[v6.1] INFO: rcu detected stall in schedule_timeout

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 6741e066ec76 Linux 6.1.87
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1797ac0d180000
kernel config: https://syzkaller.appspot.com/x/.config?x=3fc2f61bd0ae457
dashboard link: https://syzkaller.appspot.com/bug?extid=43a223a437624461ab5d
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/b606a22ddf4b/disk-6741e066.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e31c21737449/vmlinux-6741e066.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ee0cb8c049e9/bzImage-6741e066.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+43a223...@syzkaller.appspotmail.com

rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 0-...!: (1 GPs behind) idle=5f44/1/0x4000000000000000 softirq=8300/8301 fqs=376
(t=10500 jiffies g=6901 q=206 ncpus=2)
rcu: rcu_preempt kthread starved for 9626 jiffies! g6901 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:27032 pid:16 ppid:2 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5245 [inline]
__schedule+0x142d/0x4550 kernel/sched/core.c:6558
preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6870
irqentry_exit+0x53/0x80 kernel/entry/common.c:439
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:653
RIP: 0010:schedule+0xae/0x180 kernel/sched/core.c:6633
Code: e8 f7 fd 4e f7 49 8b 3e 48 85 ff 74 0a be 01 00 00 00 e8 95 f2 87 f9 4c 89 e3 48 c1 eb 03 eb 0a 49 f7 04 24 08 00 00 00 74 39 <bf> 01 00 00 00 e8 48 49 cb f6 31 ff e8 f1 b9 ff ff bf 01 00 00 00
RSP: 0018:ffffc90000157b98 EFLAGS: 00000202
RAX: 0000000000000001 RBX: 1ffff11027fddb28 RCX: ffffffff8a9308f6
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff88813feed940
RBP: ffffc90000157cb0 R08: dffffc0000000000 R09: ffffed1027fddb29
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff88813feed940
R13: 1ffff9200002af78 R14: ffff88813feeebb8 R15: dffffc0000000000
schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1965
rcu_gp_fqs_loop+0x2d2/0x1150 kernel/rcu/tree.c:1706
rcu_gp_kthread+0xa3/0x3b0 kernel/rcu/tree.c:1905
kthread+0x28d/0x320 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
</TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 3816 Comm: syz-executor.2 Not tainted 6.1.87-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
RIP: 0010:xrstor_from_user_sigframe arch/x86/kernel/fpu/xstate.h:304 [inline]
RIP: 0010:__restore_fpregs_from_user arch/x86/kernel/fpu/signal.c:259 [inline]
RIP: 0010:restore_fpregs_from_user arch/x86/kernel/fpu/signal.c:289 [inline]
RIP: 0010:__fpu_restore_sig arch/x86/kernel/fpu/signal.c:359 [inline]
RIP: 0010:fpu__restore_sig+0x63f/0x1300 arch/x86/kernel/fpu/signal.c:493
Code: c7 22 af 00 48 8b 3b 48 8b 5c 24 48 48 89 de ba 01 00 00 00 e8 82 37 00 00 0f 01 cb 48 8b 7c 24 20 89 d8 44 89 ea 48 0f ae 2f <31> c0 41 89 c6 0f 01 ca 31 ff 44 89 f6 e8 af ae 57 00 31 ff 4c 89
RSP: 0018:ffffc90004f0faa0 EFLAGS: 00040282
RAX: 0000000000000007 RBX: 0000000000000007 RCX: 0000000000040000
RDX: 0000000000000000 RSI: 000000000003ffff RDI: 00007f0067e00d80
RBP: ffffc90004f0fc50 R08: ffffffff81331bd0 R09: fffff520009e1f7c
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000000
R13: 0000000000000000 R14: ffff88802222b530 R15: 1ffff110044456a6
FS: 00007f0067e016c0(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000900 CR3: 0000000074210000 CR4: 00000000003526e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<NMI>
</NMI>
<TASK>
restore_sigcontext+0x633/0x700 arch/x86/kernel/signal.c:140
__do_sys_rt_sigreturn+0x190/0x250 arch/x86/kernel/signal.c:675
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f006707dea7
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:00007f0067e01178 EFLAGS: 00000246
RAX: 00000000000000ca RBX: 00007f00671abf88 RCX: 00007f006707dea9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f00671abf88
RBP: 00007f00671abf80 R08: 00007f0067e016c0 R09: 00007f0067e016c0
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f00671abf8c
R13: 000000000000000b R14: 00007ffcfab0ff60 R15: 00007ffcfab10048
</TASK>
CPU: 0 PID: 3610 Comm: kworker/0:6 Not tainted 6.1.87-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Workqueue: 0x0 (events_power_efficient)
RIP: 0010:finish_task_switch+0x1d3/0x810 kernel/sched/core.c:5124
Code: 39 0b 00 48 83 c4 08 4c 89 f7 e8 98 30 00 00 0f 1f 44 00 00 4c 89 f7 e8 7b a0 35 09 e8 76 28 32 00 fb 49 8d bc 24 f8 15 00 00 <48> 89 f8 48 c1 e8 03 49 bd 00 00 00 00 00 fc ff df 42 0f b6 04 28
RSP: 0018:ffffc900048bfba8 EFLAGS: 00000286
RAX: 1ac86e6b46dcea00 RBX: ffff88805a353bb4 RCX: ffffffff91c92103
RDX: dffffc0000000000 RSI: ffffffff8aec01c0 RDI: ffff88801f63d178
RBP: ffffc900048bfbf0 R08: dffffc0000000000 R09: ffffed1017307541
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff88801f63bb80
R13: 1ffff110173076eb R14: ffff8880b983aa00 R15: ffff8880b983b758
FS: 0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000900 CR3: 0000000079ddf000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
</IRQ>
<TASK>
context_switch kernel/sched/core.c:5248 [inline]
__schedule+0x1435/0x4550 kernel/sched/core.c:6558
schedule+0xbf/0x180 kernel/sched/core.c:6634
worker_thread+0xe9d/0x1200 kernel/workqueue.c:2460
kthread+0x28d/0x320 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
</TASK>
vkms_vblank_simulate: vblank timer overrun


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