INFO: rcu detected stall in sys_sendmmsg (3)

Status: auto-obsoleted due to no activity on 2026/06/13 03:55
Reported-by: syzbot+cedf6a23be74bf99204c@syzkaller.appspotmail.com
First crash: 247d, last: 150d
▶ ▼ Similar bugs (19)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in sys_sendmmsg (2) mm 1 2 2434d 2434d 0/29 closed as invalid on 2019/12/04 14:14
upstream INFO: rcu detected stall in sys_sendmmsg (6) mm 1 3 963d 1010d 0/29 auto-obsoleted due to no activity on 2024/03/11 17:33
linux-6.1 INFO: rcu detected stall in sys_sendmmsg 1 2 739d 785d 0/3 auto-obsoleted due to no activity on 2024/11/01 14:13
linux-5.15 INFO: rcu detected stall in sys_sendmmsg (4) origin:lts-only 1 syz, C inconclusive 7 213d 296d 0/3 upstream: reported C repro on 2025/10/10 06:08
linux-6.1 BUG: soft lockup in sys_sendmmsg 1 2 1128d 1157d 0/3 auto-obsoleted due to no activity on 2023/10/08 22:57
linux-5.15 INFO: rcu detected stall in sys_sendmmsg 1 1 1216d 1216d 0/3 auto-obsoleted due to no activity on 2023/08/02 15:37
upstream INFO: rcu detected stall in sys_sendmmsg (3) kernel 1 3 1669d 1768d 0/29 closed as invalid on 2022/02/08 10:00
linux-5.15 INFO: rcu detected stall in sys_sendmmsg (2) 1 1 815d 815d 0/3 auto-obsoleted due to no activity on 2024/08/17 11:17
upstream INFO: rcu detected stall in sys_sendmmsg (5) net 1 3 1154d 1168d 0/29 auto-obsoleted due to no activity on 2023/09/03 00:09
linux-5.15 INFO: rcu detected stall in sys_sendmmsg (3) 1 16 457d 676d 0/3 auto-obsoleted due to no activity on 2025/08/10 13:38
linux-6.6 INFO: rcu detected stall in sys_sendmmsg 1 2 33d 33d 0/2 upstream: reported on 2026/06/30 08:33
upstream INFO: rcu detected stall in sys_sendmmsg (7) prio:high net mm 1 143 4d17h 609d 0/29 upstream: reported on 2024/11/30 18:05
linux-6.1 INFO: rcu detected stall in sys_sendmmsg (2) 1 1 436d 436d 0/3 auto-obsoleted due to no activity on 2025/08/31 10:43
upstream INFO: rcu detected stall in sys_sendmmsg net 1 2 2518d 2518d 13/29 fixed on 2019/10/09 10:54
upstream INFO: rcu detected stall in sys_sendmmsg (4) net 1 1 1467d 1467d 0/29 auto-obsoleted due to no activity on 2022/10/25 00:28
android-5-15 BUG: soft lockup in sys_sendmmsg 1 1 798d 798d 0/2 auto-obsoleted due to no activity on 2024/08/24 08:55
android-6-1 BUG: soft lockup in sys_sendmmsg 1 1 1010d 1010d 0/2 auto-obsoleted due to no activity on 2024/01/25 01:21
android-5-10 BUG: soft lockup in sys_sendmmsg 1 2 713d 713d 0/2 auto-obsoleted due to no activity on 2024/11/17 00:13
android-5-10 BUG: soft lockup in sys_sendmmsg (2) 1 syz error 19 209d 587d 0/2 premoderation: reported syz repro on 2024/12/23 13:44

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P15730/1:b..l P15731/1:b..l P15692/2:b..l
	(detected by 0, t=10502 jiffies, g=92533, q=871 ncpus=2)
task:syz.8.2454      state:R  running task     stack:23600 pid:15692 ppid:8472   flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562
 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6874
 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:check_kcov_mode kernel/kcov.c:193 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:245 [inline]
RIP: 0010:__sanitizer_cov_trace_const_cmp1+0x32/0x80 kernel/kcov.c:299
Code: 64 fa 7f 7e 65 8b 0d 65 fa 7f 7e 81 e1 00 01 ff 00 74 11 81 f9 00 01 00 00 75 5b 83 ba 1c 16 00 00 00 74 52 8b 8a f8 15 00 00 <83> f9 03 75 47 48 8b 8a 00 16 00 00 44 8b 8a fc 15 00 00 49 c1 e1
RSP: 0018:ffffc90006226db8 EFLAGS: 00000246
RAX: ffffffff890d3e88 RBX: 1ffffffff1bc8155 RCX: 0000000000000002
RDX: ffff88802d1d8000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000040 R08: ffff8880742d812f R09: ffff8880742d80e8
R10: dffffc0000000000 R11: ffffed100e85b026 R12: ffffffff8de40a80
R13: ffffffff8de40aa8 R14: 0000000000000001 R15: 0000000000000001
 pfkey_send_acquire+0x1828/0x2d70 net/key/af_key.c:-1
 km_query+0x10e/0x200 net/xfrm/xfrm_state.c:2244
 xfrm_state_find+0x2016/0x2c10 net/xfrm/xfrm_state.c:1158
 xfrm_tmpl_resolve_one net/xfrm/xfrm_policy.c:2424 [inline]
 xfrm_tmpl_resolve net/xfrm/xfrm_policy.c:2469 [inline]
 xfrm_resolve_and_create_bundle+0x774/0x2d30 net/xfrm/xfrm_policy.c:2762
 xfrm_lookup_with_ifid+0x272/0x2050 net/xfrm/xfrm_policy.c:3096
 xfrm_lookup net/xfrm/xfrm_policy.c:3225 [inline]
 xfrm_lookup_route+0x38/0x1b0 net/xfrm/xfrm_policy.c:3236
 udp_sendmsg+0x1626/0x23b0 net/ipv4/udp.c:1247
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:730 [inline]
 ____sys_sendmsg+0x5be/0x970 net/socket.c:2518
 ___sys_sendmsg+0x2a2/0x360 net/socket.c:2572
 __sys_sendmmsg+0x2c3/0x510 net/socket.c:2658
 __do_sys_sendmmsg net/socket.c:2687 [inline]
 __se_sys_sendmmsg net/socket.c:2684 [inline]
 __x64_sys_sendmmsg+0x9c/0xb0 net/socket.c:2684
 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: 0033:0x7fa2dff9aeb9
RSP: 002b:00007fa2e0f14028 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00007fa2e0216090 RCX: 00007fa2dff9aeb9
RDX: 000000000800001d RSI: 0000200000007fc0 RDI: 0000000000000003
RBP: 00007fa2e0008c1f R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000001c R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa2e0216128 R14: 00007fa2e0216090 R15: 00007ffd57272b88
 </TASK>
task:modprobe        state:R  running task     stack:23696 pid:15731 ppid:4658   flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562
 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6874
 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:mt_validate_nulls arch/x86/include/asm/atomic.h:-1 [inline]
RIP: 0010:mt_validate+0x4447/0x4cb0 lib/maple_tree.c:7249
Code: 97 be 04 00 00 00 e8 48 68 b9 f7 f0 ff 05 01 85 ec 0c 48 c7 c7 e0 7b 06 97 be 04 00 00 00 e8 30 68 b9 f7 f0 ff 05 09 85 ec 0c <48> bb 00 00 00 00 00 fc ff df 4c 8b b4 24 b8 00 00 00 45 89 f7 41
RSP: 0018:ffffc9000c5df480 EFLAGS: 00000207
RAX: ffffffff8a19f601 RBX: 0000000000000005 RCX: ffffffff8a19f6d0
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffffff97067be0
RBP: ffffc9000c5df630 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff2e0cf7c R12: ffff88801dbe96d8
R13: ffff888060418080 R14: 0000000000000001 R15: 0000000000000300
 validate_mm_mt+0xe2/0x440 mm/mmap.c:295
 __split_vma+0x30/0x500 mm/mmap.c:2355
 do_mas_align_munmap+0x7b9/0x12b0 mm/mmap.c:2501
 do_mas_munmap+0x240/0x2b0 mm/mmap.c:2650
 __mmap_region mm/mmap.c:2698 [inline]
 mmap_region+0x6e0/0x1ca0 mm/mmap.c:2916
 do_mmap+0x964/0xfd0 mm/mmap.c:1436
 vm_mmap_pgoff+0x1c1/0x2d0 mm/util.c:520
 ksys_mmap_pgoff+0x516/0x6f0 mm/mmap.c:1482
 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: 0033:0x7fe80037b242
RSP: 002b:00007ffe64b372a8 EFLAGS: 00000206 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007fe800088000 RCX: 00007fe80037b242
RDX: 0000000000000003 RSI: 0000000000002000 RDI: 00007fe800088000
RBP: 0000000000000812 R08: 0000000000000000 R09: 000000000002c000
R10: 0000000000000812 R11: 0000000000000206 R12: 00007ffe64b37368
R13: 00007fe800358ab0 R14: 00007ffe64b37720 R15: 00000fffcc966e58
 </TASK>
task:modprobe        state:R  running task     stack:24336 pid:15730 ppid:4495   flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562
 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6874
 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:lock_acquire+0x225/0x4a0 kernel/locking/lockdep.c:5666
Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3d 04 f8 0f 85 f0 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 44 3d 00 00 00 00 00 43 c7 44 3d 08 00 00 00 00 65 48 8b 04
RSP: 0018:ffffc9000c60f0e0 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 87568367f20f4100
RDX: 0000000000000000 RSI: ffffffff8a8c23a0 RDI: ffffffff8adf0c20
RBP: ffffc9000c60f1f8 R08: dffffc0000000000 R09: 1ffffffff215e648
R10: dffffc0000000000 R11: fffffbfff215e649 R12: 0000000000000001
R13: 1ffff920018c1e28 R14: 0000000000000246 R15: dffffc0000000000
 rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 rcu_read_lock include/linux/rcupdate.h:791 [inline]
 is_bpf_text_address+0x43/0x2a0 kernel/bpf/core.c:735
 kernel_text_address+0x9c/0xd0 kernel/extable.c:125
 __kernel_text_address+0x9/0x30 kernel/extable.c:79
 unwind_get_return_address+0x49/0x80 arch/x86/kernel/unwind_orc.c:323
 arch_stack_walk+0xf2/0x140 arch/x86/kernel/stacktrace.c:26
 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_slab_alloc+0x6b/0x80 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook+0x4b/0x480 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+0x123/0x2f0 mm/slub.c:3383
 mt_alloc_one lib/maple_tree.c:154 [inline]
 mas_alloc_nodes+0x2ec/0x890 lib/maple_tree.c:1279
 mas_node_count_gfp lib/maple_tree.c:1361 [inline]
 mas_preallocate+0x161/0x3c0 lib/maple_tree.c:5809
 do_mas_align_munmap+0x239/0x12b0 mm/mmap.c:2453
 do_mas_munmap+0x240/0x2b0 mm/mmap.c:2650
 __mmap_region mm/mmap.c:2698 [inline]
 mmap_region+0x6e0/0x1ca0 mm/mmap.c:2916
 do_mmap+0x964/0xfd0 mm/mmap.c:1436
 vm_mmap_pgoff+0x1c1/0x2d0 mm/util.c:520
 ksys_mmap_pgoff+0x516/0x6f0 mm/mmap.c:1482
 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: 0033:0x7f7117ce9242
RSP: 002b:00007fffd369d678 EFLAGS: 00000206 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007f7117a15000 RCX: 00007f7117ce9242
RDX: 0000000000000005 RSI: 0000000000008000 RDI: 00007f7117a15000
RBP: 0000000000000812 R08: 0000000000000000 R09: 0000000000003000
R10: 0000000000000812 R11: 0000000000000206 R12: 00007fffd369d6c8
R13: 00007f7117cc5b20 R14: 00007fffd369dab0 R15: 00000ffffa6d3ad2
 </TASK>
rcu: rcu_preempt kthread starved for 10591 jiffies! g92533 f0x0 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:26992 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562
 schedule+0xb9/0x180 kernel/sched/core.c:6638
 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2168
 rcu_gp_fqs_loop+0x303/0x1340 kernel/rcu/tree.c:1706
 rcu_gp_kthread+0x99/0x3b0 kernel/rcu/tree.c:1905
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:default_idle+0xb/0x10 arch/x86/kernel/process.c:742
Code: 48 89 df e8 a7 10 9d f7 e9 44 ff ff ff e8 7d 07 f6 ff 00 00 cc cc 00 00 cc cc 00 00 cc cc 00 66 90 0f 00 2d 87 5d 50 00 fb f4 <c3> 0f 1f 40 00 41 57 41 56 53 49 be 00 00 00 00 00 fc ff df 65 48
RSP: 0018:ffffffff8c807d88 EFLAGS: 000002c6
RAX: ed6f06be66559200 RBX: ffffffff8a3651a7 RCX: ed6f06be66559200
RDX: 0000000000000001 RSI: ffffffff8a8c1220 RDI: ffffffff8adf0c20
RBP: ffffffff8c807ec0 R08: ffff8880b8e3580b R09: 1ffff110171c6b01
R10: dffffc0000000000 R11: ffffed10171c6b02 R12: 1ffffffff1900fbc
R13: dffffc0000000000 R14: ffffffff8c8bc740 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007feccfee9a90 CR3: 000000007ef43000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 default_idle_call+0x84/0xc0 kernel/sched/idle.c:109
 cpuidle_idle_call kernel/sched/idle.c:191 [inline]
 do_idle+0x20d/0x5a0 kernel/sched/idle.c:303
 cpu_startup_entry+0x3f/0x60 kernel/sched/idle.c:401
 rest_init+0x2dc/0x300 init/main.c:745
 arch_call_rest_init+0xa/0xa init/main.c:905
 start_kernel+0x493/0x53c init/main.c:1152
 secondary_startup_64_no_verify+0xcf/0xdb
 </TASK>

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/02/03 18:40 linux-6.1.y cd9b81672742 6df4c87a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_sendmmsg
2025/11/28 13:26 linux-6.1.y f6e38ae624cf d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_sendmmsg
2026/03/05 03:54 linux-6.1.y 2f66dd9cff42 a9fe5c9e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: rcu detected stall in sys_sendmmsg
* Struck through repros no longer work on HEAD.