================== ->usb_ffs_open_thread() ->UDC write ->open_functionfs() ->configfs_write_iter() ->adb_open() ->gadget_dev_desc_UDC_store() ->adb_write() ->usb_gadget_register_driver_owner ->driver_register() ->StartMonitor() ->bus_add_driver() ->adb_read() ->gadget_bind_driver() <times-out without BIND event> ->configfs_composite_bind() ->usb_add_function() ->open_functionfs() ->ffs_func_bind() ->adb_open() ->functionfs_bind() <ffs->state !=FFS_ACTIVE> The adb_open, adb_read, and adb_write operations are invoked from the daemon, but trying to bind the function is a process that is invoked by UDC write through configfs, which opens up the possibility of a race condition between the two paths. In this race scenario, the kernel panic occurs due to the WARN_ON from functionfs_bind when panic_on_warn is enabled. This commit fixes the kernel panic by removing the unnecessary WARN_ON. Kernel panic - not syncing: kernel: panic_on_warn set ... [ 14.542395] Call trace: [ 14.542464] ffs_func_bind+0x1c8/0x14a8 [ 14.542468] usb_add_function+0xcc/0x1f0 [ 14.542473] configfs_composite_bind+0x468/0x588 [ 14.542478] gadget_bind_driver+0x108/0x27c [ 14.542483] really_probe+0x190/0x374 [ 14.542488] __driver_probe_device+0xa0/0x12c [ 14.542492] driver_probe_device+0x3c/0x220 [ 14.542498] __driver_attach+0x11c/0x1fc [ 14.542502] bus_for_each_dev+0x104/0x160 [ 14.542506] driver_attach+0x24/0x34 [ 14.542510] bus_add_driver+0x154/0x270 [ 14.542514] driver_register+0x68/0x104 [ 14.542518] usb_gadget_register_driver_owner+0x48/0xf4 [ 14.542523] gadget_dev_desc_UDC_store+0xf8/0x144 [ 14.542526] configfs_write_iter+0xf0/0x138

A race condition was discovered in get_old_root in fs/btrfs/ctree.c in the Linux kernel through 5.11.8. It allows attackers to cause a denial of service (BUG) because of a lack of locking on an extent buffer before a cloning operation, aka CID-dbcc7d57bffc.

In the Linux kernel, the following vulnerability has been resolved: scsi: ufs: core: Flush exception handling work when RPM level is zero Ensure that the exception event handling work is explicitly flushed during suspend when the runtime power management level is set to UFS_PM_LVL_0. When the RPM level is zero, the device power mode and link state both remain active. Previously, the UFS core driver bypassed flushing exception event handling jobs in this configuration. This created a race condition where the driver could attempt to access the host controller to handle an exception after the system had already entered a deep power-down state, resulting in a system crash. Explicitly flush this work and disable auto BKOPs before the suspend callback proceeds. This guarantees that pending exception tasks complete and prevents illegal hardware access during the power-down sequence.

In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_rndis: Protect RNDIS options with mutex The class/subclass/protocol options are suspectible to race conditions as they can be accessed concurrently through configfs. Use existing mutex to protect these options. This issue was identified during code inspection.

In the Linux kernel, the following vulnerability has been resolved: netfilter: ipset: Hold module reference while requesting a module User space may unload ip_set.ko while it is itself requesting a set type backend module, leading to a kernel crash. The race condition may be provoked by inserting an mdelay() right after the nfnl_unlock() call.

In the Linux kernel, the following vulnerability has been resolved: tracing/synthetic: Fix races on freeing last_cmd Currently, the "last_cmd" variable can be accessed by multiple processes asynchronously when multiple users manipulate synthetic_events node at the same time, it could lead to use-after-free or double-free. This patch add "lastcmd_mutex" to prevent "last_cmd" from being accessed asynchronously. ================================================================ It's easy to reproduce in the KASAN environment by running the two scripts below in different shells. script 1: while : do echo -n -e '\x88' > /sys/kernel/tracing/synthetic_events done script 2: while : do echo -n -e '\xb0' > /sys/kernel/tracing/synthetic_events done ================================================================ double-free scenario: process A process B ------------------- --------------- 1.kstrdup last_cmd 2.free last_cmd 3.free last_cmd(double-free) ================================================================ use-after-free scenario: process A process B ------------------- --------------- 1.kstrdup last_cmd 2.free last_cmd 3.tracing_log_err(use-after-free) ================================================================ Appendix 1. KASAN report double-free: BUG: KASAN: double-free in kfree+0xdc/0x1d4 Free of addr ***** by task sh/4879 Call trace: ... kfree+0xdc/0x1d4 create_or_delete_synth_event+0x60/0x1e8 trace_parse_run_command+0x2bc/0x4b8 synth_events_write+0x20/0x30 vfs_write+0x200/0x830 ... Allocated by task 4879: ... kstrdup+0x5c/0x98 create_or_delete_synth_event+0x6c/0x1e8 trace_parse_run_command+0x2bc/0x4b8 synth_events_write+0x20/0x30 vfs_write+0x200/0x830 ... Freed by task 5464: ... kfree+0xdc/0x1d4 create_or_delete_synth_event+0x60/0x1e8 trace_parse_run_command+0x2bc/0x4b8 synth_events_write+0x20/0x30 vfs_write+0x200/0x830 ... ================================================================ Appendix 2. KASAN report use-after-free: BUG: KASAN: use-after-free in strlen+0x5c/0x7c Read of size 1 at addr ***** by task sh/5483 sh: CPU: 7 PID: 5483 Comm: sh ... __asan_report_load1_noabort+0x34/0x44 strlen+0x5c/0x7c tracing_log_err+0x60/0x444 create_or_delete_synth_event+0xc4/0x204 trace_parse_run_command+0x2bc/0x4b8 synth_events_write+0x20/0x30 vfs_write+0x200/0x830 ... Allocated by task 5483: ... kstrdup+0x5c/0x98 create_or_delete_synth_event+0x80/0x204 trace_parse_run_command+0x2bc/0x4b8 synth_events_write+0x20/0x30 vfs_write+0x200/0x830 ... Freed by task 5480: ... kfree+0xdc/0x1d4 create_or_delete_synth_event+0x74/0x204 trace_parse_run_command+0x2bc/0x4b8 synth_events_write+0x20/0x30 vfs_write+0x200/0x830 ...

In the Linux kernel, the following vulnerability has been resolved: net: ethernet: oa_tc6: fix tx skb race condition between reference pointers There are two skb pointers to manage tx skb's enqueued from n/w stack. waiting_tx_skb pointer points to the tx skb which needs to be processed and ongoing_tx_skb pointer points to the tx skb which is being processed. SPI thread prepares the tx data chunks from the tx skb pointed by the ongoing_tx_skb pointer. When the tx skb pointed by the ongoing_tx_skb is processed, the tx skb pointed by the waiting_tx_skb is assigned to ongoing_tx_skb and the waiting_tx_skb pointer is assigned with NULL. Whenever there is a new tx skb from n/w stack, it will be assigned to waiting_tx_skb pointer if it is NULL. Enqueuing and processing of a tx skb handled in two different threads. Consider a scenario where the SPI thread processed an ongoing_tx_skb and it moves next tx skb from waiting_tx_skb pointer to ongoing_tx_skb pointer without doing any NULL check. At this time, if the waiting_tx_skb pointer is NULL then ongoing_tx_skb pointer is also assigned with NULL. After that, if a new tx skb is assigned to waiting_tx_skb pointer by the n/w stack and there is a chance to overwrite the tx skb pointer with NULL in the SPI thread. Finally one of the tx skb will be left as unhandled, resulting packet missing and memory leak. - Consider the below scenario where the TXC reported from the previous transfer is 10 and ongoing_tx_skb holds an tx ethernet frame which can be transported in 20 TXCs and waiting_tx_skb is still NULL. tx_credits = 10; /* 21 are filled in the previous transfer */ ongoing_tx_skb = 20; waiting_tx_skb = NULL; /* Still NULL */ - So, (tc6->ongoing_tx_skb || tc6->waiting_tx_skb) becomes true. - After oa_tc6_prepare_spi_tx_buf_for_tx_skbs() ongoing_tx_skb = 10; waiting_tx_skb = NULL; /* Still NULL */ - Perform SPI transfer. - Process SPI rx buffer to get the TXC from footers. - Now let's assume previously filled 21 TXCs are freed so we are good to transport the next remaining 10 tx chunks from ongoing_tx_skb. tx_credits = 21; ongoing_tx_skb = 10; waiting_tx_skb = NULL; - So, (tc6->ongoing_tx_skb || tc6->waiting_tx_skb) becomes true again. - In the oa_tc6_prepare_spi_tx_buf_for_tx_skbs() ongoing_tx_skb = NULL; waiting_tx_skb = NULL; - Now the below bad case might happen, Thread1 (oa_tc6_start_xmit) Thread2 (oa_tc6_spi_thread_handler) --------------------------- ----------------------------------- - if waiting_tx_skb is NULL - if ongoing_tx_skb is NULL - ongoing_tx_skb = waiting_tx_skb - waiting_tx_skb = skb - waiting_tx_skb = NULL ... - ongoing_tx_skb = NULL - if waiting_tx_skb is NULL - waiting_tx_skb = skb To overcome the above issue, protect the moving of tx skb reference from waiting_tx_skb pointer to ongoing_tx_skb pointer and assigning new tx skb to waiting_tx_skb pointer, so that the other thread can't access the waiting_tx_skb pointer until the current thread completes moving the tx skb reference safely.

In the Linux kernel, the following vulnerability has been resolved: accel/ivpu: Prevent recovery invocation during probe and resume Refactor IPC send and receive functions to allow correct handling of operations that should not trigger a recovery process. Expose ivpu_send_receive_internal(), which is now utilized by the D0i3 entry, DCT initialization, and HWS initialization functions. These functions have been modified to return error codes gracefully, rather than initiating recovery. The updated functions are invoked within ivpu_probe() and ivpu_resume(), ensuring that any errors encountered during these stages result in a proper teardown or shutdown sequence. The previous approach of triggering recovery within these functions could lead to a race condition, potentially causing undefined behavior and kernel crashes due to null pointer dereferences.

In the Linux kernel, the following vulnerability has been resolved: usb: yurex: fix race in probe The bbu member of the descriptor must be set to the value standing for uninitialized values before the URB whose completion handler sets bbu is submitted. Otherwise there is a window during which probing can overwrite already retrieved data.

In the Linux kernel, the following vulnerability has been resolved: drm/xe/guc_submit: fix race around suspend_pending Currently in some testcases we can trigger: xe 0000:03:00.0: [drm] Assertion `exec_queue_destroyed(q)` failed! .... WARNING: CPU: 18 PID: 2640 at drivers/gpu/drm/xe/xe_guc_submit.c:1826 xe_guc_sched_done_handler+0xa54/0xef0 [xe] xe 0000:03:00.0: [drm] *ERROR* GT1: DEREGISTER_DONE: Unexpected engine state 0x00a1, guc_id=57 Looking at a snippet of corresponding ftrace for this GuC id we can see: 162.673311: xe_sched_msg_add: dev=0000:03:00.0, gt=1 guc_id=57, opcode=3 162.673317: xe_sched_msg_recv: dev=0000:03:00.0, gt=1 guc_id=57, opcode=3 162.673319: xe_exec_queue_scheduling_disable: dev=0000:03:00.0, 1:0x2, gt=1, width=1, guc_id=57, guc_state=0x29, flags=0x0 162.674089: xe_exec_queue_kill: dev=0000:03:00.0, 1:0x2, gt=1, width=1, guc_id=57, guc_state=0x29, flags=0x0 162.674108: xe_exec_queue_close: dev=0000:03:00.0, 1:0x2, gt=1, width=1, guc_id=57, guc_state=0xa9, flags=0x0 162.674488: xe_exec_queue_scheduling_done: dev=0000:03:00.0, 1:0x2, gt=1, width=1, guc_id=57, guc_state=0xa9, flags=0x0 162.678452: xe_exec_queue_deregister: dev=0000:03:00.0, 1:0x2, gt=1, width=1, guc_id=57, guc_state=0xa1, flags=0x0 It looks like we try to suspend the queue (opcode=3), setting suspend_pending and triggering a disable_scheduling. The user then closes the queue. However the close will also forcefully signal the suspend fence after killing the queue, later when the G2H response for disable_scheduling comes back we have now cleared suspend_pending when signalling the suspend fence, so the disable_scheduling now incorrectly tries to also deregister the queue. This leads to warnings since the queue has yet to even be marked for destruction. We also seem to trigger errors later with trying to double unregister the same queue. To fix this tweak the ordering when handling the response to ensure we don't race with a disable_scheduling that didn't actually intend to perform an unregister. The destruction path should now also correctly wait for any pending_disable before marking as destroyed. (cherry picked from commit f161809b362f027b6d72bd998e47f8f0bad60a2e)

In the Linux kernel, the following vulnerability has been resolved: iommu/arm-smmu: Defer probe of clients after smmu device bound Null pointer dereference occurs due to a race between smmu driver probe and client driver probe, when of_dma_configure() for client is called after the iommu_device_register() for smmu driver probe has executed but before the driver_bound() for smmu driver has been called. Following is how the race occurs: T1:Smmu device probe T2: Client device probe really_probe() arm_smmu_device_probe() iommu_device_register() really_probe() platform_dma_configure() of_dma_configure() of_dma_configure_id() of_iommu_configure() iommu_probe_device() iommu_init_device() arm_smmu_probe_device() arm_smmu_get_by_fwnode() driver_find_device_by_fwnode() driver_find_device() next_device() klist_next() /* null ptr assigned to smmu */ /* null ptr dereference while smmu->streamid_mask */ driver_bound() klist_add_tail() When this null smmu pointer is dereferenced later in arm_smmu_probe_device, the device crashes. Fix this by deferring the probe of the client device until the smmu device has bound to the arm smmu driver. [will: Add comment]

In the Linux kernel, the following vulnerability has been resolved: io_uring/zcrx: fix user_ref race between scrub and refill paths The io_zcrx_put_niov_uref() function uses a non-atomic check-then-decrement pattern (atomic_read followed by separate atomic_dec) to manipulate user_refs. This is serialized against other callers by rq_lock, but io_zcrx_scrub() modifies the same counter with atomic_xchg() WITHOUT holding rq_lock. On SMP systems, the following race exists: CPU0 (refill, holds rq_lock) CPU1 (scrub, no rq_lock) put_niov_uref: atomic_read(uref) - 1 // window opens atomic_xchg(uref, 0) - 1 return_niov_freelist(niov) [PUSH #1] // window closes atomic_dec(uref) - wraps to -1 returns true return_niov(niov) return_niov_freelist(niov) [PUSH #2: DOUBLE-FREE] The same niov is pushed to the freelist twice, causing free_count to exceed nr_iovs. Subsequent freelist pushes then perform an out-of-bounds write (a u32 value) past the kvmalloc'd freelist array into the adjacent slab object. Fix this by replacing the non-atomic read-then-dec in io_zcrx_put_niov_uref() with an atomic_try_cmpxchg loop that atomically tests and decrements user_refs. This makes the operation safe against concurrent atomic_xchg from scrub without requiring scrub to acquire rq_lock. [pavel: removed a warning and a comment]

In the Linux kernel, the following vulnerability has been resolved: md/bitmap: fix GPF in write_page caused by resize race A General Protection Fault occurs in write_page() during array resize: RIP: 0010:write_page+0x22b/0x3c0 [md_mod] This is a use-after-free race between bitmap_daemon_work() and __bitmap_resize(). The daemon iterates over `bitmap->storage.filemap` without locking, while the resize path frees that storage via md_bitmap_file_unmap(). `quiesce()` does not stop the md thread, allowing concurrent access to freed pages. Fix by holding `mddev->bitmap_info.mutex` during the bitmap update.

In the Linux kernel, the following vulnerability has been resolved: scsi: qla2xxx: Complete command early within lock A crash was observed while performing NPIV and FW reset, BUG: kernel NULL pointer dereference, address: 000000000000001c #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 1 PREEMPT_RT SMP NOPTI RIP: 0010:dma_direct_unmap_sg+0x51/0x1e0 RSP: 0018:ffffc90026f47b88 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000021 RCX: 0000000000000002 RDX: 0000000000000021 RSI: 0000000000000000 RDI: ffff8881041130d0 RBP: ffff8881041130d0 R08: 0000000000000000 R09: 0000000000000034 R10: ffffc90026f47c48 R11: 0000000000000031 R12: 0000000000000000 R13: 0000000000000000 R14: ffff8881565e4a20 R15: 0000000000000000 FS: 00007f4c69ed3d00(0000) GS:ffff889faac80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000000001c CR3: 0000000288a50002 CR4: 00000000007706e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: <TASK> ? __die_body+0x1a/0x60 ? page_fault_oops+0x16f/0x4a0 ? do_user_addr_fault+0x174/0x7f0 ? exc_page_fault+0x69/0x1a0 ? asm_exc_page_fault+0x22/0x30 ? dma_direct_unmap_sg+0x51/0x1e0 ? preempt_count_sub+0x96/0xe0 qla2xxx_qpair_sp_free_dma+0x29f/0x3b0 [qla2xxx] qla2xxx_qpair_sp_compl+0x60/0x80 [qla2xxx] __qla2x00_abort_all_cmds+0xa2/0x450 [qla2xxx] The command completion was done early while aborting the commands in driver unload path but outside lock to avoid the WARN_ON condition of performing dma_free_attr within the lock. However this caused race condition while command completion via multiple paths causing system crash. Hence complete the command early in unload path but within the lock to avoid race condition.