[syzbot] [kernel?] possible deadlock in run_timer_base
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syzbot
May 25, 2024, 4:46:25 PMMay 25
to linux-...@vger.kernel.org, syzkall...@googlegroups.com
Hello,
syzbot found the following issue on:
HEAD commit: 2a8120d7b482 Merge tag 's390-6.10-2' of git://git.kernel.o..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1107d9cc980000
kernel config: https://syzkaller.appspot.com/x/.config?x=5dd4fde1337a9e18
dashboard link: https://syzkaller.appspot.com/bug?extid=9a474438d0c960487fcf
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: i386
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7bc7510fe41f/non_bootable_disk-2a8120d7.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/78c72ae6bdaf/vmlinux-2a8120d7.xz
kernel image: https://storage.googleapis.com/syzbot-assets/99dbb805b738/bzImage-2a8120d7.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+9a4744...@syzkaller.appspotmail.com
------------[ cut here ]------------
======================================================
WARNING: possible circular locking dependency detected
6.9.0-syzkaller-10713-g2a8120d7b482 #0 Not tainted
------------------------------------------------------
swapper/0/0 is trying to acquire lock:
ffffffff8dba2e98 ((console_sem).lock){-.-.}-{2:2}, at: down_trylock+0x12/0x70 kernel/locking/semaphore.c:139
but task is already holding lock:
ffff88802c02a858 (&base->lock){-.-.}-{2:2}, at: __run_timer_base kernel/time/timer.c:2427 [inline]
ffff88802c02a858 (&base->lock){-.-.}-{2:2}, at: __run_timer_base kernel/time/timer.c:2421 [inline]
ffff88802c02a858 (&base->lock){-.-.}-{2:2}, at: run_timer_base+0x109/0x190 kernel/time/timer.c:2437
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #3 (&base->lock){-.-.}-{2:2}:
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162
lock_timer_base+0x5d/0x220 kernel/time/timer.c:1051
__mod_timer+0x426/0xdc0 kernel/time/timer.c:1132
add_timer_global+0x8a/0xc0 kernel/time/timer.c:1330
__queue_delayed_work+0x1ba/0x2e0 kernel/workqueue.c:2543
queue_delayed_work_on+0x12a/0x150 kernel/workqueue.c:2572
psi_task_change+0x1b4/0x2e0 kernel/sched/psi.c:912
psi_enqueue kernel/sched/stats.h:139 [inline]
enqueue_task kernel/sched/core.c:2112 [inline]
activate_task+0x213/0x400 kernel/sched/core.c:2146
wake_up_new_task+0x574/0xc90 kernel/sched/core.c:4900
kernel_clone+0x236/0x980 kernel/fork.c:2828
user_mode_thread+0xb4/0xf0 kernel/fork.c:2875
rest_init+0x23/0x2b0 init/main.c:712
start_kernel+0x3df/0x4c0 init/main.c:1103
x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:507
x86_64_start_kernel+0xb2/0xc0 arch/x86/kernel/head64.c:488
common_startup_64+0x13e/0x148
-> #2 (&rq->__lock){-.-.}-{2:2}:
_raw_spin_lock_nested+0x31/0x40 kernel/locking/spinlock.c:378
raw_spin_rq_lock_nested+0x29/0x130 kernel/sched/core.c:559
raw_spin_rq_lock kernel/sched/sched.h:1406 [inline]
rq_lock kernel/sched/sched.h:1702 [inline]
task_fork_fair+0x73/0x250 kernel/sched/fair.c:12710
sched_cgroup_fork+0x3cf/0x510 kernel/sched/core.c:4844
copy_process+0x4710/0x6f50 kernel/fork.c:2499
kernel_clone+0xfd/0x980 kernel/fork.c:2797
user_mode_thread+0xb4/0xf0 kernel/fork.c:2875
rest_init+0x23/0x2b0 init/main.c:712
start_kernel+0x3df/0x4c0 init/main.c:1103
x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:507
x86_64_start_kernel+0xb2/0xc0 arch/x86/kernel/head64.c:488
common_startup_64+0x13e/0x148
-> #1 (&p->pi_lock){-.-.}-{2:2}:
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162
class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:553 [inline]
try_to_wake_up+0x9a/0x13e0 kernel/sched/core.c:4262
up+0x79/0xb0 kernel/locking/semaphore.c:191
__up_console_sem kernel/printk/printk.c:340 [inline]
__console_unlock kernel/printk/printk.c:2731 [inline]
console_unlock+0x23e/0x290 kernel/printk/printk.c:3050
vga_remove_vgacon drivers/pci/vgaarb.c:186 [inline]
vga_remove_vgacon+0x90/0xd0 drivers/pci/vgaarb.c:167
__aperture_remove_legacy_vga_devices drivers/video/aperture.c:331 [inline]
aperture_remove_conflicting_pci_devices+0x17f/0x210 drivers/video/aperture.c:374
bochs_pci_probe+0x101/0x1150 drivers/gpu/drm/tiny/bochs.c:651
local_pci_probe+0xde/0x1b0 drivers/pci/pci-driver.c:324
pci_call_probe drivers/pci/pci-driver.c:392 [inline]
__pci_device_probe drivers/pci/pci-driver.c:417 [inline]
pci_device_probe+0x294/0x7a0 drivers/pci/pci-driver.c:451
call_driver_probe drivers/base/dd.c:578 [inline]
really_probe+0x23e/0xa90 drivers/base/dd.c:656
__driver_probe_device+0x1de/0x440 drivers/base/dd.c:798
driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:828
__driver_attach+0x283/0x580 drivers/base/dd.c:1214
bus_for_each_dev+0x13c/0x1d0 drivers/base/bus.c:368
bus_add_driver+0x2ed/0x640 drivers/base/bus.c:673
driver_register+0x15c/0x4b0 drivers/base/driver.c:246
drm_pci_register_driver_if_modeset include/drm/drm_module.h:69 [inline]
bochs_pci_driver_init+0x67/0x80 drivers/gpu/drm/tiny/bochs.c:735
do_one_initcall+0x128/0x630 init/main.c:1267
do_initcall_level init/main.c:1329 [inline]
do_initcalls init/main.c:1345 [inline]
do_basic_setup init/main.c:1364 [inline]
kernel_init_freeable+0x660/0xc50 init/main.c:1578
kernel_init+0x1c/0x2b0 init/main.c:1467
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
-> #0 ((console_sem).lock){-.-.}-{2:2}:
check_prev_add kernel/locking/lockdep.c:3134 [inline]
check_prevs_add kernel/locking/lockdep.c:3253 [inline]
validate_chain kernel/locking/lockdep.c:3869 [inline]
__lock_acquire+0x2478/0x3b30 kernel/locking/lockdep.c:5137
lock_acquire kernel/locking/lockdep.c:5754 [inline]
lock_acquire+0x1b1/0x560 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
down_trylock+0x12/0x70 kernel/locking/semaphore.c:139
__down_trylock_console_sem+0x40/0x140 kernel/printk/printk.c:323
console_trylock kernel/printk/printk.c:2684 [inline]
console_trylock_spinning kernel/printk/printk.c:1958 [inline]
vprintk_emit kernel/printk/printk.c:2347 [inline]
vprintk_emit+0xe4/0x5a0 kernel/printk/printk.c:2303
vprintk+0x7f/0xa0 kernel/printk/printk_safe.c:45
_printk+0xc8/0x100 kernel/printk/printk.c:2373
__report_bug lib/bug.c:195 [inline]
report_bug+0x4ac/0x580 lib/bug.c:219
handle_bug+0x3d/0x70 arch/x86/kernel/traps.c:239
exc_invalid_op+0x17/0x50 arch/x86/kernel/traps.c:260
asm_exc_invalid_op+0x1a/0x20 arch/x86/include/asm/idtentry.h:621
expire_timers kernel/time/timer.c:1830 [inline]
__run_timers+0x8ec/0xaf0 kernel/time/timer.c:2417
__run_timer_base kernel/time/timer.c:2428 [inline]
__run_timer_base kernel/time/timer.c:2421 [inline]
run_timer_base+0x111/0x190 kernel/time/timer.c:2437
run_timer_softirq+0x1a/0x40 kernel/time/timer.c:2447
handle_softirqs+0x216/0x8f0 kernel/softirq.c:554
__do_softirq kernel/softirq.c:588 [inline]
invoke_softirq kernel/softirq.c:428 [inline]
__irq_exit_rcu kernel/softirq.c:637 [inline]
irq_exit_rcu+0xbb/0x120 kernel/softirq.c:649
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
sysvec_apic_timer_interrupt+0x95/0xb0 arch/x86/kernel/apic/apic.c:1043
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline]
arch_safe_halt arch/x86/include/asm/irqflags.h:86 [inline]
default_idle+0xf/0x20 arch/x86/kernel/process.c:742
default_idle_call+0x6d/0xb0 kernel/sched/idle.c:117
cpuidle_idle_call kernel/sched/idle.c:191 [inline]
do_idle+0x32c/0x3f0 kernel/sched/idle.c:332
cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:430
rest_init+0x16b/0x2b0 init/main.c:747
start_kernel+0x3df/0x4c0 init/main.c:1103
x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:507
x86_64_start_kernel+0xb2/0xc0 arch/x86/kernel/head64.c:488
common_startup_64+0x13e/0x148
other info that might help us debug this:
Chain exists of:
(console_sem).lock --> &rq->__lock --> &base->lock
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&base->lock);
lock(&rq->__lock);
lock(&base->lock);
lock((console_sem).lock);
*** DEADLOCK ***
1 lock held by swapper/0/0:
#0: ffff88802c02a858 (&base->lock){-.-.}-{2:2}, at: __run_timer_base kernel/time/timer.c:2427 [inline]
#0: ffff88802c02a858 (&base->lock){-.-.}-{2:2}, at: __run_timer_base kernel/time/timer.c:2421 [inline]
#0: ffff88802c02a858 (&base->lock){-.-.}-{2:2}, at: run_timer_base+0x109/0x190 kernel/time/timer.c:2437
stack backtrace:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.9.0-syzkaller-10713-g2a8120d7b482 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114
check_noncircular+0x31a/0x400 kernel/locking/lockdep.c:2187
check_prev_add kernel/locking/lockdep.c:3134 [inline]
check_prevs_add kernel/locking/lockdep.c:3253 [inline]
validate_chain kernel/locking/lockdep.c:3869 [inline]
__lock_acquire+0x2478/0x3b30 kernel/locking/lockdep.c:5137
lock_acquire kernel/locking/lockdep.c:5754 [inline]
lock_acquire+0x1b1/0x560 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
down_trylock+0x12/0x70 kernel/locking/semaphore.c:139
__down_trylock_console_sem+0x40/0x140 kernel/printk/printk.c:323
console_trylock kernel/printk/printk.c:2684 [inline]
console_trylock_spinning kernel/printk/printk.c:1958 [inline]
vprintk_emit kernel/printk/printk.c:2347 [inline]
vprintk_emit+0xe4/0x5a0 kernel/printk/printk.c:2303
vprintk+0x7f/0xa0 kernel/printk/printk_safe.c:45
_printk+0xc8/0x100 kernel/printk/printk.c:2373
__report_bug lib/bug.c:195 [inline]
report_bug+0x4ac/0x580 lib/bug.c:219
handle_bug+0x3d/0x70 arch/x86/kernel/traps.c:239
exc_invalid_op+0x17/0x50 arch/x86/kernel/traps.c:260
asm_exc_invalid_op+0x1a/0x20 arch/x86/include/asm/idtentry.h:621
RIP: 0010:expire_timers kernel/time/timer.c:1830 [inline]
RIP: 0010:__run_timers+0x8ec/0xaf0 kernel/time/timer.c:2417
Code: 6e 48 e8 77 34 13 00 89 de 31 ff 83 eb 01 e8 6b 2f 13 00 8b 44 24 18 85 c0 0f 85 18 fc ff ff e9 91 fb ff ff e8 55 34 13 00 90 <0f> 0b 90 e9 7b fc ff ff e8 47 34 13 00 90 0f 0b 90 e9 04 fd ff ff
RSP: 0018:ffffc90000007d58 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffffe8ffad07be10 RCX: ffffffff817b4d49
RDX: ffffffff8d8957c0 RSI: ffffffff817b4ddb RDI: ffffe8ffad07be28
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: ffffc90000007e10
R13: ffffc90000007e10 R14: ffff88802c02a840 R15: dffffc0000000000
__run_timer_base kernel/time/timer.c:2428 [inline]
__run_timer_base kernel/time/timer.c:2421 [inline]
run_timer_base+0x111/0x190 kernel/time/timer.c:2437
run_timer_softirq+0x1a/0x40 kernel/time/timer.c:2447
handle_softirqs+0x216/0x8f0 kernel/softirq.c:554
__do_softirq kernel/softirq.c:588 [inline]
invoke_softirq kernel/softirq.c:428 [inline]
__irq_exit_rcu kernel/softirq.c:637 [inline]
irq_exit_rcu+0xbb/0x120 kernel/softirq.c:649
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
sysvec_apic_timer_interrupt+0x95/0xb0 arch/x86/kernel/apic/apic.c:1043
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:native_irq_disable arch/x86/include/asm/irqflags.h:37 [inline]
RIP: 0010:arch_local_irq_disable arch/x86/include/asm/irqflags.h:72 [inline]
RIP: 0010:default_idle+0xf/0x20 arch/x86/kernel/process.c:743
Code: 4c 01 c7 4c 29 c2 e9 72 ff ff ff 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d c3 36 48 00 fb f4 <fa> c3 cc cc cc cc 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90
RSP: 0018:ffffffff8d807e20 EFLAGS: 00000246
RAX: 0000000000140011 RBX: 0000000000000000 RCX: ffffffff8ade3e29
RDX: 0000000000000000 RSI: ffffffff8b2cb6c0 RDI: ffffffff8b8fae60
RBP: fffffbfff1b12af8 R08: 0000000000000001 R09: ffffed1005806fe5
R10: ffff88802c037f2b R11: 0000000000000000 R12: 0000000000000000
R13: ffffffff8d8957c0 R14: ffffffff8fe29810 R15: 0000000000000000
default_idle_call+0x6d/0xb0 kernel/sched/idle.c:117
cpuidle_idle_call kernel/sched/idle.c:191 [inline]
do_idle+0x32c/0x3f0 kernel/sched/idle.c:332
cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:430
rest_init+0x16b/0x2b0 init/main.c:747
start_kernel+0x3df/0x4c0 init/main.c:1103
x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:507
x86_64_start_kernel+0xb2/0xc0 arch/x86/kernel/head64.c:488
common_startup_64+0x13e/0x148
</TASK>
WARNING: CPU: 0 PID: 0 at kernel/time/timer.c:1830 expire_timers kernel/time/timer.c:1830 [inline]
WARNING: CPU: 0 PID: 0 at kernel/time/timer.c:1830 __run_timers+0x8ec/0xaf0 kernel/time/timer.c:2417
Modules linked in:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.9.0-syzkaller-10713-g2a8120d7b482 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:expire_timers kernel/time/timer.c:1830 [inline]
RIP: 0010:__run_timers+0x8ec/0xaf0 kernel/time/timer.c:2417
Code: 6e 48 e8 77 34 13 00 89 de 31 ff 83 eb 01 e8 6b 2f 13 00 8b 44 24 18 85 c0 0f 85 18 fc ff ff e9 91 fb ff ff e8 55 34 13 00 90 <0f> 0b 90 e9 7b fc ff ff e8 47 34 13 00 90 0f 0b 90 e9 04 fd ff ff
RSP: 0018:ffffc90000007d58 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffffe8ffad07be10 RCX: ffffffff817b4d49
RDX: ffffffff8d8957c0 RSI: ffffffff817b4ddb RDI: ffffe8ffad07be28
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: ffffc90000007e10
R13: ffffc90000007e10 R14: ffff88802c02a840 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff88802c000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000f7493f1c CR3: 0000000054c9e000 CR4: 0000000000350ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
__run_timer_base kernel/time/timer.c:2428 [inline]
__run_timer_base kernel/time/timer.c:2421 [inline]
run_timer_base+0x111/0x190 kernel/time/timer.c:2437
run_timer_softirq+0x1a/0x40 kernel/time/timer.c:2447
handle_softirqs+0x216/0x8f0 kernel/softirq.c:554
__do_softirq kernel/softirq.c:588 [inline]
invoke_softirq kernel/softirq.c:428 [inline]
__irq_exit_rcu kernel/softirq.c:637 [inline]
irq_exit_rcu+0xbb/0x120 kernel/softirq.c:649
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
sysvec_apic_timer_interrupt+0x95/0xb0 arch/x86/kernel/apic/apic.c:1043
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:native_irq_disable arch/x86/include/asm/irqflags.h:37 [inline]
RIP: 0010:arch_local_irq_disable arch/x86/include/asm/irqflags.h:72 [inline]
RIP: 0010:default_idle+0xf/0x20 arch/x86/kernel/process.c:743
Code: 4c 01 c7 4c 29 c2 e9 72 ff ff ff 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d c3 36 48 00 fb f4 <fa> c3 cc cc cc cc 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90
RSP: 0018:ffffffff8d807e20 EFLAGS: 00000246
RAX: 0000000000140011 RBX: 0000000000000000 RCX: ffffffff8ade3e29
RDX: 0000000000000000 RSI: ffffffff8b2cb6c0 RDI: ffffffff8b8fae60
RBP: fffffbfff1b12af8 R08: 0000000000000001 R09: ffffed1005806fe5
R10: ffff88802c037f2b R11: 0000000000000000 R12: 0000000000000000
R13: ffffffff8d8957c0 R14: ffffffff8fe29810 R15: 0000000000000000
default_idle_call+0x6d/0xb0 kernel/sched/idle.c:117
cpuidle_idle_call kernel/sched/idle.c:191 [inline]
do_idle+0x32c/0x3f0 kernel/sched/idle.c:332
cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:430
rest_init+0x16b/0x2b0 init/main.c:747
start_kernel+0x3df/0x4c0 init/main.c:1103
x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:507
x86_64_start_kernel+0xb2/0xc0 arch/x86/kernel/head64.c:488
common_startup_64+0x13e/0x148
</TASK>
----------------
Code disassembly (best guess):
0: 4c 01 c7 add %r8,%rdi
3: 4c 29 c2 sub %r8,%rdx
6: e9 72 ff ff ff jmp 0xffffff7d
b: 90 nop
c: 90 nop
d: 90 nop
e: 90 nop
f: 90 nop
10: 90 nop
11: 90 nop
12: 90 nop
13: 90 nop
14: 90 nop
15: 90 nop
16: 90 nop
17: 90 nop
18: 90 nop
19: 90 nop
1a: 90 nop
1b: f3 0f 1e fa endbr64
1f: 66 90 xchg %ax,%ax
21: 0f 00 2d c3 36 48 00 verw 0x4836c3(%rip) # 0x4836eb
28: fb sti
29: f4 hlt
* 2a: fa cli <-- trapping instruction
2b: c3 ret
2c: cc int3
2d: cc int3
2e: cc int3
2f: cc int3
30: 66 66 2e 0f 1f 84 00 data16 cs nopw 0x0(%rax,%rax,1)
37: 00 00 00 00
3b: 90 nop
3c: 90 nop
3d: 90 nop
3e: 90 nop
3f: 90 nop
---
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syzbot found the following issue on:
HEAD commit: 2a8120d7b482 Merge tag 's390-6.10-2' of git://git.kernel.o..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1107d9cc980000
kernel config: https://syzkaller.appspot.com/x/.config?x=5dd4fde1337a9e18
dashboard link: https://syzkaller.appspot.com/bug?extid=9a474438d0c960487fcf
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: i386
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7bc7510fe41f/non_bootable_disk-2a8120d7.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/78c72ae6bdaf/vmlinux-2a8120d7.xz
kernel image: https://storage.googleapis.com/syzbot-assets/99dbb805b738/bzImage-2a8120d7.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+9a4744...@syzkaller.appspotmail.com
------------[ cut here ]------------
======================================================
WARNING: possible circular locking dependency detected
6.9.0-syzkaller-10713-g2a8120d7b482 #0 Not tainted
------------------------------------------------------
swapper/0/0 is trying to acquire lock:
ffffffff8dba2e98 ((console_sem).lock){-.-.}-{2:2}, at: down_trylock+0x12/0x70 kernel/locking/semaphore.c:139
but task is already holding lock:
ffff88802c02a858 (&base->lock){-.-.}-{2:2}, at: __run_timer_base kernel/time/timer.c:2427 [inline]
ffff88802c02a858 (&base->lock){-.-.}-{2:2}, at: __run_timer_base kernel/time/timer.c:2421 [inline]
ffff88802c02a858 (&base->lock){-.-.}-{2:2}, at: run_timer_base+0x109/0x190 kernel/time/timer.c:2437
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #3 (&base->lock){-.-.}-{2:2}:
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162
lock_timer_base+0x5d/0x220 kernel/time/timer.c:1051
__mod_timer+0x426/0xdc0 kernel/time/timer.c:1132
add_timer_global+0x8a/0xc0 kernel/time/timer.c:1330
__queue_delayed_work+0x1ba/0x2e0 kernel/workqueue.c:2543
queue_delayed_work_on+0x12a/0x150 kernel/workqueue.c:2572
psi_task_change+0x1b4/0x2e0 kernel/sched/psi.c:912
psi_enqueue kernel/sched/stats.h:139 [inline]
enqueue_task kernel/sched/core.c:2112 [inline]
activate_task+0x213/0x400 kernel/sched/core.c:2146
wake_up_new_task+0x574/0xc90 kernel/sched/core.c:4900
kernel_clone+0x236/0x980 kernel/fork.c:2828
user_mode_thread+0xb4/0xf0 kernel/fork.c:2875
rest_init+0x23/0x2b0 init/main.c:712
start_kernel+0x3df/0x4c0 init/main.c:1103
x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:507
x86_64_start_kernel+0xb2/0xc0 arch/x86/kernel/head64.c:488
common_startup_64+0x13e/0x148
-> #2 (&rq->__lock){-.-.}-{2:2}:
_raw_spin_lock_nested+0x31/0x40 kernel/locking/spinlock.c:378
raw_spin_rq_lock_nested+0x29/0x130 kernel/sched/core.c:559
raw_spin_rq_lock kernel/sched/sched.h:1406 [inline]
rq_lock kernel/sched/sched.h:1702 [inline]
task_fork_fair+0x73/0x250 kernel/sched/fair.c:12710
sched_cgroup_fork+0x3cf/0x510 kernel/sched/core.c:4844
copy_process+0x4710/0x6f50 kernel/fork.c:2499
kernel_clone+0xfd/0x980 kernel/fork.c:2797
user_mode_thread+0xb4/0xf0 kernel/fork.c:2875
rest_init+0x23/0x2b0 init/main.c:712
start_kernel+0x3df/0x4c0 init/main.c:1103
x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:507
x86_64_start_kernel+0xb2/0xc0 arch/x86/kernel/head64.c:488
common_startup_64+0x13e/0x148
-> #1 (&p->pi_lock){-.-.}-{2:2}:
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162
class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:553 [inline]
try_to_wake_up+0x9a/0x13e0 kernel/sched/core.c:4262
up+0x79/0xb0 kernel/locking/semaphore.c:191
__up_console_sem kernel/printk/printk.c:340 [inline]
__console_unlock kernel/printk/printk.c:2731 [inline]
console_unlock+0x23e/0x290 kernel/printk/printk.c:3050
vga_remove_vgacon drivers/pci/vgaarb.c:186 [inline]
vga_remove_vgacon+0x90/0xd0 drivers/pci/vgaarb.c:167
__aperture_remove_legacy_vga_devices drivers/video/aperture.c:331 [inline]
aperture_remove_conflicting_pci_devices+0x17f/0x210 drivers/video/aperture.c:374
bochs_pci_probe+0x101/0x1150 drivers/gpu/drm/tiny/bochs.c:651
local_pci_probe+0xde/0x1b0 drivers/pci/pci-driver.c:324
pci_call_probe drivers/pci/pci-driver.c:392 [inline]
__pci_device_probe drivers/pci/pci-driver.c:417 [inline]
pci_device_probe+0x294/0x7a0 drivers/pci/pci-driver.c:451
call_driver_probe drivers/base/dd.c:578 [inline]
really_probe+0x23e/0xa90 drivers/base/dd.c:656
__driver_probe_device+0x1de/0x440 drivers/base/dd.c:798
driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:828
__driver_attach+0x283/0x580 drivers/base/dd.c:1214
bus_for_each_dev+0x13c/0x1d0 drivers/base/bus.c:368
bus_add_driver+0x2ed/0x640 drivers/base/bus.c:673
driver_register+0x15c/0x4b0 drivers/base/driver.c:246
drm_pci_register_driver_if_modeset include/drm/drm_module.h:69 [inline]
bochs_pci_driver_init+0x67/0x80 drivers/gpu/drm/tiny/bochs.c:735
do_one_initcall+0x128/0x630 init/main.c:1267
do_initcall_level init/main.c:1329 [inline]
do_initcalls init/main.c:1345 [inline]
do_basic_setup init/main.c:1364 [inline]
kernel_init_freeable+0x660/0xc50 init/main.c:1578
kernel_init+0x1c/0x2b0 init/main.c:1467
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
-> #0 ((console_sem).lock){-.-.}-{2:2}:
check_prev_add kernel/locking/lockdep.c:3134 [inline]
check_prevs_add kernel/locking/lockdep.c:3253 [inline]
validate_chain kernel/locking/lockdep.c:3869 [inline]
__lock_acquire+0x2478/0x3b30 kernel/locking/lockdep.c:5137
lock_acquire kernel/locking/lockdep.c:5754 [inline]
lock_acquire+0x1b1/0x560 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
down_trylock+0x12/0x70 kernel/locking/semaphore.c:139
__down_trylock_console_sem+0x40/0x140 kernel/printk/printk.c:323
console_trylock kernel/printk/printk.c:2684 [inline]
console_trylock_spinning kernel/printk/printk.c:1958 [inline]
vprintk_emit kernel/printk/printk.c:2347 [inline]
vprintk_emit+0xe4/0x5a0 kernel/printk/printk.c:2303
vprintk+0x7f/0xa0 kernel/printk/printk_safe.c:45
_printk+0xc8/0x100 kernel/printk/printk.c:2373
__report_bug lib/bug.c:195 [inline]
report_bug+0x4ac/0x580 lib/bug.c:219
handle_bug+0x3d/0x70 arch/x86/kernel/traps.c:239
exc_invalid_op+0x17/0x50 arch/x86/kernel/traps.c:260
asm_exc_invalid_op+0x1a/0x20 arch/x86/include/asm/idtentry.h:621
expire_timers kernel/time/timer.c:1830 [inline]
__run_timers+0x8ec/0xaf0 kernel/time/timer.c:2417
__run_timer_base kernel/time/timer.c:2428 [inline]
__run_timer_base kernel/time/timer.c:2421 [inline]
run_timer_base+0x111/0x190 kernel/time/timer.c:2437
run_timer_softirq+0x1a/0x40 kernel/time/timer.c:2447
handle_softirqs+0x216/0x8f0 kernel/softirq.c:554
__do_softirq kernel/softirq.c:588 [inline]
invoke_softirq kernel/softirq.c:428 [inline]
__irq_exit_rcu kernel/softirq.c:637 [inline]
irq_exit_rcu+0xbb/0x120 kernel/softirq.c:649
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
sysvec_apic_timer_interrupt+0x95/0xb0 arch/x86/kernel/apic/apic.c:1043
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline]
arch_safe_halt arch/x86/include/asm/irqflags.h:86 [inline]
default_idle+0xf/0x20 arch/x86/kernel/process.c:742
default_idle_call+0x6d/0xb0 kernel/sched/idle.c:117
cpuidle_idle_call kernel/sched/idle.c:191 [inline]
do_idle+0x32c/0x3f0 kernel/sched/idle.c:332
cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:430
rest_init+0x16b/0x2b0 init/main.c:747
start_kernel+0x3df/0x4c0 init/main.c:1103
x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:507
x86_64_start_kernel+0xb2/0xc0 arch/x86/kernel/head64.c:488
common_startup_64+0x13e/0x148
other info that might help us debug this:
Chain exists of:
(console_sem).lock --> &rq->__lock --> &base->lock
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&base->lock);
lock(&rq->__lock);
lock(&base->lock);
lock((console_sem).lock);
*** DEADLOCK ***
1 lock held by swapper/0/0:
#0: ffff88802c02a858 (&base->lock){-.-.}-{2:2}, at: __run_timer_base kernel/time/timer.c:2427 [inline]
#0: ffff88802c02a858 (&base->lock){-.-.}-{2:2}, at: __run_timer_base kernel/time/timer.c:2421 [inline]
#0: ffff88802c02a858 (&base->lock){-.-.}-{2:2}, at: run_timer_base+0x109/0x190 kernel/time/timer.c:2437
stack backtrace:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.9.0-syzkaller-10713-g2a8120d7b482 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114
check_noncircular+0x31a/0x400 kernel/locking/lockdep.c:2187
check_prev_add kernel/locking/lockdep.c:3134 [inline]
check_prevs_add kernel/locking/lockdep.c:3253 [inline]
validate_chain kernel/locking/lockdep.c:3869 [inline]
__lock_acquire+0x2478/0x3b30 kernel/locking/lockdep.c:5137
lock_acquire kernel/locking/lockdep.c:5754 [inline]
lock_acquire+0x1b1/0x560 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
down_trylock+0x12/0x70 kernel/locking/semaphore.c:139
__down_trylock_console_sem+0x40/0x140 kernel/printk/printk.c:323
console_trylock kernel/printk/printk.c:2684 [inline]
console_trylock_spinning kernel/printk/printk.c:1958 [inline]
vprintk_emit kernel/printk/printk.c:2347 [inline]
vprintk_emit+0xe4/0x5a0 kernel/printk/printk.c:2303
vprintk+0x7f/0xa0 kernel/printk/printk_safe.c:45
_printk+0xc8/0x100 kernel/printk/printk.c:2373
__report_bug lib/bug.c:195 [inline]
report_bug+0x4ac/0x580 lib/bug.c:219
handle_bug+0x3d/0x70 arch/x86/kernel/traps.c:239
exc_invalid_op+0x17/0x50 arch/x86/kernel/traps.c:260
asm_exc_invalid_op+0x1a/0x20 arch/x86/include/asm/idtentry.h:621
RIP: 0010:expire_timers kernel/time/timer.c:1830 [inline]
RIP: 0010:__run_timers+0x8ec/0xaf0 kernel/time/timer.c:2417
Code: 6e 48 e8 77 34 13 00 89 de 31 ff 83 eb 01 e8 6b 2f 13 00 8b 44 24 18 85 c0 0f 85 18 fc ff ff e9 91 fb ff ff e8 55 34 13 00 90 <0f> 0b 90 e9 7b fc ff ff e8 47 34 13 00 90 0f 0b 90 e9 04 fd ff ff
RSP: 0018:ffffc90000007d58 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffffe8ffad07be10 RCX: ffffffff817b4d49
RDX: ffffffff8d8957c0 RSI: ffffffff817b4ddb RDI: ffffe8ffad07be28
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: ffffc90000007e10
R13: ffffc90000007e10 R14: ffff88802c02a840 R15: dffffc0000000000
__run_timer_base kernel/time/timer.c:2428 [inline]
__run_timer_base kernel/time/timer.c:2421 [inline]
run_timer_base+0x111/0x190 kernel/time/timer.c:2437
run_timer_softirq+0x1a/0x40 kernel/time/timer.c:2447
handle_softirqs+0x216/0x8f0 kernel/softirq.c:554
__do_softirq kernel/softirq.c:588 [inline]
invoke_softirq kernel/softirq.c:428 [inline]
__irq_exit_rcu kernel/softirq.c:637 [inline]
irq_exit_rcu+0xbb/0x120 kernel/softirq.c:649
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
sysvec_apic_timer_interrupt+0x95/0xb0 arch/x86/kernel/apic/apic.c:1043
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:native_irq_disable arch/x86/include/asm/irqflags.h:37 [inline]
RIP: 0010:arch_local_irq_disable arch/x86/include/asm/irqflags.h:72 [inline]
RIP: 0010:default_idle+0xf/0x20 arch/x86/kernel/process.c:743
Code: 4c 01 c7 4c 29 c2 e9 72 ff ff ff 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d c3 36 48 00 fb f4 <fa> c3 cc cc cc cc 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90
RSP: 0018:ffffffff8d807e20 EFLAGS: 00000246
RAX: 0000000000140011 RBX: 0000000000000000 RCX: ffffffff8ade3e29
RDX: 0000000000000000 RSI: ffffffff8b2cb6c0 RDI: ffffffff8b8fae60
RBP: fffffbfff1b12af8 R08: 0000000000000001 R09: ffffed1005806fe5
R10: ffff88802c037f2b R11: 0000000000000000 R12: 0000000000000000
R13: ffffffff8d8957c0 R14: ffffffff8fe29810 R15: 0000000000000000
default_idle_call+0x6d/0xb0 kernel/sched/idle.c:117
cpuidle_idle_call kernel/sched/idle.c:191 [inline]
do_idle+0x32c/0x3f0 kernel/sched/idle.c:332
cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:430
rest_init+0x16b/0x2b0 init/main.c:747
start_kernel+0x3df/0x4c0 init/main.c:1103
x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:507
x86_64_start_kernel+0xb2/0xc0 arch/x86/kernel/head64.c:488
common_startup_64+0x13e/0x148
</TASK>
WARNING: CPU: 0 PID: 0 at kernel/time/timer.c:1830 expire_timers kernel/time/timer.c:1830 [inline]
WARNING: CPU: 0 PID: 0 at kernel/time/timer.c:1830 __run_timers+0x8ec/0xaf0 kernel/time/timer.c:2417
Modules linked in:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.9.0-syzkaller-10713-g2a8120d7b482 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:expire_timers kernel/time/timer.c:1830 [inline]
RIP: 0010:__run_timers+0x8ec/0xaf0 kernel/time/timer.c:2417
Code: 6e 48 e8 77 34 13 00 89 de 31 ff 83 eb 01 e8 6b 2f 13 00 8b 44 24 18 85 c0 0f 85 18 fc ff ff e9 91 fb ff ff e8 55 34 13 00 90 <0f> 0b 90 e9 7b fc ff ff e8 47 34 13 00 90 0f 0b 90 e9 04 fd ff ff
RSP: 0018:ffffc90000007d58 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffffe8ffad07be10 RCX: ffffffff817b4d49
RDX: ffffffff8d8957c0 RSI: ffffffff817b4ddb RDI: ffffe8ffad07be28
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: ffffc90000007e10
R13: ffffc90000007e10 R14: ffff88802c02a840 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff88802c000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000f7493f1c CR3: 0000000054c9e000 CR4: 0000000000350ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
__run_timer_base kernel/time/timer.c:2428 [inline]
__run_timer_base kernel/time/timer.c:2421 [inline]
run_timer_base+0x111/0x190 kernel/time/timer.c:2437
run_timer_softirq+0x1a/0x40 kernel/time/timer.c:2447
handle_softirqs+0x216/0x8f0 kernel/softirq.c:554
__do_softirq kernel/softirq.c:588 [inline]
invoke_softirq kernel/softirq.c:428 [inline]
__irq_exit_rcu kernel/softirq.c:637 [inline]
irq_exit_rcu+0xbb/0x120 kernel/softirq.c:649
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
sysvec_apic_timer_interrupt+0x95/0xb0 arch/x86/kernel/apic/apic.c:1043
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:native_irq_disable arch/x86/include/asm/irqflags.h:37 [inline]
RIP: 0010:arch_local_irq_disable arch/x86/include/asm/irqflags.h:72 [inline]
RIP: 0010:default_idle+0xf/0x20 arch/x86/kernel/process.c:743
Code: 4c 01 c7 4c 29 c2 e9 72 ff ff ff 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d c3 36 48 00 fb f4 <fa> c3 cc cc cc cc 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90
RSP: 0018:ffffffff8d807e20 EFLAGS: 00000246
RAX: 0000000000140011 RBX: 0000000000000000 RCX: ffffffff8ade3e29
RDX: 0000000000000000 RSI: ffffffff8b2cb6c0 RDI: ffffffff8b8fae60
RBP: fffffbfff1b12af8 R08: 0000000000000001 R09: ffffed1005806fe5
R10: ffff88802c037f2b R11: 0000000000000000 R12: 0000000000000000
R13: ffffffff8d8957c0 R14: ffffffff8fe29810 R15: 0000000000000000
default_idle_call+0x6d/0xb0 kernel/sched/idle.c:117
cpuidle_idle_call kernel/sched/idle.c:191 [inline]
do_idle+0x32c/0x3f0 kernel/sched/idle.c:332
cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:430
rest_init+0x16b/0x2b0 init/main.c:747
start_kernel+0x3df/0x4c0 init/main.c:1103
x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:507
x86_64_start_kernel+0xb2/0xc0 arch/x86/kernel/head64.c:488
common_startup_64+0x13e/0x148
</TASK>
----------------
Code disassembly (best guess):
0: 4c 01 c7 add %r8,%rdi
3: 4c 29 c2 sub %r8,%rdx
6: e9 72 ff ff ff jmp 0xffffff7d
b: 90 nop
c: 90 nop
d: 90 nop
e: 90 nop
f: 90 nop
10: 90 nop
11: 90 nop
12: 90 nop
13: 90 nop
14: 90 nop
15: 90 nop
16: 90 nop
17: 90 nop
18: 90 nop
19: 90 nop
1a: 90 nop
1b: f3 0f 1e fa endbr64
1f: 66 90 xchg %ax,%ax
21: 0f 00 2d c3 36 48 00 verw 0x4836c3(%rip) # 0x4836eb
28: fb sti
29: f4 hlt
* 2a: fa cli <-- trapping instruction
2b: c3 ret
2c: cc int3
2d: cc int3
2e: cc int3
2f: cc int3
30: 66 66 2e 0f 1f 84 00 data16 cs nopw 0x0(%rax,%rax,1)
37: 00 00 00 00
3b: 90 nop
3c: 90 nop
3d: 90 nop
3e: 90 nop
3f: 90 nop
---
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