rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-...!: (0 ticks this GP) idle=381/1/0x4000000000000002 softirq=53667/53667 fqs=0
(detected by 1, t=10502 jiffies, g=55313, q=1162)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 26905 Comm: syz.2.9393 Not tainted syzkaller #0
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:172 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:227 [inline]
RIP: 0010:__sanitizer_cov_trace_const_cmp4+0xc/0x80 kernel/kcov.c:293
Code: 44 02 08 03 00 00 00 4a 89 7c 02 10 4a 89 74 02 18 4a 89 44 02 20 48 ff c1 48 89 0a c3 90 48 8b 04 24 65 48 8b 0d 04 a2 8a 7e <65> 8b 15 05 a2 8a 7e 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75
RSP: 0000:ffffc90003b7f160 EFLAGS: 00000046
RAX: ffffffff817de846 RBX: 0000000000000001 RCX: ffff8880225f8000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000000 R08: dffffc0000000000 R09: ffffed1027fd4481
R10: ffffed1027fd4481 R11: 1ffff11027fd4480 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS: 00005555855d2500(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2db63fff CR3: 00000000228f7000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
trace_hardirqs_on+0x16/0x80 kernel/trace/trace_preemptirq.c:42
asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713
RIP: 0010:rcu_read_unlock_special+0x84/0x480 kernel/rcu/tree_plugin.h:674
Code: f1 f1 f1 00 f2 f2 f2 4a 89 04 2b 66 42 c7 44 2b 09 f3 f3 42 c6 44 2b 0b f3 65 44 8b 35 ad 13 9e 7e 41 f7 c6 00 00 f0 00 74 45 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b
RSP: 0000:ffffc90003b7f220 EFLAGS: 00000206
RAX: a3bd18f406a69100 RBX: 1ffff9200076fe48 RCX: a3bd18f406a69100
RDX: dffffc0000000000 RSI: ffffffff8a0b1820 RDI: ffffffff8a59a4c0
RBP: ffffc90003b7f300 R08: dffffc0000000000 R09: fffffbfff1ff7a36
R10: fffffbfff1ff7a36 R11: 1ffffffff1ff7a35 R12: ffffffff8c120b00
R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001
__rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422
rcu_read_unlock include/linux/rcupdate.h:771 [inline]
mod_objcg_mlstate+0x225/0x2d0 mm/memcontrol.c:832
drain_obj_stock+0x159/0x370 mm/memcontrol.c:3197
refill_obj_stock+0x121/0x440 mm/memcontrol.c:3242
memcg_slab_free_hook+0x157/0x1f0 mm/slab.h:364
do_slab_free mm/slub.c:3437 [inline]
___cache_free+0x63/0x120 mm/slub.c:3511
qlist_free_all+0x35/0x90 mm/kasan/quarantine.c:176
kasan_quarantine_reduce+0x150/0x160 mm/kasan/quarantine.c:283
__kasan_slab_alloc+0x2f/0xd0 mm/kasan/common.c:444
kasan_slab_alloc include/linux/kasan.h:254 [inline]
slab_post_alloc_hook+0x4c/0x380 mm/slab.h:519
slab_alloc_node mm/slub.c:3225 [inline]
slab_alloc mm/slub.c:3233 [inline]
kmem_cache_alloc+0x100/0x290 mm/slub.c:3238
kmem_cache_zalloc include/linux/slab.h:725 [inline]
jbd2_alloc_handle include/linux/jbd2.h:1597 [inline]
new_handle fs/jbd2/transaction.c:477 [inline]
jbd2__journal_start+0x13c/0x5a0 fs/jbd2/transaction.c:504
__ext4_journal_start_sb+0x167/0x360 fs/ext4/ext4_jbd2.c:105
__ext4_journal_start fs/ext4/ext4_jbd2.h:326 [inline]
ext4_dirty_inode+0x8b/0x100 fs/ext4/inode.c:6037
__mark_inode_dirty+0x2c8/0xc90 fs/fs-writeback.c:2464
generic_update_time+0x1cd/0x1f0 fs/inode.c:1881
inode_update_time fs/inode.c:1894 [inline]
file_update_time+0x38b/0x400 fs/inode.c:2083
ext4_page_mkwrite+0x1b4/0x1240 fs/ext4/inode.c:6158
do_page_mkwrite+0x168/0x3c0 mm/memory.c:2922
do_shared_fault mm/memory.c:4328 [inline]
do_fault mm/memory.c:4396 [inline]
handle_pte_fault mm/memory.c:4650 [inline]
__handle_mm_fault mm/memory.c:4785 [inline]
handle_mm_fault+0x1d4b/0x43c0 mm/memory.c:4883
do_user_addr_fault+0x489/0xc80 arch/x86/mm/fault.c:1357
handle_page_fault arch/x86/mm/fault.c:1445 [inline]
exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1501
asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606
RIP: 0033:0x7fc4e7228021
Code: 85 5a ff ff 48 8b 05 56 47 ea 00 0f b6 4c 24 10 be 08 00 00 00 48 89 df 83 05 32 47 ea 00 01 48 8d 50 ff 48 89 15 37 47 ea 00 <88> 48 ff 8b 2d 1e 47 ea 00 e8 51 5a ff ff 48 8b 05 2a 47 ea 00 41
RSP: 002b:00007ffc159fc690 EFLAGS: 00010202
RAX: 0000001b2db64000 RBX: 00007fc4e80cc720 RCX: 0000000000000003
RDX: 0000001b2db63fff RSI: 0000000000000008 RDI: 00007fc4e80cc720
RBP: 00007fc4e759d038 R08: 0000000000000000 R09: 0000000000000000
R10: 00007fc4e80cc700 R11: 0000000000000001 R12: 0000000000004c03
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g55313 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: Possible timer handling issue on cpu=0 timer-softirq=13037
rcu: rcu_preempt kthread starved for 10502 jiffies! g55313 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:27584 pid: 15 ppid: 2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11bb/0x4390 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
schedule_timeout+0x15c/0x280 kernel/time/timer.c:1914
rcu_gp_fqs_loop+0x29e/0x11b0 kernel/rcu/tree.c:1972
rcu_gp_kthread+0x98/0x350 kernel/rcu/tree.c:2145
kthread+0x436/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
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: 26905 Comm: syz.2.9393 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:check_wait_context kernel/locking/lockdep.c:4709 [inline]
RIP: 0010:__lock_acquire+0x883/0x7c60 kernel/locking/lockdep.c:4962
Code: 00 42 0f b6 04 00 84 c0 0f 85 3c 64 00 00 41 83 3f 00 41 0f 94 c5 45 00 ed 41 80 c5 02 48 8b 84 24 88 00 00 00 42 0f b6 04 00 <84> c0 0f 85 99 61 00 00 44 3b 33 0f 8d 86 02 00 00 49 63 de 48 8d
RSP: 0000:ffffc90003b7e800 EFLAGS: 00000002
RAX: 0000000000000000 RBX: ffff8880225f8ae8 RCX: 0000000000000001
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8ffbd0c0
RBP: ffffc90003b7ea50 R08: dffffc0000000000 R09: fffffbfff1ff7a19
R10: fffffbfff1ff7a19 R11: 1ffffffff1ff7a18 R12: 0000000000000000
R13: ffff8880225f8b04 R14: 0000000000000000 R15: ffff8880225f8ad4
FS: 00005555855d2500(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2db63fff CR3: 00000000228f7000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623
rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:312
rcu_read_lock include/linux/rcupdate.h:739 [inline]
__perf_event_output kernel/events/core.c:7800 [inline]
perf_event_output_forward+0x9e/0x280 kernel/events/core.c:7822
__perf_event_overflow+0x364/0x530 kernel/events/core.c:9515
perf_tp_event+0x32c/0xb50 kernel/events/core.c:10047
perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10021
perf_trace_preemptirq_template+0x2be/0x380 include/trace/events/preemptirq.h:14
trace_irq_enable_rcuidle+0x108/0x180 include/trace/events/preemptirq.h:40
trace_hardirqs_on+0x57/0x80 kernel/trace/trace_preemptirq.c:44
asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713
RIP: 0010:rcu_read_unlock_special+0x84/0x480 kernel/rcu/tree_plugin.h:674
Code: f1 f1 f1 00 f2 f2 f2 4a 89 04 2b 66 42 c7 44 2b 09 f3 f3 42 c6 44 2b 0b f3 65 44 8b 35 ad 13 9e 7e 41 f7 c6 00 00 f0 00 74 45 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b
RSP: 0000:ffffc90003b7f220 EFLAGS: 00000206
RAX: a3bd18f406a69100 RBX: 1ffff9200076fe48 RCX: a3bd18f406a69100
RDX: dffffc0000000000 RSI: ffffffff8a0b1820 RDI: ffffffff8a59a4c0
RBP: ffffc90003b7f300 R08: dffffc0000000000 R09: fffffbfff1ff7a36
R10: fffffbfff1ff7a36 R11: 1ffffffff1ff7a35 R12: ffffffff8c120b00
R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001
__rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422
rcu_read_unlock include/linux/rcupdate.h:771 [inline]
mod_objcg_mlstate+0x225/0x2d0 mm/memcontrol.c:832
drain_obj_stock+0x159/0x370 mm/memcontrol.c:3197
refill_obj_stock+0x121/0x440 mm/memcontrol.c:3242
memcg_slab_free_hook+0x157/0x1f0 mm/slab.h:364
do_slab_free mm/slub.c:3437 [inline]
___cache_free+0x63/0x120 mm/slub.c:3511
qlist_free_all+0x35/0x90 mm/kasan/quarantine.c:176
kasan_quarantine_reduce+0x150/0x160 mm/kasan/quarantine.c:283
__kasan_slab_alloc+0x2f/0xd0 mm/kasan/common.c:444
kasan_slab_alloc include/linux/kasan.h:254 [inline]
slab_post_alloc_hook+0x4c/0x380 mm/slab.h:519
slab_alloc_node mm/slub.c:3225 [inline]
slab_alloc mm/slub.c:3233 [inline]
kmem_cache_alloc+0x100/0x290 mm/slub.c:3238
kmem_cache_zalloc include/linux/slab.h:725 [inline]
jbd2_alloc_handle include/linux/jbd2.h:1597 [inline]
new_handle fs/jbd2/transaction.c:477 [inline]
jbd2__journal_start+0x13c/0x5a0 fs/jbd2/transaction.c:504
__ext4_journal_start_sb+0x167/0x360 fs/ext4/ext4_jbd2.c:105
__ext4_journal_start fs/ext4/ext4_jbd2.h:326 [inline]
ext4_dirty_inode+0x8b/0x100 fs/ext4/inode.c:6037
__mark_inode_dirty+0x2c8/0xc90 fs/fs-writeback.c:2464
generic_update_time+0x1cd/0x1f0 fs/inode.c:1881
inode_update_time fs/inode.c:1894 [inline]
file_update_time+0x38b/0x400 fs/inode.c:2083
ext4_page_mkwrite+0x1b4/0x1240 fs/ext4/inode.c:6158
do_page_mkwrite+0x168/0x3c0 mm/memory.c:2922
do_shared_fault mm/memory.c:4328 [inline]
do_fault mm/memory.c:4396 [inline]
handle_pte_fault mm/memory.c:4650 [inline]
__handle_mm_fault mm/memory.c:4785 [inline]
handle_mm_fault+0x1d4b/0x43c0 mm/memory.c:4883
do_user_addr_fault+0x489/0xc80 arch/x86/mm/fault.c:1357
handle_page_fault arch/x86/mm/fault.c:1445 [inline]
exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1501
asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606
RIP: 0033:0x7fc4e7228021
Code: 85 5a ff ff 48 8b 05 56 47 ea 00 0f b6 4c 24 10 be 08 00 00 00 48 89 df 83 05 32 47 ea 00 01 48 8d 50 ff 48 89 15 37 47 ea 00 <88> 48 ff 8b 2d 1e 47 ea 00 e8 51 5a ff ff 48 8b 05 2a 47 ea 00 41
RSP: 002b:00007ffc159fc690 EFLAGS: 00010202
RAX: 0000001b2db64000 RBX: 00007fc4e80cc720 RCX: 0000000000000003
RDX: 0000001b2db63fff RSI: 0000000000000008 RDI: 00007fc4e80cc720
RBP: 00007fc4e759d038 R08: 0000000000000000 R09: 0000000000000000
R10: 00007fc4e80cc700 R11: 0000000000000001 R12: 0000000000004c03
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000