========================================================
WARNING: possible irq lock inversion dependency detected
5.1.0-rc2-next-20190328 #13 Not tainted
--------------------------------------------------------
syz-executor687/7743 just changed the state of lock:
000000002da71473 (&ctx->fault_pending_wqh){+.+.}, at: spin_lock include/linux/spinlock.h:329 [inline]
000000002da71473 (&ctx->fault_pending_wqh){+.+.}, at: userfaultfd_release+0x48e/0x6d0 fs/userfaultfd.c:916
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-executor687/7743.
the shortest dependencies between 2nd lock and 1st 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
native_safe_halt+0x2/0x10 arch/x86/include/asm/irqflags.h:57
arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:567
default_idle_call+0x36/0x90 kernel/sched/idle.c:93
cpuidle_idle_call kernel/sched/idle.c:153 [inline]
do_idle+0x386/0x570 kernel/sched/idle.c:262
cpu_startup_entry+0x1b/0x20 kernel/sched/idle.c:353
rest_init+0x245/0x37b init/main.c:450
arch_call_rest_init+0xe/0x1b
start_kernel+0x816/0x84f init/main.c:747
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+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]
aio_poll fs/aio.c:1761 [inline]
__io_submit_one fs/aio.c:1868 [inline]
io_submit_one+0xe0c/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
}
... key at: [<ffffffff8a5f60a0>] __key.52784+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_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]
userfaultfd_ctx_read fs/userfaultfd.c:1036 [inline]
userfaultfd_read+0x27a/0x1940 fs/userfaultfd.c:1198
do_loop_readv_writev fs/read_write.c:700 [inline]
do_loop_readv_writev fs/read_write.c:687 [inline]
do_iter_read+0x4a9/0x660 fs/read_write.c:921
vfs_readv+0xf0/0x160 fs/read_write.c:983
do_readv+0xf6/0x290 fs/read_write.c:1016
__do_sys_readv fs/read_write.c:1103 [inline]
__se_sys_readv fs/read_write.c:1100 [inline]
__x64_sys_readv+0x75/0xb0 fs/read_write.c:1100
do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
}
... key at: [<ffffffff8a5f5e20>] __key.45593+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]
userfaultfd_ctx_read fs/userfaultfd.c:1040 [inline]
userfaultfd_read+0x540/0x1940 fs/userfaultfd.c:1198
do_loop_readv_writev fs/read_write.c:700 [inline]
do_loop_readv_writev fs/read_write.c:687 [inline]
do_iter_read+0x4a9/0x660 fs/read_write.c:921
vfs_readv+0xf0/0x160 fs/read_write.c:983
do_readv+0xf6/0x290 fs/read_write.c:1016
__do_sys_readv fs/read_write.c:1103 [inline]
__se_sys_readv fs/read_write.c:1100 [inline]
__x64_sys_readv+0x75/0xb0 fs/read_write.c:1100
do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
-> (&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
exit_task_work include/linux/task_work.h:22 [inline]
do_exit+0x90a/0x2fa0 kernel/exit.c:876
do_group_exit+0x135/0x370 kernel/exit.c:980
get_signal+0x399/0x1d50 kernel/signal.c:2577
do_signal+0x87/0x1940 arch/x86/kernel/signal.c:816
exit_to_usermode_loop+0x244/0x2c0 arch/x86/entry/common.c:162
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
exit_task_work include/linux/task_work.h:22 [inline]
do_exit+0x90a/0x2fa0 kernel/exit.c:876
do_group_exit+0x135/0x370 kernel/exit.c:980
get_signal+0x399/0x1d50 kernel/signal.c:2577
do_signal+0x87/0x1940 arch/x86/kernel/signal.c:816
exit_to_usermode_loop+0x244/0x2c0 arch/x86/entry/common.c:162
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_ctx_read fs/userfaultfd.c:1040 [inline]
userfaultfd_read+0x540/0x1940 fs/userfaultfd.c:1198
do_loop_readv_writev fs/read_write.c:700 [inline]
do_loop_readv_writev fs/read_write.c:687 [inline]
do_iter_read+0x4a9/0x660 fs/read_write.c:921
vfs_readv+0xf0/0x160 fs/read_write.c:983
do_readv+0xf6/0x290 fs/read_write.c:1016
__do_sys_readv fs/read_write.c:1103 [inline]
__se_sys_readv fs/read_write.c:1100 [inline]
__x64_sys_readv+0x75/0xb0 fs/read_write.c:1100
do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
}
... key at: [<ffffffff8a5f5ee0>] __key.45590+0x0/0x40
... acquired at:
mark_lock_irq kernel/locking/lockdep.c:3054 [inline]
mark_lock+0x427/0x1380 kernel/locking/lockdep.c:3421
mark_irqflags kernel/locking/lockdep.c:3317 [inline]
__lock_acquire+0x1317/0x3fb0 kernel/locking/lockdep.c:3653
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
exit_task_work include/linux/task_work.h:22 [inline]
do_exit+0x90a/0x2fa0 kernel/exit.c:876
do_group_exit+0x135/0x370 kernel/exit.c:980
get_signal+0x399/0x1d50 kernel/signal.c:2577
do_signal+0x87/0x1940 arch/x86/kernel/signal.c:816
exit_to_usermode_loop+0x244/0x2c0 arch/x86/entry/common.c:162
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
stack backtrace:
CPU: 0 PID: 7743 Comm: syz-executor687 Not tainted 5.1.0-rc2-next-20190328 #13
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+0x2c0/0x2cd kernel/locking/lockdep.c:2920
print_irq_inversion_bug kernel/locking/lockdep.c:2923 [inline]
check_usage_backwards.cold+0x1d/0x26 kernel/locking/lockdep.c:2969
mark_lock_irq kernel/locking/lockdep.c:3054 [inline]
mark_lock+0x427/0x1380 kernel/locking/lockdep.c:3421
mark_irqflags kernel/locking/lockdep.c:3317 [inline]
__lock_acquire+0x1317/0x3fb0 kernel/locking/lockdep.c:3653
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
exit_task_work include/linux/task_work.h:22 [inline]
do_exit+0x90a/0x2fa0 kernel/exit.c:876
do_group_exit+0x135/0x370 kernel/exit.c:980
get_signal+0x399/0x1d50 kernel/signal.c:2577
do_signal+0x87/0x1940 arch/x86/kernel/signal.c:816
exit_to_usermode_loop+0x244/0x2c0 arch/x86/entry/common.c:162
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
RIP: 0033:0x4458f9
Code: Bad RIP value.
RSP: 002b:00007fe45e690db8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00000000006dac58 RCX: 00000000004458f9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00000000006dac58
RBP: 00000000006dac50 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 00