=====================================================
WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected
5.1.0-rc2 #36 Not tainted
-----------------------------------------------------
syz-executor.4/3437 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire:
000000007814cb6b (&ctx->fault_pending_wqh){+.+.}, at: spin_lock include/linux/spinlock.h:329 [inline]
000000007814cb6b (&ctx->fault_pending_wqh){+.+.}, at: userfaultfd_ctx_read fs/userfaultfd.c:1040 [inline]
000000007814cb6b (&ctx->fault_pending_wqh){+.+.}, at: userfaultfd_read+0x540/0x1940 fs/userfaultfd.c:1198
and this task is already holding:
00000000948726b8 (&ctx->fd_wqh){....}, at: spin_lock_irq include/linux/spinlock.h:354 [inline]
00000000948726b8 (&ctx->fd_wqh){....}, at: userfaultfd_ctx_read fs/userfaultfd.c:1036 [inline]
00000000948726b8 (&ctx->fd_wqh){....}, at: userfaultfd_read+0x27a/0x1940 fs/userfaultfd.c:1198
which would create a new lock dependency:
(&ctx->fd_wqh){....} -> (&ctx->fault_pending_wqh){+.+.}
but this new dependency connects a SOFTIRQ-irq-safe lock:
(&(&ctx->ctx_lock)->rlock){..-.}
... which became SOFTIRQ-irq-safe at:
lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4211
__raw_spin_lock_irq include/linux/spinlock_api_smp.h:128 [inline]
_raw_spin_lock_irq+0x60/0x80 kernel/locking/spinlock.c:160
spin_lock_irq include/linux/spinlock.h:354 [inline]
free_ioctx_users+0x2d/0x4a0 fs/aio.c:621
percpu_ref_put_many include/linux/percpu-refcount.h:285 [inline]
percpu_ref_put include/linux/percpu-refcount.h:301 [inline]
percpu_ref_call_confirm_rcu lib/percpu-refcount.c:123 [inline]
percpu_ref_switch_to_atomic_rcu+0x3e7/0x520 lib/percpu-refcount.c:158
__rcu_reclaim kernel/rcu/rcu.h:227 [inline]
rcu_do_batch kernel/rcu/tree.c:2475 [inline]
invoke_rcu_callbacks kernel/rcu/tree.c:2788 [inline]
rcu_core+0x928/0x1390 kernel/rcu/tree.c:2769
__do_softirq+0x266/0x95a kernel/softirq.c:293
invoke_softirq kernel/softirq.c:374 [inline]
irq_exit+0x180/0x1d0 kernel/softirq.c:414
exiting_irq arch/x86/include/asm/apic.h:536 [inline]
smp_apic_timer_interrupt+0x14a/0x570 arch/x86/kernel/apic/apic.c:1062
apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807
arch_local_irq_restore arch/x86/include/asm/paravirt.h:767 [inline]
lock_acquire+0x1ea/0x3f0 kernel/locking/lockdep.c:4214
rcu_lock_acquire include/linux/rcupdate.h:210 [inline]
rcu_read_lock include/linux/rcupdate.h:595 [inline]
batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:419 [inline]
batadv_nc_worker+0x117/0x760 net/batman-adv/network-coding.c:730
process_one_work+0x98e/0x1790 kernel/workqueue.c:2269
worker_thread+0x98/0xe40 kernel/workqueue.c:2415
kthread+0x357/0x430 kernel/kthread.c:253
ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352
to a SOFTIRQ-irq-unsafe lock:
(&ctx->fault_pending_wqh){+.+.}
... which became SOFTIRQ-irq-unsafe at:
...
lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4211
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:144
spin_lock include/linux/spinlock.h:329 [inline]
userfaultfd_release+0x48e/0x6d0 fs/userfaultfd.c:916
__fput+0x2e5/0x8d0 fs/file_table.c:278
____fput+0x16/0x20 fs/file_table.c:309
task_work_run+0x14a/0x1c0 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:188 [inline]
exit_to_usermode_loop+0x273/0x2c0 arch/x86/entry/common.c:166
prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
do_syscall_64+0x52d/0x610 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
other info that might help us debug this:
Chain exists of:
&(&ctx->ctx_lock)->rlock --> &ctx->fd_wqh --> &ctx->fault_pending_wqh
Possible interrupt unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&ctx->fault_pending_wqh);
local_irq_disable();
lock(&(&ctx->ctx_lock)->rlock);
lock(&ctx->fd_wqh);
<Interrupt>
lock(&(&ctx->ctx_lock)->rlock);
*** DEADLOCK ***
1 lock held by syz-executor.4/3437:
#0: 00000000948726b8 (&ctx->fd_wqh){....}, at: spin_lock_irq include/linux/spinlock.h:354 [inline]
#0: 00000000948726b8 (&ctx->fd_wqh){....}, at: userfaultfd_ctx_read fs/userfaultfd.c:1036 [inline]
#0: 00000000948726b8 (&ctx->fd_wqh){....}, at: userfaultfd_read+0x27a/0x1940 fs/userfaultfd.c:1198
the dependencies between SOFTIRQ-irq-safe lock and the holding lock:
-> (&(&ctx->ctx_lock)->rlock){..-.} {
IN-SOFTIRQ-W at:
lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4211
__raw_spin_lock_irq include/linux/spinlock_api_smp.h:128 [inline]
_raw_spin_lock_irq+0x60/0x80 kernel/locking/spinlock.c:160
spin_lock_irq include/linux/spinlock.h:354 [inline]
free_ioctx_users+0x2d/0x4a0 fs/aio.c:621
percpu_ref_put_many include/linux/percpu-refcount.h:285 [inline]
percpu_ref_put include/linux/percpu-refcount.h:301 [inline]
percpu_ref_call_confirm_rcu lib/percpu-refcount.c:123 [inline]
percpu_ref_switch_to_atomic_rcu+0x3e7/0x520 lib/percpu-refcount.c:158
__rcu_reclaim kernel/rcu/rcu.h:227 [inline]
rcu_do_batch kernel/rcu/tree.c:2475 [inline]
invoke_rcu_callbacks kernel/rcu/tree.c:2788 [inline]
rcu_core+0x928/0x1390 kernel/rcu/tree.c:2769
__do_softirq+0x266/0x95a kernel/softirq.c:293
invoke_softirq kernel/softirq.c:374 [inline]
irq_exit+0x180/0x1d0 kernel/softirq.c:414
exiting_irq arch/x86/include/asm/apic.h:536 [inline]
smp_apic_timer_interrupt+0x14a/0x570 arch/x86/kernel/apic/apic.c:1062
apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807
arch_local_irq_restore arch/x86/include/asm/paravirt.h:767 [inline]
lock_acquire+0x1ea/0x3f0 kernel/locking/lockdep.c:4214
rcu_lock_acquire include/linux/rcupdate.h:210 [inline]
rcu_read_lock include/linux/rcupdate.h:595 [inline]
batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:419 [inline]
batadv_nc_worker+0x117/0x760 net/batman-adv/network-coding.c:730
process_one_work+0x98e/0x1790 kernel/workqueue.c:2269
worker_thread+0x98/0xe40 kernel/workqueue.c:2415
kthread+0x357/0x430 kernel/kthread.c:253
ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352
INITIAL USE at:
lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4211
__raw_spin_lock_irq include/linux/spinlock_api_smp.h:128 [inline]
_raw_spin_lock_irq+0x60/0x80 kernel/locking/spinlock.c:160
spin_lock_irq include/linux/spinlock.h:354 [inline]
free_ioctx_users+0x2d/0x4a0 fs/aio.c:621
percpu_ref_put_many include/linux/percpu-refcount.h:285 [inline]
percpu_ref_put include/linux/percpu-refcount.h:301 [inline]
percpu_ref_call_confirm_rcu lib/percpu-refcount.c:123 [inline]
percpu_ref_switch_to_atomic_rcu+0x3e7/0x520 lib/percpu-refcount.c:158
__rcu_reclaim kernel/rcu/rcu.h:227 [inline]
rcu_do_batch kernel/rcu/tree.c:2475 [inline]
invoke_rcu_callbacks kernel/rcu/tree.c:2788 [inline]
rcu_core+0x928/0x1390 kernel/rcu/tree.c:2769
__do_softirq+0x266/0x95a kernel/softirq.c:293
invoke_softirq kernel/softirq.c:374 [inline]
irq_exit+0x180/0x1d0 kernel/softirq.c:414
exiting_irq arch/x86/include/asm/apic.h:536 [inline]
smp_apic_timer_interrupt+0x14a/0x570 arch/x86/kernel/apic/apic.c:1062
apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807
arch_local_irq_restore arch/x86/include/asm/paravirt.h:767 [inline]
lock_acquire+0x1ea/0x3f0 kernel/locking/lockdep.c:4214
rcu_lock_acquire include/linux/rcupdate.h:210 [inline]
rcu_read_lock include/linux/rcupdate.h:595 [inline]
batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:419 [inline]
batadv_nc_worker+0x117/0x760 net/batman-adv/network-coding.c:730
process_one_work+0x98e/0x1790 kernel/workqueue.c:2269
worker_thread+0x98/0xe40 kernel/workqueue.c:2415
kthread+0x357/0x430 kernel/kthread.c:253
ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352
}
... key at: [<ffffffff8a5e8ea0>] __key.52644+0x0/0x40
... acquired at:
lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4211
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:144
spin_lock include/linux/spinlock.h:329 [inline]
aio_poll fs/aio.c:1762 [inline]
__io_submit_one fs/aio.c:1868 [inline]
io_submit_one+0xe35/0x1cf0 fs/aio.c:1901
__do_sys_io_submit fs/aio.c:1946 [inline]
__se_sys_io_submit fs/aio.c:1916 [inline]
__x64_sys_io_submit+0x1bd/0x580 fs/aio.c:1916
do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
-> (&ctx->fd_wqh){....} {
INITIAL USE at:
lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4211
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x95/0xcd kernel/locking/spinlock.c:152
__wake_up_common_lock+0xc7/0x190 kernel/sched/wait.c:120
__wake_up+0xe/0x10 kernel/sched/wait.c:145
userfaultfd_release+0x4ec/0x6d0 fs/userfaultfd.c:924
__fput+0x2e5/0x8d0 fs/file_table.c:278
____fput+0x16/0x20 fs/file_table.c:309
task_work_run+0x14a/0x1c0 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:188 [inline]
exit_to_usermode_loop+0x273/0x2c0 arch/x86/entry/common.c:166
prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
do_syscall_64+0x52d/0x610 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
}
... key at: [<ffffffff8a5e8c20>] __key.45453+0x0/0x40
... acquired at:
check_prevs_add kernel/locking/lockdep.c:2333 [inline]
validate_chain kernel/locking/lockdep.c:2714 [inline]
__lock_acquire+0x239c/0x3fb0 kernel/locking/lockdep.c:3701
lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4211
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:144
spin_lock include/linux/spinlock.h:329 [inline]
userfaultfd_ctx_read fs/userfaultfd.c:1040 [inline]
userfaultfd_read+0x540/0x1940 fs/userfaultfd.c:1198
__vfs_read+0x8d/0x110 fs/read_write.c:416
vfs_read+0x194/0x3e0 fs/read_write.c:452
ksys_read+0xea/0x1f0 fs/read_write.c:578
__do_sys_read fs/read_write.c:588 [inline]
__se_sys_read fs/read_write.c:586 [inline]
__x64_sys_read+0x73/0xb0 fs/read_write.c:586
do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
the dependencies between the lock to be acquired
and SOFTIRQ-irq-unsafe lock:
-> (&ctx->fault_pending_wqh){+.+.} {
HARDIRQ-ON-W at:
lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4211
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:144
spin_lock include/linux/spinlock.h:329 [inline]
userfaultfd_release+0x48e/0x6d0 fs/userfaultfd.c:916
__fput+0x2e5/0x8d0 fs/file_table.c:278
____fput+0x16/0x20 fs/file_table.c:309
task_work_run+0x14a/0x1c0 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:188 [inline]
exit_to_usermode_loop+0x273/0x2c0 arch/x86/entry/common.c:166
prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
do_syscall_64+0x52d/0x610 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
SOFTIRQ-ON-W at:
lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4211
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:144
spin_lock include/linux/spinlock.h:329 [inline]
userfaultfd_release+0x48e/0x6d0 fs/userfaultfd.c:916
__fput+0x2e5/0x8d0 fs/file_table.c:278
____fput+0x16/0x20 fs/file_table.c:309
task_work_run+0x14a/0x1c0 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:188 [inline]
exit_to_usermode_loop+0x273/0x2c0 arch/x86/entry/common.c:166
prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
do_syscall_64+0x52d/0x610 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
INITIAL USE at:
lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4211
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:144
spin_lock include/linux/spinlock.h:329 [inline]
userfaultfd_release+0x48e/0x6d0 fs/userfaultfd.c:916
__fput+0x2e5/0x8d0 fs/file_table.c:278
____fput+0x16/0x20 fs/file_table.c:309
task_work_run+0x14a/0x1c0 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:188 [inline]
exit_to_usermode_loop+0x273/0x2c0 arch/x86/entry/common.c:166
prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
do_syscall_64+0x52d/0x610 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
}
... key at: [<ffffffff8a5e8ce0>] __key.45450+0x0/0x40
... acquired at:
check_prevs_add kernel/locking/lockdep.c:2333 [inline]
validate_chain kernel/locking/lockdep.c:2714 [inline]
__lock_acquire+0x239c/0x3fb0 kernel/locking/lockdep.c:3701
lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4211
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:144
spin_lock include/linux/spinlock.h:329 [inline]
userfaultfd_ctx_read fs/userfaultfd.c:1040 [inline]
userfaultfd_read+0x540/0x1940 fs/userfaultfd.c:1198
__vfs_read+0x8d/0x110 fs/read_write.c:416
vfs_read+0x194/0x3e0 fs/read_write.c:452
ksys_read+0xea/0x1f0 fs/read_write.c:578
__do_sys_read fs/read_write.c:588 [inline]
__se_sys_read fs/read_write.c:586 [inline]
__x64_sys_read+0x73/0xb0 fs/read_write.c:586
do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
stack backtrace:
CPU: 0 PID: 3437 Comm: syz-executor.4 Not tainted 5.1.0-rc2 #36
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x172/0x1f0 lib/dump_stack.c:113
print_bad_irq_dependency kernel/locking/lockdep.c:1920 [inline]
check_usage.cold+0x60f/0x940 kernel/locking/lockdep.c:1952
check_irq_usage kernel/locking/lockdep.c:1997 [inline]
check_prev_add_irq kernel/locking/lockdep_states.h:8 [inline]
check_prev_add.constprop.0+0x2e3/0x23c0 kernel/locking/lockdep.c:2225
check_prevs_add kernel/locking/lockdep.c:2333 [inline]
validate_chain kernel/locking/lockdep.c:2714 [inline]
__lock_acquire+0x239c/0x3fb0 kernel/locking/lockdep.c:3701
lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4211
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:144
spin_lock include/linux/spinlock.h:329 [inline]
userfaultfd_ctx_read fs/userfaultfd.c:1040 [inline]
userfaultfd_read+0x540/0x1940 fs/userfaultfd.c:1198
__vfs_read+0x8d/0x110 fs/read_write.c:416
vfs_read+0x194/0x3e0 fs/read_write.c:452
ksys_read+0xea/0x1f0 fs/read_write.c:578
__do_sys_read fs/read_write.c:588 [inline]
__se_sys_read fs/read_write.c:586 [inline]
__x64_sys_read+0x73/0xb0 fs/read_write.c:586
do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x458209
Code: ad b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fb1195b3c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000458209
RDX: 0000000000000064 RSI: 0000000020009f9c RDI: 0000000000000004
RBP: 000000000073bfa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fb1195b46d4
R13: 00000000004c3cbe R14: 00000000004d87e8 R15: 00000000ffffffff