syzbot


WARNING: refcount bug in nr_del_neigh

Status: closed as invalid on 2025/06/26 13:33
Subsystems: hams
[Documentation on labels]
First crash: 96d, last: 96d

Sample crash report:
------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 0 PID: 13501 at lib/refcount.c:28 refcount_warn_saturate+0x11a/0x1d0 lib/refcount.c:28
Modules linked in:
CPU: 0 UID: 0 PID: 13501 Comm: syz.2.1963 Not tainted 6.15.0-rc7-syzkaller-01675-ge45b7196df60 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:refcount_warn_saturate+0x11a/0x1d0 lib/refcount.c:28
Code: 80 aa c1 8b e8 e7 5e cb fc 90 0f 0b 90 90 eb d7 e8 4b 02 07 fd c6 05 f6 b7 b0 0a 01 90 48 c7 c7 e0 aa c1 8b e8 c7 5e cb fc 90 <0f> 0b 90 90 eb b7 e8 2b 02 07 fd c6 05 d3 b7 b0 0a 01 90 48 c7 c7
RSP: 0018:ffffc9000428fa78 EFLAGS: 00010246
RAX: 2e60a6f63da1a000 RBX: 0000000000000003 RCX: ffff88801a1f0000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000002
RBP: 0000000000000000 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff1bba984 R12: dffffc0000000000
R13: ffffffff8c82bba8 R14: ffff888020f51a3c R15: 0000000000000000
FS:  00007f0c36b966c0(0000) GS:ffff8881260b2000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0c36b74f98 CR3: 0000000062240000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 nr_del_neigh+0x16c/0x1d0 net/netrom/nr_route.c:440
 nr_rt_ioctl+0xb1b/0xd50 net/netrom/nr_route.c:682
 sock_do_ioctl+0xdc/0x300 net/socket.c:1190
 sock_ioctl+0x576/0x790 net/socket.c:1311
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:906 [inline]
 __se_sys_ioctl+0xf9/0x170 fs/ioctl.c:892
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0c35d8e969
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f0c36b96038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f0c35fb5fa0 RCX: 00007f0c35d8e969
RDX: 0000200000000680 RSI: 000000000000890c RDI: 0000000000000007
RBP: 00007f0c35e10ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f0c35fb5fa0 R15: 00007fff50f17488
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/05/26 16:58 net-next e45b7196df60 2d4582d0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce WARNING: refcount bug in nr_del_neigh
* Struck through repros no longer work on HEAD.