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Message-ID: <2aaa1663-fa9c-43ce-9421-60019899bac1@redhat.com>
Date: Tue, 11 Feb 2025 21:14:12 -0500
From: Waiman Long <llong@...hat.com>
To: syzbot <syzbot+ed801a886dfdbfe7136d@...kaller.appspotmail.com>,
cgroups@...r.kernel.org, hannes@...xchg.org, linux-kernel@...r.kernel.org,
mkoutny@...e.com, syzkaller-bugs@...glegroups.com, tj@...nel.org,
Peter Zijlstra <peterz@...radead.org>
Subject: Re: [syzbot] [cgroups?] possible deadlock in __run_timer_base (2)
On 2/9/25 3:43 PM, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: 92514ef226f5 Merge tag 'for-6.14-rc1-tag' of git://git.ker..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=179453df980000
> kernel config: https://syzkaller.appspot.com/x/.config?x=1909f2f0d8e641ce
> dashboard link: https://syzkaller.appspot.com/bug?extid=ed801a886dfdbfe7136d
> compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
>
> Unfortunately, I don't have any reproducer for this issue yet.
>
> Downloadable assets:
> disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-92514ef2.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/c4d8b91f8769/vmlinux-92514ef2.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/c24ec4365966/bzImage-92514ef2.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+ed801a886dfdbfe7136d@...kaller.appspotmail.com
This problem should be fixed by the following upstream patch once it is
merged into mainline.
https://lore.kernel.org/lkml/20250127013127.3913153-1-longman@redhat.com/
Peter, are you planning to merge this patch? This is another instance
where the old way of calling wake_up_process() inside the lock critical
region can lead to deadlock.
Cheers,
Longman
>
> ------------[ cut here ]------------
> ======================================================
> WARNING: possible circular locking dependency detected
> 6.14.0-rc1-syzkaller-00034-g92514ef226f5 #0 Not tainted
> ------------------------------------------------------
> syz.0.0/5328 is trying to acquire lock:
> ffffffff8e814418 ((console_sem).lock){-.-.}-{2:2}, at: down_trylock+0x20/0xa0 kernel/locking/semaphore.c:139
>
> but task is already holding lock:
> ffff88801fc2a398 (&base->lock){-.-.}-{2:2}, at: expire_timers kernel/time/timer.c:1836 [inline]
> ffff88801fc2a398 (&base->lock){-.-.}-{2:2}, at: __run_timers kernel/time/timer.c:2414 [inline]
> ffff88801fc2a398 (&base->lock){-.-.}-{2:2}, at: __run_timer_base+0x69d/0x8e0 kernel/time/timer.c:2426
>
> which lock already depends on the new lock.
>
>
> the existing dependency chain (in reverse order) is:
>
> -> #3 (&base->lock){-.-.}-{2:2}:
> lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
> __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
> _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162
> lock_timer_base kernel/time/timer.c:1046 [inline]
> __mod_timer+0x24a/0x10e0 kernel/time/timer.c:1127
> queue_delayed_work_on+0x1ca/0x390 kernel/workqueue.c:2559
> psi_task_change+0xed/0x270 kernel/sched/psi.c:912
> psi_enqueue kernel/sched/stats.h:166 [inline]
> enqueue_task+0x306/0x3d0 kernel/sched/core.c:2076
> activate_task kernel/sched/core.c:2116 [inline]
> wake_up_new_task+0x576/0xc70 kernel/sched/core.c:4878
> kernel_clone+0x4ee/0x8e0 kernel/fork.c:2846
> user_mode_thread+0x132/0x1a0 kernel/fork.c:2893
> rest_init+0x23/0x300 init/main.c:708
> start_kernel+0x484/0x510 init/main.c:1099
> x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:515
> x86_64_start_kernel+0x9f/0xa0 arch/x86/kernel/head64.c:496
> common_startup_64+0x13e/0x147
>
> -> #2 (&rq->__lock){-.-.}-{2:2}:
> lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
> _raw_spin_lock_nested+0x31/0x40 kernel/locking/spinlock.c:378
> raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:598
> raw_spin_rq_lock kernel/sched/sched.h:1521 [inline]
> task_rq_lock+0xc6/0x360 kernel/sched/core.c:700
> cgroup_move_task+0x9b/0x5a0 kernel/sched/psi.c:1161
> css_set_move_task+0x72e/0x950 kernel/cgroup/cgroup.c:898
> cgroup_post_fork+0x256/0x880 kernel/cgroup/cgroup.c:6691
> copy_process+0x39e9/0x3d50 kernel/fork.c:2629
> kernel_clone+0x226/0x8e0 kernel/fork.c:2815
> user_mode_thread+0x132/0x1a0 kernel/fork.c:2893
> rest_init+0x23/0x300 init/main.c:708
> start_kernel+0x484/0x510 init/main.c:1099
> x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:515
> x86_64_start_kernel+0x9f/0xa0 arch/x86/kernel/head64.c:496
> common_startup_64+0x13e/0x147
>
> -> #1 (&p->pi_lock){-.-.}-{2:2}:
> lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
> __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
> _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162
> class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:551 [inline]
> try_to_wake_up+0xc2/0x1470 kernel/sched/core.c:4213
> up+0x72/0x90 kernel/locking/semaphore.c:191
> __up_console_sem kernel/printk/printk.c:343 [inline]
> __console_unlock+0x123/0x1f0 kernel/printk/printk.c:2869
> __console_flush_and_unlock kernel/printk/printk.c:3271 [inline]
> console_unlock+0x18f/0x3b0 kernel/printk/printk.c:3309
> vga_remove_vgacon+0xbe/0xd0 drivers/pci/vgaarb.c:186
> virtio_gpu_pci_quirk drivers/gpu/drm/virtio/virtgpu_drv.c:62 [inline]
> virtio_gpu_probe+0x33f/0x3c0 drivers/gpu/drm/virtio/virtgpu_drv.c:93
> virtio_dev_probe+0x931/0xc80 drivers/virtio/virtio.c:341
> really_probe+0x2b9/0xad0 drivers/base/dd.c:658
> __driver_probe_device+0x1a2/0x390 drivers/base/dd.c:800
> driver_probe_device+0x50/0x430 drivers/base/dd.c:830
> __driver_attach+0x45f/0x710 drivers/base/dd.c:1216
> bus_for_each_dev+0x239/0x2b0 drivers/base/bus.c:370
> bus_add_driver+0x346/0x670 drivers/base/bus.c:678
> driver_register+0x23a/0x320 drivers/base/driver.c:249
> do_one_initcall+0x248/0x870 init/main.c:1257
> do_initcall_level+0x157/0x210 init/main.c:1319
> do_initcalls+0x3f/0x80 init/main.c:1335
> kernel_init_freeable+0x435/0x5d0 init/main.c:1568
> kernel_init+0x1d/0x2b0 init/main.c:1457
> ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
> 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:3163 [inline]
> check_prevs_add kernel/locking/lockdep.c:3282 [inline]
> validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3906
> __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5228
> lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
> __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
> _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162
> down_trylock+0x20/0xa0 kernel/locking/semaphore.c:139
> __down_trylock_console_sem+0x109/0x250 kernel/printk/printk.c:326
> console_trylock kernel/printk/printk.c:2852 [inline]
> console_trylock_spinning kernel/printk/printk.c:2009 [inline]
> vprintk_emit+0x3d7/0xa10 kernel/printk/printk.c:2431
> _printk+0xd5/0x120 kernel/printk/printk.c:2457
> __report_bug lib/bug.c:195 [inline]
> report_bug+0x346/0x500 lib/bug.c:219
> handle_bug+0x60/0x90 arch/x86/kernel/traps.c:285
> exc_invalid_op+0x1a/0x50 arch/x86/kernel/traps.c:309
> asm_exc_invalid_op+0x1a/0x20 arch/x86/include/asm/idtentry.h:621
> expire_timers kernel/time/timer.c:1827 [inline]
> __run_timers kernel/time/timer.c:2414 [inline]
> __run_timer_base+0x6f4/0x8e0 kernel/time/timer.c:2426
> run_timer_base kernel/time/timer.c:2435 [inline]
> run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2445
> handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:561
> __do_softirq kernel/softirq.c:595 [inline]
> invoke_softirq kernel/softirq.c:435 [inline]
> __irq_exit_rcu+0xf7/0x220 kernel/softirq.c:662
> irq_exit_rcu+0x9/0x30 kernel/softirq.c:678
> instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
> sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1049
> asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
> get_stack_info+0x4/0xf0 arch/x86/kernel/dumpstack_64.c:193
> __unwind_start+0x434/0x740 arch/x86/kernel/unwind_orc.c:729
> unwind_start arch/x86/include/asm/unwind.h:64 [inline]
> arch_stack_walk+0xe5/0x150 arch/x86/kernel/stacktrace.c:24
> stack_trace_save+0x118/0x1d0 kernel/stacktrace.c:122
> kasan_save_stack mm/kasan/common.c:47 [inline]
> kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
> kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:576
> poison_slab_object mm/kasan/common.c:247 [inline]
> __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264
> kasan_slab_free include/linux/kasan.h:233 [inline]
> slab_free_hook mm/slub.c:2353 [inline]
> slab_free mm/slub.c:4609 [inline]
> kfree+0x196/0x430 mm/slub.c:4757
> bch2_printbuf_exit+0x6d/0xa0 fs/bcachefs/printbuf.c:219
> __bch2_fsck_err+0x11a0/0x1420 fs/bcachefs/error.c:458
> bch2_alloc_write_key fs/bcachefs/btree_gc.c:860 [inline]
> bch2_gc_alloc_done fs/bcachefs/btree_gc.c:894 [inline]
> bch2_check_allocations+0x47ad/0x6aa0 fs/bcachefs/btree_gc.c:1044
> bch2_run_recovery_pass+0xf0/0x1e0 fs/bcachefs/recovery_passes.c:226
> bch2_run_recovery_passes+0x2ad/0xa90 fs/bcachefs/recovery_passes.c:291
> bch2_fs_recovery+0x265a/0x3de0 fs/bcachefs/recovery.c:936
> bch2_fs_start+0x37c/0x610 fs/bcachefs/super.c:1030
> bch2_fs_get_tree+0xd8d/0x1740 fs/bcachefs/fs.c:2203
> vfs_get_tree+0x90/0x2b0 fs/super.c:1814
> do_new_mount+0x2be/0xb40 fs/namespace.c:3560
> do_mount fs/namespace.c:3900 [inline]
> __do_sys_mount fs/namespace.c:4111 [inline]
> __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4088
> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
> entry_SYSCALL_64_after_hwframe+0x77/0x7f
>
> 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 ***
>
> 5 locks held by syz.0.0/5328:
> #0: ffff888052b80278 (&c->state_lock){+.+.}-{4:4}, at: bch2_fs_start+0x45/0x610 fs/bcachefs/super.c:999
> #1: ffff888052ba66d0 (&c->gc_lock){+.+.}-{4:4}, at: bch2_check_allocations+0x1df/0x6aa0 fs/bcachefs/btree_gc.c:1020
> #2: ffff888052b84378 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:164 [inline]
> #2: ffff888052b84378 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:256 [inline]
> #2: ffff888052b84378 (&c->btree_trans_barrier){.+.+}-{0:0}, at: bch2_trans_srcu_lock+0x9a/0x1a0 fs/bcachefs/btree_iter.c:3202
> #3: ffff888052368140 (bcachefs_btree){+.+.}-{0:0}, at: trans_set_locked fs/bcachefs/btree_locking.h:198 [inline]
> #3: ffff888052368140 (bcachefs_btree){+.+.}-{0:0}, at: bch2_trans_begin+0x9ca/0x1d90 fs/bcachefs/btree_iter.c:3274
> #4: ffff88801fc2a398 (&base->lock){-.-.}-{2:2}, at: expire_timers kernel/time/timer.c:1836 [inline]
> #4: ffff88801fc2a398 (&base->lock){-.-.}-{2:2}, at: __run_timers kernel/time/timer.c:2414 [inline]
> #4: ffff88801fc2a398 (&base->lock){-.-.}-{2:2}, at: __run_timer_base+0x69d/0x8e0 kernel/time/timer.c:2426
>
> stack backtrace:
> CPU: 0 UID: 0 PID: 5328 Comm: syz.0.0 Not tainted 6.14.0-rc1-syzkaller-00034-g92514ef226f5 #0
> Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
> Call Trace:
> <IRQ>
> __dump_stack lib/dump_stack.c:94 [inline]
> dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
> print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2076
> check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2208
> check_prev_add kernel/locking/lockdep.c:3163 [inline]
> check_prevs_add kernel/locking/lockdep.c:3282 [inline]
> validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3906
> __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5228
> lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
> __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
> _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162
> down_trylock+0x20/0xa0 kernel/locking/semaphore.c:139
> __down_trylock_console_sem+0x109/0x250 kernel/printk/printk.c:326
> console_trylock kernel/printk/printk.c:2852 [inline]
> console_trylock_spinning kernel/printk/printk.c:2009 [inline]
> vprintk_emit+0x3d7/0xa10 kernel/printk/printk.c:2431
> _printk+0xd5/0x120 kernel/printk/printk.c:2457
> __report_bug lib/bug.c:195 [inline]
> report_bug+0x346/0x500 lib/bug.c:219
> handle_bug+0x60/0x90 arch/x86/kernel/traps.c:285
> exc_invalid_op+0x1a/0x50 arch/x86/kernel/traps.c:309
> asm_exc_invalid_op+0x1a/0x20 arch/x86/include/asm/idtentry.h:621
> RIP: 0010:expire_timers kernel/time/timer.c:1827 [inline]
> RIP: 0010:__run_timers kernel/time/timer.c:2414 [inline]
> RIP: 0010:__run_timer_base+0x6f4/0x8e0 kernel/time/timer.c:2426
> Code: 24 38 42 80 3c 30 00 74 08 4c 89 ef e8 a5 c4 79 00 4d 8b 7d 00 4d 85 ff 74 33 e8 27 2c 13 00 e9 dd fe ff ff e8 1d 2c 13 00 90 <0f> 0b 90 eb ae 44 89 f1 80 e1 07 80 c1 03 38 c1 0f 8c 25 ff ff ff
> RSP: 0018:ffffc90000007ca0 EFLAGS: 00010046
> RAX: ffffffff81ac3203 RBX: ffff888044012cf0 RCX: ffff888000cc2440
> RDX: 0000000000000100 RSI: ffffffff8c6089e0 RDI: ffffffff8c6089a0
> RBP: ffffc90000007df0 R08: ffffffff81ac6c04 R09: 1ffffffff2036a2e
> R10: dffffc0000000000 R11: fffffbfff2036a2f R12: 0000000000000000
> R13: ffffc90000007d48 R14: dffffc0000000000 R15: ffff888044012cd8
> run_timer_base kernel/time/timer.c:2435 [inline]
> run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2445
> handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:561
> __do_softirq kernel/softirq.c:595 [inline]
> invoke_softirq kernel/softirq.c:435 [inline]
> __irq_exit_rcu+0xf7/0x220 kernel/softirq.c:662
> irq_exit_rcu+0x9/0x30 kernel/softirq.c:678
> instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
> sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1049
> </IRQ>
> <TASK>
> asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
> RIP: 0010:get_stack_info+0x4/0xf0 arch/x86/kernel/dumpstack_64.c:193
> Code: c5 c0 23 05 8c c3 cc cc cc cc 31 c0 c3 cc cc cc cc 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 66 0f 1f 00 <55> 41 57 41 56 41 55 41 54 53 49 89 ce 48 89 d3 48 89 f5 48 85 f6
> RSP: 0018:ffffc9000d486358 EFLAGS: 00000246
> RAX: 1ffff92001a90c7f RBX: ffffc9000d486360 RCX: ffffc9000d4863e0
> RDX: ffffc9000d4863c0 RSI: ffff888000cc2440 RDI: ffffc9000d486360
> RBP: ffffc9000d486401 R08: ffffc9000d48641f R09: 0000000000000000
> R10: ffffc9000d4863c0 R11: fffff52001a90c84 R12: ffffc9000d4863e0
> R13: ffffc9000d4863e8 R14: ffffc9000d4863c0 R15: 1ffff92001a90c7d
> __unwind_start+0x434/0x740 arch/x86/kernel/unwind_orc.c:729
> unwind_start arch/x86/include/asm/unwind.h:64 [inline]
> arch_stack_walk+0xe5/0x150 arch/x86/kernel/stacktrace.c:24
> stack_trace_save+0x118/0x1d0 kernel/stacktrace.c:122
> kasan_save_stack mm/kasan/common.c:47 [inline]
> kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
> kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:576
> poison_slab_object mm/kasan/common.c:247 [inline]
> __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264
> kasan_slab_free include/linux/kasan.h:233 [inline]
> slab_free_hook mm/slub.c:2353 [inline]
> slab_free mm/slub.c:4609 [inline]
> kfree+0x196/0x430 mm/slub.c:4757
> bch2_printbuf_exit+0x6d/0xa0 fs/bcachefs/printbuf.c:219
> __bch2_fsck_err+0x11a0/0x1420 fs/bcachefs/error.c:458
> bch2_alloc_write_key fs/bcachefs/btree_gc.c:860 [inline]
> bch2_gc_alloc_done fs/bcachefs/btree_gc.c:894 [inline]
> bch2_check_allocations+0x47ad/0x6aa0 fs/bcachefs/btree_gc.c:1044
> bch2_run_recovery_pass+0xf0/0x1e0 fs/bcachefs/recovery_passes.c:226
> bch2_run_recovery_passes+0x2ad/0xa90 fs/bcachefs/recovery_passes.c:291
> bch2_fs_recovery+0x265a/0x3de0 fs/bcachefs/recovery.c:936
> bch2_fs_start+0x37c/0x610 fs/bcachefs/super.c:1030
> bch2_fs_get_tree+0xd8d/0x1740 fs/bcachefs/fs.c:2203
> vfs_get_tree+0x90/0x2b0 fs/super.c:1814
> do_new_mount+0x2be/0xb40 fs/namespace.c:3560
> do_mount fs/namespace.c:3900 [inline]
> __do_sys_mount fs/namespace.c:4111 [inline]
> __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4088
> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
> entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7f903af8e58a
> Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007f903bd70e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
> RAX: ffffffffffffffda RBX: 00007f903bd70ef0 RCX: 00007f903af8e58a
> RDX: 0000200000000000 RSI: 0000200000000040 RDI: 00007f903bd70eb0
> RBP: 0000200000000000 R08: 00007f903bd70ef0 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000200000000040
> R13: 00007f903bd70eb0 R14: 000000000000593f R15: 0000200000000380
> </TASK>
> WARNING: CPU: 0 PID: 5328 at kernel/time/timer.c:1827 expire_timers kernel/time/timer.c:1827 [inline]
> WARNING: CPU: 0 PID: 5328 at kernel/time/timer.c:1827 __run_timers kernel/time/timer.c:2414 [inline]
> WARNING: CPU: 0 PID: 5328 at kernel/time/timer.c:1827 __run_timer_base+0x6f4/0x8e0 kernel/time/timer.c:2426
> Modules linked in:
> CPU: 0 UID: 0 PID: 5328 Comm: syz.0.0 Not tainted 6.14.0-rc1-syzkaller-00034-g92514ef226f5 #0
> Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
> RIP: 0010:expire_timers kernel/time/timer.c:1827 [inline]
> RIP: 0010:__run_timers kernel/time/timer.c:2414 [inline]
> RIP: 0010:__run_timer_base+0x6f4/0x8e0 kernel/time/timer.c:2426
> Code: 24 38 42 80 3c 30 00 74 08 4c 89 ef e8 a5 c4 79 00 4d 8b 7d 00 4d 85 ff 74 33 e8 27 2c 13 00 e9 dd fe ff ff e8 1d 2c 13 00 90 <0f> 0b 90 eb ae 44 89 f1 80 e1 07 80 c1 03 38 c1 0f 8c 25 ff ff ff
> RSP: 0018:ffffc90000007ca0 EFLAGS: 00010046
> RAX: ffffffff81ac3203 RBX: ffff888044012cf0 RCX: ffff888000cc2440
> RDX: 0000000000000100 RSI: ffffffff8c6089e0 RDI: ffffffff8c6089a0
> RBP: ffffc90000007df0 R08: ffffffff81ac6c04 R09: 1ffffffff2036a2e
> R10: dffffc0000000000 R11: fffffbfff2036a2f R12: 0000000000000000
> R13: ffffc90000007d48 R14: dffffc0000000000 R15: ffff888044012cd8
> FS: 00007f903bd716c0(0000) GS:ffff88801fc00000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 000056372c09c0c8 CR3: 000000003bc66000 CR4: 0000000000352ef0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
> <IRQ>
> run_timer_base kernel/time/timer.c:2435 [inline]
> run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2445
> handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:561
> __do_softirq kernel/softirq.c:595 [inline]
> invoke_softirq kernel/softirq.c:435 [inline]
> __irq_exit_rcu+0xf7/0x220 kernel/softirq.c:662
> irq_exit_rcu+0x9/0x30 kernel/softirq.c:678
> instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
> sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1049
> </IRQ>
> <TASK>
> asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
> RIP: 0010:get_stack_info+0x4/0xf0 arch/x86/kernel/dumpstack_64.c:193
> Code: c5 c0 23 05 8c c3 cc cc cc cc 31 c0 c3 cc cc cc cc 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 66 0f 1f 00 <55> 41 57 41 56 41 55 41 54 53 49 89 ce 48 89 d3 48 89 f5 48 85 f6
> RSP: 0018:ffffc9000d486358 EFLAGS: 00000246
> RAX: 1ffff92001a90c7f RBX: ffffc9000d486360 RCX: ffffc9000d4863e0
> RDX: ffffc9000d4863c0 RSI: ffff888000cc2440 RDI: ffffc9000d486360
> RBP: ffffc9000d486401 R08: ffffc9000d48641f R09: 0000000000000000
> R10: ffffc9000d4863c0 R11: fffff52001a90c84 R12: ffffc9000d4863e0
> R13: ffffc9000d4863e8 R14: ffffc9000d4863c0 R15: 1ffff92001a90c7d
> __unwind_start+0x434/0x740 arch/x86/kernel/unwind_orc.c:729
> unwind_start arch/x86/include/asm/unwind.h:64 [inline]
> arch_stack_walk+0xe5/0x150 arch/x86/kernel/stacktrace.c:24
> stack_trace_save+0x118/0x1d0 kernel/stacktrace.c:122
> kasan_save_stack mm/kasan/common.c:47 [inline]
> kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
> kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:576
> poison_slab_object mm/kasan/common.c:247 [inline]
> __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264
> kasan_slab_free include/linux/kasan.h:233 [inline]
> slab_free_hook mm/slub.c:2353 [inline]
> slab_free mm/slub.c:4609 [inline]
> kfree+0x196/0x430 mm/slub.c:4757
> bch2_printbuf_exit+0x6d/0xa0 fs/bcachefs/printbuf.c:219
> __bch2_fsck_err+0x11a0/0x1420 fs/bcachefs/error.c:458
> bch2_alloc_write_key fs/bcachefs/btree_gc.c:860 [inline]
> bch2_gc_alloc_done fs/bcachefs/btree_gc.c:894 [inline]
> bch2_check_allocations+0x47ad/0x6aa0 fs/bcachefs/btree_gc.c:1044
> bch2_run_recovery_pass+0xf0/0x1e0 fs/bcachefs/recovery_passes.c:226
> bch2_run_recovery_passes+0x2ad/0xa90 fs/bcachefs/recovery_passes.c:291
> bch2_fs_recovery+0x265a/0x3de0 fs/bcachefs/recovery.c:936
> bch2_fs_start+0x37c/0x610 fs/bcachefs/super.c:1030
> bch2_fs_get_tree+0xd8d/0x1740 fs/bcachefs/fs.c:2203
> vfs_get_tree+0x90/0x2b0 fs/super.c:1814
> do_new_mount+0x2be/0xb40 fs/namespace.c:3560
> do_mount fs/namespace.c:3900 [inline]
> __do_sys_mount fs/namespace.c:4111 [inline]
> __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4088
> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
> entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7f903af8e58a
> Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007f903bd70e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
> RAX: ffffffffffffffda RBX: 00007f903bd70ef0 RCX: 00007f903af8e58a
> RDX: 0000200000000000 RSI: 0000200000000040 RDI: 00007f903bd70eb0
> RBP: 0000200000000000 R08: 00007f903bd70ef0 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000200000000040
> R13: 00007f903bd70eb0 R14: 000000000000593f R15: 0000200000000380
> </TASK>
> ----------------
> Code disassembly (best guess), 1 bytes skipped:
> 0: c0 23 05 shlb $0x5,(%rbx)
> 3: 8c c3 mov %es,%ebx
> 5: cc int3
> 6: cc int3
> 7: cc int3
> 8: cc int3
> 9: 31 c0 xor %eax,%eax
> b: c3 ret
> c: cc int3
> d: cc int3
> e: cc int3
> f: cc int3
> 10: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1)
> 15: 90 nop
> 16: 90 nop
> 17: 90 nop
> 18: 90 nop
> 19: 90 nop
> 1a: 90 nop
> 1b: 90 nop
> 1c: 90 nop
> 1d: 90 nop
> 1e: 90 nop
> 1f: 90 nop
> 20: 90 nop
> 21: 90 nop
> 22: 90 nop
> 23: 90 nop
> 24: 90 nop
> 25: 66 0f 1f 00 nopw (%rax)
> * 29: 55 push %rbp <-- trapping instruction
> 2a: 41 57 push %r15
> 2c: 41 56 push %r14
> 2e: 41 55 push %r13
> 30: 41 54 push %r12
> 32: 53 push %rbx
> 33: 49 89 ce mov %rcx,%r14
> 36: 48 89 d3 mov %rdx,%rbx
> 39: 48 89 f5 mov %rsi,%rbp
> 3c: 48 85 f6 test %rsi,%rsi
>
>
> ---
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