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INFO: rcu detected stall in br_handle_frame (2)

Status: upstream: reported on 2025/10/06 18:18
Reported-by: syzbot+f80e255c3d4ba8ded1e0@syzkaller.appspotmail.com
First crash: 116d, last: 2d12h
▶ ▼ Similar bugs (15)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in br_handle_frame (5) bridge 1 syz 24 447d 475d 28/29 fixed on 2024/11/12 23:31
linux-4.14 INFO: rcu detected stall in br_handle_frame (3) 1 1 1948d 1948d 0/1 auto-closed as invalid on 2021/01/28 07:46
upstream INFO: rcu detected stall in br_handle_frame 1 C done 341 2329d 2334d 13/29 fixed on 2019/10/09 10:54
upstream INFO: rcu detected stall in br_handle_frame (2) net 1 C done 2 2233d 2229d 15/29 fixed on 2020/02/18 14:31
upstream INFO: rcu detected stall in br_handle_frame (3) bridge 1 1 1658d 1658d 0/29 auto-closed as invalid on 2021/10/15 13:41
linux-4.14 INFO: rcu detected stall in br_handle_frame (2) 1 C done 1 2234d 2234d 1/1 fixed on 2020/01/19 15:05
linux-4.14 INFO: rcu detected stall in br_handle_frame 1 C done 15 2326d 2338d 1/1 fixed on 2019/12/07 19:24
linux-4.19 INFO: rcu detected stall in br_handle_frame (2) 1 C error 31 1093d 1934d 0/1 upstream: reported C repro on 2020/10/14 18:56
linux-4.19 INFO: rcu detected stall in br_handle_frame 1 C done 41 2326d 2338d 1/1 fixed on 2019/12/07 19:18
linux-5.15 INFO: rcu detected stall in br_handle_frame origin:lts-only 1 C inconclusive 3 72d 722d 0/3 upstream: reported C repro on 2024/02/08 13:52
upstream INFO: rcu detected stall in br_handle_frame (6) bridge 1 C error 52 12d 17d 0/29 upstream: reported C repro on 2026/01/13 18:06
linux-6.1 INFO: rcu detected stall in br_handle_frame 1 2 522d 604d 0/3 auto-obsoleted due to no activity on 2024/12/04 21:21
upstream INFO: rcu detected stall in br_handle_frame (4) kernel 1 1 1497d 1497d 0/29 closed as invalid on 2022/02/08 10:10
linux-6.6 INFO: rcu detected stall in br_handle_frame 1 8 3d11h 71d 0/2 upstream: reported on 2025/11/21 04:49
android-5-15 BUG: soft lockup in br_handle_frame 1 2 531d 536d 0/2 auto-obsoleted due to no activity on 2024/11/16 05:31

Sample crash report:
rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 1-.... } 2712 jiffies s: 2257 root: 0x2/.
rcu: blocking rcu_node structures (internal RCU debug):
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 4487 Comm: syz.4.26 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:pvclock_clocksource_read+0xa/0x760 arch/x86/kernel/pvclock.c:68
Code: 08 e9 f3 fe ff ff 22 05 cc f5 e6 0c 48 83 c4 18 5b 41 5c 41 5d 41 5e 41 5f 5d c3 0f 1f 44 00 00 55 41 57 41 56 41 55 41 54 53 <48> 81 ec a0 00 00 00 4c 8d 47 08 4c 8d 4f 18 48 8d 77 1c 4c 8d 57
RSP: 0018:ffffc900001e01a0 EFLAGS: 00000006
RAX: f3f3f3f8f1f1f1f1 RBX: ffffc900001e0220 RCX: 851b6158cb3ddb00
RDX: 0000000000000000 RSI: ffffffff8adf0c00 RDI: ffffffff8fa08040
RBP: ffffc900001e0298 R08: ffffffff8e1fc32f R09: 1ffffffff1c3f865
R10: dffffc0000000000 R11: fffffbfff1c3f866 R12: dffffc0000000000
R13: dffffc0000000000 R14: 1ffff9200003c040 R15: ffffffff8c64f988
FS:  00007f7d4da456c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f877b72f040 CR3: 000000005c480000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 kvm_clock_read arch/x86/kernel/kvmclock.c:79 [inline]
 kvm_sched_clock_read+0x14/0x40 arch/x86/kernel/kvmclock.c:91
 sched_clock_cpu+0x6e/0x260 kernel/sched/clock.c:369
 irqtime_account_irq+0x6a/0x1b0 kernel/sched/cputime.c:60
 account_hardirq_exit include/linux/vtime.h:159 [inline]
 __irq_exit_rcu+0x99/0x230 kernel/softirq.c:676
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:691
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
 sysvec_apic_timer_interrupt+0x52/0xc0 arch/x86/kernel/apic/apic.c:1118
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:rht_ptr_rcu include/linux/rhashtable.h:369 [inline]
RIP: 0010:__rhashtable_lookup include/linux/rhashtable.h:599 [inline]
RIP: 0010:rhashtable_lookup include/linux/rhashtable.h:638 [inline]
RIP: 0010:rhashtable_lookup_fast+0x363/0x930 include/linux/rhashtable.h:664
Code: 84 c1 80 00 00 00 48 89 c1 48 83 c9 01 48 89 4c 24 40 48 89 44 24 78 48 c1 e8 03 48 89 44 24 70 48 8b 44 24 70 42 80 3c 20 00 <48> 8b 5c 24 78 74 08 48 89 df e8 ee ff cf f8 4c 8b 3b e8 16 fd 28
RSP: 0018:ffffc900001e0440 EFLAGS: 00000246
RAX: 1ffff1100b48e7f1 RBX: 00000000000007e1 RCX: ffff88805a473f89
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900001e05a8 R08: ffff888019301dc0 R09: 0000000000000004
R10: 0000000000000003 R11: 0000000000000100 R12: dffffc0000000000
R13: ffffffff890373c0 R14: 0000000000000000 R15: ffff88802bdb4800
 ila_lookup_wildcards net/ipv6/ila/ila_xlat.c:133 [inline]
 ila_xlat_addr net/ipv6/ila/ila_xlat.c:664 [inline]
 ila_nf_input+0x1ea/0x3a0 net/ipv6/ila/ila_xlat.c:191
 nf_hook_entry_hookfn include/linux/netfilter.h:142 [inline]
 nf_hook_slow+0xb9/0x200 net/netfilter/core.c:614
 nf_hook include/linux/netfilter.h:257 [inline]
 NF_HOOK include/linux/netfilter.h:300 [inline]
 br_nf_pre_routing_ipv6+0x55f/0x6b0 net/bridge/br_netfilter_ipv6.c:243
 nf_hook_entry_hookfn include/linux/netfilter.h:142 [inline]
 nf_hook_bridge_pre net/bridge/br_input.c:260 [inline]
 br_handle_frame+0x919/0x1360 net/bridge/br_input.c:406
 __netif_receive_skb_core+0x1004/0x38f0 net/core/dev.c:5475
 __netif_receive_skb_one_core net/core/dev.c:5579 [inline]
 __netif_receive_skb+0x74/0x290 net/core/dev.c:5695
 process_backlog+0x38d/0x6f0 net/core/dev.c:6023
 __napi_poll+0xc0/0x460 net/core/dev.c:6590
 napi_poll net/core/dev.c:6657 [inline]
 net_rx_action+0x5dd/0xb20 net/core/dev.c:6771
 handle_softirqs+0x2a1/0x930 kernel/softirq.c:596
 __do_softirq kernel/softirq.c:630 [inline]
 invoke_softirq kernel/softirq.c:470 [inline]
 __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:679
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:691
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
 sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:__sanitizer_cov_trace_pc+0x37/0x60 kernel/kcov.c:219
Code: 8b 15 c5 fc 7f 7e 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 1c 16 00 00 00 74 2c 8b 91 f8 15 00 00 83 fa 02 75 21 <48> 8b 91 00 16 00 00 48 8b 32 48 8d 7e 01 8b 89 fc 15 00 00 48 39
RSP: 0018:ffffc90004d4f538 EFLAGS: 00000246
RAX: ffffffff81bf19a1 RBX: 0000000000000060 RCX: ffff888019301dc0
RDX: 0000000000000002 RSI: 000000000007ffff RDI: 0000000000080000
RBP: ffffc90004d4f850 R08: ffffffff8e1fc32f R09: 1ffffffff1c3f865
R10: dffffc0000000000 R11: fffffbfff1c3f866 R12: 00007f7d4c41d000
R13: ffff88807d51d088 R14: 0000000000000010 R15: ffff88807d51d088
 copy_pte_range mm/memory.c:1110 [inline]
 copy_pmd_range mm/memory.c:1177 [inline]
 copy_pud_range mm/memory.c:1214 [inline]
 copy_p4d_range mm/memory.c:1238 [inline]
 copy_page_range+0x1951/0x3900 mm/memory.c:1332
 dup_mmap kernel/fork.c:702 [inline]
 dup_mm kernel/fork.c:1546 [inline]
 copy_mm+0xec3/0x1690 kernel/fork.c:1595
 copy_process+0x1979/0x4030 kernel/fork.c:2356
 kernel_clone+0x24b/0x900 kernel/fork.c:2762
 __do_sys_clone kernel/fork.c:2903 [inline]
 __se_sys_clone kernel/fork.c:2887 [inline]
 __x64_sys_clone+0x1a7/0x220 kernel/fork.c:2887
 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: 0033:0x7f7d4cb9aeb9
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:00007f7d4da44fd8 EFLAGS: 00000206 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007f7d4ce16090 RCX: 00007f7d4cb9aeb9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000001000
RBP: 00007f7d4cc08c1f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007f7d4ce16128 R14: 00007f7d4ce16090 R15: 00007ffc64dc54e8
 </TASK>

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/01/28 17:06 linux-6.1.y cd9b81672742 004c195c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in br_handle_frame
2026/01/25 14:09 linux-6.1.y cd9b81672742 40acda8a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in br_handle_frame
2025/12/08 16:59 linux-6.1.y 50cbba13faa2 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in br_handle_frame
2025/10/06 18:17 linux-6.1.y 882efbdd9d34 91305dbe .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in br_handle_frame
* Struck through repros no longer work on HEAD.