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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: 624d, last: 3d06h
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 Error
4a3c6bd7-1c78-4cc4-a080-cfdbbbfcca18 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 6b4a844333e83556da95d61d7f207e7ef5cd4bc6
4b7f2912-e34d-47fc-8d81-05eca925a366 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 6ccb967e465e832a7bfd7a116ad00d52a0923a5d failed to run ["make" "KERNELVERSION=syzkaller" "KERNELRELEASE=syzkaller" "LOCALVERSION=-syzkaller" "-j" "32" "ARCH=x86_64" "CC=ccache clang" "LD=ld.lld" "O=/app/workdir/cache/build/222a90c65565bedf03b9f79ba6ed4230286d5394" "-s" "bzImage" "compile_commands.json"]: exit status 2 Root cause: error: unable to open output file 'sound/usb/caiaq/device.o': 'No such file or directory' /app/workdir/cache/src/1e39944fbafaaa3768fe503059b27f6727d79506/lib/maple_tree.c:3514:20: warning: stack frame size (2424) exceeds limit (2048) in 'mas_wr_store_entry' [-Wframe-larger-than] 3514 | static inline void mas_wr_store_entry(struct ma_wr_state *wr_mas) | ^ 1 warning generated. /app/workdir/cache/src/1e39944fbafaaa3768fe503059b27f6727d79506/security/apparmor/apparmorfs.c:177:28: warning: unused function 'get_loaddata_common_ref' [-Wunused-function] 177 | static struct aa_loaddata *get_loaddata_common_ref(struct aa_common_ref *ref) | ^~~~~~~~~~~~~~~~~~~~~~~ 1 warning generated. /app/workdir/cache/src/1e39944fbafaaa3768fe503059b27f6727d79506/security/apparmor/policy_unpack.c:1727:5: warning: stack frame size (2872) exceeds limit (2048) in 'aa_unpack' [-Wframe-larger-than] 1727 | int aa_unpack(struct aa_loaddata *udata, struct list_head *lh, | ^ 1 warning generated. /app/workdir/cache/src/1e39944fbafaaa3768fe503059b27f6727d79506/sound/usb/mixer_s1810c.c:634:5: warning: stack frame size (2360) exceeds limit (2048) in 'snd_sc1810_init_mixer' [-Wframe-larger-than] 634 | int snd_sc1810_init_mixer(struct usb_mixer_interface *mixer) | ^ 1 warning generated. /app/workdir/cache/src/1e39944fbafaaa3768fe503059b27f6727d79506/net/ethtool/cmis_fw_update.c:432:1: warning: stack frame size (2392) exceeds limit (2048) in 'ethtool_cmis_fw_update' [-Wframe-larger-than] 432 | ethtool_cmis_fw_update(struct ethtool_cmis_fw_update_params *fw_update) | ^ 1 warning generated. /bin/sh: 1: printf: printf: I/O error ar: net/ethtool/built-in.a: No space left on device make[6]: *** [/app/workdir/cache/src/1e39944fbafaaa3768fe503059b27f6727d79506/scripts/Makefile.build:487: drivers/vdpa/vdpa_sim/modules.order] Error 1 make[6]: *** Deleting file 'drivers/vdpa/vdpa_sim/modules.order' make[5]: *** [/app/workdir/cache/src/1e39944fbafaaa3768fe503059b27f6727d79506/scripts/Makefile.build:477: net/ethtool/built-in.a] Error 123 make[5]: *** [/app/workdir/cache/src/1e39944fbafaaa3768fe503059b27f6727d79506/scripts/Makefile.build:548: drivers/vdpa/vdpa_sim] Error 2 make[4]: *** [/app/workdir/cache/src/1e39944fbafaaa3768fe503059b27f6727d79506/scripts/Makefile.build:548: net/ethtool] Error 2 make[4]: *** Waiting for unfinished jobs.... make[4]: *** [/app/workdir/cache/src/1e39944fbafaaa3768fe503059b27f6727d79506/scripts/Makefile.build:548: drivers/vdpa] Error 2 make[4]: *** Waiting for unfinished jobs.... mkdir: cannot create directory 'kernel/livepatch': No space left on device ar: kernel/livepatch/built-in.a: No such file or directory make[5]: *** [/app/workdir/cache/src/1e39944fbafaaa3768fe503059b27f6727d79506/scripts/Makefile.build:477: kernel/livepatch/built-in.a] Error 1 make[4]: *** [/app/workdir/cache/src/1e39944fbafaaa3768fe503059b27f6727d79506/scripts/Makefile.build:548: kernel/livepatch] Error 2 make[4]: *** Waiting for unfinished jobs.... fatal error: error in backend: IO failure on output stream: No space left on device PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace, preprocessed source, and associated run script. Stack dump: 0. Program arguments: /usr/bin/clang --target=x86_64-linux-gnu -fintegrated-as -Werror=unknown-warning-option -Werror=ignored-optimization-argument -Werror=option-ignored -Werror=unused-command-line-argument -fmacro-prefix-map=/app/workdir/cache/src/1e39944fbafaaa3768fe503059b27f6727d79506/= -fshort-wchar -funsigned-char -fno-common -fno-PIE -fno-strict-aliasing -std=gnu11 -fms-extensions -Wno-gnu -Wno-microsoft-anon-tag -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx -mno-sse4a -fcf-protection=branc
▶ ▼ 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 143d 183d 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 1691d 1691d 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:
GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P4988/1:b..l P14679/1:b..l P5621/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=141789, q=1375059 ncpus=2)
task:syz-executor    state:R  running task     stack:22072 pid:5621  tgid:5621  ppid:5620   task_flags:0x400100 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5388 [inline]
 __schedule+0x1821/0x5740 kernel/sched/core.c:7189
 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7513
 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline]
 irqentry_exit+0x14f/0x8b0 kernel/entry/common.c:164
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:memset_orig+0x11/0xb0 arch/x86/lib/memset_64.S:54
Code: cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 49 89 fa 40 0f b6 ce 48 b8 01 01 01 01 01 01 01 01 <48> 0f af c1 41 89 f9 41 83 e1 07 75 74 48 89 d1 48 c1 e9 06 74 39
RSP: 0018:ffffc90003b276f0 EFLAGS: 00000202
RAX: 0101010101010101 RBX: ffffc90003b27818 RCX: 0000000000000000
RDX: 0000000000000010 RSI: 0000000000000000 RDI: ffffc90003b27818
RBP: dffffc0000000000 R08: ffffc90003b27827 R09: 1ffff92000764f04
R10: ffffc90003b27818 R11: fffff52000764f05 R12: ffffc90003b27d20
R13: 1ffff92000764efb R14: ffffc90003b277c8 R15: ffffc90003b27810
 unwind_next_frame+0xf33/0x2550 arch/x86/kernel/unwind_orc.c:621
 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:165
 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:320
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1397 [inline]
 __free_frozen_pages+0xc1c/0xd30 mm/page_alloc.c:2938
 __slab_free+0x274/0x2c0 mm/slub.c:5613
 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:350
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4570 [inline]
 slab_alloc_node mm/slub.c:4899 [inline]
 kmem_cache_alloc_noprof+0x2bc/0x650 mm/slub.c:4906
 lsm_inode_alloc security/security.c:254 [inline]
 security_inode_alloc+0x39/0x310 security/security.c:1215
 inode_init_always_gfp+0x995/0xd50 fs/inode.c:305
 inode_init_always include/linux/fs.h:2936 [inline]
 alloc_inode+0x82/0x1b0 fs/inode.c:352
 new_inode_pseudo include/linux/fs.h:3015 [inline]
 get_pipe_inode fs/pipe.c:888 [inline]
 create_pipe_files+0x51/0x7e0 fs/pipe.c:928
 __do_pipe_flags+0x46/0x1f0 fs/pipe.c:990
 do_pipe2+0xaa/0x190 fs/pipe.c:1038
 __do_sys_pipe2 fs/pipe.c:1056 [inline]
 __se_sys_pipe2 fs/pipe.c:1054 [inline]
 __x64_sys_pipe2+0x5a/0x70 fs/pipe.c:1054
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa7d019be89
RSP: 002b:00007fff7c87cb78 EFLAGS: 00000246 ORIG_RAX: 0000000000000125
RAX: ffffffffffffffda RBX: 000055558861c830 RCX: 00007fa7d019be89
RDX: 0000000000000003 RSI: 0000000000000000 RDI: 00007fff7c87cb88
RBP: 00007fff7c87d150 R08: 0000000000000040 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff7c87ccb0
R13: 0000555588611160 R14: 000055558861cb08 R15: 00007fff7c87ccd0
 </TASK>
task:dhcpcd-run-hook state:R  running task     stack:24088 pid:14679 tgid:14679 ppid:5295   task_flags:0x400000 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5388 [inline]
 __schedule+0x1821/0x5740 kernel/sched/core.c:7189
 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7513
 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline]
 irqentry_exit+0x14f/0x8b0 kernel/entry/common.c:164
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:unwind_next_frame+0x19ec/0x2550 arch/x86/kernel/unwind_orc.c:693
Code: 03 49 01 c4 49 8d 56 40 4c 89 f7 4c 89 e6 e8 1b 0e 00 00 84 c0 0f 84 46 01 00 00 48 bd 00 00 00 00 00 fc ff df 48 8b 44 24 20 <0f> b6 04 28 84 c0 0f 85 6a 08 00 00 b3 01 8b 84 24 8c 00 00 00 41
RSP: 0018:ffffc900038b7438 EFLAGS: 00000202
RAX: 1ffff92000716ea1 RBX: ffffffff90d17a4e RCX: 0000000000000001
RDX: ffffc900038b7548 RSI: dffffc0000000000 RDI: ffffc900038b78c0
RBP: dffffc0000000000 R08: ffffc900038b78c0 R09: 0000000000000000
R10: ffffc900038b7558 R11: fffff52000716ead R12: ffffc900038b78c0
R13: 1ffff92000716ea3 R14: ffffc900038b7508 R15: 1ffffffff21a2f4a
 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:165
 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:320
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1397 [inline]
 __free_frozen_pages+0xc1c/0xd30 mm/page_alloc.c:2938
 __slab_free+0x274/0x2c0 mm/slub.c:5613
 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:350
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4570 [inline]
 slab_alloc_node mm/slub.c:4899 [inline]
 kmem_cache_alloc_node_noprof+0x384/0x690 mm/slub.c:4951
 alloc_task_struct_node kernel/fork.c:187 [inline]
 dup_task_struct+0x52/0x840 kernel/fork.c:918
 copy_process+0x89b/0x4440 kernel/fork.c:2090
 kernel_clone+0x2d7/0x940 kernel/fork.c:2722
 __do_sys_clone kernel/fork.c:2863 [inline]
 __se_sys_clone kernel/fork.c:2847 [inline]
 __x64_sys_clone+0x1b6/0x230 kernel/fork.c:2847
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4a7c09a636
RSP: 002b:00007ffcf4c555c0 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007ffcf4c555c8 RCX: 00007f4a7c09a636
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 000055d7e5bdac30 R08: 0000000000000000 R09: 0000000000000040
R10: 00007f4a7bf00f50 R11: 0000000000000246 R12: 000055d7e5be8b88
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
task:klogd           state:R  running task     stack:24312 pid:4988  tgid:4988  ppid:1      task_flags:0x400100 flags:0x00080800
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5388 [inline]
 __schedule+0x1821/0x5740 kernel/sched/core.c:7189
 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7513
 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline]
 irqentry_exit+0x14f/0x8b0 kernel/entry/common.c:164
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:deref_stack_reg arch/x86/kernel/unwind_orc.c:422 [inline]
RIP: 0010:unwind_next_frame+0xecf/0x2550 arch/x86/kernel/unwind_orc.c:614
Code: 49 39 dc 0f 97 c0 20 c8 3c 01 0f 85 6e 0c 00 00 48 8d 43 08 4c 39 f8 0f 97 c1 4c 39 e0 0f 96 c0 20 c8 3c 01 0f 85 54 0c 00 00 <48> 89 df e8 c9 22 00 00 48 89 c3 48 bd 00 00 00 00 00 fc ff df 48
RSP: 0018:ffffc90002f272b8 EFLAGS: 00000202
RAX: ffffc90002f27601 RBX: ffffc90002f27640 RCX: 1ffff920005e4e01
RDX: ffffffff90d311f8 RSI: 0000000000000002 RDI: ffffffff8c28b880
RBP: 1ffff920005e4e72 R08: 0000000000000001 R09: ffffffff8e95cc20
R10: ffffc90002f273d8 R11: ffffffff81b0e0e0 R12: ffffc90002f28000
R13: 1ffff920005e4e73 R14: ffffc90002f27388 R15: ffffc90002f20000
 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:165
 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:320
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1397 [inline]
 __free_frozen_pages+0xc1c/0xd30 mm/page_alloc.c:2938
 __slab_free+0x274/0x2c0 mm/slub.c:5613
 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:350
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4570 [inline]
 slab_alloc_node mm/slub.c:4899 [inline]
 __do_kmalloc_node mm/slub.c:5295 [inline]
 __kmalloc_node_track_caller_noprof+0x493/0x7b0 mm/slub.c:5408
 kmalloc_reserve net/core/skbuff.c:635 [inline]
 __alloc_skb+0x2c1/0x7d0 net/core/skbuff.c:713
 alloc_skb include/linux/skbuff.h:1385 [inline]
 alloc_skb_with_frags+0xc8/0x760 net/core/skbuff.c:6766
 sock_alloc_send_pskb+0x878/0x990 net/core/sock.c:2998
 unix_dgram_sendmsg+0x460/0x18d0 net/unix/af_unix.c:2141
 sock_sendmsg_nosec net/socket.c:787 [inline]
 __sock_sendmsg net/socket.c:802 [inline]
 __sys_sendto+0x672/0x710 net/socket.c:2265
 __do_sys_sendto net/socket.c:2272 [inline]
 __se_sys_sendto net/socket.c:2268 [inline]
 __x64_sys_sendto+0xde/0x100 net/socket.c:2268
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe508479407
RSP: 002b:00007ffddee1a000 EFLAGS: 00000202 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007fe508329c80 RCX: 00007fe508479407
RDX: 0000000000000074 RSI: 00007ffddee1a140 RDI: 0000000000000003
RBP: 00007ffddee1a570 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000004000 R11: 0000000000000202 R12: 00007ffddee1a588
R13: 00007ffddee1a140 R14: 0000000000000059 R15: 00007ffddee1a140
 </TASK>
rcu: rcu_preempt kthread starved for 8560 jiffies! g141789 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:27536 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5388 [inline]
 __schedule+0x1821/0x5740 kernel/sched/core.c:7189
 __schedule_loop kernel/sched/core.c:7268 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7283
 schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095
 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297
 kthread+0x389/0x470 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 04/18/2026
RIP: 0010:arch_atomic_read arch/x86/include/asm/atomic.h:23 [inline]
RIP: 0010:raw_atomic_read include/linux/atomic/atomic-arch-fallback.h:457 [inline]
RIP: 0010:rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline]
RIP: 0010:rcu_is_watching+0x5a/0xb0 kernel/rcu/tree.c:752
Code: f0 48 c1 e8 03 42 80 3c 38 00 74 08 4c 89 f7 e8 ec 41 86 00 48 c7 c3 d8 79 39 93 49 03 1e 48 89 d8 48 c1 e8 03 42 0f b6 04 38 <84> c0 75 34 8b 03 65 ff 0d d9 72 8d 11 74 11 83 e0 04 c1 e8 02 5b
RSP: 0018:ffffc90000006eb8 EFLAGS: 00000a02
RAX: 0000000000000000 RBX: ffff8880b86339d8 RCX: 0000000000000102
RDX: 0000000000000001 RSI: ffffffff8c28b8c0 RDI: ffffffff8c28b880
RBP: dffffc0000000000 R08: ffffc90000007007 R09: 0000000000000000
R10: ffffc90000006ff8 R11: fffff52000000e01 R12: ffffffff8e607de0
R13: ffffffff8e600000 R14: ffffffff8e262790 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff88812529c000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000002e0030 CR3: 00000000767e4000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 rcu_read_unlock include/linux/rcupdate.h:867 [inline]
 class_rcu_destructor include/linux/rcupdate.h:1181 [inline]
 unwind_next_frame+0x1b76/0x2550 arch/x86/kernel/unwind_orc.c:709
 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2689 [inline]
 slab_free mm/slub.c:6251 [inline]
 kmem_cache_free+0x182/0x650 mm/slub.c:6378
 nft_synproxy_eval_v4+0x352/0x4e0 net/netfilter/nft_synproxy.c:61
 nft_synproxy_do_eval+0x305/0x580 net/netfilter/nft_synproxy.c:142
 expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline]
 nft_do_chain+0x48d/0x1ae0 net/netfilter/nf_tables_core.c:285
 nft_do_chain_inet+0x360/0x4b0 net/netfilter/nft_chain_filter.c:162
 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
 nf_hook_slow+0xc5/0x220 net/netfilter/core.c:619
 nf_hook include/linux/netfilter.h:273 [inline]
 NF_HOOK+0x21f/0x3c0 include/linux/netfilter.h:316
 NF_HOOK+0x336/0x3c0 include/linux/netfilter.h:318
 __netif_receive_skb_one_core net/core/dev.c:6202 [inline]
 __netif_receive_skb net/core/dev.c:6315 [inline]
 process_backlog+0xaa3/0x1950 net/core/dev.c:6666
 __napi_poll+0xae/0x340 net/core/dev.c:7733
 napi_poll net/core/dev.c:7796 [inline]
 net_rx_action+0x627/0xf70 net/core/dev.c:7953
 handle_softirqs+0x22a/0x840 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0xca/0x220 kernel/softirq.c:735
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1061
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:63
Code: cb 7e 02 e9 c3 f8 02 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 01 22 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:ffffffff8e607dc0 EFLAGS: 00000246
RAX: 00000000013c0963 RBX: ffffffff819a845a RCX: 0000000080000001
RDX: 0000000000000001 RSI: ffffffff8dfa4398 RDI: ffffffff8c28b8e0
RBP: ffffffff8e607eb0 R08: ffff8880b86339db R09: 1ffff110170c673b
R10: dffffc0000000000 R11: ffffed10170c673c R12: 0000000000000000
R13: 1ffffffff1cd25d8 R14: 0000000000000000 R15: 1ffffffff1cd25d8
 arch_safe_halt arch/x86/kernel/process.c:766 [inline]
 default_idle+0x9/0x20 arch/x86/kernel/process.c:767
 default_idle_call+0x72/0xb0 kernel/sched/idle.c:122
 cpuidle_idle_call kernel/sched/idle.c:199 [inline]
 do_idle+0x36a/0x5f0 kernel/sched/idle.c:352
 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:451
 rest_init+0x2de/0x300 init/main.c:762
 start_kernel+0x38a/0x3e0 init/main.c:1220
 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
 x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291
 common_startup_64+0x13e/0x147
 </TASK>

Crashes (122):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
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
2025/08/07 07:35 upstream cca7a0aae895 4bd24a3e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce 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
2025/07/10 07:35 upstream 8c2e52ebbe88 956bd956 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in sys_pipe2
2025/06/20 02:31 upstream 24770983ccfe ed3e87f7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in sys_pipe2
2025/04/21 13:08 upstream 9d7a0577c9db 2a20f901 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in sys_pipe2
2025/04/19 19:37 upstream 8560697b23dc 2a20f901 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in sys_pipe2
2025/04/09 05:45 upstream bec7dcbc242c b133e63a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in sys_pipe2
2025/04/05 03:53 upstream e48e99b6edf4 1c4febdb .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in sys_pipe2
2025/03/27 13:17 upstream 1e1ba8d23dae 20510e88 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in sys_pipe2
2025/03/21 00:25 upstream 5fc319360819 62330552 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in sys_pipe2
2025/03/03 00:42 upstream b91872c56940 c3901742 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in sys_pipe2
2025/02/28 22:48 upstream 76544811c850 1e7a43e1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in sys_pipe2
2025/02/18 15:01 upstream 2408a807bfc3 c37c7249 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in sys_pipe2
2025/02/13 04:02 upstream 4dc1d1bec898 b27c2402 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in sys_pipe2
2025/02/07 06:00 upstream bb066fe812d6 53657d1b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in sys_pipe2
2025/01/16 04:11 upstream 619f0b6fad52 968edaf4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in sys_pipe2
2025/01/13 11:46 upstream 5bc55a333a2f 6dbc6a9b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in sys_pipe2
2025/01/10 01:33 upstream eea6e4b4dfb8 40f46913 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in sys_pipe2
2025/01/07 14:54 upstream fbfd64d25c7a f3558dbf .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in sys_pipe2
2025/01/06 09:44 upstream ab75170520d4 f3558dbf .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce 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
2025/06/12 16:12 upstream 2c4a1f3fe03e 98683f8f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 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
2025/01/21 09:44 net d640627663bf 6e87cfa2 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: rcu detected stall in sys_pipe2
2025/01/20 23:38 net 4395a44acb15 6e87cfa2 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: rcu detected stall in sys_pipe2
2025/01/20 02:51 net bc50835e83f6 f2cb035c .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: rcu detected stall in sys_pipe2
2025/01/15 17:18 net 001ba0902046 7315a7cf .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: rcu detected stall in sys_pipe2
2025/01/13 03:47 net 47e55e4b410f 6dbc6a9b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-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
2025/05/16 08:37 net-next 1119e5519dcd cfde8269 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: rcu detected stall in sys_pipe2
2025/01/07 17:00 net-next 912d6f669725 f3558dbf .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
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
2025/07/22 15:05 linux-next d086c886ceb9 1555463b .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.