[v5.15] INFO: rcu detected stall in schedule_timeout

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 83655231580b Linux 5.15.159
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1538e644980000
kernel config: https://syzkaller.appspot.com/x/.config?x=ea870d7ee19c0a5c
dashboard link: https://syzkaller.appspot.com/bug?extid=7cb65445f1326f641b08
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: https://storage.googleapis.com/syzbot-assets/d5444b7453a0/disk-83655231.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/76ae736a43a3/vmlinux-83655231.xz
kernel image: https://storage.googleapis.com/syzbot-assets/2540e00ba747/bzImage-83655231.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7cb654...@syzkaller.appspotmail.com

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P3791/1:b..l
(detected by 1, t=10503 jiffies, g=10997, q=64)
task:syz-executor.3 state:R running task stack:20888 pid: 3791 ppid: 3781 flags:0x00004006
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5030 [inline]
__schedule+0x12c4/0x45b0 kernel/sched/core.c:6376
preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6780
irqentry_exit+0x53/0x80 kernel/entry/common.c:432
asm_sysvec_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:643
RIP: 0010:__sanitizer_cov_trace_const_cmp4+0x7c/0x80 kernel/kcov.c:286
Code: 8d 42 28 4c 39 d0 77 22 89 f8 89 f6 48 c7 44 0a 08 05 00 00 00 48 89 44 0a 10 48 89 74 0a 18 4c 89 44 0a 20 49 ff c1 4c 89 09 <c3> 0f 1f 00 4c 8b 04 24 65 48 8b 0d 14 0f 82 7e 65 8b 05 15 0f 82
RSP: 0018:ffffc90004d975f8 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffff88801e230000
RDX: ffff88801e230000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffffffff818cff69 R09: fffffbfff1f7f019
R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000
R13: 0000000000000000 R14: 00007f1a055876c7 R15: 0000000000000144
rcu_read_unlock include/linux/rcupdate.h:768 [inline]
is_bpf_text_address+0x1c9/0x260 kernel/bpf/core.c:723
kernel_text_address kernel/extable.c:151 [inline]
__kernel_text_address+0x94/0x100 kernel/extable.c:105
unwind_get_return_address+0x49/0x80 arch/x86/kernel/unwind_orc.c:323
arch_stack_walk+0xf3/0x140 arch/x86/kernel/stacktrace.c:26
stack_trace_save+0x113/0x1c0 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track+0x4b/0x80 mm/kasan/common.c:46
kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360
____kasan_slab_free+0xd8/0x120 mm/kasan/common.c:366
kasan_slab_free include/linux/kasan.h:230 [inline]
slab_free_hook mm/slub.c:1705 [inline]
slab_free_freelist_hook+0xdd/0x160 mm/slub.c:1731
slab_free mm/slub.c:3499 [inline]
kmem_cache_free+0x91/0x1f0 mm/slub.c:3515
jbd2_free_handle include/linux/jbd2.h:1602 [inline]
jbd2_journal_stop+0x8d9/0xd70 fs/jbd2/transaction.c:1964
__ext4_journal_stop+0xf8/0x190 fs/ext4/ext4_jbd2.c:127
ext4_rmdir+0x8fb/0xa80 fs/ext4/namei.c:3228
vfs_rmdir+0x305/0x460 fs/namei.c:4149
do_rmdir+0x368/0x670 fs/namei.c:4210
__do_sys_unlinkat fs/namei.c:4390 [inline]
__se_sys_unlinkat fs/namei.c:4384 [inline]
__x64_sys_unlinkat+0xdc/0xf0 fs/namei.c:4384
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: 0033:0x7f1a055876c7
RSP: 002b:00007ffdb8ce2aa8 EFLAGS: 00000207 ORIG_RAX: 0000000000000107
RAX: ffffffffffffffda RBX: 0000000000000065 RCX: 00007f1a055876c7
RDX: 0000000000000200 RSI: 00007ffdb8ce3c20 RDI: 00000000ffffff9c
RBP: 00007f1a055d3336 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000100 R11: 0000000000000207 R12: 00007ffdb8ce3c20
R13: 00007f1a055d3336 R14: 0000000000017c8b R15: 0000000000000005
</TASK>
rcu: rcu_preempt kthread starved for 10548 jiffies! g10997 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:27000 pid: 15 ppid: 2 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5030 [inline]
__schedule+0x12c4/0x45b0 kernel/sched/core.c:6376
preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6780
irqentry_exit+0x53/0x80 kernel/entry/common.c:432
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0010:schedule+0x108/0x1f0 kernel/sched/core.c:6461
Code: 0e eb a3 f7 49 8b 07 4c 39 f8 74 0d 4c 89 f7 be 01 00 00 00 e8 a9 c2 c6 f9 4c 89 eb 48 c1 eb 03 eb 0a 49 f7 45 00 08 00 00 00 <74> 39 bf 01 00 00 00 e8 7c 20 31 f7 31 ff e8 35 b9 ff ff bf 01 00
RSP: 0018:ffffc90000d47b70 EFLAGS: 00000202
RAX: 0000000000000001 RBX: 1ffff11027fc4770 RCX: ffffffff8a264012
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff88813fe23b80
RBP: ffffc90000d47c90 R08: dffffc0000000000 R09: ffffed1027fc4771
R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000
R13: ffff88813fe23b80 R14: 0000000000000000 R15: 00000000ffffb06a
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:300
</TASK>
rcu: Stack dump where RCU GP kthread last ran:
NMI backtrace for cpu 1
CPU: 1 PID: 4551 Comm: syz-executor.4 Not tainted 5.15.159-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
Call Trace:
<TASK>
__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:1686 [inline]
__hrtimer_run_queues+0x55b/0xcf0 kernel/time/hrtimer.c:1750
hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1812
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1085 [inline]
__sysvec_apic_timer_interrupt+0x139/0x470 arch/x86/kernel/apic/apic.c:1102
sysvec_apic_timer_interrupt+0x3e/0xb0 arch/x86/kernel/apic/apic.c:1096
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0033:0x7f57f1352ee7
Code: 14 25 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 c7 c1 b0 ff ff ff f7 d8 64 89
RSP: 002b:00007f57ef8a5178 EFLAGS: 00000246
RAX: 00000000000000ca RBX: 00007f57f1482058 RCX: 00007f57f1352ee9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f57f1482058
RBP: 00007f57f1482050 R08: 00007f57ef8a56c0 R09: 00007f57ef8a56c0
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f57f148205c
R13: 000000000000006e R14: 00007fffeec37120 R15: 00007fffeec37208
</TASK>
sched: RT throttling activated


---
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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 83655231580b Linux 5.15.159
git tree: linux-5.15.y

console output: https://syzkaller.appspot.com/x/log.txt?x=160d9414980000

kernel config: https://syzkaller.appspot.com/x/.config?x=ea870d7ee19c0a5c
dashboard link: https://syzkaller.appspot.com/bug?extid=7cb65445f1326f641b08
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=16446634980000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17db9e52980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d5444b7453a0/disk-83655231.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/76ae736a43a3/vmlinux-83655231.xz
kernel image: https://storage.googleapis.com/syzbot-assets/2540e00ba747/bzImage-83655231.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7cb654...@syzkaller.appspotmail.com

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:

(detected by 1, t=10502 jiffies, g=3685, q=6)
rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4294967356-4294956854), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 10502 jiffies! g3685 f0x2 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:25688 pid: 15 ppid: 2 flags:0x00004000

Call Trace:
<TASK>
context_switch kernel/sched/core.c:5030 [inline]
__schedule+0x12c4/0x45b0 kernel/sched/core.c:6376
preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6780
irqentry_exit+0x53/0x80 kernel/entry/common.c:432
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:638

RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:27 [inline]
RIP: 0010:preempt_count_add+0x32/0x180 kernel/sched/core.c:5485
Code: c7 c0 c0 ff 3e 91 48 c1 e8 03 49 bf 00 00 00 00 00 fc ff df 42 0f b6 04 38 84 c0 0f 85 e2 00 00 00 83 3d 20 9f e7 0f 00 75 07 <65> 8b 05 1f 0f ab 7e 65 01 1d 18 0f ab 7e 48 c7 c0 c0 ff 3e 91 48
RSP: 0018:ffffc90000d47b50 EFLAGS: 00000246
RAX: 0000000000000004 RBX: 0000000000000001 RCX: ffffffff913eff03
RDX: 0000000000000000 RSI: 0000000000000008 RDI: 0000000000000001

RBP: ffffc90000d47c90 R08: dffffc0000000000 R09: ffffed1027fc4771
R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000

R13: ffff88813fe23b80 R14: 0000000000000000 R15: dffffc0000000000
schedule+0x114/0x1f0 kernel/sched/core.c:6458

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:300
</TASK>
rcu: Stack dump where RCU GP kthread last ran:

Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 3522 Comm: syz-executor220 Not tainted 5.15.159-syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024

RIP: 0010:__rcu_read_unlock+0x65/0x100 kernel/rcu/tree_plugin.h:421
Code: b6 04 23 84 c0 75 69 41 89 6d 00 85 ed 75 1d 4d 8d be 40 04 00 00 4c 89 f8 48 c1 e8 03 42 0f b6 04 20 84 c0 75 78 41 83 3f 00 <75> 23 42 0f b6 04 23 84 c0 75 52 41 8b 45 00 3d 00 00 00 40 73 0b
RSP: 0018:ffffc90000007da8 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 1ffff1100f01b087 RCX: ffff8880780d8000
RDX: 0000000080010001 RSI: ffffffff8ad8f660 RDI: ffffffff8ad8f620
RBP: 0000000000000000 R08: ffffffff814f8faf R09: fffffbfff1f7f019

R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000

R13: ffff8880780d843c R14: ffff8880780d8000 R15: ffff8880780d8440
FS: 00007ffa697516c0(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffa69750e40 CR3: 0000000023c1b000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<NMI>
</NMI>
<IRQ>
rcu_read_unlock include/linux/rcupdate.h:771 [inline]
group_send_sig_info+0x18e/0x2d0 kernel/signal.c:1439
do_bpf_send_signal+0x81/0x150 kernel/trace/bpf_trace.c:779
irq_work_single kernel/irq_work.c:155 [inline]
irq_work_run_list+0x20b/0x370 kernel/irq_work.c:177
irq_work_run+0x63/0xe0 kernel/irq_work.c:186
__sysvec_irq_work+0x9a/0x250 arch/x86/kernel/irq_work.c:22
sysvec_irq_work+0x89/0xb0 arch/x86/kernel/irq_work.c:17
</IRQ>
<TASK>
asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:664
RIP: 0010:finish_lock_switch+0x91/0x100 kernel/sched/core.c:4785
Code: 45 31 c9 68 b7 90 59 81 e8 cc 1a 09 00 48 83 c4 08 4c 89 ff e8 60 da fe ff 66 90 4c 89 ff e8 f6 ea cd 08 e8 d1 4b 2d 00 fb 5b <41> 5c 41 5d 41 5e 41 5f c3 44 89 f1 80 e1 07 80 c1 03 38 c1 7c 87
RSP: 0018:ffffc90002ce7698 EFLAGS: 00000286
RAX: c912400c68919f00 RBX: ffff8880780dbbb4 RCX: ffffffff913eff03
RDX: dffffc0000000000 RSI: ffffffff8a8b2980 RDI: ffffffff8ad8f680
RBP: ffffc90002ce7710 R08: ffffffff8186dcf0 R09: ffffed1017347469

R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000

R13: 1ffff11017347613 R14: ffff8880b9a3b098 R15: ffff8880b9a3a340
finish_task_switch+0x134/0x630 kernel/sched/core.c:4902
context_switch kernel/sched/core.c:5033 [inline]
__schedule+0x12cc/0x45b0 kernel/sched/core.c:6376
schedule+0x11b/0x1f0 kernel/sched/core.c:6459
freezable_schedule include/linux/freezer.h:172 [inline]
futex_wait_queue_me+0x25b/0x480 kernel/futex/core.c:2863
futex_wait+0x2f8/0x740 kernel/futex/core.c:2964
do_futex+0x1414/0x1810 kernel/futex/core.c:3982
__do_sys_futex kernel/futex/core.c:4059 [inline]
__se_sys_futex+0x407/0x490 kernel/futex/core.c:4040

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: 0033:0x7ffa697905d9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 51 18 00 00 90 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 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffa69751228 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 00007ffa6981a308 RCX: 00007ffa697905d9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007ffa6981a308
RBP: 00007ffa6981a300 R08: 00007ffa697516c0 R09: 00007ffa697516c0
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffa697e7074
R13: b635773f06ebbeef R14: 656c6c616b7a7973 R15: 00007ffe8444ce18
</TASK>
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.509 msecs


---
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