[syzbot] [bpf?] [net?] possible deadlock in swake_up_one

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: fe46a7dd189e Merge tag 'sound-6.9-rc1' of git://git.kernel..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1683dbcb180000
kernel config: https://syzkaller.appspot.com/x/.config?x=aef2a55903e5791c
dashboard link: https://syzkaller.appspot.com/bug?extid=c1571e01da4f845b858f
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10698467180000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16c80f4d180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/089e25869df5/disk-fe46a7dd.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/423b1787914f/vmlinux-fe46a7dd.xz
kernel image: https://storage.googleapis.com/syzbot-assets/4c043e30c07d/bzImage-fe46a7dd.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c1571e...@syzkaller.appspotmail.com

=====================================================
WARNING: HARDIRQ-safe -> HARDIRQ-unsafe lock order detected
6.8.0-syzkaller-08951-gfe46a7dd189e #0 Not tainted
-----------------------------------------------------
rcu_exp_gp_kthr/18 [HC0[0]:SC0[2]:HE0:SE0] is trying to acquire:
ffff88802f1b4820 (&htab->buckets[i].lock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
ffff88802f1b4820 (&htab->buckets[i].lock){+...}-{2:2}, at: sock_hash_delete_elem+0xcb/0x260 net/core/sock_map.c:939

and this task is already holding:
ffffffff8d7bc598 (&rcu_state.expedited_wq){-.-.}-{2:2}, at: finish_swait+0xc5/0x280 kernel/sched/swait.c:139
which would create a new lock dependency:
(&rcu_state.expedited_wq){-.-.}-{2:2} -> (&htab->buckets[i].lock){+...}-{2:2}

but this new dependency connects a HARDIRQ-irq-safe lock:
(&rcu_state.expedited_wq){-.-.}-{2:2}

... which became HARDIRQ-irq-safe at:
lock_acquire kernel/locking/lockdep.c:5754 [inline]
lock_acquire+0x1b1/0x540 kernel/locking/lockdep.c:5719
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162
swake_up_one+0x1a/0x1b0 kernel/sched/swait.c:51
csd_do_func kernel/smp.c:133 [inline]
__flush_smp_call_function_queue+0x41f/0x8c0 kernel/smp.c:542
__sysvec_call_function_single+0x8c/0x3a0 arch/x86/kernel/smp.c:271
instr_sysvec_call_function_single arch/x86/kernel/smp.c:266 [inline]
sysvec_call_function_single+0x90/0xb0 arch/x86/kernel/smp.c:266
asm_sysvec_call_function_single+0x1a/0x20 arch/x86/include/asm/idtentry.h:709
trace_event_eval_update+0x1de/0xfe0 kernel/trace/trace_events.c:2916
trace_insert_eval_map kernel/trace/trace.c:6294 [inline]
eval_map_work_func+0x3d/0x50 kernel/trace/trace.c:10069
process_one_work+0x9a9/0x1a60 kernel/workqueue.c:3254
process_scheduled_works kernel/workqueue.c:3335 [inline]
worker_thread+0x6c8/0xf70 kernel/workqueue.c:3416
kthread+0x2c1/0x3a0 kernel/kthread.c:388
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243

to a HARDIRQ-irq-unsafe lock:
(&htab->buckets[i].lock){+...}-{2:2}

... which became HARDIRQ-irq-unsafe at:
...
lock_acquire kernel/locking/lockdep.c:5754 [inline]
lock_acquire+0x1b1/0x540 kernel/locking/lockdep.c:5719
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
_raw_spin_lock_bh+0x33/0x40 kernel/locking/spinlock.c:178
spin_lock_bh include/linux/spinlock.h:356 [inline]
sock_hash_delete_elem+0xcb/0x260 net/core/sock_map.c:939
___bpf_prog_run+0x3e51/0xae80 kernel/bpf/core.c:1997
__bpf_prog_run32+0xc1/0x100 kernel/bpf/core.c:2236
bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline]
__bpf_prog_run include/linux/filter.h:657 [inline]
bpf_prog_run include/linux/filter.h:664 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2381 [inline]
bpf_trace_run2+0x151/0x420 kernel/trace/bpf_trace.c:2420
__bpf_trace_contention_end+0xca/0x110 include/trace/events/lock.h:122
trace_contention_end+0xce/0x120 include/trace/events/lock.h:122
__mutex_lock_common kernel/locking/mutex.c:617 [inline]
__mutex_lock+0x19c/0x9c0 kernel/locking/mutex.c:752
futex_cleanup_begin kernel/futex/core.c:1091 [inline]
futex_exit_release+0x2a/0x220 kernel/futex/core.c:1143
exit_mm_release+0x19/0x30 kernel/fork.c:1652
exit_mm kernel/exit.c:542 [inline]
do_exit+0x865/0x2be0 kernel/exit.c:865
do_group_exit+0xd3/0x2a0 kernel/exit.c:1027
__do_sys_exit_group kernel/exit.c:1038 [inline]
__se_sys_exit_group kernel/exit.c:1036 [inline]
__x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1036
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xd2/0x260 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x6d/0x75

other info that might help us debug this:

Possible interrupt unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&htab->buckets[i].lock);
local_irq_disable();
lock(&rcu_state.expedited_wq);
lock(&htab->buckets[i].lock);
<Interrupt>
lock(&rcu_state.expedited_wq);

*** DEADLOCK ***

2 locks held by rcu_exp_gp_kthr/18:
#0: ffffffff8d7bc598 (&rcu_state.expedited_wq){-.-.}-{2:2}, at: finish_swait+0xc5/0x280 kernel/sched/swait.c:139
#1: ffffffff8d7b08e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:298 [inline]
#1: ffffffff8d7b08e0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:750 [inline]
#1: ffffffff8d7b08e0 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2380 [inline]
#1: ffffffff8d7b08e0 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0xe4/0x420 kernel/trace/bpf_trace.c:2420

the dependencies between HARDIRQ-irq-safe lock and the holding lock:
-> (&rcu_state.expedited_wq){-.-.}-{2:2} {
IN-HARDIRQ-W at:
lock_acquire kernel/locking/lockdep.c:5754 [inline]
lock_acquire+0x1b1/0x540 kernel/locking/lockdep.c:5719
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162
swake_up_one+0x1a/0x1b0 kernel/sched/swait.c:51
csd_do_func kernel/smp.c:133 [inline]
__flush_smp_call_function_queue+0x41f/0x8c0 kernel/smp.c:542
__sysvec_call_function_single+0x8c/0x3a0 arch/x86/kernel/smp.c:271
instr_sysvec_call_function_single arch/x86/kernel/smp.c:266 [inline]
sysvec_call_function_single+0x90/0xb0 arch/x86/kernel/smp.c:266
asm_sysvec_call_function_single+0x1a/0x20 arch/x86/include/asm/idtentry.h:709
trace_event_eval_update+0x1de/0xfe0 kernel/trace/trace_events.c:2916
trace_insert_eval_map kernel/trace/trace.c:6294 [inline]
eval_map_work_func+0x3d/0x50 kernel/trace/trace.c:10069
process_one_work+0x9a9/0x1a60 kernel/workqueue.c:3254
process_scheduled_works kernel/workqueue.c:3335 [inline]
worker_thread+0x6c8/0xf70 kernel/workqueue.c:3416
kthread+0x2c1/0x3a0 kernel/kthread.c:388
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243
IN-SOFTIRQ-W at:
lock_acquire kernel/locking/lockdep.c:5754 [inline]
lock_acquire+0x1b1/0x540 kernel/locking/lockdep.c:5719
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162
swake_up_one+0x1a/0x1b0 kernel/sched/swait.c:51
rcu_report_exp_rdp kernel/rcu/tree_exp.h:260 [inline]
rcu_preempt_deferred_qs_irqrestore+0x592/0xb80 kernel/rcu/tree_plugin.h:506
rcu_softirq_qs+0x1b/0x1c0 kernel/rcu/tree.c:246
__do_softirq+0x71a/0x8de kernel/softirq.c:568
run_ksoftirqd kernel/softirq.c:924 [inline]
run_ksoftirqd+0x35/0x60 kernel/softirq.c:916
smpboot_thread_fn+0x661/0xa10 kernel/smpboot.c:164
kthread+0x2c1/0x3a0 kernel/kthread.c:388
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243
INITIAL USE at:
lock_acquire kernel/locking/lockdep.c:5754 [inline]
lock_acquire+0x1b1/0x540 kernel/locking/lockdep.c:5719
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162
prepare_to_swait_event+0x1f/0x470 kernel/sched/swait.c:107
synchronize_rcu_expedited_wait_once kernel/rcu/tree_exp.h:516 [inline]
synchronize_rcu_expedited_wait kernel/rcu/tree_exp.h:570 [inline]
rcu_exp_wait_wake+0x2a2/0x15e0 kernel/rcu/tree_exp.h:641
kthread_worker_fn+0x305/0xab0 kernel/kthread.c:841
kthread+0x2c1/0x3a0 kernel/kthread.c:388
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243
}
... key at: [<ffffffff946869c0>] __key.3+0x0/0x40

the dependencies between the lock to be acquired
and HARDIRQ-irq-unsafe lock:
-> (&htab->buckets[i].lock){+...}-{2:2} {
HARDIRQ-ON-W at:
lock_acquire kernel/locking/lockdep.c:5754 [inline]
lock_acquire+0x1b1/0x540 kernel/locking/lockdep.c:5719
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
_raw_spin_lock_bh+0x33/0x40 kernel/locking/spinlock.c:178
spin_lock_bh include/linux/spinlock.h:356 [inline]
sock_hash_delete_elem+0xcb/0x260 net/core/sock_map.c:939
___bpf_prog_run+0x3e51/0xae80 kernel/bpf/core.c:1997
__bpf_prog_run32+0xc1/0x100 kernel/bpf/core.c:2236
bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline]
__bpf_prog_run include/linux/filter.h:657 [inline]
bpf_prog_run include/linux/filter.h:664 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2381 [inline]
bpf_trace_run2+0x151/0x420 kernel/trace/bpf_trace.c:2420
__bpf_trace_contention_end+0xca/0x110 include/trace/events/lock.h:122
trace_contention_end+0xce/0x120 include/trace/events/lock.h:122
__mutex_lock_common kernel/locking/mutex.c:617 [inline]
__mutex_lock+0x19c/0x9c0 kernel/locking/mutex.c:752
futex_cleanup_begin kernel/futex/core.c:1091 [inline]
futex_exit_release+0x2a/0x220 kernel/futex/core.c:1143
exit_mm_release+0x19/0x30 kernel/fork.c:1652
exit_mm kernel/exit.c:542 [inline]
do_exit+0x865/0x2be0 kernel/exit.c:865
do_group_exit+0xd3/0x2a0 kernel/exit.c:1027
__do_sys_exit_group kernel/exit.c:1038 [inline]
__se_sys_exit_group kernel/exit.c:1036 [inline]
__x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1036
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xd2/0x260 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x6d/0x75
INITIAL USE at:
lock_acquire kernel/locking/lockdep.c:5754 [inline]
lock_acquire+0x1b1/0x540 kernel/locking/lockdep.c:5719
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
_raw_spin_lock_bh+0x33/0x40 kernel/locking/spinlock.c:178
spin_lock_bh include/linux/spinlock.h:356 [inline]
sock_hash_delete_elem+0xcb/0x260 net/core/sock_map.c:939
___bpf_prog_run+0x3e51/0xae80 kernel/bpf/core.c:1997
__bpf_prog_run32+0xc1/0x100 kernel/bpf/core.c:2236
bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline]
__bpf_prog_run include/linux/filter.h:657 [inline]
bpf_prog_run include/linux/filter.h:664 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2381 [inline]
bpf_trace_run2+0x151/0x420 kernel/trace/bpf_trace.c:2420
__bpf_trace_contention_end+0xca/0x110 include/trace/events/lock.h:122
trace_contention_end+0xce/0x120 include/trace/events/lock.h:122
__mutex_lock_common kernel/locking/mutex.c:617 [inline]
__mutex_lock+0x19c/0x9c0 kernel/locking/mutex.c:752
futex_cleanup_begin kernel/futex/core.c:1091 [inline]
futex_exit_release+0x2a/0x220 kernel/futex/core.c:1143
exit_mm_release+0x19/0x30 kernel/fork.c:1652
exit_mm kernel/exit.c:542 [inline]
do_exit+0x865/0x2be0 kernel/exit.c:865
do_group_exit+0xd3/0x2a0 kernel/exit.c:1027
__do_sys_exit_group kernel/exit.c:1038 [inline]
__se_sys_exit_group kernel/exit.c:1036 [inline]
__x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1036
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xd2/0x260 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x6d/0x75
}
... key at: [<ffffffff949c67c0>] __key.0+0x0/0x40
... acquired at:
lock_acquire kernel/locking/lockdep.c:5754 [inline]
lock_acquire+0x1b1/0x540 kernel/locking/lockdep.c:5719
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
_raw_spin_lock_bh+0x33/0x40 kernel/locking/spinlock.c:178
spin_lock_bh include/linux/spinlock.h:356 [inline]
sock_hash_delete_elem+0xcb/0x260 net/core/sock_map.c:939
___bpf_prog_run+0x3e51/0xae80 kernel/bpf/core.c:1997
__bpf_prog_run32+0xc1/0x100 kernel/bpf/core.c:2236
bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline]
__bpf_prog_run include/linux/filter.h:657 [inline]
bpf_prog_run include/linux/filter.h:664 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2381 [inline]
bpf_trace_run2+0x151/0x420 kernel/trace/bpf_trace.c:2420
__bpf_trace_contention_end+0xca/0x110 include/trace/events/lock.h:122
trace_contention_end.constprop.0+0xe2/0x140 include/trace/events/lock.h:122
__pv_queued_spin_lock_slowpath+0x266/0xc80 kernel/locking/qspinlock.c:560
pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:584 [inline]
queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:51 [inline]
queued_spin_lock include/asm-generic/qspinlock.h:114 [inline]
do_raw_spin_lock+0x210/0x2c0 kernel/locking/spinlock_debug.c:116
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline]
_raw_spin_lock_irqsave+0x42/0x60 kernel/locking/spinlock.c:162
finish_swait+0xc5/0x280 kernel/sched/swait.c:139
synchronize_rcu_expedited_wait_once kernel/rcu/tree_exp.h:516 [inline]
synchronize_rcu_expedited_wait kernel/rcu/tree_exp.h:570 [inline]
rcu_exp_wait_wake+0x2db/0x15e0 kernel/rcu/tree_exp.h:641
kthread_worker_fn+0x305/0xab0 kernel/kthread.c:841
kthread+0x2c1/0x3a0 kernel/kthread.c:388
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243


stack backtrace:
CPU: 1 PID: 18 Comm: rcu_exp_gp_kthr Not tainted 6.8.0-syzkaller-08951-gfe46a7dd189e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114
print_bad_irq_dependency kernel/locking/lockdep.c:2626 [inline]
check_irq_usage+0xe3c/0x1490 kernel/locking/lockdep.c:2865
check_prev_add kernel/locking/lockdep.c:3138 [inline]
check_prevs_add kernel/locking/lockdep.c:3253 [inline]
validate_chain kernel/locking/lockdep.c:3869 [inline]
__lock_acquire+0x248e/0x3b30 kernel/locking/lockdep.c:5137
lock_acquire kernel/locking/lockdep.c:5754 [inline]
lock_acquire+0x1b1/0x540 kernel/locking/lockdep.c:5719
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
_raw_spin_lock_bh+0x33/0x40 kernel/locking/spinlock.c:178
spin_lock_bh include/linux/spinlock.h:356 [inline]
sock_hash_delete_elem+0xcb/0x260 net/core/sock_map.c:939
___bpf_prog_run+0x3e51/0xae80 kernel/bpf/core.c:1997
__bpf_prog_run32+0xc1/0x100 kernel/bpf/core.c:2236
bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline]
__bpf_prog_run include/linux/filter.h:657 [inline]
bpf_prog_run include/linux/filter.h:664 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2381 [inline]
bpf_trace_run2+0x151/0x420 kernel/trace/bpf_trace.c:2420
__bpf_trace_contention_end+0xca/0x110 include/trace/events/lock.h:122
trace_contention_end.constprop.0+0xe2/0x140 include/trace/events/lock.h:122
__pv_queued_spin_lock_slowpath+0x266/0xc80 kernel/locking/qspinlock.c:560
pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:584 [inline]
queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:51 [inline]
queued_spin_lock include/asm-generic/qspinlock.h:114 [inline]
do_raw_spin_lock+0x210/0x2c0 kernel/locking/spinlock_debug.c:116
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline]
_raw_spin_lock_irqsave+0x42/0x60 kernel/locking/spinlock.c:162
finish_swait+0xc5/0x280 kernel/sched/swait.c:139
synchronize_rcu_expedited_wait_once kernel/rcu/tree_exp.h:516 [inline]
synchronize_rcu_expedited_wait kernel/rcu/tree_exp.h:570 [inline]
rcu_exp_wait_wake+0x2db/0x15e0 kernel/rcu/tree_exp.h:641
kthread_worker_fn+0x305/0xab0 kernel/kthread.c:841
kthread+0x2c1/0x3a0 kernel/kthread.c:388
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243
</TASK>
------------[ cut here ]------------
raw_local_irq_restore() called with IRQs enabled
WARNING: CPU: 1 PID: 18 at kernel/locking/irqflag-debug.c:10 warn_bogus_irq_restore+0x29/0x30 kernel/locking/irqflag-debug.c:10
Modules linked in:
CPU: 1 PID: 18 Comm: rcu_exp_gp_kthr Not tainted 6.8.0-syzkaller-08951-gfe46a7dd189e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
RIP: 0010:warn_bogus_irq_restore+0x29/0x30 kernel/locking/irqflag-debug.c:10
Code: 90 f3 0f 1e fa 90 80 3d 72 d0 b5 04 00 74 06 90 c3 cc cc cc cc c6 05 63 d0 b5 04 01 90 48 c7 c7 c0 b1 0c 8b e8 78 6b 7d f6 90 <0f> 0b 90 90 eb df 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90000177d38 EFLAGS: 00010286
RAX: 0000000000000000 RBX: ffffffff8d7bc580 RCX: ffffffff814fafe9
RDX: ffff888016ef9e00 RSI: ffffffff814faff6 RDI: 0000000000000001
RBP: 0000000000000283 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000a42
R13: ffffffff8f9e7034 R14: 0000000000000000 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055558bbfdca8 CR3: 000000000d57a000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline]
_raw_spin_unlock_irqrestore+0x74/0x80 kernel/locking/spinlock.c:194
synchronize_rcu_expedited_wait_once kernel/rcu/tree_exp.h:516 [inline]
synchronize_rcu_expedited_wait kernel/rcu/tree_exp.h:570 [inline]
rcu_exp_wait_wake+0x2db/0x15e0 kernel/rcu/tree_exp.h:641
kthread_worker_fn+0x305/0xab0 kernel/kthread.c:841
kthread+0x2c1/0x3a0 kernel/kthread.c:388
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243
</TASK>


---
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[Tetsuo Handa]

#syz fix: bpf, sockmap: Prevent lock inversion deadlock in map delete elem