On Tue, Sep 03, 2019 at 09:31:29AM +0200, Miklos Szeredi wrote:
> On Fri, Aug 23, 2019 at 1:35 AM Eric Biggers <ebiggers@xxxxxxxxxx> wrote:
> >
> > From: Eric Biggers <ebiggers@xxxxxxxxxx>
> >
> > When IOCB_CMD_POLL is used on the FUSE device, aio_poll() disables IRQs
> > and takes kioctx::ctx_lock, then fuse_iqueue::waitq.lock.
>
> Not in -linus.
>
> Which tree was this reproduced with?
>
> Thanks,
> Miklos
Linus's tree. Here's the full symbolized output on v5.3-rc7:
=====================================================
WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected
5.3.0-rc7 #1 Not tainted
-----------------------------------------------------
syz_fuse/150 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire:
00000000c2701b26 (&fiq->waitq){+.+.}, at: spin_lock include/linux/spinlock.h:338 [inline]
00000000c2701b26 (&fiq->waitq){+.+.}, at: aio_poll fs/aio.c:1751 [inline]
00000000c2701b26 (&fiq->waitq){+.+.}, at: __io_submit_one.constprop.0+0x203/0x5b0 fs/aio.c:1825
and this task is already holding:
00000000f4c02e81 (&(&ctx->ctx_lock)->rlock){..-.}, at: spin_lock_irq include/linux/spinlock.h:363 [inline]
00000000f4c02e81 (&(&ctx->ctx_lock)->rlock){..-.}, at: aio_poll fs/aio.c:1749 [inline]
00000000f4c02e81 (&(&ctx->ctx_lock)->rlock){..-.}, at: __io_submit_one.constprop.0+0x1f4/0x5b0 fs/aio.c:1825
which would create a new lock dependency:
(&(&ctx->ctx_lock)->rlock){..-.} -> (&fiq->waitq){+.+.}
but this new dependency connects a SOFTIRQ-irq-safe lock:
(&(&ctx->ctx_lock)->rlock){..-.}
... which became SOFTIRQ-irq-safe at:
lock_acquire+0x99/0x180 kernel/locking/lockdep.c:4412
__raw_spin_lock_irq include/linux/spinlock_api_smp.h:128 [inline]
_raw_spin_lock_irq+0x32/0x50 kernel/locking/spinlock.c:167
spin_lock_irq include/linux/spinlock.h:363 [inline]
free_ioctx_users+0x25/0x190 fs/aio.c:618
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+0x202/0x210 lib/percpu-refcount.c:165
__rcu_reclaim kernel/rcu/rcu.h:222 [inline]
rcu_do_batch+0x2ae/0x890 kernel/rcu/tree.c:2114
rcu_core+0x13a/0x370 kernel/rcu/tree.c:2314
rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2323
__do_softirq+0xbe/0x400 kernel/softirq.c:292
invoke_softirq kernel/softirq.c:373 [inline]
irq_exit+0x8f/0xc0 kernel/softirq.c:413
exiting_irq arch/x86/include/asm/apic.h:537 [inline]
smp_apic_timer_interrupt+0x8e/0x210 arch/x86/kernel/apic/apic.c:1133
apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830
native_safe_halt arch/x86/include/asm/irqflags.h:60 [inline]
arch_safe_halt arch/x86/include/asm/irqflags.h:103 [inline]
default_idle+0x29/0x160 arch/x86/kernel/process.c:580
arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:571
default_idle_call+0x1e/0x30 kernel/sched/idle.c:94
cpuidle_idle_call kernel/sched/idle.c:154 [inline]
do_idle+0x1f0/0x220 kernel/sched/idle.c:263
cpu_startup_entry+0x1b/0x20 kernel/sched/idle.c:354
rest_init+0x18a/0x24d init/main.c:451
arch_call_rest_init+0x9/0xc
start_kernel+0x530/0x54e init/main.c:785
x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:472
x86_64_start_kernel+0x6d/0x71 arch/x86/kernel/head64.c:453
secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:241
to a SOFTIRQ-irq-unsafe lock:
(&fiq->waitq){+.+.}
... which became SOFTIRQ-irq-unsafe at:
...
lock_acquire+0x99/0x180 kernel/locking/lockdep.c:4412
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2b/0x40 kernel/locking/spinlock.c:151
spin_lock include/linux/spinlock.h:338 [inline]
flush_bg_queue+0x91/0xf0 fs/fuse/dev.c:415
fuse_request_queue_background+0xd1/0x140 fs/fuse/dev.c:676
fuse_request_send_background+0x27/0x60 fs/fuse/dev.c:687
fuse_send_init fs/fuse/inode.c:986 [inline]
fuse_fill_super+0x656/0x681 fs/fuse/inode.c:1211
mount_nodev+0x42/0x90 fs/super.c:1329
fuse_mount+0x13/0x20 fs/fuse/inode.c:1236
legacy_get_tree+0x2c/0x50 fs/fs_context.c:661
vfs_get_tree+0x22/0xc0 fs/super.c:1413
do_new_mount fs/namespace.c:2791 [inline]
do_mount+0x7e3/0xa60 fs/namespace.c:3111
ksys_mount+0x7d/0xd0 fs/namespace.c:3320
__do_sys_mount fs/namespace.c:3334 [inline]
__se_sys_mount fs/namespace.c:3331 [inline]
__x64_sys_mount+0x20/0x30 fs/namespace.c:3331
do_syscall_64+0x4a/0x1a0 arch/x86/entry/common.c:296
entry_SYSCALL_64_after_hwframe+0x49/0xbe
other info that might help us debug this:
Possible interrupt unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&fiq->waitq);
local_irq_disable();
lock(&(&ctx->ctx_lock)->rlock);
lock(&fiq->waitq);
<Interrupt>
lock(&(&ctx->ctx_lock)->rlock);
*** DEADLOCK ***
1 lock held by syz_fuse/150:
#0: 00000000f4c02e81 (&(&ctx->ctx_lock)->rlock){..-.}, at: spin_lock_irq include/linux/spinlock.h:363 [inline]
#0: 00000000f4c02e81 (&(&ctx->ctx_lock)->rlock){..-.}, at: aio_poll fs/aio.c:1749 [inline]
#0: 00000000f4c02e81 (&(&ctx->ctx_lock)->rlock){..-.}, at: __io_submit_one.constprop.0+0x1f4/0x5b0 fs/aio.c:1825
the dependencies between SOFTIRQ-irq-safe lock and the holding lock:
-> (&(&ctx->ctx_lock)->rlock){..-.} {
IN-SOFTIRQ-W at:
lock_acquire+0x99/0x180 kernel/locking/lockdep.c:4412
__raw_spin_lock_irq include/linux/spinlock_api_smp.h:128 [inline]
_raw_spin_lock_irq+0x32/0x50 kernel/locking/spinlock.c:167
spin_lock_irq include/linux/spinlock.h:363 [inline]
free_ioctx_users+0x25/0x190 fs/aio.c:618
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+0x202/0x210 lib/percpu-refcount.c:165
__rcu_reclaim kernel/rcu/rcu.h:222 [inline]
rcu_do_batch+0x2ae/0x890 kernel/rcu/tree.c:2114
rcu_core+0x13a/0x370 kernel/rcu/tree.c:2314
rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2323
__do_softirq+0xbe/0x400 kernel/softirq.c:292
invoke_softirq kernel/softirq.c:373 [inline]
irq_exit+0x8f/0xc0 kernel/softirq.c:413
exiting_irq arch/x86/include/asm/apic.h:537 [inline]
smp_apic_timer_interrupt+0x8e/0x210 arch/x86/kernel/apic/apic.c:1133
apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830
native_safe_halt arch/x86/include/asm/irqflags.h:60 [inline]
arch_safe_halt arch/x86/include/asm/irqflags.h:103 [inline]
default_idle+0x29/0x160 arch/x86/kernel/process.c:580
arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:571
default_idle_call+0x1e/0x30 kernel/sched/idle.c:94
cpuidle_idle_call kernel/sched/idle.c:154 [inline]
do_idle+0x1f0/0x220 kernel/sched/idle.c:263
cpu_startup_entry+0x1b/0x20 kernel/sched/idle.c:354
rest_init+0x18a/0x24d init/main.c:451
arch_call_rest_init+0x9/0xc
start_kernel+0x530/0x54e init/main.c:785
x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:472
x86_64_start_kernel+0x6d/0x71 arch/x86/kernel/head64.c:453
secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:241
INITIAL USE at:
lock_acquire+0x99/0x180 kernel/locking/lockdep.c:4412
__raw_spin_lock_irq include/linux/spinlock_api_smp.h:128 [inline]
_raw_spin_lock_irq+0x32/0x50 kernel/locking/spinlock.c:167
spin_lock_irq include/linux/spinlock.h:363 [inline]
free_ioctx_users+0x25/0x190 fs/aio.c:618
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+0x202/0x210 lib/percpu-refcount.c:165
__rcu_reclaim kernel/rcu/rcu.h:222 [inline]
rcu_do_batch+0x2ae/0x890 kernel/rcu/tree.c:2114
rcu_core+0x13a/0x370 kernel/rcu/tree.c:2314
rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2323
__do_softirq+0xbe/0x400 kernel/softirq.c:292
invoke_softirq kernel/softirq.c:373 [inline]
irq_exit+0x8f/0xc0 kernel/softirq.c:413
exiting_irq arch/x86/include/asm/apic.h:537 [inline]
smp_apic_timer_interrupt+0x8e/0x210 arch/x86/kernel/apic/apic.c:1133
apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830
native_safe_halt arch/x86/include/asm/irqflags.h:60 [inline]
arch_safe_halt arch/x86/include/asm/irqflags.h:103 [inline]
default_idle+0x29/0x160 arch/x86/kernel/process.c:580
arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:571
default_idle_call+0x1e/0x30 kernel/sched/idle.c:94
cpuidle_idle_call kernel/sched/idle.c:154 [inline]
do_idle+0x1f0/0x220 kernel/sched/idle.c:263
cpu_startup_entry+0x1b/0x20 kernel/sched/idle.c:354
rest_init+0x18a/0x24d init/main.c:451
arch_call_rest_init+0x9/0xc
start_kernel+0x530/0x54e init/main.c:785
x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:472
x86_64_start_kernel+0x6d/0x71 arch/x86/kernel/head64.c:453
secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:241
}
... key at: [<ffffffff82860670>] __key.50377+0x0/0x10
... acquired at:
check_prev_add+0xa7/0x950 kernel/locking/lockdep.c:2409
check_prevs_add kernel/locking/lockdep.c:2507 [inline]
validate_chain+0x483/0x870 kernel/locking/lockdep.c:2897
__lock_acquire+0x447/0x7d0 kernel/locking/lockdep.c:3880
lock_acquire+0x99/0x180 kernel/locking/lockdep.c:4412
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2b/0x40 kernel/locking/spinlock.c:151
spin_lock include/linux/spinlock.h:338 [inline]
aio_poll fs/aio.c:1751 [inline]
__io_submit_one.constprop.0+0x203/0x5b0 fs/aio.c:1825
io_submit_one+0x146/0x5b0 fs/aio.c:1862
__do_sys_io_submit fs/aio.c:1921 [inline]
__se_sys_io_submit+0x8e/0x270 fs/aio.c:1891
__x64_sys_io_submit+0x15/0x20 fs/aio.c:1891
do_syscall_64+0x4a/0x1a0 arch/x86/entry/common.c:296
entry_SYSCALL_64_after_hwframe+0x49/0xbe
the dependencies between the lock to be acquired
and SOFTIRQ-irq-unsafe lock:
-> (&fiq->waitq){+.+.} {
HARDIRQ-ON-W at:
lock_acquire+0x99/0x180 kernel/locking/lockdep.c:4412
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2b/0x40 kernel/locking/spinlock.c:151
spin_lock include/linux/spinlock.h:338 [inline]
flush_bg_queue+0x91/0xf0 fs/fuse/dev.c:415
fuse_request_queue_background+0xd1/0x140 fs/fuse/dev.c:676
fuse_request_send_background+0x27/0x60 fs/fuse/dev.c:687
fuse_send_init fs/fuse/inode.c:986 [inline]
fuse_fill_super+0x656/0x681 fs/fuse/inode.c:1211
mount_nodev+0x42/0x90 fs/super.c:1329
fuse_mount+0x13/0x20 fs/fuse/inode.c:1236
legacy_get_tree+0x2c/0x50 fs/fs_context.c:661
vfs_get_tree+0x22/0xc0 fs/super.c:1413
do_new_mount fs/namespace.c:2791 [inline]
do_mount+0x7e3/0xa60 fs/namespace.c:3111
ksys_mount+0x7d/0xd0 fs/namespace.c:3320
__do_sys_mount fs/namespace.c:3334 [inline]
__se_sys_mount fs/namespace.c:3331 [inline]
__x64_sys_mount+0x20/0x30 fs/namespace.c:3331
do_syscall_64+0x4a/0x1a0 arch/x86/entry/common.c:296
entry_SYSCALL_64_after_hwframe+0x49/0xbe
SOFTIRQ-ON-W at:
lock_acquire+0x99/0x180 kernel/locking/lockdep.c:4412
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2b/0x40 kernel/locking/spinlock.c:151
spin_lock include/linux/spinlock.h:338 [inline]
flush_bg_queue+0x91/0xf0 fs/fuse/dev.c:415
fuse_request_queue_background+0xd1/0x140 fs/fuse/dev.c:676
fuse_request_send_background+0x27/0x60 fs/fuse/dev.c:687
fuse_send_init fs/fuse/inode.c:986 [inline]
fuse_fill_super+0x656/0x681 fs/fuse/inode.c:1211
mount_nodev+0x42/0x90 fs/super.c:1329
fuse_mount+0x13/0x20 fs/fuse/inode.c:1236
legacy_get_tree+0x2c/0x50 fs/fs_context.c:661
vfs_get_tree+0x22/0xc0 fs/super.c:1413
do_new_mount fs/namespace.c:2791 [inline]
do_mount+0x7e3/0xa60 fs/namespace.c:3111
ksys_mount+0x7d/0xd0 fs/namespace.c:3320
__do_sys_mount fs/namespace.c:3334 [inline]
__se_sys_mount fs/namespace.c:3331 [inline]
__x64_sys_mount+0x20/0x30 fs/namespace.c:3331
do_syscall_64+0x4a/0x1a0 arch/x86/entry/common.c:296
entry_SYSCALL_64_after_hwframe+0x49/0xbe
INITIAL USE at:
lock_acquire+0x99/0x180 kernel/locking/lockdep.c:4412
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2b/0x40 kernel/locking/spinlock.c:151
spin_lock include/linux/spinlock.h:338 [inline]
flush_bg_queue+0x91/0xf0 fs/fuse/dev.c:415
fuse_request_queue_background+0xd1/0x140 fs/fuse/dev.c:676
fuse_request_send_background+0x27/0x60 fs/fuse/dev.c:687
fuse_send_init fs/fuse/inode.c:986 [inline]
fuse_fill_super+0x656/0x681 fs/fuse/inode.c:1211
mount_nodev+0x42/0x90 fs/super.c:1329
fuse_mount+0x13/0x20 fs/fuse/inode.c:1236
legacy_get_tree+0x2c/0x50 fs/fs_context.c:661
vfs_get_tree+0x22/0xc0 fs/super.c:1413
do_new_mount fs/namespace.c:2791 [inline]
do_mount+0x7e3/0xa60 fs/namespace.c:3111
ksys_mount+0x7d/0xd0 fs/namespace.c:3320
__do_sys_mount fs/namespace.c:3334 [inline]
__se_sys_mount fs/namespace.c:3331 [inline]
__x64_sys_mount+0x20/0x30 fs/namespace.c:3331
do_syscall_64+0x4a/0x1a0 arch/x86/entry/common.c:296
entry_SYSCALL_64_after_hwframe+0x49/0xbe
}
... key at: [<ffffffff82863ea0>] __key.40870+0x0/0x10
... acquired at:
check_prev_add+0xa7/0x950 kernel/locking/lockdep.c:2409
check_prevs_add kernel/locking/lockdep.c:2507 [inline]
validate_chain+0x483/0x870 kernel/locking/lockdep.c:2897
__lock_acquire+0x447/0x7d0 kernel/locking/lockdep.c:3880
lock_acquire+0x99/0x180 kernel/locking/lockdep.c:4412
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2b/0x40 kernel/locking/spinlock.c:151
spin_lock include/linux/spinlock.h:338 [inline]
aio_poll fs/aio.c:1751 [inline]
__io_submit_one.constprop.0+0x203/0x5b0 fs/aio.c:1825
io_submit_one+0x146/0x5b0 fs/aio.c:1862
__do_sys_io_submit fs/aio.c:1921 [inline]
__se_sys_io_submit+0x8e/0x270 fs/aio.c:1891
__x64_sys_io_submit+0x15/0x20 fs/aio.c:1891
do_syscall_64+0x4a/0x1a0 arch/x86/entry/common.c:296
entry_SYSCALL_64_after_hwframe+0x49/0xbe
stack backtrace:
CPU: 1 PID: 150 Comm: syz_fuse Not tainted 5.3.0-rc7 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-20181126_142135-anatol 04/01/2014
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x70/0x9a lib/dump_stack.c:113
print_bad_irq_dependency.cold+0x380/0x3d8 kernel/locking/lockdep.c:2025
check_irq_usage+0x337/0x400 kernel/locking/lockdep.c:2223
check_prev_add+0xa7/0x950 kernel/locking/lockdep.c:2409
check_prevs_add kernel/locking/lockdep.c:2507 [inline]
validate_chain+0x483/0x870 kernel/locking/lockdep.c:2897
__lock_acquire+0x447/0x7d0 kernel/locking/lockdep.c:3880
lock_acquire+0x99/0x180 kernel/locking/lockdep.c:4412
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2b/0x40 kernel/locking/spinlock.c:151
spin_lock include/linux/spinlock.h:338 [inline]
aio_poll fs/aio.c:1751 [inline]
__io_submit_one.constprop.0+0x203/0x5b0 fs/aio.c:1825
io_submit_one+0x146/0x5b0 fs/aio.c:1862
__do_sys_io_submit fs/aio.c:1921 [inline]
__se_sys_io_submit+0x8e/0x270 fs/aio.c:1891
__x64_sys_io_submit+0x15/0x20 fs/aio.c:1891
do_syscall_64+0x4a/0x1a0 arch/x86/entry/common.c:296
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f1bbde7ec6d
Code: 00 c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 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 73 01 c3 48 8b 0d f3 51 0c 00 f7 d8 64 89 01 48
RSP: 002b:00007ffffa3a70e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000d1
RAX: ffffffffffffffda RBX: 00007ffffa3a7140 RCX: 00007f1bbde7ec6d
RDX: 00007ffffa3a70f8 RSI: 0000000000000001 RDI: 00007f1bbe27d000
RBP: 0000559337c29290 R08: 0000000000000000 R09: 00007f1bbe27d000
R10: 0000000000000029 R11: 0000000000000246 R12: 0000559337c29190
R13: 00007ffffa3a72b0 R14: 0000000000000000 R15: 0000000000000000
