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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: 176d, last: 13h47m
▶ ▼ 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 (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in close_range fs 1 1 288d 288d 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 1 C done 3 145d 339d 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 21d 95d 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-....: (1 GPs behind) idle=6fe4/1/0x4000000000000000 softirq=13385/13387 fqs=4877
rcu: 	         hardirqs   softirqs   csw/system
rcu: 	 number:  1352825          0            0
rcu: 	cputime:    18611      33878           69   ==> 52510(ms)
rcu: 	(t=10502 jiffies g=12477 q=1327 ncpus=2)
CPU: 1 PID: 6001 Comm: syz.1.18 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:rcu_preempt_read_enter kernel/rcu/tree_plugin.h:379 [inline]
RIP: 0010:__rcu_read_lock+0x29/0x60 kernel/rcu/tree_plugin.h:402
Code: 00 f3 0f 1e fa 53 65 48 8b 1d a3 0d 92 7e 48 81 c3 3c 04 00 00 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 0f b6 04 08 <84> c0 75 11 ff 03 8b 03 3d 00 00 00 40 7d 02 5b c3 0f 0b eb fa 89
RSP: 0018:ffffc900001efd38 EFLAGS: 00000a03
RAX: 0000000000000000 RBX: ffff88807e0d5e3c RCX: dffffc0000000000
RDX: 0000000000000100 RSI: ffffffff8b1c81c0 RDI: 00007fc2eaf9aeb9
RBP: 0000000000000001 R08: ffff88807e0d5a00 R09: 0000000000000003
R10: 0000000000000004 R11: 0000000000000100 R12: ffffffff8aa000d0
R13: 1ffff9200003e040 R14: 00007fc2eaf9aeb9 R15: 1ffff9200003dfc6
FS:  0000555558334500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000001d695 CR3: 000000002bf70000 CR4: 00000000003506e0
Call Trace:
 <IRQ>
 rcu_read_lock include/linux/rcupdate.h:784 [inline]
 is_bpf_text_address+0x1f/0x2a0 kernel/bpf/core.c:741
 kernel_text_address+0xa0/0xd0 kernel/extable.c:125
 __kernel_text_address+0xd/0x30 kernel/extable.c:79
 unwind_get_return_address+0x5d/0xc0 arch/x86/kernel/unwind_orc.c:369
 arch_stack_walk+0x11d/0x190 arch/x86/kernel/stacktrace.c:26
 stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122
 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:46
 __kasan_record_aux_stack+0xaf/0xc0 mm/kasan/generic.c:492
 __call_rcu_common kernel/rcu/tree.c:2721 [inline]
 call_rcu+0x153/0x950 kernel/rcu/tree.c:2837
 refdst_drop include/net/dst.h:270 [inline]
 skb_dst_drop include/net/dst.h:282 [inline]
 skb_release_head_state+0x71/0x240 net/core/skbuff.c:1040
 skb_release_all net/core/skbuff.c:1055 [inline]
 __kfree_skb net/core/skbuff.c:1071 [inline]
 kfree_skb_reason+0xd7/0x170 net/core/skbuff.c:1107
 kfree_skb include/linux/skbuff.h:1232 [inline]
 xfrmi_xmit+0xd15/0x1750 net/xfrm/xfrm_interface_core.c:583
 __netdev_start_xmit include/linux/netdevice.h:4943 [inline]
 netdev_start_xmit include/linux/netdevice.h:4957 [inline]
 xmit_one net/core/dev.c:3658 [inline]
 dev_hard_start_xmit+0x246/0x740 net/core/dev.c:3674
 __dev_queue_xmit+0x1ac2/0x36b0 net/core/dev.c:4464
 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:get_lock_parent_ip include/linux/ftrace.h:-1 [inline]
RIP: 0010:preempt_latency_start kernel/sched/core.c:5827 [inline]
RIP: 0010:preempt_count_add+0x95/0x1a0 kernel/sched/core.c:5852
Code: b6 c0 3d f5 00 00 00 73 58 65 8b 05 fd 37 a7 7e 25 ff ff ff 7f 39 f8 75 42 48 8b 5c 24 18 48 89 df e8 2f e5 0c 00 85 c0 74 09 <31> db 31 ff e8 22 e5 0c 00 65 4c 8b 35 ca 37 a7 7e 49 81 c6 c8 14
RSP: 0018:ffffc900036c7df0 EFLAGS: 00000202
RAX: 0000000000000001 RBX: ffffffff8a8de1b2 RCX: ffffffff972c6401
RDX: ffff88807e0d5a00 RSI: 0000000000000000 RDI: ffffffff8a8de1b2
RBP: ffffc900036c7ee8 R08: ffffffff8e8adfaf R09: 1ffffffff1d15bf5
R10: dffffc0000000000 R11: fffffbfff1d15bf6 R12: 0000000000000003
R13: ffff88803069cfc0 R14: ffff88807e0d6201 R15: dffffc0000000000
 __raw_spin_lock include/linux/spinlock_api_smp.h:132 [inline]
 _raw_spin_lock+0x12/0x40 kernel/locking/spinlock.c:154
 __close_range+0x1e7/0x660 fs/file.c:-1
 __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: 0033:0x7fc2eaf9aeb9
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:00007ffe84db65c8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: ffffffffffffffda RBX: 00007ffe84db66b0 RCX: 00007fc2eaf9aeb9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 000000000001d695 R08: 0000000000000001 R09: 0000000000000000
R10: 0000001b2c120000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc2eb215fac R14: 00007fc2eb215fa8 R15: 00007fc2eb215fa0
 </TASK>

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
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.