syzbot

 sign-in | mailing list | source | docs
🐞 Open [867]
🐞 Fixed [141]
🐞 Invalid [996]
⬇ Missing Backports [73]
≡ Crashes
Kernel Health Bugs/Month Bug Lifetimes Fuzzing
💬 Send us feedback

INFO: rcu detected stall in sock_write_iter (2)

Status: upstream: reported on 2025/11/15 21:15
Reported-by: syzbot+db830ed9f47053f1b3a0@syzkaller.appspotmail.com
First crash: 74d, last: 10d
▶ ▼ Similar bugs (11)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 INFO: rcu detected stall in sock_write_iter (4) origin:lts-only 1 syz done 4 55d 319d 0/3 upstream: reported syz repro on 2025/03/16 07:14
linux-6.6 INFO: rcu detected stall in sock_write_iter origin:upstream missing-backport 1 C inconclusive 5 40d 147d 0/2 upstream: reported C repro on 2025/09/03 11:54
upstream INFO: rcu detected stall in sock_write_iter mm 1 1 2248d 2248d 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 463d 463d 0/3 auto-obsoleted due to no activity on 2025/01/31 00:48
upstream INFO: rcu detected stall in sock_write_iter (3) net 1 C done error 189 38d 631d 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 832d 832d 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 650d 650d 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 664d 664d 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 817d 817d 0/29 auto-obsoleted due to no activity on 2024/01/03 00:51
android-5-10 BUG: soft lockup in sock_write_iter 1 1 322d 322d 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 533d 669d 0/2 auto-obsoleted due to no activity on 2024/11/03 03:04

Sample crash report:
rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 1-.... } 2627 jiffies s: 147329 root: 0x2/.
rcu: blocking rcu_node structures (internal RCU debug):
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 28594 Comm: syz.5.6261 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:check_region_inline mm/kasan/generic.c:-1 [inline]
RIP: 0010:kasan_check_range+0x33/0x290 mm/kasan/generic.c:189
Code: 00 00 55 41 57 41 56 41 54 53 49 89 f8 49 01 f0 0f 82 0e 02 00 00 49 89 f8 49 c1 e8 2f 41 81 f8 ff ff 01 00 0f 82 fa 01 00 00 <49> bc 01 00 00 00 00 fc ff df 49 89 fe 49 c1 ee 03 49 ba 00 00 00
RSP: 0018:ffffc900001e03b0 EFLAGS: 00000046
RAX: 0000000000000001 RBX: 000000000000002c RCX: ffffffff81642ab1
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff90ad8240
RBP: ffffc900001e0630 R08: 000000000001ffff R09: 0000000000000001
R10: dffffc0000000000 R11: fffffbfff1c3e906 R12: ffff888027e33b80
R13: 0000000000000000 R14: 0000000000000000 R15: 000000000000002c
FS:  00007f18d23e26c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000007573c000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000008d24
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 instrument_atomic_read include/linux/instrumented.h:72 [inline]
 _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
 hlock_class kernel/locking/lockdep.c:228 [inline]
 check_wait_context kernel/locking/lockdep.c:4723 [inline]
 __lock_acquire+0x541/0x7d10 kernel/locking/lockdep.c:4999
 lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5662
 rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 rcu_read_lock include/linux/rcupdate.h:791 [inline]
 trace_call_bpf+0xe0/0x6b0 kernel/trace/bpf_trace.c:134
 perf_trace_run_bpf_submit+0x79/0x1c0 kernel/events/core.c:9997
 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: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 92 50 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:ffffc900001e0aa0 EFLAGS: 00000206
RAX: 6200c3dc9b4a4f00 RBX: 1ffff9200003c15c RCX: 6200c3dc9b4a4f00
RDX: dffffc0000000000 RSI: ffffffff8a8c0620 RDI: ffffffff8adf0020
RBP: ffffc900001e0b90 R08: ffff8880b8f3580b R09: 1ffff110171e6b01
R10: dffffc0000000000 R11: ffffed10171e6b02 R12: 0000000000000246
R13: dffffc0000000000 R14: ffff8880b8f3b900 R15: 0000000000000002
 __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:1747 [inline]
 __hrtimer_run_queues+0x560/0xd70 kernel/time/hrtimer.c:1811
 hrtimer_run_softirq+0x183/0x2a0 kernel/time/hrtimer.c:1828
 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:seqcount_lockdep_reader_access+0x144/0x190 include/linux/seqlock.h:105
Code: 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 41 c6 04 07 f8 75 42 41 f7 c5 00 02 00 00 74 01 fb 48 c7 04 24 0e 36 e0 45 <4b> c7 04 27 00 00 00 00 43 c7 44 27 08 00 00 00 00 65 48 8b 04 25
RSP: 0018:ffffc9000c53f4e0 EFLAGS: 00000206
RAX: dffffc0000000004 RBX: ffff88813fffa7c8 RCX: 6200c3dc9b4a4f00
RDX: dffffc0000000000 RSI: ffffffff8a8c0620 RDI: ffffffff8adf0020
RBP: ffffc9000c53f598 R08: ffff8880b8f3580b R09: 1ffff110171e6b01
R10: dffffc0000000000 R11: ffffed10171e6b02 R12: dffffc0000000000
R13: 0000000000000a06 R14: ffffffff81c8c24a R15: 1ffff920018a7e9c
 read_seqbegin include/linux/seqlock.h:893 [inline]
 zone_span_seqbegin include/linux/memory_hotplug.h:132 [inline]
 page_outside_zone_boundaries mm/page_alloc.c:627 [inline]
 bad_range+0x7a/0x2d0 mm/page_alloc.c:654
 rmqueue mm/page_alloc.c:3887 [inline]
 get_page_from_freelist+0x1a02/0x1ab0 mm/page_alloc.c:4325
 __alloc_pages+0x1ec/0x4f0 mm/page_alloc.c:5614
 vm_area_alloc_pages mm/vmalloc.c:3002 [inline]
 __vmalloc_area_node mm/vmalloc.c:3071 [inline]
 __vmalloc_node_range+0x944/0x13b0 mm/vmalloc.c:3243
 __vmalloc_node mm/vmalloc.c:3308 [inline]
 vmalloc+0x75/0x80 mm/vmalloc.c:3341
 netlink_alloc_large_skb net/netlink/af_netlink.c:1187 [inline]
 netlink_sendmsg+0x5ec/0xbd0 net/netlink/af_netlink.c:1847
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:730 [inline]
 sock_write_iter+0x2d9/0x3e0 net/socket.c:1143
 call_write_iter include/linux/fs.h:2265 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x4b1/0xa30 fs/read_write.c:584
 ksys_write+0x14c/0x250 fs/read_write.c:637
 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: 0033:0x7f18d159acb9
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:00007f18d23e2028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f18d1815fa0 RCX: 00007f18d159acb9
RDX: 000000000000fe33 RSI: 0000200000000040 RDI: 0000000000000005
RBP: 00007f18d1608bf7 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f18d1816038 R14: 00007f18d1815fa0 R15: 00007ffd49ba4d78
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/01/19 05:13 linux-6.1.y cd9b81672742 20d37d28 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in sock_write_iter
2025/11/15 21:15 linux-6.1.y f6e38ae624cf f7988ea4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in sock_write_iter
* Struck through repros no longer work on HEAD.