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

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: ca48fc16c493 Linux 6.1.27
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=124ad18c280000
kernel config: https://syzkaller.appspot.com/x/.config?x=47d3bbfdb3b1ddd2
dashboard link: https://syzkaller.appspot.com/bug?extid=a5f75e36363f7b129a45
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/658765c915fa/disk-ca48fc16.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d69e8a1aff2d/vmlinux-ca48fc16.xz
kernel image: https://storage.googleapis.com/syzbot-assets/0317a9546209/bzImage-ca48fc16.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a5f75e...@syzkaller.appspotmail.com

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
(detected by 1, t=10502 jiffies, g=68417, q=19 ncpus=2)
rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4295051881-4295041379), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 10502 jiffies! g68417 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:26528 pid:16 ppid:2 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5241 [inline]
__schedule+0x132c/0x4330 kernel/sched/core.c:6554
schedule+0xbf/0x180 kernel/sched/core.c:6630
schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1935
rcu_gp_fqs_loop+0x2c2/0x1010 kernel/rcu/tree.c:1660
rcu_gp_kthread+0xa3/0x3a0 kernel/rcu/tree.c:1859
kthread+0x26e/0x300 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
</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: 3602 Comm: syz-executor.4 Not tainted 6.1.27-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023
RIP: 0010:debug_spin_unlock kernel/locking/spinlock_debug.c:105 [inline]
RIP: 0010:do_raw_spin_unlock+0x104/0x8a0 kernel/locking/spinlock_debug.c:140
Code: 41 80 3c 2c 00 74 08 4c 89 ef e8 37 df 74 00 49 c7 45 00 ff ff ff ff 0f b6 04 2b 84 c0 0f 85 c9 03 00 00 41 c7 06 ff ff ff ff <48> c7 c0 60 8a d9 8c 48 c1 e8 03 80 3c 28 00 74 0c 48 c7 c7 60 8a
RSP: 0018:ffffc90000007ba0 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 1ffffffff23accde RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffffff91d666e8
RBP: dffffc0000000000 R08: dffffc0000000000 R09: fffffbfff23accde
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffffffff23accdf
R13: ffffffff91d666f8 R14: ffffffff91d666f0 R15: ffffffff91d666e8
FS: 0000555556801400(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020001700 CR3: 00000000391ad000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:150 [inline]
_raw_spin_unlock_irqrestore+0x7d/0x130 kernel/locking/spinlock.c:194
debug_object_activate+0x274/0x690 lib/debugobjects.c:693
debug_hrtimer_activate kernel/time/hrtimer.c:420 [inline]
debug_activate kernel/time/hrtimer.c:475 [inline]
enqueue_hrtimer+0x30/0x390 kernel/time/hrtimer.c:1084
__run_hrtimer kernel/time/hrtimer.c:1702 [inline]
__hrtimer_run_queues+0x728/0xe50 kernel/time/hrtimer.c:1749
hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1811
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1096 [inline]
__sysvec_apic_timer_interrupt+0x156/0x580 arch/x86/kernel/apic/apic.c:1113
sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1107
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:649
RIP: 0010:lock_acquire+0x26f/0x5a0 kernel/locking/lockdep.c:5673
Code: 2b 00 74 08 4c 89 f7 e8 0f 40 76 00 f6 44 24 61 02 0f 85 84 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 09 00 00 00 00 43 c7 44 25
RSP: 0018:ffffc900056ef2e0 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 1ffff92000adde68 RCX: 1ffff92000adde08
RDX: dffffc0000000000 RSI: ffffffff8aebe1a0 RDI: ffffffff8b3cbfa0
RBP: ffffc900056ef438 R08: dffffc0000000000 R09: fffffbfff2050445
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff92000adde64
R13: dffffc0000000000 R14: ffffc900056ef340 R15: 0000000000000246
rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:306
rcu_read_lock include/linux/rcupdate.h:747 [inline]
page_ext_get+0x18/0x270 mm/page_ext.c:157
page_table_check_set+0x1fa/0x550 mm/page_table_check.c:107
page_table_check_pte_set include/linux/page_table_check.h:83 [inline]
set_pte_at arch/x86/include/asm/pgtable.h:1009 [inline]
copy_present_pte mm/memory.c:990 [inline]
copy_pte_range mm/memory.c:1081 [inline]
copy_pmd_range mm/memory.c:1167 [inline]
copy_pud_range mm/memory.c:1204 [inline]
copy_p4d_range mm/memory.c:1228 [inline]
copy_page_range+0x2ca2/0x4580 mm/memory.c:1326
dup_mmap kernel/fork.c:695 [inline]
dup_mm+0xddf/0x1610 kernel/fork.c:1532
copy_mm+0xca/0x160 kernel/fork.c:1581
copy_process+0x19a2/0x4020 kernel/fork.c:2259
kernel_clone+0x222/0x920 kernel/fork.c:2679
__do_sys_clone kernel/fork.c:2820 [inline]
__se_sys_clone kernel/fork.c:2804 [inline]
__x64_sys_clone+0x231/0x280 kernel/fork.c:2804
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f6ecbc89e9b
Code: ed 0f 85 60 01 00 00 64 4c 8b 0c 25 10 00 00 00 45 31 c0 4d 8d 91 d0 02 00 00 31 d2 31 f6 bf 11 00 20 01 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 0f 87 89 00 00 00 41 89 c5 85 c0 0f 85 90 00 00
RSP: 002b:00007ffe6d14bc60 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f6ecbc89e9b
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000555556801400
R10: 00005555568016d0 R11: 0000000000000246 R12: 0000000000000001
R13: 0000000000000000 R14: 0000000000000001 R15: 00007ffe6d14bd40
</TASK>


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.