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rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { P28101 1-.... } 2828 jiffies s: 102477 root: 0x2/T
rcu: blocking rcu_node structures (internal RCU debug):
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 28101 Comm: syz.1.8059 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:__lock_release kernel/locking/lockdep.c:5348 [inline]
RIP: 0010:lock_release+0x253/0x920 kernel/locking/lockdep.c:5682
Code: e4 0f 84 03 03 00 00 4d 8d 74 24 24 4c 89 f0 48 c1 e8 03 42 0f b6 04 28 84 c0 0f 85 bb 04 00 00 41 83 3e 00 0f 85 cc 03 00 00 <4d> 8d 74 24 20 4c 89 f3 48 c1 eb 03 42 0f b6 04 2b 84 c0 4c 8b 7c
RSP: 0018:ffffc900001dfba0 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 0000000000000023 RCX: 0000000000000001
RDX: 0000000000000007 RSI: ffffffff8cb2db60 RDI: ffff88807660e5f8
RBP: ffffc900001dfcb0 R08: ffffffff8e2123ef R09: 1ffffffff1c4247d
R10: dffffc0000000000 R11: fffffbfff1c4247e R12: ffff88807660e5f8
R13: dffffc0000000000 R14: ffff88807660e61c R15: 0000000000000007
FS: 00007f83769fd6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffd87571c90 CR3: 00000000611dd000 CR4: 00000000003506e0
DR0: 0000000000008d24 DR1: 0000000000008d24 DR2: 0000200000000300
DR3: 0000200000000300 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
<IRQ>
__perf_output_begin kernel/events/ring_buffer.c:263 [inline]
perf_output_begin_forward+0x7e4/0xa70 kernel/events/ring_buffer.c:272
__perf_event_output kernel/events/core.c:7732 [inline]
perf_event_output_forward+0x1ad/0x2f0 kernel/events/core.c:7750
__perf_event_overflow+0x457/0x630 kernel/events/core.c:9496
perf_event_overflow kernel/events/core.c:9517 [inline]
perf_swevent_hrtimer+0x472/0x630 kernel/events/core.c:10967
__run_hrtimer kernel/time/hrtimer.c:1751 [inline]
__hrtimer_run_queues+0x4e7/0xc90 kernel/time/hrtimer.c:1815
hrtimer_interrupt+0x399/0x980 kernel/time/hrtimer.c:1877
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1107 [inline]
__sysvec_apic_timer_interrupt+0x153/0x5a0 arch/x86/kernel/apic/apic.c:1124
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
sysvec_apic_timer_interrupt+0x4d/0xc0 arch/x86/kernel/apic/apic.c:1118
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:on_stack arch/x86/include/asm/stacktrace.h:56 [inline]
RIP: 0010:stack_access_ok arch/x86/kernel/unwind_orc.c:351 [inline]
RIP: 0010:deref_stack_reg arch/x86/kernel/unwind_orc.c:357 [inline]
RIP: 0010:unwind_next_frame+0x805/0x1fd0 arch/x86/kernel/unwind_orc.c:539
Code: f4 ff 85 c0 0f 85 55 0f 00 00 49 bc 00 00 00 00 00 fc ff df 43 80 3c 27 00 4c 8d 7b 08 74 08 4c 89 ff e8 2e 46 9a 00 4d 8b 3f <43> 80 3c 26 00 4c 8b 6c 24 10 74 09 48 8d 7b 10 e8 16 46 9a 00 4c
RSP: 0018:ffffc900001e0540 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffffc900001e05e8 RCX: 0000000000000001
RDX: 0000000000000002 RSI: ffffc90004c30000 RDI: ffffc90004c2f0f0
RBP: ffffc90004c2f0f0 R08: 0000000000000001 R09: 000000000000000f
R10: dffffc0000000000 R11: fffff5200003c0c9 R12: dffffc0000000000
R13: ffffc900001e1000 R14: 1ffff9200003c0bf R15: ffffc90004c28000
arch_stack_walk+0x10c/0x140 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xa6/0xf0 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:46 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
kasan_save_free_info+0x27/0x40 mm/kasan/generic.c:516
____kasan_slab_free+0x126/0x1f0 mm/kasan/common.c:237
kasan_slab_free include/linux/kasan.h:177 [inline]
slab_free_hook mm/slub.c:1729 [inline]
slab_free_freelist_hook+0x133/0x1b0 mm/slub.c:1755
slab_free mm/slub.c:3687 [inline]
kmem_cache_free+0xf7/0x2a0 mm/slub.c:3709
tcp_write_queue_purge+0x13c/0x300 net/ipv4/tcp.c:3123
tcp_done_with_error+0x3f/0xc0 net/ipv4/tcp_input.c:4408
tcp_write_err net/ipv4/tcp_timer.c:70 [inline]
tcp_write_timeout net/ipv4/tcp_timer.c:273 [inline]
tcp_retransmit_timer+0x1299/0x27c0 net/ipv4/tcp_timer.c:547
tcp_write_timer+0x126/0x280 net/ipv4/tcp_timer.c:676
call_timer_fn+0x1ac/0x670 kernel/time/timer.c:1701
expire_timers kernel/time/timer.c:1752 [inline]
__run_timers+0x56c/0x810 kernel/time/timer.c:2023
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:2036
handle_softirqs+0x291/0x910 kernel/softirq.c:596
__do_softirq kernel/softirq.c:630 [inline]
invoke_softirq kernel/softirq.c:470 [inline]
__irq_exit_rcu+0x13b/0x230 kernel/softirq.c:679
irq_exit_rcu+0x5/0x20 kernel/softirq.c:691
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:preempt_schedule_irq+0xb6/0x160 kernel/sched/core.c:6874
Code: 00 00 43 c6 44 37 04 f8 74 0b 0f 0b 48 f7 03 08 00 00 00 74 7f bf 01 00 00 00 e8 b5 ef 1f f7 e8 d0 ba 4f f7 fb bf 01 00 00 00 <e8> 25 ba ff ff 43 c6 44 37 08 00 48 c7 44 24 40 00 00 00 00 9c 8f
RSP: 0018:ffffc90004c2f1a0 EFLAGS: 00000286
RAX: 1758c520ad74df00 RBX: 0000000000000000 RCX: 1758c520ad74df00
RDX: dffffc0000000000 RSI: ffffffff8a8c17a0 RDI: 0000000000000001
RBP: ffffc90004c2f250 R08: ffffffff90b1024f R09: 1ffffffff2162049
R10: dffffc0000000000 R11: fffffbfff216204a R12: 0000000000000000
R13: 0000000000000000 R14: dffffc0000000000 R15: 1ffff92000985e34
irqentry_exit+0x63/0x70 kernel/entry/common.c:439
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:__sanitizer_cov_trace_pc+0x41/0x60 kernel/kcov.c:221
Code: ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 1c 16 00 00 00 74 2c 8b 91 f8 15 00 00 83 fa 02 75 21 48 8b 91 00 16 00 00 48 8b 32 <48> 8d 7e 01 8b 89 fc 15 00 00 48 39 cf 73 08 48 89 3a 48 89 44 f2
RSP: 0018:ffffc90004c2f318 EFLAGS: 00000246
RAX: ffffffff81dbf5b5 RBX: ffff88807660df70 RCX: ffff88807660da00
RDX: ffffc9001c1ae000 RSI: 000000000000269e RDI: 0000000000000000
RBP: ffffc90004c2f450 R08: 0000000000002800 R09: ffff88823b400000
R10: 000000003f4912cf R11: 00000000fafb55a4 R12: dffffc0000000000
R13: 1ffff1100ecc1bee R14: 0000000005d90397 R15: 1ffff92000985e68
save_stack+0x145/0x230 mm/page_owner.c:129
__reset_page_owner+0x51/0x190 mm/page_owner.c:148
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1487 [inline]
free_pcp_prepare mm/page_alloc.c:1537 [inline]
free_unref_page_prepare+0x8e5/0x9e0 mm/page_alloc.c:3414
free_unref_page+0x2e/0x3f0 mm/page_alloc.c:3509
qlink_free mm/kasan/quarantine.c:168 [inline]
qlist_free_all+0x76/0xe0 mm/kasan/quarantine.c:187
kasan_quarantine_reduce+0x144/0x160 mm/kasan/quarantine.c:294
__kasan_slab_alloc+0x1e/0x80 mm/kasan/common.c:306
kasan_slab_alloc include/linux/kasan.h:201 [inline]
slab_post_alloc_hook+0x4b/0x490 mm/slab.h:737
slab_alloc_node mm/slub.c:3359 [inline]
slab_alloc mm/slub.c:3367 [inline]
__kmem_cache_alloc_lru mm/slub.c:3374 [inline]
kmem_cache_alloc+0x18b/0x2f0 mm/slub.c:3383
kmem_cache_zalloc include/linux/slab.h:689 [inline]
__kernfs_new_node+0xe1/0x7f0 fs/kernfs/dir.c:614
kernfs_new_node+0x148/0x250 fs/kernfs/dir.c:690
__kernfs_create_file+0x47/0x2e0 fs/kernfs/file.c:1068
sysfs_add_file_mode_ns+0x233/0x2f0 fs/sysfs/file.c:294
create_files fs/sysfs/group.c:64 [inline]
internal_create_group+0x490/0xce0 fs/sysfs/group.c:148
internal_create_groups fs/sysfs/group.c:188 [inline]
sysfs_create_groups+0x55/0x120 fs/sysfs/group.c:214
device_add_groups drivers/base/core.c:2752 [inline]
device_add_attrs+0x1ae/0x830 drivers/base/core.c:2911
device_add+0x677/0x1050 drivers/base/core.c:3648
netdev_register_kobject+0x184/0x320 net/core/net-sysfs.c:2013
register_netdevice+0x133a/0x1b80 net/core/dev.c:10243
ppp_unit_register drivers/net/ppp/ppp_generic.c:1232 [inline]
ppp_dev_configure+0x875/0xad0 drivers/net/ppp/ppp_generic.c:1288
ppp_create_interface drivers/net/ppp/ppp_generic.c:3365 [inline]
ppp_unattached_ioctl drivers/net/ppp/ppp_generic.c:1073 [inline]
ppp_ioctl+0x8c2/0x1a40 drivers/net/ppp/ppp_generic.c:743
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl+0xfa/0x170 fs/ioctl.c:856
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f8375b9de59
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:00007f83769fd028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f8375e25fa0 RCX: 00007f8375b9de59
RDX: 000000110e22fff6 RSI: 00000000c004743e RDI: 0000000000000004
RBP: 00007f8375c33e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8375e26038 R14: 00007f8375e25fa0 R15: 00007ffdc77573b8
</TASK>
| Time | Kernel | Commit | Syzkaller | Config | Log | Report | Syz repro | C repro | VM info | Assets (help?) | Manager | Title |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2026/07/03 12:51 | linux-6.1.y | fdb6fcb41cc7 | 58bf2096 | .config | console log | report | info | [disk image] [vmlinux] [kernel image] | ci2-linux-6-1-kasan-perf | INFO: rcu detected stall in tcp_write_timer | ||
| 2026/04/23 01:41 | linux-6.1.y | 7c87defbd336 | b10da5ec | .config | console log | report | info | [disk image] [vmlinux] [kernel image] | ci2-linux-6-1-kasan-perf | INFO: rcu detected stall in tcp_write_timer | ||
| 2026/03/06 03:15 | linux-6.1.y | f2ddafa93a25 | 31e9c887 | .config | console log | report | info | [disk image] [vmlinux] [kernel image] | ci2-linux-6-1-kasan-perf | INFO: rcu detected stall in tcp_write_timer |