syzbot


INFO: rcu detected stall in sendmsg

Status: upstream: reported on 2025/07/31 17:16
Reported-by: syzbot+e8d3f56cde2a4d5e38ae@syzkaller.appspotmail.com
First crash: 194d, last: 7d03h
Similar bugs (21)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 INFO: rcu detected stall in sendmsg (5) 1 syz 13 17h46m 232d 0/3 upstream: reported syz repro on 2025/06/23 07:43
linux-6.1 INFO: rcu detected stall in sendmsg (3) 1 4 497d 564d 0/3 auto-obsoleted due to no activity on 2025/01/09 18:13
upstream INFO: rcu detected stall in sendmsg net 1 1 1589d 1589d 0/29 auto-closed as invalid on 2022/01/03 17:11
linux-6.1 INFO: rcu detected stall in sendmsg (4) 1 2 336d 347d 0/3 auto-obsoleted due to no activity on 2025/06/19 03:57
linux-6.1 INFO: rcu detected stall in sendmsg (2) 1 1 686d 686d 0/3 auto-obsoleted due to no activity on 2024/07/04 03:49
upstream INFO: rcu detected stall in sendmsg (2) batman 1 1 1459d 1459d 0/29 auto-closed as invalid on 2022/05/13 12:25
upstream INFO: rcu detected stall in sendmsg (4) mm 1 C error 62 16d 627d 0/29 upstream: reported C repro on 2024/05/24 06:18
upstream INFO: rcu detected stall in sendmsg (3) net 1 4 736d 820d 0/29 auto-obsoleted due to no activity on 2024/05/05 18:15
linux-5.15 INFO: rcu detected stall in sys_sendmsg origin:upstream 1 C error 32 17d 693d 0/3 upstream: reported C repro on 2024/03/19 21:37
linux-6.1 INFO: rcu detected stall in sendmsg 1 1 921d 921d 0/3 auto-obsoleted due to no activity on 2023/11/12 19:28
upstream BUG: soft lockup in sys_sendmsg (2) net 1 C error 33 9h55m 250d 0/29 upstream: reported C repro on 2025/06/05 02:15
upstream INFO: rcu detected stall in sys_sendmsg (2) cgroups mm 1 5 2260d 2262d 0/29 closed as invalid on 2019/12/04 14:14
upstream INFO: rcu detected stall in sys_sendmsg (3) kernel 1 1 2225d 2225d 0/29 closed as invalid on 2020/01/08 05:33
linux-6.1 INFO: rcu detected stall in sys_sendmsg 1 6 500d 586d 0/3 auto-obsoleted due to no activity on 2025/01/06 11:24
upstream INFO: rcu detected stall in sys_sendmsg net 1 C done 2 2341d 2342d 13/29 fixed on 2019/10/09 10:54
android-6-1 BUG: soft lockup in sys_sendmsg origin:upstream 1 C 3 645d 672d 0/2 upstream: reported C repro on 2024/04/09 06:46
linux-6.1 BUG: soft lockup in sys_sendmsg 1 2 974d 980d 0/3 auto-obsoleted due to no activity on 2023/09/20 17:26
android-5-10 BUG: soft lockup in sys_sendmsg 1 C error 61 39d 690d 0/2 upstream: reported C repro on 2024/03/22 10:41
upstream BUG: soft lockup in sys_sendmsg tipc batman 1 C 3 688d 729d 25/29 fixed on 2024/05/22 23:36
android-5-15 BUG: soft lockup in sys_sendmsg origin:upstream 1 C error 13 516d 690d 0/2 upstream: reported C repro on 2024/03/22 10:44
linux-6.1 BUG: soft lockup in sys_sendmsg (2) origin:upstream 1 C done 1 675d 675d 3/3 fixed on 2024/05/15 09:17

Sample crash report:
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P5886/1:b..l P5137/1:b..l
rcu: 	(detected by 1, t=10502 jiffies, g=10549, q=725 ncpus=2)
task:udevd           state:R  running task     stack:25160 pid:5137  ppid:1      flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5381 [inline]
 __schedule+0x1553/0x45a0 kernel/sched/core.c:6700
 preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6867
 preempt_schedule+0xc0/0xd0 kernel/sched/core.c:6891
 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45
 unwind_next_frame+0x200f/0x2970 arch/x86/kernel/unwind_orc.c:672
 arch_stack_walk+0x144/0x190 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122
 save_stack+0x125/0x230 mm/page_owner.c:128
 __reset_page_owner+0x4e/0x190 mm/page_owner.c:149
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1181 [inline]
 free_unref_page_prepare+0x7b2/0x8c0 mm/page_alloc.c:2365
 free_unref_page+0x32/0x2e0 mm/page_alloc.c:2458
 __slab_free+0x35a/0x400 mm/slub.c:3736
 qlink_free mm/kasan/quarantine.c:166 [inline]
 qlist_free_all+0x75/0xd0 mm/kasan/quarantine.c:185
 kasan_quarantine_reduce+0x143/0x160 mm/kasan/quarantine.c:292
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:306
 kasan_slab_alloc include/linux/kasan.h:188 [inline]
 slab_post_alloc_hook+0x6e/0x4b0 mm/slab.h:767
 slab_alloc_node mm/slub.c:3495 [inline]
 __kmem_cache_alloc_node+0x13a/0x250 mm/slub.c:3534
 __do_kmalloc_node mm/slab_common.c:1006 [inline]
 __kmalloc+0xa4/0x230 mm/slab_common.c:1020
 kmalloc include/linux/slab.h:604 [inline]
 tomoyo_realpath_from_path+0xe3/0x5d0 security/tomoyo/realpath.c:251
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_path_perm+0x282/0x560 security/tomoyo/file.c:822
 security_inode_getattr+0xd3/0x120 security/security.c:2153
 vfs_getattr fs/stat.c:173 [inline]
 vfs_statx+0x172/0x680 fs/stat.c:248
 vfs_fstatat+0x12a/0x1b0 fs/stat.c:299
 __do_sys_newfstatat fs/stat.c:463 [inline]
 __se_sys_newfstatat fs/stat.c:457 [inline]
 __x64_sys_newfstatat+0x149/0x1f0 fs/stat.c:457
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f6d44111b0a
RSP: 002b:00007fffa34c11e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000106
RAX: ffffffffffffffda RBX: 0000559405b3d400 RCX: 00007f6d44111b0a
RDX: 00007fffa34c11f0 RSI: 0000559405b2b296 RDI: 00000000ffffff9c
RBP: 00005594428a7148 R08: 0000000005d74dca R09: 0000000000745d1e
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007fffa34c11f0 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
task:syz.2.9         state:R  running task     stack:26440 pid:5886  ppid:5769   flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5381 [inline]
 __schedule+0x1553/0x45a0 kernel/sched/core.c:6700
 preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6867
 preempt_schedule+0xc0/0xd0 kernel/sched/core.c:6891
 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45
 __local_bh_enable_ip+0x14b/0x1c0 kernel/softirq.c:413
 spin_unlock_bh include/linux/spinlock.h:396 [inline]
 nl80211_netlink_notify+0x6fa/0x840 net/wireless/nl80211.c:20028
 notifier_call_chain+0x197/0x380 kernel/notifier.c:93
 blocking_notifier_call_chain+0x6a/0x90 kernel/notifier.c:388
 netlink_release+0x1279/0x1ad0 net/netlink/af_netlink.c:767
 __sock_release net/socket.c:659 [inline]
 sock_close+0xbd/0x230 net/socket.c:1420
 __fput+0x234/0x970 fs/file_table.c:384
 task_work_run+0x1d4/0x260 kernel/task_work.c:245
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
 do_syscall_64+0x61/0xa0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f167db9aeb9
RSP: 002b:00007f167bdd5028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: 0000000000000000 RBX: 00007f167de16180 RCX: 00007f167db9aeb9
RDX: 0000200000002280 RSI: 0000000000008943 RDI: 0000000000000007
RBP: 00007f167dc08c1f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f167de16218 R14: 00007f167de16180 R15: 00007ffe177b7e88
 </TASK>
rcu: rcu_preempt kthread starved for 2781 jiffies! g10549 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
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:27656 pid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5381 [inline]
 __schedule+0x1553/0x45a0 kernel/sched/core.c:6700
 schedule+0xbd/0x170 kernel/sched/core.c:6774
 schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168
 rcu_gp_fqs_loop+0x313/0x1590 kernel/rcu/tree.c:1667
 rcu_gp_kthread+0x9d/0x3b0 kernel/rcu/tree.c:1866
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 PID: 5891 Comm: syz.3.11 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xc0/0x120 kernel/locking/spinlock.c:194
Code: c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 41 c6 04 07 f8 75 4b f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> cb 99 ce f6 65 8b 05 9c d0 75 75 85 c0 74 3c 48 c7 04 24 0e 36
RSP: 0018:ffffc900001ef820 EFLAGS: 00000206
RAX: dffffc0000000004 RBX: 0000000000000a02 RCX: 34100e4b78249200
RDX: dffffc0000000000 RSI: ffffffff8acac900 RDI: 0000000000000001
RBP: ffffc900001ef8a0 R08: ffffffff911bf5c7 R09: 1ffffffff2237eb8
R10: dffffc0000000000 R11: fffffbfff2237eb9 R12: dffffc0000000000
R13: ffff888057a88a00 R14: ffffffff9755b658 R15: 1ffff9200003df04
FS:  00007fe3968b16c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2d70aff8 CR3: 000000005d93d000 CR4: 00000000003506e0
Call Trace:
 <IRQ>
 __debug_check_no_obj_freed lib/debugobjects.c:999 [inline]
 debug_check_no_obj_freed+0x51f/0x540 lib/debugobjects.c:1020
 slab_free_hook mm/slub.c:1786 [inline]
 slab_free_freelist_hook+0xd2/0x1a0 mm/slub.c:1837
 slab_free mm/slub.c:3830 [inline]
 kmem_cache_free+0xf8/0x270 mm/slub.c:3852
 skb_ext_del include/linux/skbuff.h:4786 [inline]
 nf_bridge_info_free net/bridge/br_netfilter_hooks.c:152 [inline]
 br_nf_dev_queue_xmit+0x492/0x1b80 net/bridge/br_netfilter_hooks.c:-1
 NF_HOOK+0x66e/0x700 include/linux/netfilter.h:304
 br_nf_post_routing+0xb41/0xfb0 net/bridge/br_netfilter_hooks.c:977
 nf_hook_entry_hookfn include/linux/netfilter.h:144 [inline]
 nf_hook_slow+0xbd/0x200 net/netfilter/core.c:626
 nf_hook include/linux/netfilter.h:259 [inline]
 NF_HOOK+0x23e/0x3e0 include/linux/netfilter.h:302
 br_forward_finish+0xd3/0x130 net/bridge/br_forward.c:66
 br_nf_hook_thresh net/bridge/br_netfilter_hooks.c:1184 [inline]
 br_nf_forward_finish+0xa51/0xe80 net/bridge/br_netfilter_hooks.c:684
 NF_HOOK+0x66e/0x700 include/linux/netfilter.h:304
 br_nf_forward_ip+0xcc1/0x1110 net/bridge/br_netfilter_hooks.c:754
 nf_hook_entry_hookfn include/linux/netfilter.h:144 [inline]
 nf_hook_slow+0xbd/0x200 net/netfilter/core.c:626
 nf_hook include/linux/netfilter.h:259 [inline]
 NF_HOOK+0x23e/0x3e0 include/linux/netfilter.h:302
 __br_forward+0x433/0x610 net/bridge/br_forward.c:115
 br_handle_frame_finish+0x149b/0x19b0 net/bridge/br_input.c:215
 br_nf_hook_thresh+0x3cd/0x4a0 net/bridge/br_netfilter_hooks.c:1184
 br_nf_pre_routing_finish_ipv6+0x9dc/0xd00 net/bridge/br_netfilter_ipv6.c:-1
 NF_HOOK include/linux/netfilter.h:304 [inline]
 br_nf_pre_routing_ipv6+0x349/0x6b0 net/bridge/br_netfilter_ipv6.c:184
 nf_hook_entry_hookfn include/linux/netfilter.h:144 [inline]
 nf_hook_bridge_pre net/bridge/br_input.c:277 [inline]
 br_handle_frame+0x96b/0x14e0 net/bridge/br_input.c:424
 __netif_receive_skb_core+0xfab/0x3af0 net/core/dev.c:5545
 __netif_receive_skb_one_core net/core/dev.c:5649 [inline]
 __netif_receive_skb+0x74/0x290 net/core/dev.c:5765
 process_backlog+0x396/0x700 net/core/dev.c:6093
 __napi_poll+0xc0/0x460 net/core/dev.c:6655
 napi_poll net/core/dev.c:6722 [inline]
 net_rx_action+0x616/0xc50 net/core/dev.c:6859
 handle_softirqs+0x280/0x820 kernel/softirq.c:578
 __do_softirq kernel/softirq.c:612 [inline]
 invoke_softirq kernel/softirq.c:452 [inline]
 __irq_exit_rcu+0xd3/0x190 kernel/softirq.c:661
 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
 sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:lock_acquire+0x208/0x420 kernel/locking/lockdep.c:5758
Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3c 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 04 3c 00 00 00 00 43 c7 44 3c 08 00 00 00 00 65 48 8b 04 25
RSP: 0018:ffffc90004c4f1a0 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 34100e4b78249200
RDX: 0000000000000000 RSI: ffffffff8acada80 RDI: ffffffff8b1c81e0
RBP: ffffc90004c4f2b8 R08: dffffc0000000000 R09: 1ffffffff2237eb8
R10: dffffc0000000000 R11: fffffbfff2237eb9 R12: 1ffff92000989e40
R13: ffffffff8e3c02c0 R14: 0000000000000246 R15: dffffc0000000000
 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
 _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
 __mutex_lock_common kernel/locking/mutex.c:699 [inline]
 __mutex_lock+0x5e7/0xcc0 kernel/locking/mutex.c:747
 tipc_nl_bearer_enable+0x17/0x30 net/tipc/bearer.c:1055
 genl_family_rcv_msg_doit+0x211/0x310 net/netlink/genetlink.c:971
 genl_family_rcv_msg net/netlink/genetlink.c:1051 [inline]
 genl_rcv_msg+0x619/0x7a0 net/netlink/genetlink.c:1066
 netlink_rcv_skb+0x241/0x4d0 net/netlink/af_netlink.c:2545
 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1075
 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
 netlink_unicast+0x751/0x8d0 net/netlink/af_netlink.c:1346
 netlink_sendmsg+0x8d0/0xbf0 net/netlink/af_netlink.c:1894
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 ____sys_sendmsg+0x5ba/0x960 net/socket.c:2594
 ___sys_sendmsg+0x2a6/0x360 net/socket.c:2648
 __sys_sendmsg net/socket.c:2677 [inline]
 __do_sys_sendmsg net/socket.c:2686 [inline]
 __se_sys_sendmsg+0x1c2/0x2b0 net/socket.c:2684
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fe39599aeb9
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:00007fe3968b1028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fe395c16090 RCX: 00007fe39599aeb9
RDX: 0000000000000000 RSI: 0000200000000000 RDI: 0000000000000007
RBP: 00007fe395a08c1f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe395c16128 R14: 00007fe395c16090 R15: 00007ffeab02c208
 </TASK>
net_ratelimit: 5726 callbacks suppressed
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/02/03 20:45 linux-6.6.y 2cf6f68313dc 6df4c87a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in sendmsg
2025/12/14 05:51 linux-6.6.y 5fa4793a2d2d d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in sendmsg
2025/11/19 17:46 linux-6.6.y 0a805b6ea8cd 26ee5237 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in sendmsg
2025/08/22 19:57 linux-6.6.y bb9c90ab9c5a bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in sendmsg
2025/07/31 17:15 linux-6.6.y dbcb8d8e4163 0c075d67 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in sendmsg
* Struck through repros no longer work on HEAD.