rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-...!: (1 ticks this GP) idle=8d7/1/0x4000000000000000 softirq=11333/11333 fqs=0
(detected by 1, t=10502 jiffies, g=15529, q=349)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 5382 Comm: syz.3.231 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x60 kernel/kcov.c:202
Code: 2e 0f 1f 84 00 00 00 00 00 90 53 48 89 fb e8 17 00 00 00 48 8b 3d 80 fa 11 0c 48 89 de 5b e9 07 56 44 00 00 00 cc cc 00 00 cc <48> 8b 04 24 65 48 8b 0d 14 7d 89 7e 65 8b 15 15 7d 89 7e 81 e2 00
RSP: 0018:ffffc90000007d58 EFLAGS: 00000046
RAX: ffffffff8168b116 RBX: 0000000000000000 RCX: ffff8880281b9dc0
RDX: 0000000000010000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90000007ec0 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52000000f88 R12: ffff8880b902a340
R13: ffff88807c3fdb40 R14: ffff8880b902a398 R15: dffffc0000000000
FS: 00007f8c120c36c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8c120a2d58 CR3: 0000000075551000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
__run_hrtimer kernel/time/hrtimer.c:1702 [inline]
__hrtimer_run_queues+0x5e0/0xb60 kernel/time/hrtimer.c:1749
hrtimer_interrupt+0x397/0x8b0 kernel/time/hrtimer.c:1811
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
__sysvec_apic_timer_interrupt+0x137/0x4a0 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:lock_acquire+0x208/0x400 kernel/locking/lockdep.c:5627
Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3d 04 f8 0f 85 f1 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 44 3d 00 00 00 00 00 43 c7 44 3d 08 00 00 00 00 65 48 8b 04
RSP: 0018:ffffc90002fcf2a0 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 8ac5c8dcb6a72c00
RDX: ffffffff8fb93e70 RSI: ffffffff8a2b3e80 RDI: ffffffff8a7a2a40
RBP: ffffc90002fcf3b8 R08: dffffc0000000000 R09: 1ffffffff25510d9
R10: dffffc0000000000 R11: fffffbfff25510da R12: ffff888145ef7460
R13: 1ffff920005f9e60 R14: 0000000000000246 R15: dffffc0000000000
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154
spin_lock include/linux/spinlock.h:364 [inline]
__find_get_block_slow fs/buffer.c:206 [inline]
__find_get_block+0x38a/0x10d0 fs/buffer.c:1310
__getblk_gfp+0x2c/0xb20 fs/buffer.c:1332
__bread_gfp+0x28/0x380 fs/buffer.c:1381
sb_bread include/linux/buffer_head.h:337 [inline]
isofs_bread+0x1e5/0x270 fs/isofs/inode.c:1188
do_isofs_readdir fs/isofs/dir.c:105 [inline]
isofs_readdir+0x253/0x13b0 fs/isofs/dir.c:263
iterate_dir+0x213/0x550 fs/readdir.c:-1
get_name fs/exportfs/expfs.c:326 [inline]
exportfs_get_name+0x411/0x550 fs/exportfs/expfs.c:36
reconnect_one fs/exportfs/expfs.c:142 [inline]
reconnect_path+0x297/0x740 fs/exportfs/expfs.c:222
exportfs_decode_fh_raw+0x2a1/0x690 fs/exportfs/expfs.c:459
exportfs_decode_fh+0x36/0x70 fs/exportfs/expfs.c:576
do_handle_to_path fs/fhandle.c:152 [inline]
handle_to_path fs/fhandle.c:207 [inline]
do_handle_open+0x401/0x880 fs/fhandle.c:223
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f8c13e8be59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f8c120c3028 EFLAGS: 00000246 ORIG_RAX: 0000000000000130
RAX: ffffffffffffffda RBX: 00007f8c14114090 RCX: 00007f8c13e8be59
RDX: 0000000000000000 RSI: 00002000000000c0 RDI: ffffffffffffff9c
RBP: 00007f8c13f21e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8c14114128 R14: 00007f8c14114090 R15: 00007ffdf68abfc8
</TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g15529 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: Possible timer handling issue on cpu=0 timer-softirq=11962
rcu: rcu_preempt kthread starved for 10502 jiffies! g15529 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:28080 pid: 15 ppid: 2 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11c3/0x4350 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2117
rcu_gp_fqs_loop+0x2be/0x11f0 kernel/rcu/tree.c:1972
rcu_gp_kthread+0x9a/0x370 kernel/rcu/tree.c:2145
kthread+0x42e/0x520 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:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 5382 Comm: syz.3.231 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:__lock_is_held kernel/locking/lockdep.c:5363 [inline]
RIP: 0010:lock_is_held_type+0xaa/0x190 kernel/locking/lockdep.c:5666
Code: 00 00 00 7e 4b 44 89 fd 49 89 df 49 81 c7 f0 0a 00 00 45 31 e4 49 83 fc 31 73 24 4c 89 ff 4c 89 f6 e8 fa 01 00 00 85 c0 75 2a <49> ff c4 48 63 83 e8 0a 00 00 49 83 c7 28 49 39 c4 7c d8 eb 11 48
RSP: 0018:ffffc90000007c88 EFLAGS: 00000046
RAX: 0000000000000000 RBX: ffff8880281b9dc0 RCX: 0000000000000000
RDX: 0000000000010000 RSI: ffff88807c3fdb00 RDI: ffff8880281ba8b0
RBP: 00000000ffffffff R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52000000f88 R12: 0000000000000000
R13: 0000000000000046 R14: ffff88807c3fdb00 R15: ffff8880281ba8b0
FS: 00007f8c120c36c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8c120a2d58 CR3: 0000000075551000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
lock_is_held include/linux/lockdep.h:287 [inline]
advance_sched+0x13f/0x920 net/sched/sch_taprio.c:701
__run_hrtimer kernel/time/hrtimer.c:1685 [inline]
__hrtimer_run_queues+0x4ea/0xb60 kernel/time/hrtimer.c:1749
hrtimer_interrupt+0x397/0x8b0 kernel/time/hrtimer.c:1811
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
__sysvec_apic_timer_interrupt+0x137/0x4a0 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:lock_acquire+0x208/0x400 kernel/locking/lockdep.c:5627
Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3d 04 f8 0f 85 f1 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 44 3d 00 00 00 00 00 43 c7 44 3d 08 00 00 00 00 65 48 8b 04
RSP: 0018:ffffc90002fcf2a0 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 8ac5c8dcb6a72c00
RDX: ffffffff8fb93e70 RSI: ffffffff8a2b3e80 RDI: ffffffff8a7a2a40
RBP: ffffc90002fcf3b8 R08: dffffc0000000000 R09: 1ffffffff25510d9
R10: dffffc0000000000 R11: fffffbfff25510da R12: ffff888145ef7460
R13: 1ffff920005f9e60 R14: 0000000000000246 R15: dffffc0000000000
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154
spin_lock include/linux/spinlock.h:364 [inline]
__find_get_block_slow fs/buffer.c:206 [inline]
__find_get_block+0x38a/0x10d0 fs/buffer.c:1310
__getblk_gfp+0x2c/0xb20 fs/buffer.c:1332
__bread_gfp+0x28/0x380 fs/buffer.c:1381
sb_bread include/linux/buffer_head.h:337 [inline]
isofs_bread+0x1e5/0x270 fs/isofs/inode.c:1188
do_isofs_readdir fs/isofs/dir.c:105 [inline]
isofs_readdir+0x253/0x13b0 fs/isofs/dir.c:263
iterate_dir+0x213/0x550 fs/readdir.c:-1
get_name fs/exportfs/expfs.c:326 [inline]
exportfs_get_name+0x411/0x550 fs/exportfs/expfs.c:36
reconnect_one fs/exportfs/expfs.c:142 [inline]
reconnect_path+0x297/0x740 fs/exportfs/expfs.c:222
exportfs_decode_fh_raw+0x2a1/0x690 fs/exportfs/expfs.c:459
exportfs_decode_fh+0x36/0x70 fs/exportfs/expfs.c:576
do_handle_to_path fs/fhandle.c:152 [inline]
handle_to_path fs/fhandle.c:207 [inline]
do_handle_open+0x401/0x880 fs/fhandle.c:223
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f8c13e8be59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f8c120c3028 EFLAGS: 00000246 ORIG_RAX: 0000000000000130
RAX: ffffffffffffffda RBX: 00007f8c14114090 RCX: 00007f8c13e8be59
RDX: 0000000000000000 RSI: 00002000000000c0 RDI: ffffffffffffff9c
RBP: 00007f8c13f21e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8c14114128 R14: 00007f8c14114090 R15: 00007ffdf68abfc8
</TASK>