[syzbot] [fs?] [mm?] possible deadlock in flush_end_io

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syzbot

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6:09 AMĀ (4 hours ago)Ā 6:09 AM
to ak...@linux-foundation.org, linux-...@vger.kernel.org, linux-...@vger.kernel.org, linu...@kvack.org, syzkall...@googlegroups.com, wi...@infradead.org
Hello,

syzbot found the following issue on:

HEAD commit: 8f0b4cce4481 Linux 6.19-rc1
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
console output: https://syzkaller.appspot.com/x/log.txt?x=10f58422580000
kernel config: https://syzkaller.appspot.com/x/.config?x=8a8594efdc14f07a
dashboard link: https://syzkaller.appspot.com/bug?extid=56189401febf7b380090
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
userspace arch: arm64

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/cd4f5f43efc8/disk-8f0b4cce.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/aafb35ac3a3c/vmlinux-8f0b4cce.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d221fae4ab17/Image-8f0b4cce.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+561894...@syzkaller.appspotmail.com

=====================================================
WARNING: HARDIRQ-safe -> HARDIRQ-unsafe lock order detected
syzkaller #0 Not tainted
-----------------------------------------------------
ksoftirqd/0/15 [HC0[0]:SC1[1]:HE0:SE0] is trying to acquire:
ffff0000f9020240 (&xa->xa_lock#10){..-.}-{3:3}, at: __folio_end_writeback+0x10c/0x6f8 mm/page-writeback.c:2990

and this task is already holding:
ffff0000c6004818 (&fq->mq_flush_lock){-.-.}-{3:3}, at: flush_end_io+0xb4/0xd68 block/blk-flush.c:211
which would create a new lock dependency:
(&fq->mq_flush_lock){-.-.}-{3:3} -> (&xa->xa_lock#10){..-.}-{3:3}

but this new dependency connects a HARDIRQ-irq-safe lock:
(&fq->mq_flush_lock){-.-.}-{3:3}

... which became HARDIRQ-irq-safe at:
lock_acquire+0x140/0x2e0 kernel/locking/lockdep.c:5868
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x5c/0x7c kernel/locking/spinlock.c:162
flush_end_io+0xb4/0xd68 block/blk-flush.c:211
__blk_mq_end_request+0x37c/0x57c block/blk-mq.c:1159
blk_mq_end_request+0x68/0x88 block/blk-mq.c:1171
nvme_end_req drivers/nvme/host/core.c:454 [inline]
nvme_complete_rq+0x150/0x464 drivers/nvme/host/core.c:-1
nvme_pci_complete_rq drivers/nvme/host/pci.c:1343 [inline]
nvme_handle_cqe drivers/nvme/host/pci.c:1407 [inline]
nvme_poll_cq+0x644/0x1018 drivers/nvme/host/pci.c:1434
nvme_irq+0x90/0x240 drivers/nvme/host/pci.c:1448
__handle_irq_event_percpu+0x20c/0x8e4 kernel/irq/handle.c:211
handle_irq_event_percpu kernel/irq/handle.c:248 [inline]
handle_irq_event+0x9c/0x1d0 kernel/irq/handle.c:265
handle_fasteoi_irq+0x328/0x8d8 kernel/irq/chip.c:764
generic_handle_irq_desc include/linux/irqdesc.h:172 [inline]
handle_irq_desc kernel/irq/irqdesc.c:669 [inline]
generic_handle_domain_irq+0xe0/0x140 kernel/irq/irqdesc.c:725
__gic_handle_irq drivers/irqchip/irq-gic-v3.c:825 [inline]
__gic_handle_irq_from_irqson drivers/irqchip/irq-gic-v3.c:876 [inline]
gic_handle_irq+0x6c/0x18c drivers/irqchip/irq-gic-v3.c:920
call_on_irq_stack+0x30/0x48 arch/arm64/kernel/entry.S:891
do_interrupt_handler+0xd4/0x138 arch/arm64/kernel/entry-common.c:135
__el1_irq arch/arm64/kernel/entry-common.c:497 [inline]
el1_interrupt+0x3c/0x60 arch/arm64/kernel/entry-common.c:510
el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:515
el1h_64_irq+0x6c/0x70 arch/arm64/kernel/entry.S:592
__daif_local_irq_enable arch/arm64/include/asm/irqflags.h:26 [inline]
arch_local_irq_enable arch/arm64/include/asm/irqflags.h:48 [inline]
raw_spin_rq_unlock_irq kernel/sched/sched.h:1570 [inline]
finish_lock_switch+0xb4/0x1c0 kernel/sched/core.c:4995
finish_task_switch+0x104/0x5dc kernel/sched/core.c:5112
context_switch kernel/sched/core.c:5259 [inline]
__schedule+0x1254/0x2a7c kernel/sched/core.c:6863
__schedule_loop kernel/sched/core.c:6945 [inline]
schedule+0xb4/0x230 kernel/sched/core.c:6960
schedule_hrtimeout_range_clock+0x19c/0x2b4 kernel/time/sleep_timeout.c:207
schedule_hrtimeout_range+0x38/0x4c kernel/time/sleep_timeout.c:263
ep_poll+0xa70/0xd38 fs/eventpoll.c:2028
do_epoll_wait+0x194/0x204 fs/eventpoll.c:2461
do_epoll_pwait+0x70/0x18c fs/eventpoll.c:2491
__do_sys_epoll_pwait fs/eventpoll.c:2504 [inline]
__se_sys_epoll_pwait fs/eventpoll.c:2498 [inline]
__arm64_sys_epoll_pwait+0x1e0/0x234 fs/eventpoll.c:2498
__invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49
el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:132
do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
el0_svc+0x5c/0x26c arch/arm64/kernel/entry-common.c:724
el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:743
el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596

to a HARDIRQ-irq-unsafe lock:
(&p->sequence){+.-.}-{0:0}

... which became HARDIRQ-irq-unsafe at:
...
lock_acquire+0x140/0x2e0 kernel/locking/lockdep.c:5868
do_write_seqcount_begin_nested include/linux/seqlock.h:477 [inline]
do_write_seqcount_begin include/linux/seqlock.h:503 [inline]
fprop_new_period+0x3b8/0x718 lib/flex_proportions.c:74
writeout_period+0x94/0x11c mm/page-writeback.c:615
call_timer_fn+0x19c/0x814 kernel/time/timer.c:1748
expire_timers kernel/time/timer.c:1799 [inline]
__run_timers kernel/time/timer.c:2373 [inline]
__run_timer_base+0x51c/0x76c kernel/time/timer.c:2385
run_timer_base kernel/time/timer.c:2394 [inline]
run_timer_softirq+0x11c/0x194 kernel/time/timer.c:2405
handle_softirqs+0x31c/0xc88 kernel/softirq.c:622
__do_softirq+0x14/0x20 kernel/softirq.c:656
____do_softirq+0x14/0x20 arch/arm64/kernel/irq.c:68
call_on_irq_stack+0x30/0x48 arch/arm64/kernel/entry.S:891
do_softirq_own_stack+0x20/0x2c arch/arm64/kernel/irq.c:73
invoke_softirq kernel/softirq.c:503 [inline]
__irq_exit_rcu+0x1b0/0x478 kernel/softirq.c:723
irq_exit_rcu+0x14/0x84 kernel/softirq.c:739
__el1_irq arch/arm64/kernel/entry-common.c:498 [inline]
el1_interrupt+0x40/0x60 arch/arm64/kernel/entry-common.c:510
el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:515
el1h_64_irq+0x6c/0x70 arch/arm64/kernel/entry.S:592
__sanitizer_cov_trace_const_cmp4+0x4/0xa0 kernel/kcov.c:313
d_absolute_path+0xa0/0x148 fs/d_path.c:234
tomoyo_get_absolute_path security/tomoyo/realpath.c:101 [inline]
tomoyo_realpath_from_path+0x258/0x4d4 security/tomoyo/realpath.c:271
tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
tomoyo_path_perm+0x1c4/0x3dc security/tomoyo/file.c:822
tomoyo_inode_getattr+0x28/0x38 security/tomoyo/tomoyo.c:123
security_inode_getattr+0x118/0x300 security/security.c:1869
vfs_getattr fs/stat.c:259 [inline]
vfs_statx_path fs/stat.c:299 [inline]
vfs_statx+0x178/0x4bc fs/stat.c:356
vfs_fstatat+0x100/0x150 fs/stat.c:375
__do_sys_newfstatat fs/stat.c:542 [inline]
__se_sys_newfstatat fs/stat.c:536 [inline]
__arm64_sys_newfstatat+0x100/0x180 fs/stat.c:536
__invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49
el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:132
do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
el0_svc+0x5c/0x26c arch/arm64/kernel/entry-common.c:724
el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:743
el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596

other info that might help us debug this:

Chain exists of:
&fq->mq_flush_lock --> &xa->xa_lock#10 --> &p->sequence

Possible interrupt unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&p->sequence);
local_irq_disable();
lock(&fq->mq_flush_lock);
lock(&xa->xa_lock#10);
<Interrupt>
lock(&fq->mq_flush_lock);

*** DEADLOCK ***

1 lock held by ksoftirqd/0/15:
#0: ffff0000c6004818 (&fq->mq_flush_lock){-.-.}-{3:3}, at: flush_end_io+0xb4/0xd68 block/blk-flush.c:211

the dependencies between HARDIRQ-irq-safe lock and the holding lock:
-> (&fq->mq_flush_lock){-.-.}-{3:3} {
IN-HARDIRQ-W at:
lock_acquire+0x140/0x2e0 kernel/locking/lockdep.c:5868
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x5c/0x7c kernel/locking/spinlock.c:162
flush_end_io+0xb4/0xd68 block/blk-flush.c:211
__blk_mq_end_request+0x37c/0x57c block/blk-mq.c:1159
blk_mq_end_request+0x68/0x88 block/blk-mq.c:1171
nvme_end_req drivers/nvme/host/core.c:454 [inline]
nvme_complete_rq+0x150/0x464 drivers/nvme/host/core.c:-1
nvme_pci_complete_rq drivers/nvme/host/pci.c:1343 [inline]
nvme_handle_cqe drivers/nvme/host/pci.c:1407 [inline]
nvme_poll_cq+0x644/0x1018 drivers/nvme/host/pci.c:1434
nvme_irq+0x90/0x240 drivers/nvme/host/pci.c:1448
__handle_irq_event_percpu+0x20c/0x8e4 kernel/irq/handle.c:211
handle_irq_event_percpu kernel/irq/handle.c:248 [inline]
handle_irq_event+0x9c/0x1d0 kernel/irq/handle.c:265
handle_fasteoi_irq+0x328/0x8d8 kernel/irq/chip.c:764
generic_handle_irq_desc include/linux/irqdesc.h:172 [inline]
handle_irq_desc kernel/irq/irqdesc.c:669 [inline]
generic_handle_domain_irq+0xe0/0x140 kernel/irq/irqdesc.c:725
__gic_handle_irq drivers/irqchip/irq-gic-v3.c:825 [inline]
__gic_handle_irq_from_irqson drivers/irqchip/irq-gic-v3.c:876 [inline]
gic_handle_irq+0x6c/0x18c drivers/irqchip/irq-gic-v3.c:920
call_on_irq_stack+0x30/0x48 arch/arm64/kernel/entry.S:891
do_interrupt_handler+0xd4/0x138 arch/arm64/kernel/entry-common.c:135
__el1_irq arch/arm64/kernel/entry-common.c:497 [inline]
el1_interrupt+0x3c/0x60 arch/arm64/kernel/entry-common.c:510
el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:515
el1h_64_irq+0x6c/0x70 arch/arm64/kernel/entry.S:592
__daif_local_irq_enable arch/arm64/include/asm/irqflags.h:26 [inline]
arch_local_irq_enable arch/arm64/include/asm/irqflags.h:48 [inline]
raw_spin_rq_unlock_irq kernel/sched/sched.h:1570 [inline]
finish_lock_switch+0xb4/0x1c0 kernel/sched/core.c:4995
finish_task_switch+0x104/0x5dc kernel/sched/core.c:5112
context_switch kernel/sched/core.c:5259 [inline]
__schedule+0x1254/0x2a7c kernel/sched/core.c:6863
__schedule_loop kernel/sched/core.c:6945 [inline]
schedule+0xb4/0x230 kernel/sched/core.c:6960
schedule_hrtimeout_range_clock+0x19c/0x2b4 kernel/time/sleep_timeout.c:207
schedule_hrtimeout_range+0x38/0x4c kernel/time/sleep_timeout.c:263
ep_poll+0xa70/0xd38 fs/eventpoll.c:2028
do_epoll_wait+0x194/0x204 fs/eventpoll.c:2461
do_epoll_pwait+0x70/0x18c fs/eventpoll.c:2491
__do_sys_epoll_pwait fs/eventpoll.c:2504 [inline]
__se_sys_epoll_pwait fs/eventpoll.c:2498 [inline]
__arm64_sys_epoll_pwait+0x1e0/0x234 fs/eventpoll.c:2498
__invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49
el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:132
do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
el0_svc+0x5c/0x26c arch/arm64/kernel/entry-common.c:724
el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:743
el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596
IN-SOFTIRQ-W at:
lock_acquire+0x140/0x2e0 kernel/locking/lockdep.c:5868
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x5c/0x7c kernel/locking/spinlock.c:162
mq_flush_data_end_io+0x270/0x480 block/blk-flush.c:355
__blk_mq_end_request+0x37c/0x57c block/blk-mq.c:1159
blk_mq_end_request+0x68/0x88 block/blk-mq.c:1171
lo_complete_rq+0x124/0x274 drivers/block/loop.c:314
blk_complete_reqs block/blk-mq.c:1244 [inline]
blk_done_softirq+0x11c/0x168 block/blk-mq.c:1249
handle_softirqs+0x31c/0xc88 kernel/softirq.c:622
run_ksoftirqd+0x70/0xc0 kernel/softirq.c:1063
smpboot_thread_fn+0x4d8/0x9cc kernel/smpboot.c:160
kthread+0x5fc/0x75c kernel/kthread.c:463
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844
INITIAL USE at:
lock_acquire+0x140/0x2e0 kernel/locking/lockdep.c:5868
__raw_spin_lock_irq include/linux/spinlock_api_smp.h:119 [inline]
_raw_spin_lock_irq+0x58/0x70 kernel/locking/spinlock.c:170
spin_lock_irq include/linux/spinlock.h:376 [inline]
blk_insert_flush+0x360/0x4b8 block/blk-flush.c:454
blk_mq_submit_bio+0x1668/0x21e8 block/blk-mq.c:3229
__submit_bio+0x1d8/0x4d8 block/blk-core.c:637
__submit_bio_noacct_mq block/blk-core.c:724 [inline]
submit_bio_noacct_nocheck+0x274/0x990 block/blk-core.c:755
submit_bio_noacct+0xdc0/0x186c block/blk-core.c:879
submit_bio+0x3b4/0x550 block/blk-core.c:921
submit_bio_wait+0x104/0x208 block/bio.c:1391
blkdev_issue_flush+0xb4/0x100 block/blk-flush.c:473
ext4_init_inode_table+0x420/0x780 fs/ext4/ialloc.c:1602
ext4_run_li_request fs/ext4/super.c:3732 [inline]
ext4_lazyinit_thread+0x6dc/0x1730 fs/ext4/super.c:3827
kthread+0x5fc/0x75c kernel/kthread.c:463
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844
}
... key at: [<ffff8000977c83c0>] blk_alloc_flush_queue.__key+0x0/0x20

the dependencies between the lock to be acquired
and HARDIRQ-irq-unsafe lock:
-> (&p->sequence){+.-.}-{0:0} {
HARDIRQ-ON-W at:
lock_acquire+0x140/0x2e0 kernel/locking/lockdep.c:5868
do_write_seqcount_begin_nested include/linux/seqlock.h:477 [inline]
do_write_seqcount_begin include/linux/seqlock.h:503 [inline]
fprop_new_period+0x3b8/0x718 lib/flex_proportions.c:74
writeout_period+0x94/0x11c mm/page-writeback.c:615
call_timer_fn+0x19c/0x814 kernel/time/timer.c:1748
expire_timers kernel/time/timer.c:1799 [inline]
__run_timers kernel/time/timer.c:2373 [inline]
__run_timer_base+0x51c/0x76c kernel/time/timer.c:2385
run_timer_base kernel/time/timer.c:2394 [inline]
run_timer_softirq+0x11c/0x194 kernel/time/timer.c:2405
handle_softirqs+0x31c/0xc88 kernel/softirq.c:622
__do_softirq+0x14/0x20 kernel/softirq.c:656
____do_softirq+0x14/0x20 arch/arm64/kernel/irq.c:68
call_on_irq_stack+0x30/0x48 arch/arm64/kernel/entry.S:891
do_softirq_own_stack+0x20/0x2c arch/arm64/kernel/irq.c:73
invoke_softirq kernel/softirq.c:503 [inline]
__irq_exit_rcu+0x1b0/0x478 kernel/softirq.c:723
irq_exit_rcu+0x14/0x84 kernel/softirq.c:739
__el1_irq arch/arm64/kernel/entry-common.c:498 [inline]
el1_interrupt+0x40/0x60 arch/arm64/kernel/entry-common.c:510
el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:515
el1h_64_irq+0x6c/0x70 arch/arm64/kernel/entry.S:592
__sanitizer_cov_trace_const_cmp4+0x4/0xa0 kernel/kcov.c:313
d_absolute_path+0xa0/0x148 fs/d_path.c:234
tomoyo_get_absolute_path security/tomoyo/realpath.c:101 [inline]
tomoyo_realpath_from_path+0x258/0x4d4 security/tomoyo/realpath.c:271
tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
tomoyo_path_perm+0x1c4/0x3dc security/tomoyo/file.c:822
tomoyo_inode_getattr+0x28/0x38 security/tomoyo/tomoyo.c:123
security_inode_getattr+0x118/0x300 security/security.c:1869
vfs_getattr fs/stat.c:259 [inline]
vfs_statx_path fs/stat.c:299 [inline]
vfs_statx+0x178/0x4bc fs/stat.c:356
vfs_fstatat+0x100/0x150 fs/stat.c:375
__do_sys_newfstatat fs/stat.c:542 [inline]
__se_sys_newfstatat fs/stat.c:536 [inline]
__arm64_sys_newfstatat+0x100/0x180 fs/stat.c:536
__invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49
el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:132
do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
el0_svc+0x5c/0x26c arch/arm64/kernel/entry-common.c:724
el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:743
el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596
IN-SOFTIRQ-W at:
lock_acquire+0x140/0x2e0 kernel/locking/lockdep.c:5868
do_write_seqcount_begin_nested include/linux/seqlock.h:477 [inline]
do_write_seqcount_begin include/linux/seqlock.h:503 [inline]
fprop_new_period+0x3b8/0x718 lib/flex_proportions.c:74
writeout_period+0x94/0x11c mm/page-writeback.c:615
call_timer_fn+0x19c/0x814 kernel/time/timer.c:1748
expire_timers kernel/time/timer.c:1799 [inline]
__run_timers kernel/time/timer.c:2373 [inline]
__run_timer_base+0x51c/0x76c kernel/time/timer.c:2385
run_timer_base kernel/time/timer.c:2394 [inline]
run_timer_softirq+0x11c/0x194 kernel/time/timer.c:2405
handle_softirqs+0x31c/0xc88 kernel/softirq.c:622
__do_softirq+0x14/0x20 kernel/softirq.c:656
____do_softirq+0x14/0x20 arch/arm64/kernel/irq.c:68
call_on_irq_stack+0x30/0x48 arch/arm64/kernel/entry.S:891
do_softirq_own_stack+0x20/0x2c arch/arm64/kernel/irq.c:73
invoke_softirq kernel/softirq.c:503 [inline]
__irq_exit_rcu+0x1b0/0x478 kernel/softirq.c:723
irq_exit_rcu+0x14/0x84 kernel/softirq.c:739
__el1_irq arch/arm64/kernel/entry-common.c:498 [inline]
el1_interrupt+0x40/0x60 arch/arm64/kernel/entry-common.c:510
el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:515
el1h_64_irq+0x6c/0x70 arch/arm64/kernel/entry.S:592
__sanitizer_cov_trace_const_cmp4+0x4/0xa0 kernel/kcov.c:313
d_absolute_path+0xa0/0x148 fs/d_path.c:234
tomoyo_get_absolute_path security/tomoyo/realpath.c:101 [inline]
tomoyo_realpath_from_path+0x258/0x4d4 security/tomoyo/realpath.c:271
tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
tomoyo_path_perm+0x1c4/0x3dc security/tomoyo/file.c:822
tomoyo_inode_getattr+0x28/0x38 security/tomoyo/tomoyo.c:123
security_inode_getattr+0x118/0x300 security/security.c:1869
vfs_getattr fs/stat.c:259 [inline]
vfs_statx_path fs/stat.c:299 [inline]
vfs_statx+0x178/0x4bc fs/stat.c:356
vfs_fstatat+0x100/0x150 fs/stat.c:375
__do_sys_newfstatat fs/stat.c:542 [inline]
__se_sys_newfstatat fs/stat.c:536 [inline]
__arm64_sys_newfstatat+0x100/0x180 fs/stat.c:536
__invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49
el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:132
do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
el0_svc+0x5c/0x26c arch/arm64/kernel/entry-common.c:724
el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:743
el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596
INITIAL USE at:
lock_acquire+0x140/0x2e0 kernel/locking/lockdep.c:5868
do_write_seqcount_begin_nested include/linux/seqlock.h:477 [inline]
do_write_seqcount_begin include/linux/seqlock.h:503 [inline]
fprop_new_period+0x3b8/0x718 lib/flex_proportions.c:74
writeout_period+0x94/0x11c mm/page-writeback.c:615
call_timer_fn+0x19c/0x814 kernel/time/timer.c:1748
expire_timers kernel/time/timer.c:1799 [inline]
__run_timers kernel/time/timer.c:2373 [inline]
__run_timer_base+0x51c/0x76c kernel/time/timer.c:2385
run_timer_base kernel/time/timer.c:2394 [inline]
run_timer_softirq+0x11c/0x194 kernel/time/timer.c:2405
handle_softirqs+0x31c/0xc88 kernel/softirq.c:622
__do_softirq+0x14/0x20 kernel/softirq.c:656
____do_softirq+0x14/0x20 arch/arm64/kernel/irq.c:68
call_on_irq_stack+0x30/0x48 arch/arm64/kernel/entry.S:891
do_softirq_own_stack+0x20/0x2c arch/arm64/kernel/irq.c:73
invoke_softirq kernel/softirq.c:503 [inline]
__irq_exit_rcu+0x1b0/0x478 kernel/softirq.c:723
irq_exit_rcu+0x14/0x84 kernel/softirq.c:739
__el1_irq arch/arm64/kernel/entry-common.c:498 [inline]
el1_interrupt+0x40/0x60 arch/arm64/kernel/entry-common.c:510
el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:515
el1h_64_irq+0x6c/0x70 arch/arm64/kernel/entry.S:592
__sanitizer_cov_trace_const_cmp4+0x4/0xa0 kernel/kcov.c:313
d_absolute_path+0xa0/0x148 fs/d_path.c:234
tomoyo_get_absolute_path security/tomoyo/realpath.c:101 [inline]
tomoyo_realpath_from_path+0x258/0x4d4 security/tomoyo/realpath.c:271
tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
tomoyo_path_perm+0x1c4/0x3dc security/tomoyo/file.c:822
tomoyo_inode_getattr+0x28/0x38 security/tomoyo/tomoyo.c:123
security_inode_getattr+0x118/0x300 security/security.c:1869
vfs_getattr fs/stat.c:259 [inline]
vfs_statx_path fs/stat.c:299 [inline]
vfs_statx+0x178/0x4bc fs/stat.c:356
vfs_fstatat+0x100/0x150 fs/stat.c:375
__do_sys_newfstatat fs/stat.c:542 [inline]
__se_sys_newfstatat fs/stat.c:536 [inline]
__arm64_sys_newfstatat+0x100/0x180 fs/stat.c:536
__invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49
el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:132
do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
el0_svc+0x5c/0x26c arch/arm64/kernel/entry-common.c:724
el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:743
el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596
INITIAL READ USE at:
lock_acquire+0x140/0x2e0 kernel/locking/lockdep.c:5868
seqcount_lockdep_reader_access include/linux/seqlock.h:72 [inline]
fprop_fraction_percpu+0xac/0x270 lib/flex_proportions.c:155
__wb_calc_thresh+0xfc/0x3b0 mm/page-writeback.c:913
wb_bg_dirty_limits mm/page-writeback.c:2130 [inline]
domain_over_bg_thresh+0xb8/0x1f0 mm/page-writeback.c:2144
wb_over_bg_thresh+0xf8/0x17c mm/page-writeback.c:2165
wb_check_background_flush fs/fs-writeback.c:2278 [inline]
wb_do_writeback fs/fs-writeback.c:2376 [inline]
wb_workfn+0xa30/0xdc0 fs/fs-writeback.c:2403
process_one_work+0x7c0/0x1558 kernel/workqueue.c:3257
process_scheduled_works kernel/workqueue.c:3340 [inline]
worker_thread+0x958/0xed8 kernel/workqueue.c:3421
kthread+0x5fc/0x75c kernel/kthread.c:463
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844
}
... key at: [<ffff800097b99300>] fprop_global_init.__key.1+0x0/0x20
... acquired at:
seqcount_lockdep_reader_access include/linux/seqlock.h:72 [inline]
fprop_fraction_percpu+0xf0/0x270 lib/flex_proportions.c:155
__fprop_add_percpu_max+0x130/0x1f4 lib/flex_proportions.c:186
wb_domain_writeout_add mm/page-writeback.c:562 [inline]
__wb_writeout_add+0xbc/0x27c mm/page-writeback.c:586
__folio_end_writeback+0x380/0x6f8 mm/page-writeback.c:2997
folio_end_writeback_no_dropbehind+0xd0/0x204 mm/filemap.c:1661
folio_end_writeback+0xd8/0x248 mm/filemap.c:1687
iomap_finish_folio_write+0x1c0/0x2a4 fs/iomap/buffered-io.c:1713
fuse_writepage_finish fs/fuse/file.c:1903 [inline]
fuse_send_writepage fs/fuse/file.c:1954 [inline]
fuse_flush_writepages+0x578/0x788 fs/fuse/file.c:1979
fuse_writepages_send fs/fuse/file.c:2158 [inline]
fuse_iomap_writeback_submit+0x188/0x220 fs/fuse/file.c:2260
iomap_writepages+0x1dc/0x25c fs/iomap/buffered-io.c:1916
fuse_writepages+0x208/0x2bc fs/fuse/file.c:2295
do_writepages+0x270/0x468 mm/page-writeback.c:2598
filemap_writeback mm/filemap.c:387 [inline]
filemap_fdatawrite_range mm/filemap.c:412 [inline]
file_write_and_wait_range+0x1d0/0x2c4 mm/filemap.c:786
fuse_fsync+0x100/0x2b8 fs/fuse/file.c:547
vfs_fsync_range+0x160/0x19c fs/sync.c:188
generic_write_sync include/linux/fs.h:2616 [inline]
fuse_cache_write_iter fs/fuse/file.c:1527 [inline]
fuse_file_write_iter+0xa20/0xb88 fs/fuse/file.c:1849
do_iter_readv_writev+0x4bc/0x720 fs/read_write.c:-1
vfs_writev+0x29c/0x7cc fs/read_write.c:1057
do_writev+0x128/0x290 fs/read_write.c:1103
__do_sys_writev fs/read_write.c:1171 [inline]
__se_sys_writev fs/read_write.c:1168 [inline]
__arm64_sys_writev+0x80/0x94 fs/read_write.c:1168
__invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49
el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:132
do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
el0_svc+0x5c/0x26c arch/arm64/kernel/entry-common.c:724
el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:743
el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596

-> (&xa->xa_lock#10){..-.}-{3:3} {
IN-SOFTIRQ-W at:
lock_acquire+0x140/0x2e0 kernel/locking/lockdep.c:5868
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x5c/0x7c kernel/locking/spinlock.c:162
__folio_end_writeback+0x10c/0x6f8 mm/page-writeback.c:2990
folio_end_writeback_no_dropbehind+0xd0/0x204 mm/filemap.c:1661
folio_end_writeback+0xd8/0x248 mm/filemap.c:1687
end_buffer_async_write+0x20c/0x350 fs/buffer.c:419
end_bio_bh_io_sync+0xb0/0x184 fs/buffer.c:2776
bio_endio+0x8d4/0x910 block/bio.c:1675
blk_update_request+0x474/0xba8 block/blk-mq.c:1007
blk_mq_end_request+0x54/0x88 block/blk-mq.c:1169
lo_complete_rq+0x124/0x274 drivers/block/loop.c:314
blk_complete_reqs block/blk-mq.c:1244 [inline]
blk_done_softirq+0x11c/0x168 block/blk-mq.c:1249
handle_softirqs+0x31c/0xc88 kernel/softirq.c:622
run_ksoftirqd+0x70/0xc0 kernel/softirq.c:1063
smpboot_thread_fn+0x4d8/0x9cc kernel/smpboot.c:160
kthread+0x5fc/0x75c kernel/kthread.c:463
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844
INITIAL USE at:
lock_acquire+0x140/0x2e0 kernel/locking/lockdep.c:5868
__raw_spin_lock_irq include/linux/spinlock_api_smp.h:119 [inline]
_raw_spin_lock_irq+0x58/0x70 kernel/locking/spinlock.c:170
spin_lock_irq include/linux/spinlock.h:376 [inline]
shmem_add_to_page_cache+0x564/0xa24 mm/shmem.c:904
shmem_alloc_and_add_folio+0x758/0x10c4 mm/shmem.c:1958
shmem_get_folio_gfp+0x4d4/0x159c mm/shmem.c:2556
shmem_read_folio_gfp+0x8c/0xf0 mm/shmem.c:5974
drm_gem_get_pages+0x1cc/0x7c0 drivers/gpu/drm/drm_gem.c:654
drm_gem_shmem_get_pages_locked+0x1d4/0x364 drivers/gpu/drm/drm_gem_shmem_helper.c:239
drm_gem_shmem_pin_locked+0x1f8/0x410 drivers/gpu/drm/drm_gem_shmem_helper.c:300
drm_gem_shmem_vmap_locked+0x3cc/0x658 drivers/gpu/drm/drm_gem_shmem_helper.c:404
drm_gem_shmem_object_vmap+0x28/0x38 include/drm/drm_gem_shmem_helper.h:245
drm_gem_vmap_locked drivers/gpu/drm/drm_gem.c:1269 [inline]
drm_gem_vmap+0x104/0x1d8 drivers/gpu/drm/drm_gem.c:1311
drm_client_buffer_vmap+0x68/0xb0 drivers/gpu/drm/drm_client.c:355
drm_fbdev_shmem_driver_fbdev_probe+0x1f4/0x700 drivers/gpu/drm/drm_fbdev_shmem.c:159
drm_fb_helper_single_fb_probe drivers/gpu/drm/drm_fb_helper.c:1562 [inline]
__drm_fb_helper_initial_config_and_unlock+0x108c/0x1728 drivers/gpu/drm/drm_fb_helper.c:1741
drm_fb_helper_initial_config+0x3c/0x58 drivers/gpu/drm/drm_fb_helper.c:1828
drm_fbdev_client_hotplug+0x154/0x22c drivers/gpu/drm/clients/drm_fbdev_client.c:66
drm_client_register+0x13c/0x1d4 drivers/gpu/drm/drm_client.c:143
drm_fbdev_client_setup+0x194/0x3d0 drivers/gpu/drm/clients/drm_fbdev_client.c:168
drm_client_setup+0x114/0x228 drivers/gpu/drm/clients/drm_client_setup.c:46
vkms_create+0x370/0x420 drivers/gpu/drm/vkms/vkms_drv.c:211
vkms_init+0x64/0x9c drivers/gpu/drm/vkms/vkms_drv.c:239
do_one_initcall+0x248/0x9b4 init/main.c:1378
do_initcall_level+0x128/0x1c4 init/main.c:1440
do_initcalls+0x70/0xd0 init/main.c:1456
do_basic_setup+0x78/0x8c init/main.c:1475
kernel_init_freeable+0x268/0x39c init/main.c:1688
kernel_init+0x24/0x1dc init/main.c:1578
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844
}
... key at: [<ffff800097649620>] xa_init_flags.__key+0x0/0x20
... acquired at:
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x5c/0x7c kernel/locking/spinlock.c:162
__folio_end_writeback+0x10c/0x6f8 mm/page-writeback.c:2990
folio_end_writeback_no_dropbehind+0xd0/0x204 mm/filemap.c:1661
folio_end_writeback+0xd8/0x248 mm/filemap.c:1687
f2fs_write_end_io+0x6c0/0xa78 fs/f2fs/data.c:362
bio_endio+0x8d4/0x910 block/bio.c:1675
blk_update_request+0x474/0xba8 block/blk-mq.c:1007
blk_mq_end_request+0x54/0x88 block/blk-mq.c:1169
blk_flush_complete_seq+0x57c/0xad4 block/blk-flush.c:191
flush_end_io+0x9e8/0xd68 block/blk-flush.c:250
__blk_mq_end_request+0x37c/0x57c block/blk-mq.c:1159
blk_mq_end_request+0x68/0x88 block/blk-mq.c:1171
lo_complete_rq+0x124/0x274 drivers/block/loop.c:314
blk_complete_reqs block/blk-mq.c:1244 [inline]
blk_done_softirq+0x11c/0x168 block/blk-mq.c:1249
handle_softirqs+0x31c/0xc88 kernel/softirq.c:622
run_ksoftirqd+0x70/0xc0 kernel/softirq.c:1063
smpboot_thread_fn+0x4d8/0x9cc kernel/smpboot.c:160
kthread+0x5fc/0x75c kernel/kthread.c:463
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844


stack backtrace:
CPU: 0 UID: 0 PID: 15 Comm: ksoftirqd/0 Not tainted syzkaller #0 PREEMPT
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/03/2025
Call trace:
show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:499 (C)
__dump_stack+0x30/0x40 lib/dump_stack.c:94
dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120
dump_stack+0x1c/0x28 lib/dump_stack.c:129
print_bad_irq_dependency kernel/locking/lockdep.c:2616 [inline]
check_irq_usage kernel/locking/lockdep.c:2857 [inline]
check_prev_add kernel/locking/lockdep.c:3169 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain kernel/locking/lockdep.c:3908 [inline]
__lock_acquire+0x3058/0x30a4 kernel/locking/lockdep.c:5237
lock_acquire+0x140/0x2e0 kernel/locking/lockdep.c:5868
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x5c/0x7c kernel/locking/spinlock.c:162
__folio_end_writeback+0x10c/0x6f8 mm/page-writeback.c:2990
folio_end_writeback_no_dropbehind+0xd0/0x204 mm/filemap.c:1661
folio_end_writeback+0xd8/0x248 mm/filemap.c:1687
f2fs_write_end_io+0x6c0/0xa78 fs/f2fs/data.c:362
bio_endio+0x8d4/0x910 block/bio.c:1675
blk_update_request+0x474/0xba8 block/blk-mq.c:1007
blk_mq_end_request+0x54/0x88 block/blk-mq.c:1169
blk_flush_complete_seq+0x57c/0xad4 block/blk-flush.c:191
flush_end_io+0x9e8/0xd68 block/blk-flush.c:250
__blk_mq_end_request+0x37c/0x57c block/blk-mq.c:1159
blk_mq_end_request+0x68/0x88 block/blk-mq.c:1171
lo_complete_rq+0x124/0x274 drivers/block/loop.c:314
blk_complete_reqs block/blk-mq.c:1244 [inline]
blk_done_softirq+0x11c/0x168 block/blk-mq.c:1249
handle_softirqs+0x31c/0xc88 kernel/softirq.c:622
run_ksoftirqd+0x70/0xc0 kernel/softirq.c:1063
smpboot_thread_fn+0x4d8/0x9cc kernel/smpboot.c:160
kthread+0x5fc/0x75c kernel/kthread.c:463
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844


---
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