========================================================
WARNING: possible irq lock inversion dependency detected
5.2.0-rc6-next-20190624 #21 Not tainted
--------------------------------------------------------
syz-executor100/8760 just changed the state of lock:
00000000851da6e3 (&ctx->fault_pending_wqh){+.+.}, at: spin_lock include/linux/spinlock.h:338 [inline]
00000000851da6e3 (&ctx->fault_pending_wqh){+.+.}, at: userfaultfd_release+0x4ca/0x710 fs/userfaultfd.c:921
but this lock was taken by another, SOFTIRQ-safe lock in the past:
(&(&ctx->ctx_lock)->rlock){..-.}
and interrupts could create inverse lock ordering between them.
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 ***
no locks held by syz-executor100/8760.
the shortest dependencies between 2nd lock and 1st lock:
-> (&(&ctx->ctx_lock)->rlock){..-.} {
IN-SOFTIRQ-W at:
lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4418
__raw_spin_lock_irq include/linux/spinlock_api_smp.h:128 [inline]
_raw_spin_lock_irq+0x60/0x80 kernel/locking/spinlock.c:167
spin_lock_irq include/linux/spinlock.h:363 [inline]
free_ioctx_users+0x2d/0x490 fs/aio.c:620
percpu_ref_put_many include/linux/percpu-refcount.h:293 [inline]
percpu_ref_put include/linux/percpu-refcount.h:309 [inline]
percpu_ref_call_confirm_rcu lib/percpu-refcount.c:130 [inline]
percpu_ref_switch_to_atomic_rcu+0x4c0/0x570 lib/percpu-refcount.c:165
__rcu_reclaim kernel/rcu/rcu.h:222 [inline]
rcu_do_batch kernel/rcu/tree.c:2092 [inline]
invoke_rcu_callbacks kernel/rcu/tree.c:2310 [inline]
rcu_core+0xa3a/0x15a0 kernel/rcu/tree.c:2291
__do_softirq+0x262/0x98c kernel/softirq.c:292
invoke_softirq kernel/softirq.c:373 [inline]
irq_exit+0x19b/0x1e0 kernel/softirq.c:413
exiting_irq arch/x86/include/asm/apic.h:535 [inline]
smp_apic_timer_interrupt+0x1a3/0x610 arch/x86/kernel/apic/apic.c:1068
apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807
native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:60
arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:571
default_idle_call+0x84/0xb0 kernel/sched/idle.c:94
cpuidle_idle_call kernel/sched/idle.c:154 [inline]
do_idle+0x413/0x760 kernel/sched/idle.c:263
cpu_startup_entry+0x1b/0x20 kernel/sched/idle.c:354
rest_init+0x245/0x37b init/main.c:451
arch_call_rest_init+0xe/0x1b
start_kernel+0x8de/0x91d init/main.c:785
x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:470
x86_64_start_kernel+0x77/0x7b arch/x86/kernel/head64.c:451
secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243
INITIAL USE at:
lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4418
__raw_spin_lock_irq include/linux/spinlock_api_smp.h:128 [inline]
_raw_spin_lock_irq+0x60/0x80 kernel/locking/spinlock.c:167
spin_lock_irq include/linux/spinlock.h:363 [inline]
aio_poll fs/aio.c:1747 [inline]
__io_submit_one fs/aio.c:1823 [inline]
io_submit_one+0xeb5/0x2ef0 fs/aio.c:1860
__do_sys_io_submit fs/aio.c:1919 [inline]
__se_sys_io_submit fs/aio.c:1889 [inline]
__x64_sys_io_submit+0x1bd/0x570 fs/aio.c:1889
do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:301
entry_SYSCALL_64_after_hwframe+0x49/0xbe
}
... key at: [<ffffffff8a88e660>] __key.53688+0x0/0x40
... acquired at:
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151
spin_lock include/linux/spinlock.h:338 [inline]
aio_poll fs/aio.c:1749 [inline]
__io_submit_one fs/aio.c:1823 [inline]
io_submit_one+0xefa/0x2ef0 fs/aio.c:1860
__do_sys_io_submit fs/aio.c:1919 [inline]
__se_sys_io_submit fs/aio.c:1889 [inline]
__x64_sys_io_submit+0x1bd/0x570 fs/aio.c:1889
do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:301
entry_SYSCALL_64_after_hwframe+0x49/0xbe
-> (&ctx->fd_wqh){....} {
INITIAL USE at:
lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4418
__raw_spin_lock_irq include/linux/spinlock_api_smp.h:128 [inline]
_raw_spin_lock_irq+0x60/0x80 kernel/locking/spinlock.c:167
spin_lock_irq include/linux/spinlock.h:363 [inline]
userfaultfd_ctx_read fs/userfaultfd.c:1041 [inline]
userfaultfd_read+0x27a/0x1950 fs/userfaultfd.c:1203
do_loop_readv_writev fs/read_write.c:714 [inline]
do_loop_readv_writev fs/read_write.c:701 [inline]
do_iter_read+0x4a4/0x660 fs/read_write.c:935
vfs_readv+0xf0/0x160 fs/read_write.c:997
do_readv+0x15b/0x330 fs/read_write.c:1034
__do_sys_readv fs/read_write.c:1125 [inline]
__se_sys_readv fs/read_write.c:1122 [inline]
__x64_sys_readv+0x75/0xb0 fs/read_write.c:1122
do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:301
entry_SYSCALL_64_after_hwframe+0x49/0xbe
}
... key at: [<ffffffff8a88e3e0>] __key.46406+0x0/0x40
... acquired at:
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151
spin_lock include/linux/spinlock.h:338 [inline]
userfaultfd_ctx_read fs/userfaultfd.c:1045 [inline]
userfaultfd_read+0x54d/0x1950 fs/userfaultfd.c:1203
do_loop_readv_writev fs/read_write.c:714 [inline]
do_loop_readv_writev fs/read_write.c:701 [inline]
do_iter_read+0x4a4/0x660 fs/read_write.c:935
vfs_readv+0xf0/0x160 fs/read_write.c:997
do_readv+0x15b/0x330 fs/read_write.c:1034
__do_sys_readv fs/read_write.c:1125 [inline]
__se_sys_readv fs/read_write.c:1122 [inline]
__x64_sys_readv+0x75/0xb0 fs/read_write.c:1122
do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:301
entry_SYSCALL_64_after_hwframe+0x49/0xbe
-> (&ctx->fault_pending_wqh){+.+.} {
HARDIRQ-ON-W at:
lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4418
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151
spin_lock include/linux/spinlock.h:338 [inline]
userfaultfd_release+0x4ca/0x710 fs/userfaultfd.c:921
__fput+0x2ff/0x890 fs/file_table.c:280
____fput+0x16/0x20 fs/file_table.c:313
task_work_run+0x145/0x1c0 kernel/task_work.c:113
exit_task_work include/linux/task_work.h:22 [inline]
do_exit+0x904/0x2eb0 kernel/exit.c:877
do_group_exit+0x135/0x360 kernel/exit.c:981
get_signal+0x47c/0x2500 kernel/signal.c:2728
do_signal+0x87/0x1700 arch/x86/kernel/signal.c:815
exit_to_usermode_loop+0x251/0x2d0 arch/x86/entry/common.c:164
prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
syscall_return_slowpath arch/x86/entry/common.c:279 [inline]
do_syscall_64+0x5a9/0x6a0 arch/x86/entry/common.c:304
entry_SYSCALL_64_after_hwframe+0x49/0xbe
SOFTIRQ-ON-W at:
lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4418
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151
spin_lock include/linux/spinlock.h:338 [inline]
userfaultfd_release+0x4ca/0x710 fs/userfaultfd.c:921
__fput+0x2ff/0x890 fs/file_table.c:280
____fput+0x16/0x20 fs/file_table.c:313
task_work_run+0x145/0x1c0 kernel/task_work.c:113
exit_task_work include/linux/task_work.h:22 [inline]
do_exit+0x904/0x2eb0 kernel/exit.c:877
do_group_exit+0x135/0x360 kernel/exit.c:981
get_signal+0x47c/0x2500 kernel/signal.c:2728
do_signal+0x87/0x1700 arch/x86/kernel/signal.c:815
exit_to_usermode_loop+0x251/0x2d0 arch/x86/entry/common.c:164
prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
syscall_return_slowpath arch/x86/entry/common.c:279 [inline]
do_syscall_64+0x5a9/0x6a0 arch/x86/entry/common.c:304
entry_SYSCALL_64_after_hwframe+0x49/0xbe
INITIAL USE at:
lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4418
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151
spin_lock include/linux/spinlock.h:338 [inline]
userfaultfd_ctx_read fs/userfaultfd.c:1045 [inline]
userfaultfd_read+0x54d/0x1950 fs/userfaultfd.c:1203
do_loop_readv_writev fs/read_write.c:714 [inline]
do_loop_readv_writev fs/read_write.c:701 [inline]
do_iter_read+0x4a4/0x660 fs/read_write.c:935
vfs_readv+0xf0/0x160 fs/read_write.c:997
do_readv+0x15b/0x330 fs/read_write.c:1034
__do_sys_readv fs/read_write.c:1125 [inline]
__se_sys_readv fs/read_write.c:1122 [inline]
__x64_sys_readv+0x75/0xb0 fs/read_write.c:1122
do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:301
entry_SYSCALL_64_after_hwframe+0x49/0xbe
}
... key at: [<ffffffff8a88e4a0>] __key.46403+0x0/0x40
... acquired at:
mark_lock_irq kernel/locking/lockdep.c:3239 [inline]
mark_lock+0x4fa/0x11e0 kernel/locking/lockdep.c:3617
mark_usage kernel/locking/lockdep.c:3506 [inline]
__lock_acquire+0x13f7/0x4680 kernel/locking/lockdep.c:3839
lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4418
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151
spin_lock include/linux/spinlock.h:338 [inline]
userfaultfd_release+0x4ca/0x710 fs/userfaultfd.c:921
__fput+0x2ff/0x890 fs/file_table.c:280
____fput+0x16/0x20 fs/file_table.c:313
task_work_run+0x145/0x1c0 kernel/task_work.c:113
exit_task_work include/linux/task_work.h:22 [inline]
do_exit+0x904/0x2eb0 kernel/exit.c:877
do_group_exit+0x135/0x360 kernel/exit.c:981
get_signal+0x47c/0x2500 kernel/signal.c:2728
do_signal+0x87/0x1700 arch/x86/kernel/signal.c:815
exit_to_usermode_loop+0x251/0x2d0 arch/x86/entry/common.c:164
prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
syscall_return_slowpath arch/x86/entry/common.c:279 [inline]
do_syscall_64+0x5a9/0x6a0 arch/x86/entry/common.c:304
entry_SYSCALL_64_after_hwframe+0x49/0xbe
stack backtrace:
CPU: 0 PID: 8760 Comm: syz-executor100 Not tainted 5.2.0-rc6-next-20190624 #21
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_irq_inversion_bug.part.0+0x2c5/0x2d2 kernel/locking/lockdep.c:3101
print_irq_inversion_bug kernel/locking/lockdep.c:3102 [inline]
check_usage_backwards.cold+0x1d/0x26 kernel/locking/lockdep.c:3153
mark_lock_irq kernel/locking/lockdep.c:3239 [inline]
mark_lock+0x4fa/0x11e0 kernel/locking/lockdep.c:3617
mark_usage kernel/locking/lockdep.c:3506 [inline]
__lock_acquire+0x13f7/0x4680 kernel/locking/lockdep.c:3839
lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4418
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151
spin_lock include/linux/spinlock.h:338 [inline]
userfaultfd_release+0x4ca/0x710 fs/userfaultfd.c:921
__fput+0x2ff/0x890 fs/file_table.c:280
____fput+0x16/0x20 fs/file_table.c:313
task_work_run+0x145/0x1c0 kernel/task_work.c:113
exit_task_work include/linux/task_work.h:22 [inline]
do_exit+0x904/0x2eb0 kernel/exit.c:877
do_group_exit+0x135/0x360 kernel/exit.c:981
get_signal+0x47c/0x2500 kernel/signal.c:2728
do_signal+0x87/0x1700 arch/x86/kernel/signal.c:815
exit_to_usermode_loop+0x251/0x2d0 arch/x86/entry/common.c:164
prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
syscall_return_slowpath arch/x86/entry/common.c:279 [inline]
do_syscall_64+0x5a9/0x6a0 arch/x86/entry/common.c:304
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x445919
Code: Bad RIP value.
RSP: 002b:00007fa2cf973db8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RB