syzbot


INFO: rcu detected stall in __sock_create

Status: upstream: reported on 2025/08/10 05:00
Reported-by: syzbot+774bbafa0eb4d80bd2c4@syzkaller.appspotmail.com
First crash: 250d, last: 5d22h
Similar bugs (9)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 INFO: rcu detected stall in __sock_create (3) 1 14 4d13h 243d 0/3 upstream: reported on 2025/08/16 13:35
upstream INFO: rcu detected stall in __sock_create mm 1 1 2325d 2325d 0/29 closed as invalid on 2019/12/04 14:04
linux-5.15 INFO: rcu detected stall in __sock_create (2) 1 11 37d 245d 0/3 upstream: reported on 2025/08/14 08:18
upstream INFO: rcu detected stall in __sock_create (3) mm 1 21 390d 625d 0/29 auto-obsoleted due to no activity on 2025/06/20 21:57
upstream INFO: rcu detected stall in __sock_create (2) mm 1 2 2291d 2291d 0/29 closed as invalid on 2020/01/08 05:33
linux-5.15 INFO: rcu detected stall in __sock_create 1 1 694d 694d 0/3 auto-obsoleted due to no activity on 2024/08/30 14:48
linux-6.1 INFO: rcu detected stall in __sock_create 1 3 562d 664d 0/3 auto-obsoleted due to no activity on 2025/01/09 18:19
linux-6.1 INFO: rcu detected stall in __sock_create (2) 1 2 399d 432d 0/3 auto-obsoleted due to no activity on 2025/06/22 07:20
android-5-15 BUG: soft lockup in __sock_create 1 18 592d 728d 0/2 auto-obsoleted due to no activity on 2024/11/30 09:28

Sample crash report:
bridge0: received packet on veth0_to_bridge with own address as source address (addr:e6:bb:db:4d:8d:af, vlan:0)
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): P6947/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=14381, q=757 ncpus=2)
task:syz.0.312       state:R  running task     stack:27816 pid:6947  ppid:6939   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
 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
 _raw_spin_unlock+0x3a/0x40 kernel/locking/spinlock.c:186
 spin_unlock include/linux/spinlock.h:391 [inline]
 zap_pte_range mm/memory.c:1523 [inline]
 zap_pmd_range mm/memory.c:1571 [inline]
 zap_pud_range mm/memory.c:1600 [inline]
 zap_p4d_range mm/memory.c:1621 [inline]
 unmap_page_range+0x2315/0x3000 mm/memory.c:1642
 unmap_vmas+0x286/0x3f0 mm/memory.c:1732
 exit_mmap+0x238/0xb90 mm/mmap.c:3302
 __mmput+0x118/0x3c0 kernel/fork.c:1355
 exit_mm+0x1f2/0x2c0 kernel/exit.c:569
 do_exit+0x8dd/0x2460 kernel/exit.c:870
 __do_sys_exit kernel/exit.c:991 [inline]
 __se_sys_exit kernel/exit.c:989 [inline]
 __x64_sys_exit+0x40/0x40 kernel/exit.c:989
 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: 0033:0x7f431819c819
RSP: 002b:00007f4318f76fd8 EFLAGS: 00000246 ORIG_RAX: 000000000000003c
RAX: ffffffffffffffda RBX: 00007f4318415fa0 RCX: 00007f431819c819
RDX: 00007f4318f779c8 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f4318232c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4318416038 R14: 00007f4318415fa0 R15: 00007fffc327de28
 </TASK>
rcu: rcu_preempt kthread starved for 5344 jiffies! g14381 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:26920 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: 0 PID: 6943 Comm: syz.2.322 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
RIP: 0010:unwind_next_frame+0x72b/0x2970 arch/x86/kernel/unwind_orc.c:512
Code: c0 0f 85 51 1c 00 00 41 0f b7 1f c1 eb 0b 80 e3 01 48 8b 44 24 38 42 0f b6 04 28 84 c0 0f 85 55 1c 00 00 48 8b 44 24 08 88 18 <45> 0f b7 37 41 83 e6 0f 4c 89 f7 48 c7 c6 a0 07 fa 8c e8 8e e7 4b
RSP: 0018:ffffc90000006d18 EFLAGS: 00000246
RAX: ffffc90000006e1d RBX: 0000000000000000 RCX: ffff88802cb9da00
RDX: 0000000000000100 RSI: ffffffff8cfa0780 RDI: 0000000000000002
RBP: ffffc90000006e38 R08: ffff88802cb9da00 R09: 0000000000000002
R10: 0000000000000001 R11: 0000000000000100 R12: ffffc90000006de8
R13: dffffc0000000000 R14: ffffffff8f97265b R15: ffffffff8f97265a
FS:  00007efe2c67d6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f24ad472ff8 CR3: 00000000268fb000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 arch_stack_walk+0x144/0x190 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:53
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:329
 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]
 slab_alloc mm/slub.c:3503 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3510 [inline]
 kmem_cache_alloc+0x11a/0x2d0 mm/slub.c:3519
 skb_clone+0x1eb/0x370 net/core/skbuff.c:1915
 deliver_clone net/bridge/br_forward.c:125 [inline]
 br_flood+0x415/0x670 net/bridge/br_forward.c:246
 br_handle_frame_finish+0x13c5/0x18f0 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+0x1245/0x14d0 net/bridge/br_input.c:424
 __netif_receive_skb_core+0xfab/0x3af0 net/core/dev.c:5528
 __netif_receive_skb_one_core net/core/dev.c:5632 [inline]
 __netif_receive_skb+0x74/0x290 net/core/dev.c:5748
 process_backlog+0x391/0x6f0 net/core/dev.c:6076
 __napi_poll+0xc0/0x460 net/core/dev.c:6638
 napi_poll net/core/dev.c:6705 [inline]
 net_rx_action+0x616/0xc40 net/core/dev.c:6841
 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:page_ext_next include/linux/page_ext.h:93 [inline]
RIP: 0010:__reset_page_owner+0x106/0x190 mm/page_owner.c:155
Code: 44 24 04 41 89 45 0c 49 83 c5 18 4c 89 e8 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 ef e8 93 ce f6 ff 48 8b 44 24 10 49 89 45 00 <42> 80 3c 23 00 0f 84 74 ff ff ff 48 c7 c7 80 59 33 97 e8 d3 cd f6
RSP: 0018:ffffc9000bcb7a68 EFLAGS: 00000246
RAX: 00000035bcf6f920 RBX: 1ffffffff2e66b30 RCX: ffffffff81e88a77
RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffff88801bcb8ff4
RBP: 0000000000000003 R08: ffff88801bcb8fe7 R09: 1ffff110037971fc
R10: dffffc0000000000 R11: ffffed10037971fd R12: dffffc0000000000
R13: ffff88801bcb9000 R14: 0000000000000003 R15: ffff88801bcb8fe0
 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
 discard_slab mm/slub.c:2127 [inline]
 __unfreeze_partials+0x1cf/0x210 mm/slub.c:2667
 put_cpu_partial+0x17c/0x250 mm/slub.c:2743
 __slab_free+0x319/0x400 mm/slub.c:3700
 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]
 slab_alloc mm/slub.c:3503 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3510 [inline]
 kmem_cache_alloc_lru+0x111/0x2d0 mm/slub.c:3526
 alloc_inode_sb include/linux/fs.h:2946 [inline]
 sock_alloc_inode+0x28/0xc0 net/socket.c:308
 alloc_inode fs/inode.c:261 [inline]
 new_inode_pseudo+0x63/0x1d0 fs/inode.c:1049
 sock_alloc net/socket.c:634 [inline]
 __sock_create+0x12d/0x940 net/socket.c:1534
 sock_create net/socket.c:1626 [inline]
 __sys_socketpair+0x236/0x550 net/socket.c:1781
 __do_sys_socketpair net/socket.c:1830 [inline]
 __se_sys_socketpair net/socket.c:1827 [inline]
 __x64_sys_socketpair+0x9b/0xb0 net/socket.c:1827
 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: 0033:0x7efe2b79c819
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:00007efe2c67d028 EFLAGS: 00000246 ORIG_RAX: 0000000000000035
RAX: ffffffffffffffda RBX: 00007efe2ba15fa0 RCX: 00007efe2b79c819
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000001
RBP: 00007efe2b832c91 R08: 0000000000000000 R09: 0000000000000000
R10: 00002000000002c0 R11: 0000000000000246 R12: 0000000000000000
R13: 00007efe2ba16038 R14: 00007efe2ba15fa0 R15: 00007ffe181f9128
 </TASK>
net_ratelimit: 9316 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:e6:bb:db:4d:8d:af, 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:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:e6:bb:db:4d:8d:af, vlan:0)
net_ratelimit: 11551 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:e6:bb:db:4d:8d:af, 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:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:e6:bb:db:4d:8d:af, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)

Crashes (12):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/04/11 10:02 linux-6.6.y 80de0a958133 38c8e246 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in __sock_create
2026/04/09 05:22 linux-6.6.y 80de0a958133 38c8e246 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in __sock_create
2026/03/22 06:45 linux-6.6.y 4fc00fe35d46 5b92003d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in __sock_create
2026/02/16 06:06 linux-6.6.y 1b4ef5214f17 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in __sock_create
2026/01/26 15:32 linux-6.6.y cbb31f77b879 a4c52dd6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in __sock_create
2026/01/25 13:34 linux-6.6.y cbb31f77b879 40acda8a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in __sock_create
2025/10/19 19:11 linux-6.6.y f231f248323d 1c8c8cd8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in __sock_create
2025/08/27 11:31 linux-6.6.y bb9c90ab9c5a e12e5ba4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in __sock_create
2025/08/13 23:58 linux-6.6.y 3a8ababb8b6a 22ec1469 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in __sock_create
2025/08/11 20:15 linux-6.6.y 3a8ababb8b6a c06e8995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in __sock_create
2025/08/10 07:14 linux-6.6.y 3a8ababb8b6a 32a0e5ed .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in __sock_create
2025/08/10 04:59 linux-6.6.y 3a8ababb8b6a 32a0e5ed .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in __sock_create
* Struck through repros no longer work on HEAD.