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: 81d, last: 3d08h
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 199d 199d 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 300d 300d 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 940d 940d 0/29 closed as invalid on 2024/02/01 10:31
upstream INFO: rcu detected stall in sock_alloc_file (3) mm 1 5 210d 346d 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 351d 351d 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 519d 571d 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 6 10d 240d 0/3 upstream: reported on 2025/10/24 19:33
linux-6.1 INFO: rcu detected stall in sock_alloc_file 1 1 291d 291d 0/3 auto-obsoleted due to no activity on 2025/12/12 11:49

Sample crash report:
rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 0-.... } 2676 jiffies s: 195249 root: 0x1/.
rcu: blocking rcu_node structures (internal RCU debug):
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 30934 Comm: syz.1.7527 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:check_preemption_disabled+0x42/0x110 lib/smp_processor_id.c:55
Code: 65 8b 05 71 ae d2 75 65 8b 0d 12 04 d3 75 f7 c1 ff ff ff 7f 74 1f 65 48 8b 0c 25 28 00 00 00 48 3b 4c 24 08 0f 85 c4 00 00 00 <48> 83 c4 10 5b 41 5e 41 5f 5d c3 48 c7 04 24 00 00 00 00 9c 8f 04
RSP: 0018:ffffc90000007908 EFLAGS: 00000046
RAX: 0000000000000000 RBX: da2e616334457c0f RCX: a6e9b4f41c3dac00
RDX: dffffc0000000000 RSI: ffffffff8a8c2780 RDI: ffffffff8adf2060
RBP: ffffc90000007a00 R08: ffff8880b8e3580b R09: 1ffff110171c6b01
R10: dffffc0000000000 R11: ffffed10171c6b02 R12: 0000000000000000
R13: 0000000000000000 R14: ffff88802ad81e00 R15: 0000000000000000
FS:  00007f46193326c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9bcfe17dac CR3: 0000000033aac000 CR4: 00000000003506f0
DR0: 0000200000000300 DR1: 0000200000000300 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 lockdep_recursion_inc kernel/locking/lockdep.c:462 [inline]
 lockdep_hardirqs_on_prepare+0x1c1/0x770 kernel/locking/lockdep.c:4314
 trace_hardirqs_on+0x34/0x40 kernel/trace/trace_preemptirq.c:49
 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:728
RIP: 0010:rcu_read_unlock_special+0x7f/0x510 kernel/rcu/tree_plugin.h:685
Code: eb 03 48 b8 f1 f1 f1 f1 f8 f2 f2 f2 4a 89 04 2b 42 c7 44 2b 08 f8 f3 f3 f3 65 44 8b 35 82 30 95 7e 41 f7 c6 00 00 f0 00 74 40 <48> c7 44 24 40 0e 36 e0 45 4a c7 04 2b 00 00 00 00 42 c7 44 2b 08
RSP: 0018:ffffc90000007ac0 EFLAGS: 00000206
RAX: a6e9b4f41c3dac00 RBX: 1ffff92000000f60 RCX: a6e9b4f41c3dac00
RDX: dffffc0000000000 RSI: ffffffff8a8c1aa0 RDI: ffffffff8adf2060
RBP: ffffc90000007bb0 R08: ffff8880b8e3580b R09: 1ffff110171c6b01
R10: dffffc0000000000 R11: ffffed10171c6b02 R12: 0000000000000246
R13: dffffc0000000000 R14: ffff8880b8e3b900 R15: 0000000000000001
 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:426
 rcu_read_unlock include/linux/rcupdate.h:823 [inline]
 ieee80211_iterate_active_interfaces_atomic+0x156/0x170 net/mac80211/util.c:826
 mac80211_hwsim_beacon+0xb7/0x1b0 drivers/net/wireless/mac80211_hwsim.c:2147
 __run_hrtimer kernel/time/hrtimer.c:1751 [inline]
 __hrtimer_run_queues+0x54a/0xd50 kernel/time/hrtimer.c:1815
 hrtimer_run_softirq+0x183/0x2a0 kernel/time/hrtimer.c:1832
 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:virt_to_folio include/linux/mm.h:913 [inline]
RIP: 0010:virt_to_slab mm/slab.h:175 [inline]
RIP: 0010:qlink_to_cache+0x0/0xa0 mm/kasan/quarantine.c:131
Code: c6 4c 89 f8 eb af 48 89 6c 24 08 4c 89 64 24 10 48 89 e7 48 89 de e8 6f fc ff ff 48 83 c4 20 5b 41 5c 41 5d 41 5e 41 5f 5d c3 <e8> eb 79 66 ff 48 c1 e8 06 48 83 e0 c0 48 ba 00 00 00 00 00 ea ff
RSP: 0018:ffffc9000d79fb20 EFLAGS: 00000246
RAX: a6e9b4f41c3dac00 RBX: ffffc9000d79fb68 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: ffff888074364000
RBP: ffff888074364000 R08: ffff8880b8e3580b R09: 1ffff110171c6b01
R10: dffffc0000000000 R11: ffffed10171c6b02 R12: 0000000000000000
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff888074364000
 qlist_free_all+0x3a/0xe0 mm/kasan/quarantine.c:184
 kasan_quarantine_reduce+0x144/0x160 mm/kasan/quarantine.c:294
 __kasan_slab_alloc+0x1e/0x80 mm/kasan/common.c:306
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook+0x4b/0x480 mm/slab.h:737
 slab_alloc_node mm/slub.c:3359 [inline]
 slab_alloc mm/slub.c:3367 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3374 [inline]
 kmem_cache_alloc+0x123/0x2f0 mm/slub.c:3383
 kmem_cache_zalloc include/linux/slab.h:689 [inline]
 lsm_file_alloc security/security.c:576 [inline]
 security_file_alloc+0x30/0x110 security/security.c:1544
 __alloc_file+0xc2/0x230 fs/file_table.c:143
 alloc_empty_file+0x90/0x180 fs/file_table.c:187
 alloc_file+0x5c/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:1756
 __do_sys_socketpair net/socket.c:1785 [inline]
 __se_sys_socketpair net/socket.c:1782 [inline]
 __x64_sys_socketpair+0x97/0xb0 net/socket.c:1782
 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: 0033:0x7f461839ce59
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:00007f4619332028 EFLAGS: 00000246 ORIG_RAX: 0000000000000035
RAX: ffffffffffffffda RBX: 00007f4618615fa0 RCX: 00007f461839ce59
RDX: 0000000000000000 RSI: 0000000000000005 RDI: 0000000000000001
RBP: 00007f4618432e6f R08: 0000000000000000 R09: 0000000000000000
R10: 00002000000029c0 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4618616038 R14: 00007f4618615fa0 R15: 00007fffdceeb518
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
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.