linux-next.git/kernel/workqueue.c, branch assoc-array-fixes

Merge tag 'wq-for-7.3-rc6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq

2026-10-07T00:24:23+00:00

Pull workqueue fixes from Tejun Heo: - Fix a NULL dereference in the chained work check when a kworker queues work on a draining or destroying workqueue outside work item execution. * tag 'wq-for-7.3-rc6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq: workqueue: Fix NULL current_pwq deref in chained work check

workqueue: Fix NULL current_pwq deref in chained work check

2026-09-28T17:46:45+00:00

current_wq_worker() only tells us that %current is a kworker. It does not guarantee that the worker is currently executing a work item, as worker->current_pwq is populated only while process_one_work() is running the work function. is_chained_work() can be reached while queueing on a draining or destroying workqueue. If a kworker outside work-item execution reaches that path, current_wq_worker() returns a worker but worker->current_pwq is NULL, and the chained-work test can fault before it emits the intended warning. Guard the chained-work test with worker->current_pwq. A kworker without current_pwq is not executing work on the target workqueue, so the helper should return false and let the draining/destroying warning fire. Fixes: 8d03ecfe4718 ("workqueue: reimplement is_chained_work() using current_wq_worker()") Cc: stable@vger.kernel.org Signed-off-by: Pavankumar Kondeti Signed-off-by: Tejun Heo

Merge tag 'wq-for-7.3-rc4-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq

2026-09-27T15:55:24+00:00

Pull workqueue fix from Tejun Heo: - Fix a NULL dereference in the flush dependency check when a worker flushes outside a work item, such as from the OOM path during worker creation * tag 'wq-for-7.3-rc4-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq: workqueue: Fix NULL current_pwq deref in flush dependency check

workqueue: Fix NULL current_pwq deref in flush dependency check

2026-09-27T08:18:50+00:00

check_flush_dependency() uses current_wq_worker() to determine whether the caller is a workqueue worker and then dereferences worker->current_pwq to test whether the current workqueue is WQ_MEM_RECLAIM. current_wq_worker() only means that %current has PF_WQ_WORKER set. A kworker can reach check_flush_dependency() while it is not executing a work item. One such path is worker_thread() acting as the pool manager, where create_worker() does GFP_KERNEL allocation and the allocation path invokes the OOM notifier. In that state worker->current_pwq is NULL because current_pwq is set only by process_one_work() and cleared again after the work function returns. [ 416.760634][ T375] Call trace: [ 416.760638][ T375] check_flush_dependency+0x80/0x120 (P) [ 416.760648][ T375] __flush_work+0x98/0x224 [ 416.760657][ T375] flush_work+0x30/0x44 [ 416.760665][ T375] ... [ 416.760710][ T375] blocking_notifier_call_chain+0x58/0xa0 [ 416.760719][ T375] out_of_memory+0xb4/0x458 [ 416.760730][ T375] __alloc_pages_may_oom+0x11c/0x1a8 [ 416.760739][ T375] __alloc_pages_slowpath+0x314/0x46c [ 416.760746][ T375] __alloc_frozen_pages_noprof+0x110/0x1a4 [ 416.760753][ T375] new_slab+0x12c/0x484 [ 416.760759][ T375] ___slab_alloc+0x7a8/0xc7c [ 416.760765][ T375] __slab_alloc+0x74/0xd8 [ 416.760772][ T375] __kmalloc_cache_node_noprof+0x2ac/0x304 [ 416.760779][ T375] alloc_worker+0x28/0x60 [ 416.760785][ T375] create_worker+0x4c/0x20c [ 416.760790][ T375] worker_thread+0xe8/0x2b8 [ 416.760796][ T375] kthread+0x1a8/0x200 [ 416.760805][ T375] ret_from_fork+0x10/0x20 Guard the WQ_MEM_RECLAIM-worker warning with worker->current_pwq. If the kworker is not currently executing a work item, there is no current workqueue to diagnose with that warning. The PF_MEMALLOC warning is left unchanged so explicit reclaim context flushing a !WQ_MEM_RECLAIM target is still reported. Fixes: fca839c00a12 ("workqueue: warn if memory reclaim tries to flush !WQ_MEM_RECLAIM workqueue") Cc: stable@vger.kernel.org Assisted-by: LLM Signed-off-by: Pavankumar Kondeti Signed-off-by: Tejun Heo

Merge tag 'wq-for-7.3-rc1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq

2026-08-31T21:38:40+00:00

Pull workqueue fixes from Tejun Heo: - An unbound worker pool could be freed while still reachable through the pending-activation list, leading to a use-after-free. Unlink before dropping the reference - On PREEMPT_RT, the BH workqueue kick raised softirqs from preemptible context, tripping a lockdep assertion and possibly losing concurrently raised softirq bits - Draining BH work off a dead CPU nests two pools' callback locks, which lockdep misreported as recursive locking. The nesting cannot deadlock. Annotate it - Reject watchdog thresholds that overflow the conversion to jiffies - Make the drgn workqueue dump script work again on kernels and vmcores from before the workqueue attrs field rename * tag 'wq-for-7.3-rc1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq: tools/workqueue/wq_dump.py: Support backward compatibility for wq->attrs rename workqueue: reject watchdog thresholds that overflow jiffies workqueue: Fix unbound pool lifetime for pending pwqs workqueue: Use raise_softirq() to trigger softirq in irq_work handler workqueue: Annotate cb_lock nesting when draining a dead BH pool

workqueue: reject watchdog thresholds that overflow jiffies

2026-08-31T17:31:46+00:00

The watchdog threshold is supplied in seconds but is multiplied by HZ before being used as a jiffies interval. Reject values that exceed MAX_JIFFY_OFFSET / HZ so the multiplication cannot wrap and the time_after() comparisons remain within their supported range. The check is performed before changing the threshold or watchdog timer. Zero remains the value used to disable the watchdog. Fixes: 82607adcf9cdf ("workqueue: implement lockup detector") Signed-off-by: Jiacheng Xu Signed-off-by: Tejun Heo

Merge tag 'nfs-for-7.3-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs

2026-08-26T22:09:21+00:00

Pull NFS client updates from Trond Myklebust: "Highlights include: Stable fixes: - Use-after-free fixes for the sunrpc client code - Delegation hash table leak - NULL dereference on lockowner allocation failure - Fix a handshake completion race in the TLS code - Fix an error sign checking issue when deciding whether the pNFS layout is still in use, or can be returned - Fix a layout segment leak in pnfs_layout_process() Other bugfixes: - Fix a missing NULL check in the rpcbind client - annotate shared socket callbacks with READ_ONCE/WRITE_ONCE - nfs_inode_set_delegation() error paths should return the delegation - Use clear_and_wake_up_bit() in nfs_clear_invalid_mapping() and the pNFS code. - Fix the nfs4_alloc_client() error paths to free the IDR allocation - fix folio dereference before NULL check in nfs_inode_remove_request() - Fix delayed delegation return - Fix another state manager race with umount - Fix device leaks on parse failure - Avoid cancelling in-flight I/O during a layout recall if the server doesn't require it - flexfiles: report cancelled I/O as a layout error - flexfiles: fix NULL dereference for NFSv4.0 data servers - Fix incorrect argument passed to nfs4_delete_lease() - Fix several symlink issues resulting from nfs_atomic_open_v23() - Fix an uninitialised variable issue in the NFSv4.1 callback code - fix LAYOUTSTATS send buffer exhaustion Features and cleanups: - NFSv4.2: Allow the server to specify that file data may not be cached - localio: optimise I/O submission when when not doing memory reclaim - localio: Remove duplicate wait code in nfs_local_commit - flexfiles: support loosely coupled NFSv4.x data servers - pNFS: key the data server cache on the NFS version" * tag 'nfs-for-7.3-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (33 commits) NFSv4.1: fix layout segment leak on the pnfs_layout_process() forget path NFSv4/pnfs: key the data server cache on the NFS version NFSv4.2: fix LAYOUTSTATS send buffer exhaustion pNFS: Fix EBUSY check in pnfs_layout_need_return NFSv4.1: zero referring call lists before decoding nfs: fix ENXIO on O_CREAT open of existing symlink over NFSv3 SUNRPC: wait for in-flight client TLS handshake callback NFSv4: Fix incorrect argument passed to nfs4_delete_lease() in nfs4_add_lease() lockd: fix NULL dereference on lockowner allocation failure NFS: fix delegation_hash_table leak when nfs4_server_common_setup() fails NFSv4/flexfiles: support loosely coupled data servers NFSv4/flexfiles: fix NULL dereference for NFSv4.0 data servers NFSv4: pin the superblock for active state owners sunrpc: fix use-after-free in __rpc_clnt_handle_event and __rpc_clnt_remove_pipedir NFS/localio: issue commit inline when not in a memory-reclaim context NFS/localio: remove dead FLUSH_SYNC handling from nfs_local_commit NFS/localio: issue IO inline when not in a memory-reclaim context NFS: Fix delayed delegation return list handling NFS: Verify symlink inode before caching target NFS: fix folio dereference before NULL check in nfs_inode_remove_request() ...

workqueue: Fix unbound pool lifetime for pending pwqs

2026-08-24T17:42:40+00:00

KASAN reports a use-after-free of an unbound worker_pool in node_activate_pending_pwq(): BUG: KASAN: slab-use-after-free in _raw_spin_trylock+0x6d/0x120 Read of size 4 at addr ffff8880089ce000 by task kworker/u22:0/318 CPU: 1 UID: 0 PID: 318 Comm: kworker/u22:0 Not tainted 7.2.0 #1 PREEMPT(lazy) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 Workqueue: 0x0 (flush-8:0) Call Trace: dump_stack_lvl+0x53/0x70 print_report+0xce/0x610 kasan_report+0xce/0x100 _raw_spin_trylock+0x6d/0x120 pwq_dec_nr_in_flight+0x4b4/0xcb0 process_one_work+0x921/0x11a0 worker_thread+0x4d0/0xd20 kthread+0x2de/0x3c0 ret_from_fork+0x3aa/0x620 ret_from_fork_asm+0x1a/0x30 Allocated by task 311: alloc_pwq+0x439/0xca0 apply_wqattrs_prepare+0x75e/0xd10 apply_workqueue_attrs_locked+0x44/0xa0 wq_nice_store+0x350/0x450 Freed by task 0: kfree+0x127/0x3b0 rcu_core+0x523/0x1780 handle_softirqs+0x1b3/0x610 Last potentially related work creation: put_unbound_pool+0x3f3/0x7d0 pwq_release_workfn+0x494/0x8e0 kthread_worker_fn+0x1ff/0x790 Canceling the last inactive work skips pwq_dec_nr_active(), so an empty pwq can remain on pending_pwqs when its refcnt reaches zero. pwq_release_workfn() currently puts the pool before removing that pwq. If this drops the last pool reference, the pool can be RCU-freed while the pwq remains reachable, and node_activate_pending_pwq() may trylock the freed pool->lock. Remove the pwq from pending_pwqs before putting the pool. Fixes: 5797b1c18919 ("workqueue: Implement system-wide nr_active enforcement for unbound workqueues") Cc: stable@vger.kernel.org Signed-off-by: Yao Kai Signed-off-by: Tejun Heo

workqueue: Use raise_softirq() to trigger softirq in irq_work handler

2026-08-19T20:13:47+00:00

bh_pool_kick_normal() and bh_pool_kick_highpri() are registered via init_irq_work() without the IRQ_WORK_HARD_IRQ flag. On PREEMPT_RT, such irq_work items are processed by the per-CPU irq_workd kthread in preemptible task context with IRQs enabled. However, raise_softirq_irqoff() requires IRQs to be disabled. Calling it from irq_workd trips the lockdep assertion in __raise_softirq_irqoff() and the non-atomic update of the softirq pending mask can lose bits raised by an interrupt on the same CPU. Replace raise_softirq_irqoff() with raise_softirq() in the irq_work handlers. Fixes: 2f34d7337d98 ("workqueue: Fix queue_work_on() with BH workqueues") Cc: stable@vger.kernel.org # v6.9+ Signed-off-by: Zqiang Signed-off-by: Tejun Heo

workqueue: Annotate cb_lock nesting when draining a dead BH pool

2026-08-18T18:53:17+00:00

On PREEMPT_RT, bh_worker() wraps work item execution in pool->cb_lock to provide a handshake for canceling BH work items. When a CPU goes down, drain_dead_softirq_workfn() runs the dead pool's bh_worker() nested inside the local pool's bh_worker(), acquiring the cb_locks of two different pools without a nesting annotation. lockdep reports possible recursive locking: ============================================ WARNING: possible recursive locking detected -------------------------------------------- ktimers/0/16 is trying to acquire lock: ffff8880b873a990 (&pool->cb_lock){+...}-{3:3}, at: bh_worker+0x7d/0x880 but task is already holding lock: ffff8880b863a990 (&pool->cb_lock){+...}-{3:3}, at: bh_worker+0x7d/0x880 Call Trace: bh_worker+0x7d/0x880 kernel/workqueue.c:3688 drain_dead_softirq_workfn+0x95/0x220 kernel/workqueue.c:3763 process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405 bh_worker+0x46a/0x880 kernel/workqueue.c:3708 tasklet_action+0xc/0x70 kernel/softirq.c:965 The nesting can't deadlock. A pool's bh_worker() runs nested only while the pool's CPU is dead, entered from a live pool's bh_worker() on the draining CPU, so the ordering is always live to dead. CPU hotplug operations are serialized and the drain is synchronous, so the nesting depth never exceeds two. Annotate the inner acquisition with SINGLE_DEPTH_NESTING. Signed-off-by: Tejun Heo Reported-by: syzbot+1bd20115328f8254ed62@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=1bd20115328f8254ed62 Fixes: ad7c7f4b9c6c ("workqueue: Provide a handshake for canceling BH workers") Cc: stable@vger.kernel.org # v6.18+