INFO: rcu detected stall in sock_write_iter (4)

Status: upstream: reported syz repro on 2025/03/16 07:14
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+e2da15727af46874529a@syzkaller.appspotmail.com
First crash: 524d, last: 5d22h
Fix commit to backport (bisect log) :
tree: upstream
commit e634134180885574d1fe7aa162777ba41e7fcd5b
Author: Vladimir Oltean <vladimir.oltean@nxp.com>
Date: Mon May 27 15:39:54 2024 +0000

  net/sched: taprio: make q->picos_per_byte available to fill_sched_entry()

  
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2025/03/22 linux-5.15.y (ToT) 0c935c049b5c syz [report] INFO: rcu detected stall in neigh_periodic_work
2025/03/22 upstream (ToT) 183601b78a9b syz Didn't crash
▶ ▼ Similar bugs (12)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.6 INFO: rcu detected stall in sock_write_iter origin:upstream missing-backport 1 syz, C inconclusive 12 69d 353d 0/2 upstream: reported C repro on 2025/09/03 11:54
upstream INFO: rcu detected stall in sock_write_iter mm 1 1 2454d 2454d 0/29 closed as invalid on 2019/12/04 14:04
linux-5.15 INFO: rcu detected stall in sock_write_iter (3) 1 1 668d 668d 0/3 auto-obsoleted due to no activity on 2025/01/31 00:48
linux-6.1 INFO: rcu detected stall in sock_write_iter (3) 1 3 13d 88d 0/3 upstream: reported on 2026/05/26 07:14
upstream INFO: rcu detected stall in sock_write_iter (3) net prio:low 1 syz, C done error 221 27d 837d 0/29 upstream: reported C repro on 2024/05/07 12:14
linux-5.15 INFO: rcu detected stall in sock_write_iter 1 1 1037d 1037d 0/3 auto-obsoleted due to no activity on 2024/01/28 05:21
linux-5.15 INFO: rcu detected stall in sock_write_iter (2) 1 1 855d 855d 0/3 auto-obsoleted due to no activity on 2024/07/28 08:46
linux-6.1 INFO: rcu detected stall in sock_write_iter 1 1 870d 870d 0/3 auto-obsoleted due to no activity on 2024/07/13 13:13
upstream INFO: rcu detected stall in sock_write_iter (2) netfilter 1 1 1022d 1022d 0/29 auto-obsoleted due to no activity on 2024/01/03 00:51
linux-6.1 INFO: rcu detected stall in sock_write_iter (2) 1 2 215d 279d 0/3 auto-obsoleted due to no activity on 2026/04/29 05:14
android-5-10 BUG: soft lockup in sock_write_iter 1 1 528d 528d 0/2 auto-obsoleted due to no activity on 2025/06/10 11:55
android-5-15 BUG: soft lockup in sock_write_iter 1 24 738d 874d 0/2 auto-obsoleted due to no activity on 2024/11/03 03:04
▶ ▼ Last patch testing requests (7)
Created Duration User Patch Repo Result
2026/08/03 00:50 42m retest repro linux-5.15.y report log
2026/05/22 23:43 20m retest repro linux-5.15.y report log
2026/03/10 13:36 1h51m retest repro linux-5.15.y report log
2025/12/30 05:43 15m retest repro linux-5.15.y report log
2025/10/19 10:29 17m retest repro linux-5.15.y report log
2025/08/10 01:51 17m retest repro linux-5.15.y report log
2025/06/01 00:04 1h33m retest repro linux-5.15.y report log
▶ ▼ Fix bisection attempts (1)
Created Duration User Patch Repo Result
2025/04/29 07:27 9h30m fix candidate upstream OK (1) job log

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-....: (1 ticks this GP) idle=30d/1/0x4000000000000000 softirq=6647/6647 fqs=5247 
	(detected by 1, t=10502 jiffies, g=7109, q=1377)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4169 Comm: syz-execprog Not tainted 5.15.179-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
RIP: 0010:task_irq_context kernel/locking/lockdep.c:4521 [inline]
RIP: 0010:__lock_acquire+0x3d6/0x1ff0 kernel/locking/lockdep.c:4950
Code: 80 00 00 00 48 89 03 65 8b 05 7a 8b 9f 7e 31 db 85 c0 0f 95 c3 01 db 48 8d bd d4 0a 00 00 48 89 f8 48 c1 e8 03 48 89 44 24 68 <0f> b6 04 10 84 c0 4c 8b 74 24 38 48 89 f9 48 89 7c 24 10 0f 85 5c
RSP: 0018:ffffc900000079e0 EFLAGS: 00000807
RAX: 1ffff110033778ca RBX: 0000000000000002 RCX: ffff888019bbc670
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: ffff888019bbc654
RBP: ffff888019bbbb80 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000000
R13: 000000000000000f R14: 000000000000000f R15: 0000000000000000
FS:  000000c004a28a98(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f750ad6dfd4 CR3: 0000000079a3b000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <IRQ>
 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162
 debug_object_activate+0x63/0x4e0 lib/debugobjects.c:694
 debug_hrtimer_activate kernel/time/hrtimer.c:420 [inline]
 debug_activate kernel/time/hrtimer.c:475 [inline]
 enqueue_hrtimer+0x30/0x390 kernel/time/hrtimer.c:1084
 __run_hrtimer kernel/time/hrtimer.c:1705 [inline]
 __hrtimer_run_queues+0x6b6/0xcf0 kernel/time/hrtimer.c:1752
 hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1814
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
 __sysvec_apic_timer_interrupt+0x13b/0x4b0 arch/x86/kernel/apic/apic.c:1114
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:unwind_next_frame+0xd5/0x1fa0 arch/x86/kernel/unwind_orc.c:436
Code: 50 48 89 5c 24 38 bf 01 00 00 00 e8 25 e4 1e 00 48 ba 00 00 00 00 00 fc ff df 49 8d 5f 50 48 89 d8 48 c1 e8 03 48 89 44 24 30 <80> 3c 10 00 74 12 48 89 df e8 3d d5 91 00 48 ba 00 00 00 00 00 fc
RSP: 0018:ffffc90002e3ef08 EFLAGS: 00000a02
RAX: 1ffff920005c7e02 RBX: ffffc90002e3f010 RCX: ffffffff8a49ab00
RDX: dffffc0000000000 RSI: ffffffff884de13b RDI: ffffffff8138b9ab
RBP: ffffc90002e3eff8 R08: 000000000000000c R09: ffffc90002e3f0b0
R10: 0000000000000000 R11: dffffc0000000001 R12: ffffc90002e3fb60
R13: ffffffff816e2db0 R14: ffffffff884de13b R15: ffffc90002e3efc0
 arch_stack_walk+0x10d/0x140 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x113/0x1c0 kernel/stacktrace.c:122
 save_stack+0xf6/0x1e0 mm/page_owner.c:119
 __reset_page_owner+0x52/0x180 mm/page_owner.c:140
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1340 [inline]
 free_pcp_prepare mm/page_alloc.c:1391 [inline]
 free_unref_page_prepare+0xc34/0xcf0 mm/page_alloc.c:3317
 free_unref_page+0x95/0x2d0 mm/page_alloc.c:3396
 do_slab_free mm/slub.c:3487 [inline]
 ___cache_free+0xe3/0x100 mm/slub.c:3506
 qlist_free_all+0x36/0x90 mm/kasan/quarantine.c:176
 kasan_quarantine_reduce+0x162/0x180 mm/kasan/quarantine.c:283
 __kasan_slab_alloc+0x2f/0xc0 mm/kasan/common.c:444
 kasan_slab_alloc include/linux/kasan.h:254 [inline]
 slab_post_alloc_hook+0x53/0x380 mm/slab.h:519
 slab_alloc_node mm/slub.c:3220 [inline]
 __kmalloc_node_track_caller+0x14d/0x390 mm/slub.c:4958
 kmalloc_reserve net/core/skbuff.c:356 [inline]
 __alloc_skb+0x12c/0x590 net/core/skbuff.c:427
 alloc_skb_fclone include/linux/skbuff.h:1212 [inline]
 sk_stream_alloc_skb+0x1fc/0xac0 net/ipv4/tcp.c:889
 tcp_sendmsg_locked+0xd34/0x3a90 net/ipv4/tcp.c:1314
 tcp_sendmsg+0x2c/0x40 net/ipv4/tcp.c:1457
 sock_sendmsg_nosec net/socket.c:704 [inline]
 __sock_sendmsg net/socket.c:716 [inline]
 sock_write_iter+0x39b/0x530 net/socket.c:1079
 call_write_iter include/linux/fs.h:2172 [inline]
 new_sync_write fs/read_write.c:507 [inline]
 vfs_write+0xacd/0xe50 fs/read_write.c:594
 ksys_write+0x1a2/0x2c0 fs/read_write.c:647
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x47f4ce
Code: 24 28 44 8b 44 24 2c e9 70 ff ff ff cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 49 89 f2 48 89 fa 48 89 ce 48 89 df 0f 05 <48> 3d 01 f0 ff ff 76 15 48 f7 d8 48 89 c1 48 c7 c0 ff ff ff ff 48
RSP: 002b:000000c0001e73b0 EFLAGS: 00000216 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 000000000047f4ce
RDX: 00000000000003d0 RSI: 000000c0002bb030 RDI: 0000000000000006
RBP: 000000c0001e73f0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000216 R12: 000000c0001e7520
R13: 000000000000014e R14: 000000c004a52a80 R15: 000000c0002baf00
 </TASK>

Crashes (12):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/03/16 07:13 linux-5.15.y 0c935c049b5c e2826670 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in sock_write_iter
2026/08/16 18:36 linux-5.15.y aabd761612db 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sock_write_iter
2026/07/19 13:03 linux-5.15.y c86c4726e7f0 72524a66 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sock_write_iter
2026/06/26 13:18 linux-5.15.y eceeec79dbc6 7ff32d8b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sock_write_iter
2026/06/24 15:19 linux-5.15.y eceeec79dbc6 302586aa .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sock_write_iter
2026/04/25 09:20 linux-5.15.y b9d57c40a767 9c2d0995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sock_write_iter
2026/03/26 06:23 linux-5.15.y 91d48252ad4b c6143aac .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sock_write_iter
2026/03/19 15:24 linux-5.15.y 91d48252ad4b bd6dcb30 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sock_write_iter
2026/02/18 13:09 linux-5.15.y e45d5d41c134 39751c21 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sock_write_iter
2025/12/04 10:33 linux-5.15.y cc5ec8769306 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sock_write_iter
2025/08/24 16:48 linux-5.15.y c79648372d02 bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sock_write_iter
2025/08/11 16:00 linux-5.15.y c79648372d02 32a0e5ed .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in sock_write_iter
* Struck through repros no longer work on HEAD.