rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-...!: (1 ticks this GP) idle=9bec/1/0x4000000000000000 softirq=14417/14417 fqs=0
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5879/1:b..l
rcu: (detected by 1, t=10502 jiffies, g=11593, q=479 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 6130 Comm: syz.3.35 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:27 [inline]
RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x11/0x70 kernel/kcov.c:217
Code: 5b e9 63 74 5a 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 04 24 65 48 8b 0c 25 08 40 c2 92 <65> 8b 15 f8 e4 01 11 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75
RSP: 0018:ffffc90000007d38 EFLAGS: 00000082
RAX: ffffffff81ae5107 RBX: ffff8880b8627c08 RCX: ffff888027c10000
RDX: 0000000000010000 RSI: 1ffff110170c4f7a RDI: ffff88807c4ea340
RBP: ffffc90000007e90 R08: ffff88807c4ea357 R09: 0000000000000000
R10: ffff88807c4ea340 R11: ffffed100f89d46b R12: ffff88807c4ea340
R13: dffffc0000000000 R14: ffff8880b8627c18 R15: ffff8880b8627bc0
FS: 00007f34e25796c0(0000) GS:ffff8881259fc000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f89c1a35e9c CR3: 0000000032f8c000 CR4: 00000000003526f0
Call Trace:
__hrtimer_run_queues+0x6f7/0xc60 kernel/time/hrtimer.c:1821
hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline]
__sysvec_apic_timer_interrupt+0x10b/0x410 arch/x86/kernel/apic/apic.c:1058
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1052
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:zone_watermark_fast+0x3/0x230 mm/page_alloc.c:3612
Code: 03 38 c1 7c 88 48 8b 7c 24 68 e8 d8 dd 0d 00 e9 79 ff ff ff 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 41 57 <41> 56 41 55 41 54 53 48 83 ec 10 44 89 c5 41 89 cd 48 89 54 24 08
RSP: 0018:ffffc90004127468 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000003212 RCX: 0000000000000003
RDX: 0000000000003212 RSI: 0000000000000000 RDI: ffff88813fffbb80
RBP: ffffc900041276f0 R08: 0000000000000981 R09: 1ffff11027fff82f
R10: dffffc0000000000 R11: ffffed1027fff830 R12: dffffc0000000000
R13: 0000000000000981 R14: ffffc9000412775c R15: ffff88813fffbb80
get_page_from_freelist+0x54c/0x2440 mm/page_alloc.c:3828
__alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5183
alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2416
folio_alloc_mpol_noprof+0x39/0x70 mm/mempolicy.c:2435
shmem_alloc_folio mm/shmem.c:1871 [inline]
shmem_alloc_and_add_folio+0x447/0xf60 mm/shmem.c:1910
shmem_get_folio_gfp+0x59d/0x1660 mm/shmem.c:2533
shmem_get_folio mm/shmem.c:2639 [inline]
shmem_write_begin+0xf7/0x2b0 mm/shmem.c:3289
generic_perform_write+0x2c5/0x900 mm/filemap.c:4242
shmem_file_write_iter+0xf8/0x120 mm/shmem.c:3464
new_sync_write fs/read_write.c:593 [inline]
vfs_write+0x5c9/0xb30 fs/read_write.c:686
ksys_write+0x145/0x250 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f34e178d97f
Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 f9 92 02 00 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 4c 93 02 00 48
RSP: 002b:00007f34e2578df0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000001000000 RCX: 00007f34e178d97f
RDX: 0000000001000000 RSI: 00007f34d7400000 RDI: 0000000000000004
RBP: 0000000000000000 R08: 0000000000000000 R09: 00000000000097e8
R10: 0000000000000002 R11: 0000000000000293 R12: 0000000000000004
R13: 00007f34e2578ef0 R14: 00007f34e2578eb0 R15: 00007f34d7400000
task:udevd state:R running task stack:24264 pid:5879 tgid:5879 ppid:5233 task_flags:0x400140 flags:0x00080001
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6929
preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7256
irqentry_exit+0x6f/0x90 kernel/entry/common.c:211
asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:seqcount_lockdep_reader_access+0x0/0x1c0 include/linux/seqlock.h:67
Code: 89 ff e8 83 a7 ea ff e9 0e ff ff ff 66 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 55 48 89 e5 41 57 41 56 41 55 41 54 53 48 83 e4 e0 48
RSP: 0018:ffffc90004687810 EFLAGS: 00000a06
RAX: 1ffff920008d0f85 RBX: ffffc90004687c28 RCX: 1ffff920008d0f9c
RDX: ffff88806a4a3c80 RSI: 0000000000000100 RDI: ffff88803324fc08
RBP: 0000000000000100 R08: 0000000000000000 R09: ffffffff823b2adf
R10: dffffc0000000000 R11: ffffed100f034465 R12: dffffc0000000000
R13: dffffc0000000000 R14: ffff88803324fc08 R15: 1ffff11006649f81
read_seqbegin include/linux/seqlock.h:836 [inline]
set_root+0x161/0x3b0 fs/namei.c:1015
nd_jump_root+0x2b4/0x430 fs/namei.c:1036
path_init+0x373/0x1350 fs/namei.c:2583
path_openat+0x18c/0x3830 fs/namei.c:4129
do_filp_open+0x1fa/0x410 fs/namei.c:4161
do_sys_openat2+0x121/0x1c0 fs/open.c:1437
do_sys_open fs/open.c:1452 [inline]
__do_sys_openat fs/open.c:1468 [inline]
__se_sys_openat fs/open.c:1463 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1463
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f849e4a7407
RSP: 002b:00007ffe3b8f6720 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f849eb9d880 RCX: 00007f849e4a7407
RDX: 0000000000080000 RSI: 00007ffe3b8f68a0 RDI: ffffffffffffff9c
RBP: 0000000000000008 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 000056274d3b97f5
R13: 000056274d3b97f5 R14: 0000000000000001 R15: 0000000000000000
rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g11593 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: Possible timer handling issue on cpu=0 timer-softirq=5592
rcu: rcu_preempt kthread starved for 10502 jiffies! g11593 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:27496 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6929
__schedule_loop kernel/sched/core.c:7011 [inline]
schedule+0x165/0x360 kernel/sched/core.c:7026
schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245