Improper Locking

In the Linux kernel, the following vulnerability has been resolved: __legitimize_mnt(): check for MNT_SYNC_UMOUNT should be under mount_lock ... or we risk stealing final mntput from sync umount - raising mnt_count after umount(2) has verified that victim is not busy, but before it has set MNT_SYNC_UMOUNT; in that case __legitimize_mnt() doesn't see that it's safe to quietly undo mnt_count increment and leaves dropping the reference to caller, where it'll be a full-blown mntput(). Check under mount_lock is needed; leaving the current one done before taking that makes no sense - it's nowhere near common enough to bother with.Show less

In the Linux kernel, the following vulnerability has been resolved: netfilter: ipset: fix region locking in hash types Region locking introduced in v5.6-rc4 contained three macros to handle the region locks: ahash_bucket_start(), ahash_bucket_end() which gave back the start and end hash bucket values belonging to a given region lock and ahash_region() which should give back the region lock belonging to a given hash bucket. The latter was incorrect which can lead to a race condition between the garbage collector and adding new elements when a hash type of set is defined with timeouts.Show less

In the Linux kernel, the following vulnerability has been resolved: iio: imu: st_lsm6dsx: fix possible lockup in st_lsm6dsx_read_fifo Prevent st_lsm6dsx_read_fifo from falling in an infinite loop in case pattern_len is equal to zero and the device FIFO is not empty.Show less

In the Linux kernel, the following vulnerability has been resolved: iio: imu: st_lsm6dsx: fix possible lockup in st_lsm6dsx_read_tagged_fifo Prevent st_lsm6dsx_read_tagged_fifo from falling in an infinite loop in case pattern_len is equal to zero and the device FIFO is not empty.Show less

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

In the Linux kernel, the following vulnerability has been resolved: usb: typec: ucsi: displayport: Fix deadlock This patch introduces the ucsi_con_mutex_lock / ucsi_con_mutex_unlock functions to the UCSI driver. ucsi_con_mutex_lock ensures the connector mutex is only locked if a connection is established and the partner pointer is valid. This resolves a deadlock scenario where ucsi_displayport_remove_partner holds con->mutex waiting for dp_altmode_work to complete while dp_altmode_work attempts to acquire it.Show less

In the Linux kernel, the following vulnerability has been resolved: ftrace: Add cond_resched() to ftrace_graph_set_hash() When the kernel contains a large number of functions that can be traced, the loop in ftrace_graph_set_hash() may take a lot of time to execute. This may trigger the softlockup watchdog. Add cond_resched() within the loop to allow the kernel to remain responsive even when processing a large number of functions. This matches the cond_resched() that is used in other locations of the code that iterates over all functions that can be traced.Show less

In the Linux kernel, the following vulnerability has been resolved: accel/ivpu: Fix locking order in ivpu_job_submit Fix deadlock in job submission and abort handling. When a thread aborts currently executing jobs due to a fault, it first locks the global lock protecting submitted_jobs (#1). After the last job is destroyed, it proceeds to release the related context and locks file_priv (#2). Meanwhile, in the job submission thread, the file_priv lock (#2) is taken first, and then the submitted_jobs lock (#1) is obtained when a job is added to the submitted jobs list. CPU0 CPU1 ---- ---- (for example due to a fault) (jobs submissions keep coming) lock(&vdev->submitted_jobs_lock) #1 ivpu_jobs_abort_all() job_destroy() lock(&file_priv->lock) #2 lock(&vdev->submitted_jobs_lock) #1 file_priv_release() lock(&vdev->context_list_lock) lock(&file_priv->lock) #2 This order of locking causes a deadlock. To resolve this issue, change the order of locking in ivpu_job_submit().Show less

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix deadlock between rcu_tasks_trace and event_mutex. Fix the following deadlock: CPU A _free_event() perf_kprobe_destroy() mutex_lock(&event_mutex) perf_trace_event_unreg() synchronize_rcu_tasks_trace() There are several paths where _free_event() grabs event_mutex and calls sync_rcu_tasks_trace. Above is one such case. CPU B bpf_prog_test_run_syscall() rcu_read_lock_trace() bpf_prog_run_pin_on_cpu() bpf_prog_load() bpf_tracing_func_proto() trace_set_clr_event() mutex_lock(&event_mutex) Delegate trace_set_clr_event() to workqueue to avoid such lock dependency.Show less

In the Linux kernel, the following vulnerability has been resolved: um: work around sched_yield not yielding in time-travel mode sched_yield by a userspace may not actually cause scheduling in time-travel mode as no time has passed. In the case seen it appears to be a badly implemented userspace spinlock in ASAN. Unfortunately, with time-travel it causes an extreme slowdown or even deadlock depending on the kernel configuration (CONFIG_UML_MAX_USERSPACE_ITERATIONS). Work around it by accounting time to the process whenever it executes a sched_yield syscall.Show less

In the Linux kernel, the following vulnerability has been resolved: drm/xe/userptr: fix notifier vs folio deadlock User is reporting what smells like notifier vs folio deadlock, where migrate_pages_batch() on core kernel side is holding folio lock(s) and then interacting with the mappings of it, however those mappings are tied to some userptr, which means calling into the notifier callback and grabbing the notifier lock. With perfect timing it looks possible that the pages we pulled from the hmm fault can get sniped by migrate_pages_batch() at the same time that we are holding the notifier lock to mark the pages as accessed/dirty, but at this point we also want to grab the folio locks(s) to mark them as dirty, but if they are contended from notifier/migrate_pages_batch side then we deadlock since folio lock won't be dropped until we drop the notifier lock. Fortunately the mark_page_accessed/dirty is not really needed in the first place it seems and should have already been done by hmm fault, so just remove it. (cherry picked from commit bd7c0cb695e87c0e43247be8196b4919edbe0e85)Show less

In the Linux kernel, the following vulnerability has been resolved: accel/ivpu: Fix PM related deadlocks in MS IOCTLs Prevent runtime resume/suspend while MS IOCTLs are in progress. Failed suspend will call ivpu_ms_cleanup() that would try to acquire file_priv->ms_lock, which is already held by the IOCTLs.Show less

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

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

In the Linux kernel, the following vulnerability has been resolved: usb: cdns3: Fix deadlock when using NCM gadget The cdns3 driver has the same NCM deadlock as fixed in cdnsp by commit 58f2fcb3a845 ("usb: cdnsp: Fix deadlock issue during using NCM gadget"). Under PREEMPT_RT the deadlock can be readily triggered by heavy network traffic, for example using "iperf --bidir" over NCM ethernet link. The deadlock occurs because the threaded interrupt handler gets preempted by a softirq, but both are protected by the same spinlock. Prevent deadlock by disabling softirq during threaded irq handler.Show less

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix WARNING "do not call blocking ops when !TASK_RUNNING" wait_event_timeout() will set the state of the current task to TASK_UNINTERRUPTIBLE, before doing the condition check. This means that ksmbd_durable_scavenger_alive() will try to acquire the mutex while already in a sleeping state. The scheduler warns us by giving the following warning: do not call blocking ops when !TASK_RUNNING; state=2 set at [<0000000061515a6f>] prepare_to_wait_event+0x9f/0x6c0 WARNING: CPU: 2 PID: 4147 at kernel/sched/core.c:10099 __might_sleep+0x12f/0x160 mutex lock is not needed in ksmbd_durable_scavenger_alive().Show less

In the Linux kernel, the following vulnerability has been resolved: firmware: xilinx: don't make a sleepable memory allocation from an atomic context The following issue was discovered using lockdep: [ 6.691371] BUG: sleeping function called from invalid context at include/linux/sched/mm.h:209 [ 6.694602] in_atomic(): 1, irqs_disabled(): 128, non_block: 0, pid: 1, name: swapper/0 [ 6.702431] 2 locks held by swapper/0/1: [ 6.706300] #0: ffffff8800f6f188 (&dev->mutex){....}-{3:3}, at: __device_driver_lock+0x4c/0x90 [ 6.714900] #1: ffffffc009a2abb8 (enable_lock){....}-{2:2}, at: clk_enable_lock+0x4c/0x140 [ 6.723156] irq event stamp: 304030 [ 6.726596] hardirqs last enabled at (304029): [<ffffffc008d17ee0>] _raw_spin_unlock_irqrestore+0xc0/0xd0 [ 6.736142] hardirqs last disabled at (304030): [<ffffffc00876bc5c>] clk_enable_lock+0xfc/0x140 [ 6.744742] softirqs last enabled at (303958): [<ffffffc0080904f0>] _stext+0x4f0/0x894 [ 6.752655] softirqs last disabled at (303951): [<ffffffc0080e53b8>] irq_exit+0x238/0x280 [ 6.760744] CPU: 1 PID: 1 Comm: swapper/0 Tainted: G U 5.15.36 #2 [ 6.768048] Hardware name: xlnx,zynqmp (DT) [ 6.772179] Call trace: [ 6.774584] dump_backtrace+0x0/0x300 [ 6.778197] show_stack+0x18/0x30 [ 6.781465] dump_stack_lvl+0xb8/0xec [ 6.785077] dump_stack+0x1c/0x38 [ 6.788345] ___might_sleep+0x1a8/0x2a0 [ 6.792129] __might_sleep+0x6c/0xd0 [ 6.795655] kmem_cache_alloc_trace+0x270/0x3d0 [ 6.800127] do_feature_check_call+0x100/0x220 [ 6.804513] zynqmp_pm_invoke_fn+0x8c/0xb0 [ 6.808555] zynqmp_pm_clock_getstate+0x90/0xe0 [ 6.813027] zynqmp_pll_is_enabled+0x8c/0x120 [ 6.817327] zynqmp_pll_enable+0x38/0xc0 [ 6.821197] clk_core_enable+0x144/0x400 [ 6.825067] clk_core_enable+0xd4/0x400 [ 6.828851] clk_core_enable+0xd4/0x400 [ 6.832635] clk_core_enable+0xd4/0x400 [ 6.836419] clk_core_enable+0xd4/0x400 [ 6.840203] clk_core_enable+0xd4/0x400 [ 6.843987] clk_core_enable+0xd4/0x400 [ 6.847771] clk_core_enable+0xd4/0x400 [ 6.851555] clk_core_enable_lock+0x24/0x50 [ 6.855683] clk_enable+0x24/0x40 [ 6.858952] fclk_probe+0x84/0xf0 [ 6.862220] platform_probe+0x8c/0x110 [ 6.865918] really_probe+0x110/0x5f0 [ 6.869530] __driver_probe_device+0xcc/0x210 [ 6.873830] driver_probe_device+0x64/0x140 [ 6.877958] __driver_attach+0x114/0x1f0 [ 6.881828] bus_for_each_dev+0xe8/0x160 [ 6.885698] driver_attach+0x34/0x50 [ 6.889224] bus_add_driver+0x228/0x300 [ 6.893008] driver_register+0xc0/0x1e0 [ 6.896792] __platform_driver_register+0x44/0x60 [ 6.901436] fclk_driver_init+0x1c/0x28 [ 6.905220] do_one_initcall+0x104/0x590 [ 6.909091] kernel_init_freeable+0x254/0x2bc [ 6.913390] kernel_init+0x24/0x130 [ 6.916831] ret_from_fork+0x10/0x20 Fix it by passing the GFP_ATOMIC gfp flag for the corresponding memory allocation.Show less

In the Linux kernel, the following vulnerability has been resolved: igb: revert rtnl_lock() that causes deadlock The commit 6faee3d4ee8b ("igb: Add lock to avoid data race") adds rtnl_lock to eliminate a false data race shown below (FREE from device detaching) | (USE from netdev core) igb_remove | igb_ndo_get_vf_config igb_disable_sriov | vf >= adapter->vfs_allocated_count? kfree(adapter->vf_data) | adapter->vfs_allocated_count = 0 | | memcpy(... adapter->vf_data[vf] The above race will never happen and the extra rtnl_lock causes deadlock below [ 141.420169] <TASK> [ 141.420672] __schedule+0x2dd/0x840 [ 141.421427] schedule+0x50/0xc0 [ 141.422041] schedule_preempt_disabled+0x11/0x20 [ 141.422678] __mutex_lock.isra.13+0x431/0x6b0 [ 141.423324] unregister_netdev+0xe/0x20 [ 141.423578] igbvf_remove+0x45/0xe0 [igbvf] [ 141.423791] pci_device_remove+0x36/0xb0 [ 141.423990] device_release_driver_internal+0xc1/0x160 [ 141.424270] pci_stop_bus_device+0x6d/0x90 [ 141.424507] pci_stop_and_remove_bus_device+0xe/0x20 [ 141.424789] pci_iov_remove_virtfn+0xba/0x120 [ 141.425452] sriov_disable+0x2f/0xf0 [ 141.425679] igb_disable_sriov+0x4e/0x100 [igb] [ 141.426353] igb_remove+0xa0/0x130 [igb] [ 141.426599] pci_device_remove+0x36/0xb0 [ 141.426796] device_release_driver_internal+0xc1/0x160 [ 141.427060] driver_detach+0x44/0x90 [ 141.427253] bus_remove_driver+0x55/0xe0 [ 141.427477] pci_unregister_driver+0x2a/0xa0 [ 141.428296] __x64_sys_delete_module+0x141/0x2b0 [ 141.429126] ? mntput_no_expire+0x4a/0x240 [ 141.429363] ? syscall_trace_enter.isra.19+0x126/0x1a0 [ 141.429653] do_syscall_64+0x5b/0x80 [ 141.429847] ? exit_to_user_mode_prepare+0x14d/0x1c0 [ 141.430109] ? syscall_exit_to_user_mode+0x12/0x30 [ 141.430849] ? do_syscall_64+0x67/0x80 [ 141.431083] ? syscall_exit_to_user_mode_prepare+0x183/0x1b0 [ 141.431770] ? syscall_exit_to_user_mode+0x12/0x30 [ 141.432482] ? do_syscall_64+0x67/0x80 [ 141.432714] ? exc_page_fault+0x64/0x140 [ 141.432911] entry_SYSCALL_64_after_hwframe+0x72/0xdc Since the igb_disable_sriov() will call pci_disable_sriov() before releasing any resources, the netdev core will synchronize the cleanup to avoid any races. This patch removes the useless rtnl_(un)lock to guarantee correctness.Show less