syzbot


WARNING: refcount bug in ax25_release

Status: upstream: reported on 2024/06/15 15:04
Reported-by: syzbot+7ed59d42e7f489c36a83@syzkaller.appspotmail.com
First crash: 180d, last: 43d
Similar bugs (3)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING: refcount bug in ax25_release (3) hams C done 2162 1h04m 200d 0/28 upstream: reported C repro on 2024/05/26 23:38
upstream WARNING: refcount bug in ax25_release hams 1 457d 457d 0/28 closed as invalid on 2023/12/15 13:48
upstream WARNING: refcount bug in ax25_release (2) hams C 240 204d 269d 25/28 fixed on 2024/05/22 23:16

Sample crash report:
------------[ cut here ]------------
refcount_t: decrement hit 0; leaking memory.
WARNING: CPU: 0 PID: 9341 at lib/refcount.c:31 refcount_warn_saturate+0x16d/0x1a0 lib/refcount.c:31
Modules linked in:
CPU: 0 PID: 9341 Comm: syz.2.1106 Not tainted 6.1.114-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
RIP: 0010:refcount_warn_saturate+0x16d/0x1a0 lib/refcount.c:31
Code: c7 c7 20 39 5d 8b e8 a2 00 19 fd 0f 0b e9 6e ff ff ff e8 d6 e6 50 fd c6 05 9c 01 4c 0a 01 48 c7 c7 80 39 5d 8b e8 83 00 19 fd <0f> 0b e9 4f ff ff ff 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c b2 fe ff
RSP: 0018:ffffc9000392fb28 EFLAGS: 00010246
RAX: e1f418f8244a8f00 RBX: 0000000000000004 RCX: ffff8880303e0000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000004 R08: ffffffff8152afae R09: fffff52000725ec5
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff8880766ac5b8
R13: 0000000000000000 R14: ffff8880766ac5fc R15: dffffc0000000000
FS:  000055556b20e500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f089e8bf5a0 CR3: 000000007f7c6000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __refcount_dec include/linux/refcount.h:344 [inline]
 refcount_dec include/linux/refcount.h:359 [inline]
 ref_tracker_free+0x6a0/0x7d0 lib/ref_tracker.c:118
 netdev_tracker_free include/linux/netdevice.h:4028 [inline]
 netdev_put include/linux/netdevice.h:4045 [inline]
 ax25_release+0x3ef/0x940 net/ax25/af_ax25.c:1069
 __sock_release net/socket.c:654 [inline]
 sock_close+0xcd/0x230 net/socket.c:1400
 __fput+0x3f6/0x8d0 fs/file_table.c:320
 task_work_run+0x246/0x300 kernel/task_work.c:203
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xde/0x100 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x60/0x270 kernel/entry/common.c:303
 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f522557e719
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:00007ffc487ffb88 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 000000000007625e RCX: 00007f522557e719
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f5225737a80 R08: 0000000000000001 R09: 00007ffc487ffe7f
R10: 00007f5225200000 R11: 0000000000000246 R12: 00000000000762ce
R13: 00007ffc487ffc90 R14: 0000000000000032 R15: ffffffffffffffff
 </TASK>

Crashes (6):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/10/30 08:26 linux-6.1.y 7ec6f9fa3d97 66aeb999 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING: refcount bug in ax25_release
2024/08/08 06:10 linux-6.1.y 48d525b0e463 de12cf65 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING: refcount bug in ax25_release
2024/07/15 14:43 linux-6.1.y cac15753b8ce c605e6a2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING: refcount bug in ax25_release
2024/07/15 14:43 linux-6.1.y cac15753b8ce c605e6a2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING: refcount bug in ax25_release
2024/06/15 15:03 linux-6.1.y ae9f2a70d69e f429ab00 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING: refcount bug in ax25_release
2024/06/15 15:03 linux-6.1.y ae9f2a70d69e f429ab00 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING: refcount bug in ax25_release
* Struck through repros no longer work on HEAD.