BUG: sleeping function called from invalid context in x25_kill_by_neigh

Status: upstream: reported C repro on 2026/09/14 12:21
Subsystems: x25
Labels: prio:low
[Documentation on labels]
Reported-by: syzbot+9faa82ae2e94c5c7d2ef@syzkaller.appspotmail.com
First crash: 4d08h, last: 1d16h
Cause bisection: failed (error log, bisect log)
  
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ID Workflow Result Correct Bug Created Started Finished Revision
70c1323e assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ BUG: sleeping function called from invalid context in x25_kill_by_neigh 2026/09/11 01:36 2026/09/11 01:36 2026/09/11 01:51 1fe56c0a
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[syzbot] [x25?] BUG: sleeping function called from invalid context in x25_kill_by_neigh 0 (1) 2026/09/14 12:21

Sample crash report:
BUG: sleeping function called from invalid context at net/core/sock.c:3832
in_atomic(): 0, irqs_disabled(): 0, non_block: 0, pid: 29, name: ktimers/1
preempt_count: 0, expected: 0
RCU nest depth: 2, expected: 0
locks held by ktimers/1/29: 4, last CPU#1:
 #0: ffffffff8e0594c0 (local_bh){.+.+}-{1:3}, at: __local_bh_disable_ip+0x3d/0x420 kernel/softirq.c:186
 #1: ffffffff8e1c3c40 (rcu_read_lock){....}-{1:3}, at: __local_bh_disable_ip+0x3d/0x420 kernel/softirq.c:186
 #2: ffffffff8e1c3c40 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #2: ffffffff8e1c3c40 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #2: ffffffff8e1c3c40 (rcu_read_lock){....}-{1:3}, at: netif_receive_skb_core+0x33/0x2b0 net/core/dev.c:6288
 #3: ffff888038d40358 (sk_lock-AF_X25){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1713 [inline]
 #3: ffff888038d40358 (sk_lock-AF_X25){+.+.}-{0:0}, at: x25_kill_by_neigh+0x134/0x2a0 net/x25/af_x25.c:1778
CPU: 1 UID: 0 PID: 29 Comm: ktimers/1 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 __might_resched+0x31b/0x470 kernel/sched/core.c:9256
 lock_sock_nested+0x56/0x130 net/core/sock.c:3832
 lock_sock include/net/sock.h:1713 [inline]
 x25_kill_by_neigh+0x134/0x2a0 net/x25/af_x25.c:1778
 x25_lapb_receive_frame+0x1b0/0xfb0 net/x25/x25_dev.c:138
 __netif_receive_skb_one_core net/core/dev.c:6264 [inline]
 netif_receive_skb_core+0x2a6/0x2b0 net/core/dev.c:6289
 lapbeth_napi_poll+0x45/0x90 drivers/net/wan/lapbether.c:100
 __napi_poll+0xae/0x550 net/core/dev.c:7787
 napi_poll net/core/dev.c:7850 [inline]
 net_rx_action+0x621/0xd70 net/core/dev.c:8007
 handle_softirqs+0x1da/0x6d0 kernel/softirq.c:645
 __do_softirq kernel/softirq.c:679 [inline]
 run_ktimerd+0x6a/0x100 kernel/softirq.c:1174
 smpboot_thread_fn+0x565/0xa70 kernel/smpboot.c:160
 kthread+0x38b/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Crashes (9):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/10 17:49 upstream 50d05c7c76c9 4e8b1cc6 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root BUG: sleeping function called from invalid context in x25_kill_by_neigh
2026/09/10 16:19 upstream 50d05c7c76c9 4e8b1cc6 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root BUG: sleeping function called from invalid context in x25_kill_by_neigh
2026/09/10 14:22 upstream 50d05c7c76c9 4e8b1cc6 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root BUG: sleeping function called from invalid context in x25_kill_by_neigh
2026/09/13 04:15 upstream cba2348ab114 70a60e12 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root BUG: sleeping function called from invalid context in x25_kill_by_neigh
2026/09/10 14:20 upstream 50d05c7c76c9 4e8b1cc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root BUG: sleeping function called from invalid context in x25_kill_by_neigh
2026/09/10 12:34 upstream 50d05c7c76c9 4e8b1cc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root BUG: sleeping function called from invalid context in x25_kill_by_neigh
2026/09/10 12:28 upstream 50d05c7c76c9 4e8b1cc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root BUG: sleeping function called from invalid context in x25_kill_by_neigh
2026/09/10 12:23 upstream 50d05c7c76c9 4e8b1cc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root BUG: sleeping function called from invalid context in x25_kill_by_neigh
2026/09/10 12:09 upstream 50d05c7c76c9 4e8b1cc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root BUG: sleeping function called from invalid context in x25_kill_by_neigh
* Struck through repros no longer work on HEAD.