INFO: rcu detected stall in sys_pipe2 (2)

Status: upstream: reported syz repro on 2024/11/10 15:52
Subsystems: mm
Labels: prio:low
[Documentation on labels]
Reported-by: syzbot+693a483dd6ac06c62b09@syzkaller.appspotmail.com
First crash: 782d, last: 1d08h
Cause bisection: introduced by (bisect log) :
commit d15121be7485655129101f3960ae6add40204463
Author: Paolo Abeni <pabeni@redhat.com>
Date: Mon May 8 06:17:44 2023 +0000

  Revert "softirq: Let ksoftirqd do its job"

Crash: no output from test machine (log)
Repro: syz .config
  
Fix bisection: fixed by (bisect log) :
commit 66951e4860d3c688bfa550ea4a19635b57e00eca
Author: Peter Zijlstra <peterz@infradead.org>
Date: Mon Jan 13 12:50:11 2025 +0000

  sched/fair: Fix update_cfs_group() vs DELAY_DEQUEUE

  
▶ ▼ ✨ AI Jobs (2)
ID Workflow Result Correct Bug Created Started Finished Revision
4a3c6bd7 assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ INFO: rcu detected stall in sys_pipe2 (2) 2026/05/31 05:36 2026/05/31 05:36 2026/05/31 06:24 6b4a8443
4b7f2912 assessment-security 💥 INFO: rcu detected stall in sys_pipe2 (2) 2026/05/14 14:16 2026/05/14 14:16 2026/05/14 14:18 6ccb967e
▶ ▼ Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [mm?] INFO: rcu detected stall in sys_pipe2 (2) 0 (4) 2025/12/26 16:43
▶ ▼ Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.6 INFO: rcu detected stall in sys_pipe2 1 3 301d 342d 0/2 auto-obsoleted due to no activity on 2026/04/24 18:55
upstream INFO: rcu detected stall in sys_pipe2 fs 1 1 1849d 1849d 0/29 auto-closed as invalid on 2022/01/17 19:05
▶ ▼ Last patch testing requests (4)
Created Duration User Patch Repo Result
2025/11/21 02:36 23m retest repro net-next report log
2025/09/06 23:10 19m retest repro net-next report log
2025/05/05 15:17 23m retest repro net-next report log
2025/02/04 13:24 19m retest repro net-next report log

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P11717/1:b..l.. P15519/1:b..l.. P15032/1:b..l.. P5624/1:b..l.. P16644/1:b..l..
rcu: 	(detected by 0, t=10504 jiffies, g=158641, q=726 ncpus=2)
task:syz.6.3112      state:R  running task     stack:20520 pid:16644 tgid:16644 ppid:15032  task_flags:0xc00640 flags:0x00080001
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5584 [inline]
 __schedule+0x1828/0x58c0 kernel/sched/core.c:7389
 preempt_schedule_notrace+0x56/0x90 kernel/sched/core.c:7640
 preempt_schedule_notrace_thunk+0x16/0x30 arch/x86/entry/thunk.S:13
 rcu_is_watching+0x81/0xb0 kernel/rcu/tree.c:754
 trace_lock_acquire include/trace/events/lock.h:23 [inline]
 lock_acquire+0x58/0x350 kernel/locking/lockdep.c:5905
 rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 rcu_read_lock include/linux/rcupdate.h:849 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1216 [inline]
 unwind_next_frame+0xac/0x2550 arch/x86/kernel/unwind_orc.c:495
 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
 save_stack+0x122/0x230 mm/page_owner.c:183
 __set_page_owner+0x8d/0x4c0 mm/page_owner.c:359
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1860
 prep_new_page mm/page_alloc.c:1868 [inline]
 get_page_from_freelist+0x225d/0x22e0 mm/page_alloc.c:3950
 __alloc_frozen_pages_noprof+0x211/0x450 mm/page_alloc.c:5492
 alloc_pages_mpol+0x21e/0x390 mm/mempolicy.c:2513
 folio_alloc_mpol_noprof+0x39/0x160 mm/mempolicy.c:2532
 shmem_alloc_folio mm/shmem.c:2184 [inline]
 shmem_alloc_and_add_folio+0x43e/0xf60 mm/shmem.c:2226
 shmem_get_folio_gfp+0x594/0x1330 mm/shmem.c:2780
 shmem_fault+0x179/0x390 mm/shmem.c:2974
 __do_fault+0x138/0x2a0 mm/memory.c:5677
 do_read_fault mm/memory.c:6112 [inline]
 do_fault mm/memory.c:6246 [inline]
 do_pte_missing+0x21d2/0x3570 mm/memory.c:4778
 handle_pte_fault mm/memory.c:6665 [inline]
 __handle_mm_fault mm/memory.c:6817 [inline]
 handle_mm_fault+0x1807/0x2f80 mm/memory.c:6984
 faultin_page mm/gup.c:1130 [inline]
 __get_user_pages+0x102b/0x1ea0 mm/gup.c:1432
 __get_user_pages_locked mm/gup.c:1696 [inline]
 get_dump_page+0x1b5/0x410 mm/gup.c:2211
 dump_user_range+0x208/0xca0 fs/coredump.c:1595
 elf_core_dump+0x346a/0x3a70 fs/binfmt_elf.c:2106
 coredump_write fs/coredump.c:1150 [inline]
 do_coredump+0x5ed1/0x6a60 fs/coredump.c:1237
 vfs_coredump+0xac3/0x10c0 fs/coredump.c:1312
 get_signal+0x11d1/0x1430 kernel/signal.c:3098
 arch_do_signal_or_restart+0xbb/0x860 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:101 [inline]
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:244 [inline]
 irqentry_exit_to_user_mode include/linux/irq-entry-common.h:315 [inline]
 irqentry_exit+0x348/0x9b0 kernel/entry/common.c:152
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:595
RIP: 0033:0x0
RSP: 002b:0000200000000148 EFLAGS: 00010217
RAX: 0000000000000000 RBX: 00007f7fede25fa0 RCX: 00007f7fedba8f19
RDX: 0000000000000000 RSI: 0000200000000140 RDI: 0000000000020000
RBP: 00007f7fedc37f6d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007f7fede26038 R14: 00007f7fede25fa0 R15: 00007f7fedf4fa48
 </TASK>
task:syz-executor    state:R  running task     stack:22184 pid:5624  tgid:5624  ppid:5623   task_flags:0x400100 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5584 [inline]
 __schedule+0x1828/0x58c0 kernel/sched/core.c:7389
 preempt_schedule_irq+0x4b/0x90 kernel/sched/core.c:7669
 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:543 [inline]
 irqentry_exit+0x14f/0x9b0 kernel/entry/common.c:154
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:lock_acquire+0x232/0x350 kernel/locking/lockdep.c:5947
Code: ff ff ff e8 20 9c 61 0a f7 44 24 10 00 02 00 00 0f 84 38 ff ff ff 65 48 8b 05 c2 45 3d 13 48 3b 44 24 50 75 33 fb 48 83 c4 58 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 48 8d 3d c7 08 1d
RSP: 0018:ffffc9000397f6e8 EFLAGS: 00000286
RAX: 43460dadb1586600 RBX: 0000000000000000 RCX: 0000000000000046
RDX: 00000000c719f98b RSI: ffffffff8e933b1a RDI: ffffffff8c8e9b80
RBP: ffff88802c678000 R08: ffffffff817889cf R09: 0000000000000000
R10: ffffc9000397f828 R11: fffff5200072ff11 R12: ffffffff9015a260
R13: 0000000000000002 R14: 0000000000000000 R15: 0000000000000246
 rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 rcu_read_lock include/linux/rcupdate.h:849 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1216 [inline]
 unwind_next_frame+0xac/0x2550 arch/x86/kernel/unwind_orc.c:495
 __unwind_start+0x514/0x660 arch/x86/kernel/unwind_orc.c:787
 unwind_start arch/x86/include/asm/unwind.h:64 [inline]
 arch_stack_walk+0xe3/0x150 arch/x86/kernel/stacktrace.c:24
 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
 save_stack+0x122/0x230 mm/page_owner.c:183
 __reset_page_owner+0x73/0x2a0 mm/page_owner.c:338
 reset_page_owner include/linux/page_owner.h:26 [inline]
 __free_pages_prepare mm/page_alloc.c:1402 [inline]
 __free_frozen_pages+0xd1a/0xe10 mm/page_alloc.c:2958
 __slab_free+0x269/0x2c0 mm/slub.c:5926
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:361
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4720 [inline]
 slab_alloc_node mm/slub.c:5033 [inline]
 __kmalloc_cache_noprof+0x29a/0x600 mm/slub.c:5676
 _kmalloc_noprof include/linux/slab.h:991 [inline]
 _kzalloc_noprof include/linux/slab.h:1312 [inline]
 alloc_pipe_info+0xe3/0x4c0 fs/pipe.c:885
 get_pipe_inode fs/pipe.c:979 [inline]
 create_pipe_files+0x87/0x7a0 fs/pipe.c:1011
 __do_pipe_flags+0x46/0x1f0 fs/pipe.c:1073
 do_pipe2+0xaa/0x190 fs/pipe.c:1121
 __do_sys_pipe2 fs/pipe.c:1139 [inline]
 __se_sys_pipe2 fs/pipe.c:1137 [inline]
 __x64_sys_pipe2+0x5a/0x70 fs/pipe.c:1137
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x16a/0x530 arch/x86/entry/syscall_64.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa0a0da7f49
RSP: 002b:00007ffdb9fe0108 EFLAGS: 00000246 ORIG_RAX: 0000000000000125
RAX: ffffffffffffffda RBX: 0000555591ba0710 RCX: 00007fa0a0da7f49
RDX: 0000000000000007 RSI: 0000000000000000 RDI: 00007ffdb9fe0128
RBP: 00007ffdb9fe06f0 R08: 00007fa0a0ffbe20 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffdb9fe0530
R13: 0000555591b9f988 R14: 0000555591ba5440 R15: 00007ffdb9fe0270
 </TASK>
task:syz-executor    state:R  running task     stack:21992 pid:15032 tgid:15032 ppid:1      task_flags:0x40054c flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5584 [inline]
 __schedule+0x1828/0x58c0 kernel/sched/core.c:7389
 preempt_schedule_common+0x7f/0xd0 kernel/sched/core.c:7568
 preempt_schedule_thunk+0x16/0x40 arch/x86/entry/thunk.S:12
 __raw_spin_unlock include/linux/spinlock_api_smp.h:201 [inline]
 _raw_spin_unlock+0x41/0x50 kernel/locking/spinlock.c:213
 spin_unlock include/linux/spinlock.h:401 [inline]
 zap_pte_range mm/memory.c:2059 [inline]
 zap_pmd_range mm/memory.c:2117 [inline]
 zap_pud_range mm/memory.c:2145 [inline]
 zap_p4d_range mm/memory.c:2166 [inline]
 __zap_vma_range+0x3d52/0x4b80 mm/memory.c:2206
 unmap_vmas+0x38b/0x550 mm/memory.c:2275
 exit_mmap+0x290/0xa40 mm/mmap.c:1315
 __mmput+0x118/0x420 kernel/fork.c:1192
 exit_mm+0x18e/0x240 kernel/exit.c:586
 do_exit+0x6a8/0x2360 kernel/exit.c:967
 do_group_exit+0x22d/0x2f0 kernel/exit.c:1123
 get_signal+0x136a/0x1430 kernel/signal.c:3113
 arch_do_signal_or_restart+0xbb/0x860 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline]
 exit_to_user_mode_loop+0x10e/0x770 kernel/entry/common.c:101
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:343 [inline]
 do_syscall_64+0x32c/0x530 arch/x86/entry/syscall_64.c:107
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7fedb6974e
RSP: 002b:00007f7fedf4fd28 EFLAGS: 00000246 ORIG_RAX: 00000000000000e6
RAX: 0000000000000000 RBX: 000055557af32500 RCX: 00007f7fedb6974e
RDX: 00007f7fedf4fd80 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f7fedf4fdec R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000006a
R13: 0000000000000012 R14: 00000000000dee0b R15: 00007f7fedf4fe40
 </TASK>
task:syz-executor    state:R  running task     stack:22200 pid:15519 tgid:15519 ppid:15508  task_flags:0x400140 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5584 [inline]
 __schedule+0x1828/0x58c0 kernel/sched/core.c:7389
 preempt_schedule_irq+0x4b/0x90 kernel/sched/core.c:7669
 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:543 [inline]
 irqentry_exit+0x14f/0x9b0 kernel/entry/common.c:154
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:check_kcov_mode kernel/kcov.c:190 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:252 [inline]
RIP: 0010:__sanitizer_cov_trace_const_cmp4+0x52/0xb0 kernel/kcov.c:328
Code: 00 0f 41 81 f8 00 01 00 00 41 0f 95 c0 81 f9 00 00 00 10 0f 93 c1 44 08 c1 75 67 83 ba 44 17 00 00 00 74 5e 8b 8a 18 17 00 00 <83> f9 03 75 53 48 8b 8a 20 17 00 00 44 8b 8a 1c 17 00 00 48 8b 11
RSP: 0018:ffffc90003ecf820 EFLAGS: 00000246
RAX: ffffffff824cb4a6 RBX: 0000000000000001 RCX: 0000000000000000
RDX: ffff888032ad1f40 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000002 R08: ffffffff824cb162 R09: 0000000000000000
R10: dffffc0000000000 R11: fffff94000533a47 R12: ffffea000299d200
R13: dffffc0000000000 R14: ffffea000299d200 R15: 000000f0b75b19c4
 rcu_read_unlock include/linux/rcupdate.h:878 [inline]
 page_ext_put+0x26/0xc0 mm/page_ext.c:570
 __reset_page_owner+0x69/0x2a0 mm/page_owner.c:330
 reset_page_owner include/linux/page_owner.h:26 [inline]
 __free_pages_prepare mm/page_alloc.c:1402 [inline]
 __free_frozen_pages+0xd1a/0xe10 mm/page_alloc.c:2958
 __slab_free+0x269/0x2c0 mm/slub.c:5926
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:361
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4720 [inline]
 slab_alloc_node mm/slub.c:5033 [inline]
 kmem_cache_alloc_noprof+0x2b4/0x600 mm/slub.c:5047
 alloc_empty_file+0x5b/0x1d0 fs/file_table.c:262
 path_openat+0x96/0x20f0 fs/namei.c:5002
 do_file_open+0x23e/0x4a0 fs/namei.c:5045
 do_sys_openat2+0x115/0x200 fs/open.c:1443
 do_sys_open fs/open.c:1449 [inline]
 __do_sys_openat fs/open.c:1465 [inline]
 __se_sys_openat fs/open.c:1460 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1460
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x16a/0x530 arch/x86/entry/syscall_64.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2688ba823c
RSP: 002b:00007f2688f4ec50 EFLAGS: 00000206 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f2688c37363 RCX: 00007f2688ba823c
RDX: 0000000000090800 RSI: 00007f2688f4fe00 RDI: 00000000ffffff9c
RBP: 00007f2688f4fdec R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 00007f2688f4fe00
R13: 00007f2688c37363 R14: 00000000000de426 R15: 00007f2688f4fe40
 </TASK>
task:syz-executor    state:R  running task     stack:21536 pid:11717 tgid:11717 ppid:11685  task_flags:0x400140 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5584 [inline]
 __schedule+0x1828/0x58c0 kernel/sched/core.c:7389
 preempt_schedule_irq+0x4b/0x90 kernel/sched/core.c:7669
 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:543 [inline]
 irqentry_exit+0x14f/0x9b0 kernel/entry/common.c:154
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:debug_lockdep_rcu_enabled+0x29/0x40 kernel/rcu/update.c:321
Code: 90 f3 0f 1e fa 31 c0 83 3d 9b 2d b8 05 00 74 1d 83 3d 8a 5b b8 05 00 74 14 65 48 8b 0d 98 a3 db 08 31 c0 83 b9 a4 0b 00 00 00 <0f> 94 c0 c3 cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc
RSP: 0018:ffffc90006ecf158 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffffffff81b3b2e9 RCX: ffff88807921be80
RDX: 0000000038dcb1e9 RSI: ffffffff8e933b1a RDI: ffffffff8c8e9b80
RBP: 1ffff92000dd9e48 R08: ffffffff817889cf R09: 0000000000000000
R10: ffffc90006ecf258 R11: ffffffff81b3b350 R12: dffffc0000000000
R13: ffffffff817889cf R14: ffffc90006ecf208 R15: 1ffff92000dd9e41
 rcu_read_lock include/linux/rcupdate.h:850 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1216 [inline]
 unwind_next_frame+0xb5/0x2550 arch/x86/kernel/unwind_orc.c:495
 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
 save_stack+0x122/0x230 mm/page_owner.c:183
 __reset_page_owner+0x73/0x2a0 mm/page_owner.c:338
 reset_page_owner include/linux/page_owner.h:26 [inline]
 __free_pages_prepare mm/page_alloc.c:1402 [inline]
 __free_frozen_pages+0xd1a/0xe10 mm/page_alloc.c:2958
 __slab_free+0x269/0x2c0 mm/slub.c:5926
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_kmalloc+0x22/0xb0 mm/kasan/common.c:417
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5531 [inline]
 __kmalloc_noprof+0x366/0x710 mm/slub.c:5556
 _kmalloc_noprof include/linux/slab.h:995 [inline]
 _kzalloc_noprof include/linux/slab.h:1312 [inline]
 tomoyo_encode2 security/tomoyo/realpath.c:45 [inline]
 tomoyo_encode+0x2ad/0x570 security/tomoyo/realpath.c:80
 tomoyo_realpath_from_path+0x5fd/0x640 security/tomoyo/realpath.c:283
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_check_open_permission+0x229/0x470 security/tomoyo/file.c:776
 security_file_open+0xa9/0x240 security/security.c:2761
 do_dentry_open+0x495/0x1360 fs/open.c:977
 vfs_open_consume+0x4a/0x350 fs/open.c:1131
 do_open fs/namei.c:4851 [inline]
 path_openat+0x16fc/0x20f0 fs/namei.c:5016
 do_file_open+0x23e/0x4a0 fs/namei.c:5045
 do_sys_openat2+0x115/0x200 fs/open.c:1443
 do_sys_open fs/open.c:1449 [inline]
 __do_sys_openat fs/open.c:1465 [inline]
 __se_sys_openat fs/open.c:1460 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1460
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x16a/0x530 arch/x86/entry/syscall_64.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd21d5a823c
RSP: 002b:00007fd21d94fd40 EFLAGS: 00000206 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00000000000003d4 RCX: 00007fd21d5a823c
RDX: 0000000000090800 RSI: 00007fd21d63785b RDI: 00000000ffffff9c
RBP: 00007fd21d94fdec R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 000000000000013b
R13: 0000000000000000 R14: 00000000000dfca3 R15: 00007fd21d94fe40
 </TASK>
rcu: rcu_preempt kthread starved for 10643 jiffies! g158641 f0x0 RCU_GP_WAIT_FQS(5) ->state=R ->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:27432 pid:17    tgid:17    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5584 [inline]
 __schedule+0x1828/0x58c0 kernel/sched/core.c:7389
 __schedule_loop kernel/sched/core.c:7466 [inline]
 schedule+0x164/0x2b0 kernel/sched/core.c:7481
 schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x30c/0x1230 kernel/rcu/tree.c:2122
 rcu_gp_kthread+0x9c/0x340 kernel/rcu/tree.c:2330
 kthread+0x38b/0x480 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/06/2026
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:64
Code: 2a 92 02 e9 03 18 03 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d e3 ca 23 00 fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90
RSP: 0018:ffffffff8fe07ca0 EFLAGS: 00000242
RAX: 000000000222ebfb RBX: ffffffff819ca7ac RCX: 8000000000000001
RDX: 0000000000000001 RSI: ffffffff8e6a7727 RDI: ffffffff8c8e9b80
RBP: ffffffff8fe07d78 R08: ffff8880b8233d9b R09: 1ffff110170467b3
R10: dffffc0000000000 R11: ffffed10170467b4 R12: 0000000000000000
R13: 1ffffffff1fd1df8 R14: 1ffffffff1fc0f9c R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff888123409000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055556e76f4e8 CR3: 000000007f9aa000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/kernel/process.c:767 [inline]
 default_idle+0x9/0x20 arch/x86/kernel/process.c:768
 default_idle_call+0x72/0xb0 kernel/sched/idle.c:122
 cpuidle_idle_call kernel/sched/idle.c:199 [inline]
 do_idle+0x1cc/0x540 kernel/sched/idle.c:355
 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:458
 rest_init+0x378/0x3a0 init/main.c:789
 start_kernel+0x392/0x3e0 init/main.c:1247
 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
 x86_64_start_kernel+0x137/0x1b0 arch/x86/kernel/head64.c:291
 common_startup_64+0x13e/0x157
 </TASK>

Crashes (154):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/11/11 03:09 upstream 067c5c24cef2 d3056657 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in sys_pipe2
2026/10/27 18:38 upstream d135ab453a74 96923c60 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in sys_pipe2
2026/10/19 00:49 upstream f909e534f5e3 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in sys_pipe2
2026/10/16 15:33 upstream 2f2f7eeef8b0 b1757810 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: rcu detected stall in sys_pipe2
2026/09/20 18:08 upstream 518e5b794c06 853b104b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in sys_pipe2
2026/09/20 08:48 upstream 518e5b794c06 853b104b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in sys_pipe2
2026/09/20 07:34 upstream 518e5b794c06 853b104b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in sys_pipe2
2026/08/18 17:58 upstream 0f23d56f17fd 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in sys_pipe2
2026/08/10 21:15 upstream d58772d8520c 039457bd .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in sys_pipe2
2026/08/04 17:27 upstream 848acc8ffe1b d4abbeac .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in sys_pipe2
2026/07/06 22:41 upstream 8cdeaa50eae8 88b240e4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in sys_pipe2
2026/06/03 14:22 upstream ba3e43a9e601 234057e5 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in sys_pipe2
2026/05/30 21:43 upstream f5e5d3509bff 6b4a8443 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: rcu detected stall in sys_pipe2
2026/05/12 14:50 upstream 50897c955902 d5b1a17d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in sys_pipe2
2026/04/18 15:11 upstream 8541d8f725c6 303e2802 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in sys_pipe2
2026/03/07 14:37 upstream 651690480a96 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in sys_pipe2
2026/02/15 16:17 upstream ca4ee40bf13d 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in sys_pipe2
2026/01/22 11:30 upstream a66191c590b3 a16aed1d .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in sys_pipe2
2025/11/24 23:25 upstream ac3fd01e4c1e bf6fe8fe .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in sys_pipe2
2025/11/22 21:08 upstream 2eba5e05d9bc 4fb8ef37 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in sys_pipe2
2025/11/06 21:56 upstream c2c2ccfd4ba7 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in sys_pipe2
2025/11/05 05:44 upstream c9cfc122f037 a6c9c731 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in sys_pipe2
2025/10/23 11:08 upstream 250a17e8f955 c0460fcd .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: rcu detected stall in sys_pipe2
2025/09/27 12:24 upstream fec734e8d564 001c9061 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: rcu detected stall in sys_pipe2
2025/09/24 07:14 upstream cec1e6e5d1ab 0abd0691 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in sys_pipe2
2025/09/16 10:02 upstream 46a51f4f5eda e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in sys_pipe2
2025/08/17 23:28 upstream 8d561baae505 1804e95e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in sys_pipe2
2025/08/04 11:59 upstream 038d61fd6422 7368264b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in sys_pipe2
2024/11/07 19:11 upstream ff7afaeca1a1 c069283c .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in sys_pipe2
2024/11/06 08:01 upstream 2e1b3cc9d7f7 3a465482 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in sys_pipe2
2024/11/01 06:54 upstream 6c52d4da1c74 96eb609f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in sys_pipe2
2025/08/20 18:19 upstream b19a97d57c15 bd178e57 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 INFO: rcu detected stall in sys_pipe2
2026/10/08 16:47 net 6d25ffca055a 4f6a9fcf .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: rcu detected stall in sys_pipe2
2026/08/25 06:13 net 3e995a30b9e3 23caa175 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: rcu detected stall in sys_pipe2
2026/08/15 19:40 net 24ef02f934ee 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: rcu detected stall in sys_pipe2
2026/08/12 10:02 net cba9ccb47e9f f8d35649 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: rcu detected stall in sys_pipe2
2026/07/29 07:25 net e095f249e220 19622d9d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: rcu detected stall in sys_pipe2
2026/07/22 20:31 net fec15bb3dab0 881ce5c2 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: rcu detected stall in sys_pipe2
2026/07/03 18:42 net 87320be9f0d2 58bf2096 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: rcu detected stall in sys_pipe2
2026/06/24 05:45 net e82d8cc4321c 042555ff .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: rcu detected stall in sys_pipe2
2026/06/23 12:48 net a986fde914d8 4b1d8f01 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: rcu detected stall in sys_pipe2
2026/06/22 07:13 net 1579342d7113 43bfcdb0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: rcu detected stall in sys_pipe2
2026/06/20 21:29 net 96e7f9122aae 43bfcdb0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: rcu detected stall in sys_pipe2
2026/06/20 04:36 net 96e7f9122aae 43bfcdb0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: rcu detected stall in sys_pipe2
2026/06/19 09:27 net 5c121ee63568 d7ffd47b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: rcu detected stall in sys_pipe2
2026/06/12 13:22 net 9bf10032894f 1d2f3589 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: rcu detected stall in sys_pipe2
2026/06/11 22:18 net 7360b9609980 d93a6ab6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: rcu detected stall in sys_pipe2
2026/05/25 21:51 net f6f1bfc1980a c69befb3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: rcu detected stall in sys_pipe2
2026/05/23 23:34 net 87a1e0fe7776 c69befb3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: rcu detected stall in sys_pipe2
2026/05/04 22:43 net bd3a4795d574 a898ba9c .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: rcu detected stall in sys_pipe2
2026/05/03 08:32 net 1d324c2f43f7 a0d91488 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: rcu detected stall in sys_pipe2
2026/07/23 06:43 net-next 24d0af194bcc 881ce5c2 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: rcu detected stall in sys_pipe2
2026/06/26 04:40 net-next 805185b7c7a1 432fd51a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: rcu detected stall in sys_pipe2
2026/04/06 10:59 net-next 3741f8fa004b 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: rcu detected stall in sys_pipe2
2024/12/25 00:21 net-next 9268abe611b0 444551c4 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: rcu detected stall in sys_pipe2
2026/10/19 15:34 linux-next 2efb7a11f1aa 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: rcu detected stall in sys_pipe2
2026/09/27 08:37 linux-next f5f84daefcd9 a3c7249d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: rcu detected stall in sys_pipe2
2026/08/15 05:50 linux-next 2697ef8943c9 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: rcu detected stall in sys_pipe2
2025/08/23 02:18 linux-next 7fa4d8dc380f bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: rcu detected stall in sys_pipe2
* Struck through repros no longer work on HEAD.