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INFO: rcu detected stall in sys_close_range

Status: upstream: reported C repro on 2025/08/13 16:29
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+793af646fd66df0b254e@syzkaller.appspotmail.com
First crash: 241d, last: 4d21h
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2025/12/22 linux-6.6.y (ToT) 5fa4793a2d2d C [report] INFO: rcu detected stall in smp_call_function
2025/12/22 upstream (ToT) 9448598b22c5 C Didn't crash
▶ ▼ Similar bugs (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in close_range fs 1 1 353d 353d 0/29 auto-obsoleted due to no activity on 2025/07/22 12:43
linux-6.1 INFO: rcu detected stall in sys_close_range (2) origin:lts-only 1 C error 2 5d04h 60d 0/3 upstream: reported C repro on 2026/02/10 20:38
linux-6.1 INFO: rcu detected stall in sys_close_range 1 C done 3 210d 404d 0/3 auto-obsoleted due to no activity on 2025/12/22 06:21
linux-5.15 INFO: rcu detected stall in sys_close_range origin:lts-only 1 syz error 3 87d 160d 0/3 upstream: reported syz repro on 2025/11/02 13:19
▶ ▼ Fix bisection attempts (2)
Created Duration User Patch Repo Result
2026/01/04 23:24 2h33m fix candidate upstream OK (0) job log
2025/11/19 15:50 2h26m (2) fix candidate upstream OK (0) job log

Sample crash report:
rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-....: (10498 ticks this GP) idle=9fe4/1/0x4000000000000000 softirq=11619/11620 fqs=4534
rcu: 	         hardirqs   softirqs   csw/system
rcu: 	 number:  1392052          0            0
rcu: 	cputime:    16660      35829           42   ==> 52490(ms)
rcu: 	(t=10500 jiffies g=10805 q=1114 ncpus=2)
CPU: 1 PID: 5931 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
RIP: 0010:seqcount_lockdep_reader_access+0x19a/0x1d0 include/linux/seqlock.h:105
Code: 00 4d 85 e4 75 16 e8 95 c6 0f 00 eb 15 e8 8e c6 0f 00 e8 19 ca 0e 09 4d 85 e4 74 ea e8 7f c6 0f 00 fb 48 c7 04 24 0e 36 e0 45 <4b> c7 04 3e 00 00 00 00 43 c7 44 3e 08 00 00 00 00 65 48 8b 04 25
RSP: 0018:ffffc900001ef860 EFLAGS: 00000246
RAX: ffffffff81775b51 RBX: 0000000000000000 RCX: ffff888078995a00
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900001ef918 R08: ffffffff911c4607 R09: 1ffffffff22388c0
R10: dffffc0000000000 R11: fffffbfff22388c1 R12: 0000000000000200
R13: 1ffff9200003df34 R14: 1ffff9200003df0c R15: dffffc0000000000
FS:  00005555842e2500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000001da15 CR3: 00000000771d5000 CR4: 00000000003506e0
Call Trace:
 <IRQ>
 timekeeping_get_delta kernel/time/timekeeping.c:254 [inline]
 timekeeping_get_ns kernel/time/timekeeping.c:388 [inline]
 ktime_get_with_offset+0x103/0x330 kernel/time/timekeeping.c:891
 ktime_get_real include/linux/timekeeping.h:79 [inline]
 netif_rx_internal+0x344/0x4e0 net/core/dev.c:5141
 __netif_rx+0x78/0xc0 net/core/dev.c:5184
 veth_forward_skb drivers/net/veth.c:325 [inline]
 veth_xmit+0x550/0x9f0 drivers/net/veth.c:378
 __netdev_start_xmit include/linux/netdevice.h:4943 [inline]
 netdev_start_xmit include/linux/netdevice.h:4957 [inline]
 xmit_one net/core/dev.c:3632 [inline]
 dev_hard_start_xmit+0x246/0x740 net/core/dev.c:3648
 __dev_queue_xmit+0x19a3/0x3660 net/core/dev.c:4442
 dev_queue_xmit include/linux/netdevice.h:3113 [inline]
 br_dev_queue_push_xmit+0x6b3/0x870 net/bridge/br_forward.c:53
 NF_HOOK+0x351/0x3e0 include/linux/netfilter.h:304
 br_forward_finish+0xd3/0x130 net/bridge/br_forward.c:66
 NF_HOOK+0x351/0x3e0 include/linux/netfilter.h:304
 __br_forward+0x433/0x610 net/bridge/br_forward.c:115
 deliver_clone net/bridge/br_forward.c:131 [inline]
 maybe_deliver+0xb5/0x150 net/bridge/br_forward.c:191
 br_flood+0x31b/0x670 net/bridge/br_forward.c:237
 br_dev_xmit+0x1294/0x1920 net/bridge/br_device.c:106
 __netdev_start_xmit include/linux/netdevice.h:4943 [inline]
 netdev_start_xmit include/linux/netdevice.h:4957 [inline]
 xmit_one net/core/dev.c:3632 [inline]
 dev_hard_start_xmit+0x246/0x740 net/core/dev.c:3648
 __dev_queue_xmit+0x19a3/0x3660 net/core/dev.c:4442
 neigh_output include/net/neighbour.h:543 [inline]
 ip6_finish_output2+0xe3d/0x1630 net/ipv6/ip6_output.c:141
 dst_output include/net/dst.h:467 [inline]
 NF_HOOK include/linux/netfilter.h:304 [inline]
 ndisc_send_skb+0xc26/0x14f0 net/ipv6/ndisc.c:513
 addrconf_rs_timer+0x2d5/0x630 net/ipv6/addrconf.c:4024
 call_timer_fn+0x189/0x540 kernel/time/timer.c:1701
 expire_timers kernel/time/timer.c:1752 [inline]
 __run_timers+0x542/0x800 kernel/time/timer.c:2023
 run_timer_softirq+0x67/0xf0 kernel/time/timer.c:2036
 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:preempt_schedule_irq+0xba/0x150 kernel/sched/core.c:7010
Code: 00 00 43 c6 44 37 04 f8 74 0b 0f 0b 48 f7 03 08 00 00 00 74 6f bf 01 00 00 00 e8 a1 1b ce f6 e8 cc 28 ff f6 fb bf 01 00 00 00 <e8> f1 b4 ff ff 43 c6 44 37 08 00 48 c7 44 24 40 00 00 00 00 9c 8f
RSP: 0018:ffffc90003457b20 EFLAGS: 00000282
RAX: bd3a115224400b00 RBX: 0000000000000000 RCX: bd3a115224400b00
RDX: dffffc0000000000 RSI: ffffffff8acac9e0 RDI: 0000000000000001
RBP: ffffc90003457bd0 R08: ffffffff8e8b0c2f R09: 1ffffffff1d16185
R10: dffffc0000000000 R11: fffffbfff1d16186 R12: 0000000000000000
R13: 0000000000000000 R14: dffffc0000000000 R15: 1ffff9200068af64
 irqentry_exit+0x67/0x70 kernel/entry/common.c:438
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:__nr_to_section include/linux/mmzone.h:1849 [inline]
RIP: 0010:__pfn_to_section include/linux/mmzone.h:1957 [inline]
RIP: 0010:pfn_valid include/linux/mmzone.h:2010 [inline]
RIP: 0010:__virt_addr_valid+0x110/0x540 arch/x86/mm/physaddr.c:65
Code: e8 2e 74 0c e8 31 81 4a 00 31 ed e9 6a 03 00 00 49 bc 00 00 00 00 00 fc ff df 48 c7 c0 a0 58 32 97 48 c1 e8 03 42 80 3c 20 00 <74> 0c 48 c7 c7 a0 58 32 97 e8 e2 b7 a2 00 48 8b 05 cb b7 f5 15 48
RSP: 0018:ffffc90003457c98 EFLAGS: 00000246
RAX: 1ffffffff2e64b14 RBX: 00000000770d2f00 RCX: ffff888078995a00
RDX: 0000000000000000 RSI: 00000000770d2f00 RDI: 00003fffffffffff
RBP: ffffc90003457da8 R08: ffff8880770d2f5f R09: 1ffff1100ee1a5eb
R10: dffffc0000000000 R11: ffffed100ee1a5ec R12: dffffc0000000000
R13: ffff888078995a00 R14: 000000000000002e R15: 0000000000000000
 kasan_addr_to_slab+0xd/0xc0 mm/kasan/common.c:36
 __kasan_record_aux_stack+0xf/0xc0 mm/kasan/generic.c:477
 task_work_add+0xd9/0x470 kernel/task_work.c:82
 fput+0xdd/0x1a0 fs/file_table.c:440
 filp_close+0x10f/0x150 fs/open.c:1547
 __range_close fs/file.c:698 [inline]
 __close_range+0x368/0x660 fs/file.c:755
 __do_sys_close_range fs/open.c:1599 [inline]
 __se_sys_close_range fs/open.c:1596 [inline]
 __x64_sys_close_range+0x7a/0x90 fs/open.c:1596
 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: 0033:0x7fb577b9c819
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:00007ffd08265438 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: ffffffffffffffda RBX: 00007ffd08265520 RCX: 00007fb577b9c819
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 000000000001da15 R08: 0000000000000001 R09: 0000000000000000
R10: 0000001b2c120000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb577e15fac R14: 00007fb577e15fa8 R15: 00007fb577e15fa0
 </TASK>

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/04/07 05:23 linux-6.6.y 80de0a958133 4440e7c2 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in sys_close_range
2026/03/25 02:17 linux-6.6.y 4fc00fe35d46 74e70d19 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in sys_close_range
2026/02/05 06:43 linux-6.6.y 2cf6f68313dc ea10c935 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in sys_close_range
2025/12/22 09:05 linux-6.6.y 5fa4793a2d2d d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in sys_close_range
2025/08/13 16:29 linux-6.6.y 3a8ababb8b6a 22ec1469 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in sys_close_range
* Struck through repros no longer work on HEAD.