[v5.15] INFO: rcu detected stall in wb_workfn (2)
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syzbot
Feb 14, 2025, 1:15:26 AMFeb 14
Hello,
syzbot found the following issue on:
HEAD commit: c16c81c81336 Linux 5.15.178
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=10bdfbdf980000
kernel config: https://syzkaller.appspot.com/x/.config?x=d302c69e93fb6774
dashboard link: https://syzkaller.appspot.com/bug?extid=78333376e548748b2b68
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14bdfbdf980000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/4e606720793a/disk-c16c81c8.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/745de689175f/vmlinux-c16c81c8.xz
kernel image: https://storage.googleapis.com/syzbot-assets/5a91e6dfccf0/bzImage-c16c81c8.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email protected]
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-...!: (1 GPs behind) idle=989/1/0x4000000000000002 softirq=7636/7637 fqs=1101
(detected by 1, t=10502 jiffies, g=8957, q=167)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4365 Comm: syz.0.44 Not tainted 5.15.178-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
RIP: 0010:trace_lock_acquire include/trace/events/lock.h:13 [inline]
RIP: 0010:lock_acquire+0xd6/0x4f0 kernel/locking/lockdep.c:5594
Code: 83 fb 08 0f 83 e2 02 00 00 89 d8 c1 e8 06 48 8d 3c c5 68 87 0a 8e be 08 00 00 00 e8 94 a1 67 00 89 d8 48 0f a3 05 72 b9 a7 0c <73> 0d e8 83 6b 08 00 84 c0 0f 84 b9 02 00 00 48 c7 c0 14 bb 0a 8e
RSP: 0018:ffffc9000323eca0 EFLAGS: 00000057
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff8162cdec
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8e0a8768
RBP: ffffc9000323ee00 R08: dffffc0000000000 R09: fffffbfff1c150ee
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff92000647d9c
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8880201891e8
FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00004000000003c0 CR3: 000000002c713000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<NMI>
</NMI>
<TASK>
rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:312
rcu_read_lock include/linux/rcupdate.h:739 [inline]
__perf_output_begin kernel/events/ring_buffer.c:163 [inline]
perf_output_begin_forward+0xb1/0xac0 kernel/events/ring_buffer.c:271
__perf_event_output kernel/events/core.c:7779 [inline]
perf_event_output_forward+0x1c8/0x310 kernel/events/core.c:7797
__perf_event_overflow+0x35d/0x530 kernel/events/core.c:9490
perf_swevent_overflow kernel/events/core.c:9566 [inline]
perf_swevent_event+0x4c5/0x550 kernel/events/core.c:9604
perf_tp_event+0x363/0xc40 kernel/events/core.c:10022
perf_trace_run_bpf_submit+0xf7/0x1d0 kernel/events/core.c:9996
perf_trace_preemptirq_template+0x31d/0x430 include/trace/events/preemptirq.h:14
trace_irq_enable_rcuidle+0x10e/0x190 include/trace/events/preemptirq.h:40
trace_hardirqs_on+0x57/0x80 kernel/trace/trace_preemptirq.c:44
asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713
RIP: 0010:rcu_read_unlock_special+0x84/0x520 kernel/rcu/tree_plugin.h:671
Code: f1 f1 f1 00 f2 f2 f2 49 89 04 17 66 41 c7 44 17 09 f3 f3 41 c6 44 17 0b f3 65 44 8b 25 4d 82 96 7e 41 f7 c4 00 00 f0 00 74 45 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 3a 00 00 00 00 66 42 c7 44 3a
RSP: 0018:ffffc9000323f600 EFLAGS: 00000206
RAX: e7e4eb3eec7bc600 RBX: 1ffff92000647ec8 RCX: ffffffff81633dd8
RDX: dffffc0000000000 RSI: ffffffff8aab2b80 RDI: ffffffff8af9f2c0
RBP: ffffc9000323f6d8 R08: dffffc0000000000 R09: fffffbfff2131821
R10: 0000000000000000 R11: dffffc0000000001 R12: ffffffff8cb23d00
R13: ffff88802c680458 R14: ffffc9000323f640 R15: 1ffff92000647ec4
__rcu_read_unlock+0x92/0x100 kernel/rcu/tree_plugin.h:422
rcu_read_unlock include/linux/rcupdate.h:771 [inline]
__unlock_page_memcg+0xfd/0x110 mm/memcontrol.c:2090
zap_pte_range mm/memory.c:1384 [inline]
zap_pmd_range mm/memory.c:1505 [inline]
zap_pud_range mm/memory.c:1534 [inline]
zap_p4d_range mm/memory.c:1555 [inline]
unmap_page_range+0xffa/0x2630 mm/memory.c:1576
unmap_vmas+0x1f8/0x390 mm/memory.c:1653
exit_mmap+0x3b6/0x620 mm/mmap.c:3204
__mmput+0x112/0x3b0 kernel/fork.c:1127
exit_mm+0x688/0x7f0 kernel/exit.c:550
do_exit+0x626/0x2480 kernel/exit.c:861
do_group_exit+0x144/0x310 kernel/exit.c:996
__do_sys_exit_group kernel/exit.c:1007 [inline]
__se_sys_exit_group kernel/exit.c:1005 [inline]
__x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1005
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f06c559ede9
Code: Unable to access opcode bytes at RIP 0x7f06c559edbf.
RSP: 002b:00007ffffeeea9d8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f06c559ede9
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffffeeeaa3c R08: 00000002feeeaacf R09: 00000000000927c0
R10: 0000000000000001 R11: 0000000000000246 R12: 000000000000001c
R13: 00000000000927c0 R14: 0000000000024e40 R15: 00007ffffeeeaa90
</TASK>
rcu: rcu_preempt kthread starved for 8299 jiffies! g8957 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt state:R running task stack:26816 pid: 15 ppid: 2 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5027 [inline]
__schedule+0x12c4/0x45b0 kernel/sched/core.c:6373
schedule+0x11b/0x1f0 kernel/sched/core.c:6456
schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1914
rcu_gp_fqs_loop+0x2bf/0x1080 kernel/rcu/tree.c:1972
rcu_gp_kthread+0xa4/0x360 kernel/rcu/tree.c:2145
kthread+0x3f6/0x4f0 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
</TASK>
rcu: Stack dump where RCU GP kthread last ran:
NMI backtrace for cpu 1
CPU: 1 PID: 1265 Comm: kworker/u4:4 Not tainted 5.15.178-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Workqueue: writeback wb_workfn (flush-8:0)
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
nmi_cpu_backtrace+0x46a/0x4a0 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x181/0x2a0 lib/nmi_backtrace.c:62
trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline]
rcu_check_gp_kthread_starvation+0x1d2/0x240 kernel/rcu/tree_stall.h:487
print_other_cpu_stall+0x137a/0x14d0 kernel/rcu/tree_stall.h:592
check_cpu_stall kernel/rcu/tree_stall.h:745 [inline]
rcu_pending kernel/rcu/tree.c:3932 [inline]
rcu_sched_clock_irq+0xa38/0x1150 kernel/rcu/tree.c:2619
update_process_times+0x196/0x200 kernel/time/timer.c:1818
tick_sched_handle kernel/time/tick-sched.c:254 [inline]
tick_sched_timer+0x386/0x550 kernel/time/tick-sched.c:1473
__run_hrtimer kernel/time/hrtimer.c:1688 [inline]
__hrtimer_run_queues+0x55b/0xcf0 kernel/time/hrtimer.c:1752
hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1814
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
__sysvec_apic_timer_interrupt+0x13b/0x4b0 arch/x86/kernel/apic/apic.c:1114
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
RIP: 0010:arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
RIP: 0010:kvm_wait+0x1b4/0x200 arch/x86/kernel/kvm.c:918
Code: e0 48 c1 e8 03 42 0f b6 04 28 84 c0 75 42 45 0f b6 34 24 e8 ce e0 4e 00 44 3a 74 24 1c 75 10 66 90 0f 00 2d ce 5d 70 09 fb f4 <e9> c8 fe ff ff fb e9 c2 fe ff ff 44 89 e1 80 e1 07 38 c1 0f 8c 54
RSP: 0018:ffffc900047965e0 EFLAGS: 00000246
RAX: 3c16fda261136700 RBX: 1ffff920008f2cc0 RCX: ffffffff81633dd8
RDX: dffffc0000000000 RSI: ffffffff8aab2b80 RDI: ffffffff8af9f2c0
RBP: ffffc900047966b0 R08: dffffc0000000000 R09: fffffbfff2131821
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff88805d9a36c0
R13: dffffc0000000000 R14: 0000000000000003 R15: ffffc90004796620
pv_wait arch/x86/include/asm/paravirt.h:597 [inline]
pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:470 [inline]
__pv_queued_spin_lock_slowpath+0x6bc/0xc40 kernel/locking/qspinlock.c:508
pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:585 [inline]
queued_spin_lock_slowpath+0x42/0x50 arch/x86/include/asm/qspinlock.h:51
queued_spin_lock include/asm-generic/qspinlock.h:85 [inline]
do_raw_spin_lock+0x269/0x370 kernel/locking/spinlock_debug.c:115
page_vma_mapped_walk+0x15e0/0x18c0
page_mkclean_one+0x340/0x7b0 mm/rmap.c:926
rmap_walk_file+0x3f8/0x600 mm/rmap.c:2378
rmap_walk mm/rmap.c:2396 [inline]
page_mkclean+0x330/0x490 mm/rmap.c:1006
clear_page_dirty_for_io+0x3ce/0xa60 mm/page-writeback.c:2749
mpage_submit_page+0x90/0x230 fs/ext4/inode.c:2092
mpage_map_and_submit_buffers fs/ext4/inode.c:2360 [inline]
mpage_map_and_submit_extent fs/ext4/inode.c:2499 [inline]
ext4_writepages+0x204f/0x3d10 fs/ext4/inode.c:2828
do_writepages+0x481/0x730 mm/page-writeback.c:2386
__writeback_single_inode+0x15b/0xe30 fs/fs-writeback.c:1647
writeback_sb_inodes+0xbce/0x1a40 fs/fs-writeback.c:1930
__writeback_inodes_wb+0x114/0x400 fs/fs-writeback.c:2001
wb_writeback+0x465/0xc50 fs/fs-writeback.c:2106
wb_check_old_data_flush fs/fs-writeback.c:2206 [inline]
wb_do_writeback fs/fs-writeback.c:2259 [inline]
wb_workfn+0xc55/0x1130 fs/fs-writeback.c:2288
process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
kthread+0x3f6/0x4f0 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
</TASK>
---
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syzbot found the following issue on:
HEAD commit: c16c81c81336 Linux 5.15.178
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=10bdfbdf980000
kernel config: https://syzkaller.appspot.com/x/.config?x=d302c69e93fb6774
dashboard link: https://syzkaller.appspot.com/bug?extid=78333376e548748b2b68
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14bdfbdf980000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/4e606720793a/disk-c16c81c8.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/745de689175f/vmlinux-c16c81c8.xz
kernel image: https://storage.googleapis.com/syzbot-assets/5a91e6dfccf0/bzImage-c16c81c8.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email protected]
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-...!: (1 GPs behind) idle=989/1/0x4000000000000002 softirq=7636/7637 fqs=1101
(detected by 1, t=10502 jiffies, g=8957, q=167)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4365 Comm: syz.0.44 Not tainted 5.15.178-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
RIP: 0010:trace_lock_acquire include/trace/events/lock.h:13 [inline]
RIP: 0010:lock_acquire+0xd6/0x4f0 kernel/locking/lockdep.c:5594
Code: 83 fb 08 0f 83 e2 02 00 00 89 d8 c1 e8 06 48 8d 3c c5 68 87 0a 8e be 08 00 00 00 e8 94 a1 67 00 89 d8 48 0f a3 05 72 b9 a7 0c <73> 0d e8 83 6b 08 00 84 c0 0f 84 b9 02 00 00 48 c7 c0 14 bb 0a 8e
RSP: 0018:ffffc9000323eca0 EFLAGS: 00000057
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff8162cdec
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8e0a8768
RBP: ffffc9000323ee00 R08: dffffc0000000000 R09: fffffbfff1c150ee
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff92000647d9c
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8880201891e8
FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00004000000003c0 CR3: 000000002c713000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<NMI>
</NMI>
<TASK>
rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:312
rcu_read_lock include/linux/rcupdate.h:739 [inline]
__perf_output_begin kernel/events/ring_buffer.c:163 [inline]
perf_output_begin_forward+0xb1/0xac0 kernel/events/ring_buffer.c:271
__perf_event_output kernel/events/core.c:7779 [inline]
perf_event_output_forward+0x1c8/0x310 kernel/events/core.c:7797
__perf_event_overflow+0x35d/0x530 kernel/events/core.c:9490
perf_swevent_overflow kernel/events/core.c:9566 [inline]
perf_swevent_event+0x4c5/0x550 kernel/events/core.c:9604
perf_tp_event+0x363/0xc40 kernel/events/core.c:10022
perf_trace_run_bpf_submit+0xf7/0x1d0 kernel/events/core.c:9996
perf_trace_preemptirq_template+0x31d/0x430 include/trace/events/preemptirq.h:14
trace_irq_enable_rcuidle+0x10e/0x190 include/trace/events/preemptirq.h:40
trace_hardirqs_on+0x57/0x80 kernel/trace/trace_preemptirq.c:44
asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713
RIP: 0010:rcu_read_unlock_special+0x84/0x520 kernel/rcu/tree_plugin.h:671
Code: f1 f1 f1 00 f2 f2 f2 49 89 04 17 66 41 c7 44 17 09 f3 f3 41 c6 44 17 0b f3 65 44 8b 25 4d 82 96 7e 41 f7 c4 00 00 f0 00 74 45 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 3a 00 00 00 00 66 42 c7 44 3a
RSP: 0018:ffffc9000323f600 EFLAGS: 00000206
RAX: e7e4eb3eec7bc600 RBX: 1ffff92000647ec8 RCX: ffffffff81633dd8
RDX: dffffc0000000000 RSI: ffffffff8aab2b80 RDI: ffffffff8af9f2c0
RBP: ffffc9000323f6d8 R08: dffffc0000000000 R09: fffffbfff2131821
R10: 0000000000000000 R11: dffffc0000000001 R12: ffffffff8cb23d00
R13: ffff88802c680458 R14: ffffc9000323f640 R15: 1ffff92000647ec4
__rcu_read_unlock+0x92/0x100 kernel/rcu/tree_plugin.h:422
rcu_read_unlock include/linux/rcupdate.h:771 [inline]
__unlock_page_memcg+0xfd/0x110 mm/memcontrol.c:2090
zap_pte_range mm/memory.c:1384 [inline]
zap_pmd_range mm/memory.c:1505 [inline]
zap_pud_range mm/memory.c:1534 [inline]
zap_p4d_range mm/memory.c:1555 [inline]
unmap_page_range+0xffa/0x2630 mm/memory.c:1576
unmap_vmas+0x1f8/0x390 mm/memory.c:1653
exit_mmap+0x3b6/0x620 mm/mmap.c:3204
__mmput+0x112/0x3b0 kernel/fork.c:1127
exit_mm+0x688/0x7f0 kernel/exit.c:550
do_exit+0x626/0x2480 kernel/exit.c:861
do_group_exit+0x144/0x310 kernel/exit.c:996
__do_sys_exit_group kernel/exit.c:1007 [inline]
__se_sys_exit_group kernel/exit.c:1005 [inline]
__x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1005
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f06c559ede9
Code: Unable to access opcode bytes at RIP 0x7f06c559edbf.
RSP: 002b:00007ffffeeea9d8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f06c559ede9
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffffeeeaa3c R08: 00000002feeeaacf R09: 00000000000927c0
R10: 0000000000000001 R11: 0000000000000246 R12: 000000000000001c
R13: 00000000000927c0 R14: 0000000000024e40 R15: 00007ffffeeeaa90
</TASK>
rcu: rcu_preempt kthread starved for 8299 jiffies! g8957 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt state:R running task stack:26816 pid: 15 ppid: 2 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5027 [inline]
__schedule+0x12c4/0x45b0 kernel/sched/core.c:6373
schedule+0x11b/0x1f0 kernel/sched/core.c:6456
schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1914
rcu_gp_fqs_loop+0x2bf/0x1080 kernel/rcu/tree.c:1972
rcu_gp_kthread+0xa4/0x360 kernel/rcu/tree.c:2145
kthread+0x3f6/0x4f0 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
</TASK>
rcu: Stack dump where RCU GP kthread last ran:
NMI backtrace for cpu 1
CPU: 1 PID: 1265 Comm: kworker/u4:4 Not tainted 5.15.178-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Workqueue: writeback wb_workfn (flush-8:0)
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
nmi_cpu_backtrace+0x46a/0x4a0 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x181/0x2a0 lib/nmi_backtrace.c:62
trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline]
rcu_check_gp_kthread_starvation+0x1d2/0x240 kernel/rcu/tree_stall.h:487
print_other_cpu_stall+0x137a/0x14d0 kernel/rcu/tree_stall.h:592
check_cpu_stall kernel/rcu/tree_stall.h:745 [inline]
rcu_pending kernel/rcu/tree.c:3932 [inline]
rcu_sched_clock_irq+0xa38/0x1150 kernel/rcu/tree.c:2619
update_process_times+0x196/0x200 kernel/time/timer.c:1818
tick_sched_handle kernel/time/tick-sched.c:254 [inline]
tick_sched_timer+0x386/0x550 kernel/time/tick-sched.c:1473
__run_hrtimer kernel/time/hrtimer.c:1688 [inline]
__hrtimer_run_queues+0x55b/0xcf0 kernel/time/hrtimer.c:1752
hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1814
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
__sysvec_apic_timer_interrupt+0x13b/0x4b0 arch/x86/kernel/apic/apic.c:1114
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
RIP: 0010:arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
RIP: 0010:kvm_wait+0x1b4/0x200 arch/x86/kernel/kvm.c:918
Code: e0 48 c1 e8 03 42 0f b6 04 28 84 c0 75 42 45 0f b6 34 24 e8 ce e0 4e 00 44 3a 74 24 1c 75 10 66 90 0f 00 2d ce 5d 70 09 fb f4 <e9> c8 fe ff ff fb e9 c2 fe ff ff 44 89 e1 80 e1 07 38 c1 0f 8c 54
RSP: 0018:ffffc900047965e0 EFLAGS: 00000246
RAX: 3c16fda261136700 RBX: 1ffff920008f2cc0 RCX: ffffffff81633dd8
RDX: dffffc0000000000 RSI: ffffffff8aab2b80 RDI: ffffffff8af9f2c0
RBP: ffffc900047966b0 R08: dffffc0000000000 R09: fffffbfff2131821
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff88805d9a36c0
R13: dffffc0000000000 R14: 0000000000000003 R15: ffffc90004796620
pv_wait arch/x86/include/asm/paravirt.h:597 [inline]
pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:470 [inline]
__pv_queued_spin_lock_slowpath+0x6bc/0xc40 kernel/locking/qspinlock.c:508
pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:585 [inline]
queued_spin_lock_slowpath+0x42/0x50 arch/x86/include/asm/qspinlock.h:51
queued_spin_lock include/asm-generic/qspinlock.h:85 [inline]
do_raw_spin_lock+0x269/0x370 kernel/locking/spinlock_debug.c:115
page_vma_mapped_walk+0x15e0/0x18c0
page_mkclean_one+0x340/0x7b0 mm/rmap.c:926
rmap_walk_file+0x3f8/0x600 mm/rmap.c:2378
rmap_walk mm/rmap.c:2396 [inline]
page_mkclean+0x330/0x490 mm/rmap.c:1006
clear_page_dirty_for_io+0x3ce/0xa60 mm/page-writeback.c:2749
mpage_submit_page+0x90/0x230 fs/ext4/inode.c:2092
mpage_map_and_submit_buffers fs/ext4/inode.c:2360 [inline]
mpage_map_and_submit_extent fs/ext4/inode.c:2499 [inline]
ext4_writepages+0x204f/0x3d10 fs/ext4/inode.c:2828
do_writepages+0x481/0x730 mm/page-writeback.c:2386
__writeback_single_inode+0x15b/0xe30 fs/fs-writeback.c:1647
writeback_sb_inodes+0xbce/0x1a40 fs/fs-writeback.c:1930
__writeback_inodes_wb+0x114/0x400 fs/fs-writeback.c:2001
wb_writeback+0x465/0xc50 fs/fs-writeback.c:2106
wb_check_old_data_flush fs/fs-writeback.c:2206 [inline]
wb_do_writeback fs/fs-writeback.c:2259 [inline]
wb_workfn+0xc55/0x1130 fs/fs-writeback.c:2288
process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
kthread+0x3f6/0x4f0 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
</TASK>
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
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syzbot
Apr 21, 2025, 1:46:29 PMApr 21
syzbot has found a reproducer for the following issue on:
HEAD commit: f7347f400572 Linux 5.15.180
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=116a0ccc580000
kernel config: https://syzkaller.appspot.com/x/.config?x=e6c84b0caba70e14
dashboard link: https://syzkaller.appspot.com/bug?extid=78333376e548748b2b68
compiler: Debian clang version 15.0.6, Debian LLD 15.0.6
userspace arch: arm64
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16887204580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16c167ac580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/5ea7676abfeb/disk-f7347f40.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a6c1adba70a4/vmlinux-f7347f40.xz
kernel image: https://storage.googleapis.com/syzbot-assets/111bbc36e182/Image-f7347f40.gz.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email protected]
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P530/1:b..l
(detected by 0, t=10502 jiffies, g=5057, q=176)
task:kworker/u4:5 state:R running task stack: 0 pid: 530 ppid: 2 flags:0x00000008
Workqueue: writeback wb_workfn (flush-259:0)
Call trace:
__switch_to+0x308/0x588 arch/arm64/kernel/process.c:518
context_switch kernel/sched/core.c:5030 [inline]
__schedule+0xf10/0x1e48 kernel/sched/core.c:6376
preempt_schedule_irq+0x90/0x274 kernel/sched/core.c:6780
arm64_preempt_schedule_irq+0x174/0x2c4 arch/arm64/kernel/entry-common.c:260
el1_interrupt+0x40/0x58 arch/arm64/kernel/entry-common.c:463
el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:470
el1h_64_irq+0x78/0x7c arch/arm64/kernel/entry.S:522
arch_local_irq_restore arch/arm64/include/asm/irqflags.h:122 [inline]
mod_lruvec_page_state include/linux/vmstat.h:497 [inline]
inc_lruvec_page_state include/linux/vmstat.h:549 [inline]
__test_set_page_writeback+0x96c/0xc70 mm/page-writeback.c:2886
ext4_bio_write_page+0x220/0x1e40 fs/ext4/page-io.c:-1
mpage_submit_page fs/ext4/inode.c:2112 [inline]
do_writepages+0x39c/0x5ec mm/page-writeback.c:2386
__writeback_single_inode+0x148/0x13a4 fs/fs-writeback.c:1647
writeback_sb_inodes+0x94c/0x1654 fs/fs-writeback.c:1930
__writeback_inodes_wb+0x110/0x39c fs/fs-writeback.c:2001
wb_writeback+0x410/0xfc8 fs/fs-writeback.c:2106
process_one_work+0x790/0x11b8 kernel/workqueue.c:2310
worker_thread+0x910/0x1034 kernel/workqueue.c:2457
kthread+0x37c/0x45c kernel/kthread.c:334
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:870
rcu: rcu_preempt kthread starved for 10502 jiffies! g5057 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
Call trace:
__switch_to+0x308/0x588 arch/arm64/kernel/process.c:518
context_switch kernel/sched/core.c:5030 [inline]
__schedule+0xf10/0x1e48 kernel/sched/core.c:6376
schedule+0x11c/0x1c8 kernel/sched/core.c:6459
schedule_timeout+0x1d8/0x344 kernel/time/timer.c:1914
rcu_gp_fqs_loop+0x26c/0x13d4 kernel/rcu/tree.c:1972
rcu_gp_kthread+0xc4/0x2c4 kernel/rcu/tree.c:2145
kthread+0x37c/0x45c kernel/kthread.c:334
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:870
task:syz-executor306 state:R running task stack: 0 pid: 4096 ppid: 4049 flags:0x00000001
Call trace:
dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152
show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216
sched_show_task+0x43c/0x574 kernel/sched/core.c:8640
dump_cpu_task+0x84/0xa8 kernel/sched/core.c:10927
rcu_check_gp_kthread_starvation+0x1f0/0x254 kernel/rcu/tree_stall.h:488
print_other_cpu_stall+0x202c/0x2290 kernel/rcu/tree_stall.h:592
update_process_times+0x1d4/0x270 kernel/time/timer.c:1818
tick_sched_handle kernel/time/tick-sched.c:254 [inline]
tick_sched_timer+0x340/0x4f8 kernel/time/tick-sched.c:1473
__run_hrtimer kernel/time/hrtimer.c:1690 [inline]
__hrtimer_run_queues+0x458/0xca4 kernel/time/hrtimer.c:1754
hrtimer_interrupt+0x4e0/0xb64 kernel/time/hrtimer.c:1816
timer_handler drivers/clocksource/arm_arch_timer.c:659 [inline]
arch_timer_handler_virt+0x74/0x88 drivers/clocksource/arm_arch_timer.c:670
handle_percpu_devid_irq+0x29c/0x7fc kernel/irq/chip.c:930
generic_handle_irq_desc include/linux/irqdesc.h:158 [inline]
handle_irq_desc kernel/irq/irqdesc.c:652 [inline]
handle_domain_irq+0x144/0x1fc kernel/irq/irqdesc.c:707
gic_handle_irq+0x78/0x1c8 drivers/irqchip/irq-gic-v3.c:765
call_on_irq_stack+0x24/0x4c arch/arm64/kernel/entry.S:899
do_interrupt_handler+0x74/0x94 arch/arm64/kernel/entry-common.c:267
el1_interrupt+0x30/0x58 arch/arm64/kernel/entry-common.c:454
el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:470
el1h_64_irq+0x78/0x7c arch/arm64/kernel/entry.S:522
arch_local_irq_enable arch/arm64/include/asm/irqflags.h:35 [inline]
__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:168 [inline]
_raw_spin_unlock_irq+0xa4/0x134 kernel/locking/spinlock.c:202
spin_unlock_irq include/linux/spinlock.h:413 [inline]
get_signal+0x11b4/0x1550 kernel/signal.c:2903
do_signal arch/arm64/kernel/signal.c:890 [inline]
do_notify_resume+0x320/0x32b8 arch/arm64/kernel/signal.c:943
prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:133 [inline]
exit_to_user_mode arch/arm64/kernel/entry-common.c:138 [inline]
el0_svc+0xfc/0x1f0 arch/arm64/kernel/entry-common.c:609
el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584
---
HEAD commit: f7347f400572 Linux 5.15.180
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=116a0ccc580000
kernel config: https://syzkaller.appspot.com/x/.config?x=e6c84b0caba70e14
dashboard link: https://syzkaller.appspot.com/bug?extid=78333376e548748b2b68
compiler: Debian clang version 15.0.6, Debian LLD 15.0.6
userspace arch: arm64
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16887204580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16c167ac580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/5ea7676abfeb/disk-f7347f40.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a6c1adba70a4/vmlinux-f7347f40.xz
kernel image: https://storage.googleapis.com/syzbot-assets/111bbc36e182/Image-f7347f40.gz.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email protected]
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
(detected by 0, t=10502 jiffies, g=5057, q=176)
task:kworker/u4:5 state:R running task stack: 0 pid: 530 ppid: 2 flags:0x00000008
Workqueue: writeback wb_workfn (flush-259:0)
Call trace:
__switch_to+0x308/0x588 arch/arm64/kernel/process.c:518
context_switch kernel/sched/core.c:5030 [inline]
__schedule+0xf10/0x1e48 kernel/sched/core.c:6376
preempt_schedule_irq+0x90/0x274 kernel/sched/core.c:6780
arm64_preempt_schedule_irq+0x174/0x2c4 arch/arm64/kernel/entry-common.c:260
el1_interrupt+0x40/0x58 arch/arm64/kernel/entry-common.c:463
el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:470
el1h_64_irq+0x78/0x7c arch/arm64/kernel/entry.S:522
arch_local_irq_restore arch/arm64/include/asm/irqflags.h:122 [inline]
mod_lruvec_page_state include/linux/vmstat.h:497 [inline]
inc_lruvec_page_state include/linux/vmstat.h:549 [inline]
__test_set_page_writeback+0x96c/0xc70 mm/page-writeback.c:2886
ext4_bio_write_page+0x220/0x1e40 fs/ext4/page-io.c:-1
mpage_submit_page fs/ext4/inode.c:2112 [inline]
mpage_map_and_submit_buffers fs/ext4/inode.c:2360 [inline]
mpage_map_and_submit_extent fs/ext4/inode.c:2499 [inline]
ext4_writepages+0x1b90/0x36fc fs/ext4/inode.c:2828
mpage_map_and_submit_extent fs/ext4/inode.c:2499 [inline]
do_writepages+0x39c/0x5ec mm/page-writeback.c:2386
__writeback_single_inode+0x148/0x13a4 fs/fs-writeback.c:1647
writeback_sb_inodes+0x94c/0x1654 fs/fs-writeback.c:1930
__writeback_inodes_wb+0x110/0x39c fs/fs-writeback.c:2001
wb_writeback+0x410/0xfc8 fs/fs-writeback.c:2106
wb_check_old_data_flush fs/fs-writeback.c:2206 [inline]
wb_do_writeback fs/fs-writeback.c:2259 [inline]
wb_workfn+0xbb4/0x1070 fs/fs-writeback.c:2288
wb_do_writeback fs/fs-writeback.c:2259 [inline]
process_one_work+0x790/0x11b8 kernel/workqueue.c:2310
worker_thread+0x910/0x1034 kernel/workqueue.c:2457
kthread+0x37c/0x45c kernel/kthread.c:334
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:870
rcu: rcu_preempt kthread starved for 10502 jiffies! g5057 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt state:R running task stack: 0 pid: 15 ppid: 2 flags:0x00000008
rcu: RCU grace-period kthread stack dump:
Call trace:
__switch_to+0x308/0x588 arch/arm64/kernel/process.c:518
context_switch kernel/sched/core.c:5030 [inline]
__schedule+0xf10/0x1e48 kernel/sched/core.c:6376
schedule+0x11c/0x1c8 kernel/sched/core.c:6459
schedule_timeout+0x1d8/0x344 kernel/time/timer.c:1914
rcu_gp_fqs_loop+0x26c/0x13d4 kernel/rcu/tree.c:1972
rcu_gp_kthread+0xc4/0x2c4 kernel/rcu/tree.c:2145
kthread+0x37c/0x45c kernel/kthread.c:334
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:870
rcu: Stack dump where RCU GP kthread last ran:
Task dump for CPU 0:
task:syz-executor306 state:R running task stack: 0 pid: 4096 ppid: 4049 flags:0x00000001
Call trace:
dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152
show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216
sched_show_task+0x43c/0x574 kernel/sched/core.c:8640
dump_cpu_task+0x84/0xa8 kernel/sched/core.c:10927
rcu_check_gp_kthread_starvation+0x1f0/0x254 kernel/rcu/tree_stall.h:488
print_other_cpu_stall+0x202c/0x2290 kernel/rcu/tree_stall.h:592
check_cpu_stall kernel/rcu/tree_stall.h:745 [inline]
rcu_pending kernel/rcu/tree.c:3932 [inline]
rcu_sched_clock_irq+0x1894/0x1b8c kernel/rcu/tree.c:2619
rcu_pending kernel/rcu/tree.c:3932 [inline]
update_process_times+0x1d4/0x270 kernel/time/timer.c:1818
tick_sched_handle kernel/time/tick-sched.c:254 [inline]
tick_sched_timer+0x340/0x4f8 kernel/time/tick-sched.c:1473
__run_hrtimer kernel/time/hrtimer.c:1690 [inline]
__hrtimer_run_queues+0x458/0xca4 kernel/time/hrtimer.c:1754
hrtimer_interrupt+0x4e0/0xb64 kernel/time/hrtimer.c:1816
timer_handler drivers/clocksource/arm_arch_timer.c:659 [inline]
arch_timer_handler_virt+0x74/0x88 drivers/clocksource/arm_arch_timer.c:670
handle_percpu_devid_irq+0x29c/0x7fc kernel/irq/chip.c:930
generic_handle_irq_desc include/linux/irqdesc.h:158 [inline]
handle_irq_desc kernel/irq/irqdesc.c:652 [inline]
handle_domain_irq+0x144/0x1fc kernel/irq/irqdesc.c:707
gic_handle_irq+0x78/0x1c8 drivers/irqchip/irq-gic-v3.c:765
call_on_irq_stack+0x24/0x4c arch/arm64/kernel/entry.S:899
do_interrupt_handler+0x74/0x94 arch/arm64/kernel/entry-common.c:267
el1_interrupt+0x30/0x58 arch/arm64/kernel/entry-common.c:454
el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:470
el1h_64_irq+0x78/0x7c arch/arm64/kernel/entry.S:522
arch_local_irq_enable arch/arm64/include/asm/irqflags.h:35 [inline]
__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:168 [inline]
_raw_spin_unlock_irq+0xa4/0x134 kernel/locking/spinlock.c:202
spin_unlock_irq include/linux/spinlock.h:413 [inline]
get_signal+0x11b4/0x1550 kernel/signal.c:2903
do_signal arch/arm64/kernel/signal.c:890 [inline]
do_notify_resume+0x320/0x32b8 arch/arm64/kernel/signal.c:943
prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:133 [inline]
exit_to_user_mode arch/arm64/kernel/entry-common.c:138 [inline]
el0_svc+0xfc/0x1f0 arch/arm64/kernel/entry-common.c:609
el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584
---
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