syzbot


INFO: rcu detected stall in sock_alloc_file (2)

Status: upstream: reported on 2026/04/01 17:08
Reported-by: syzbot+f74682e9cfcbf29e3c25@syzkaller.appspotmail.com
First crash: 83d, last: 1d02h
Similar bugs (8)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.6 INFO: rcu detected stall in sock_alloc_file (2) 1 1 201d 201d 0/2 auto-obsoleted due to no activity on 2026/03/15 04:14
linux-6.6 INFO: rcu detected stall in sock_alloc_file 1 1 302d 302d 0/2 auto-obsoleted due to no activity on 2025/12/03 21:35
upstream INFO: rcu detected stall in sock_alloc_file fs 1 1 942d 942d 0/29 closed as invalid on 2024/02/01 10:31
upstream INFO: rcu detected stall in sock_alloc_file (3) mm 1 5 212d 348d 0/29 auto-obsoleted due to no activity on 2026/02/21 17:58
linux-5.15 INFO: rcu detected stall in sock_alloc_file 1 1 353d 353d 0/3 auto-obsoleted due to no activity on 2025/10/13 16:41
upstream INFO: rcu detected stall in sock_alloc_file (2) mm 1 6 521d 573d 0/29 auto-obsoleted due to no activity on 2025/04/19 00:40
linux-5.15 INFO: rcu detected stall in sock_alloc_file (2) 1 7 3h46m 242d 0/3 upstream: reported on 2025/10/24 19:33
linux-6.1 INFO: rcu detected stall in sock_alloc_file 1 1 293d 293d 0/3 auto-obsoleted due to no activity on 2025/12/12 11:49

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-....: (1 GPs behind) idle=8944/1/0x4000000000000000 softirq=32566/32569 fqs=5234
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P10652
	(detected by 1, t=10502 jiffies, g=43325, q=2990 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 10652 Comm: syz.0.1877 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:lock_acquire+0xfb/0x4a0 kernel/locking/lockdep.c:5635
Code: 56 6f 00 4c 0f a3 25 6c 1b bc 0c 73 0d e8 1d 2e 08 00 84 c0 0f 84 2e 02 00 00 48 c7 c0 24 44 20 8e 48 c1 e8 03 42 0f b6 04 38 <84> c0 0f 85 1d 02 00 00 83 3d fa 4f bc 0c 00 0f 84 0c 01 00 00 65
RSP: 0018:ffffc90000007600 EFLAGS: 00000807
RAX: 0000000000000000 RBX: 0000000000000000 RCX: d33881dffe804c00
RDX: 0000000000000000 RSI: ffffffff8adee180 RDI: ffffffff8adee140
RBP: ffffc90000007708 R08: ffffffff8e200f6f R09: 1ffffffff1c401ed
R10: dffffc0000000000 R11: fffffbfff1c401ee R12: 0000000000000000
R13: 1ffff92000000ecc R14: 0000000000000000 R15: dffffc0000000000
FS:  00007f6d92d726c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe36cf456b8 CR3: 0000000044fce000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000200000000300 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 rcu_read_lock include/linux/rcupdate.h:791 [inline]
 __perf_event_output kernel/events/core.c:7728 [inline]
 perf_event_output_forward+0xdf/0x2f0 kernel/events/core.c:7750
 __perf_event_overflow+0x457/0x630 kernel/events/core.c:9496
 perf_swevent_overflow kernel/events/core.c:9579 [inline]
 perf_swevent_event+0x315/0x570 kernel/events/core.c:9630
 perf_tp_event+0x36b/0xc10 kernel/events/core.c:10064
 perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10032
 perf_trace_preemptirq_template+0x268/0x320 include/trace/events/preemptirq.h:14
 trace_irq_enable_rcuidle+0xd3/0x140 include/trace/events/preemptirq.h:40
 trace_hardirqs_on+0x24/0x40 kernel/trace/trace_preemptirq.c:44
 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:728
RIP: 0010:variable_ffs arch/x86/include/asm/bitops.h:319 [inline]
RIP: 0010:handle_softirqs+0x1b7/0x910 kernel/softirq.c:584
Code: 89 7c 24 2c 0f b7 db 48 c7 c7 80 0d 8b 8a e8 e0 af db 08 65 66 c7 05 66 62 b4 7e 00 00 e8 b1 47 39 00 fb 49 c7 c5 c0 a0 80 8c <89> 5c 24 34 b8 ff ff ff ff 0f bc 44 24 34 41 89 c6 41 ff c6 0f 84
RSP: 0018:ffffc90000007e20 EFLAGS: 00000282
RAX: d33881dffe804c00 RBX: 0000000000000200 RCX: d33881dffe804c00
RDX: dffffc0000000000 RSI: ffffffff8a8c17a0 RDI: ffffffff8adee1a0
RBP: ffffc90000007f30 R08: ffff8880b8e3580b R09: 1ffff110171c6b01
R10: dffffc0000000000 R11: ffffed10171c6b02 R12: dffffc0000000000
R13: ffffffff8c80a0c0 R14: ffff8880255a1e00 R15: 000000000000000a
 __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:__rcu_read_unlock+0x51/0xd0 kernel/rcu/tree_plugin.h:425
Code: ec 03 43 0f b6 04 3c 84 c0 75 48 ff 0b 75 1d 4c 8d b7 40 04 00 00 4c 89 f0 48 c1 e8 03 42 0f b6 04 38 84 c0 75 5f 41 83 3e 00 <75> 20 43 0f b6 04 3c 84 c0 75 3a 8b 03 3d 00 00 00 40 73 0a 5b 41
RSP: 0018:ffffc9000480fbb8 EFLAGS: 00000202
RAX: 0000000000000000 RBX: ffff8880255a223c RCX: d33881dffe804c00
RDX: 0000000000000001 RSI: ffffffff8adee180 RDI: ffff8880255a1e00
RBP: 0000000000000dc0 R08: ffffffff8e200f6f R09: 1ffffffff1c401ed
R10: dffffc0000000000 R11: fffffbfff1c401ee R12: 1ffff11004ab4447
R13: 00000000000001c8 R14: ffff8880255a2240 R15: dffffc0000000000
 rcu_read_unlock include/linux/rcupdate.h:823 [inline]
 get_obj_cgroup_from_current+0x1b6/0x280 mm/memcontrol.c:3025
 memcg_slab_pre_alloc_hook mm/slab.h:485 [inline]
 slab_pre_alloc_hook+0x8c/0x300 mm/slab.h:715
 slab_alloc_node mm/slub.c:3279 [inline]
 slab_alloc mm/slub.c:3367 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3374 [inline]
 kmem_cache_alloc+0x56/0x2f0 mm/slub.c:3383
 kmem_cache_zalloc include/linux/slab.h:689 [inline]
 __alloc_file+0x25/0x230 fs/file_table.c:138
 alloc_empty_file+0x90/0x180 fs/file_table.c:187
 alloc_file+0x5b/0x5f0 fs/file_table.c:229
 alloc_file_pseudo+0x180/0x200 fs/file_table.c:272
 sock_alloc_file+0xb3/0x240 net/socket.c:467
 __sys_socketpair+0x2cc/0x540 net/socket.c:1757
 __do_sys_socketpair net/socket.c:1786 [inline]
 __se_sys_socketpair net/socket.c:1783 [inline]
 __x64_sys_socketpair+0x97/0xb0 net/socket.c:1783
 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: 0033:0x7f6d91f9ce59
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:00007f6d92d72028 EFLAGS: 00000246 ORIG_RAX: 0000000000000035
RAX: ffffffffffffffda RBX: 00007f6d92215fa0 RCX: 00007f6d91f9ce59
RDX: 0000000000000000 RSI: 0000000000000005 RDI: 0000000000000001
RBP: 00007f6d92032e6f R08: 0000000000000000 R09: 0000000000000000
R10: 00002000000029c0 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6d92216038 R14: 00007f6d92215fa0 R15: 00007ffd7e52c828
 </TASK>
task:syz.0.1877      state:R  running task     stack:26544 pid:10652 ppid:4281   flags:0x0000400c
Call Trace:
 <TASK>
 </TASK>

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/06/23 05:24 linux-6.1.y fdb6fcb41cc7 5a630be6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in sock_alloc_file
2026/06/18 23:45 linux-6.1.y 228da13e907e a776b0d0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in sock_alloc_file
2026/04/01 17:08 linux-6.1.y 1989cd3d56e2 9a1f7828 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in sock_alloc_file
* Struck through repros no longer work on HEAD.