syzbot
WARNING in as102_stream_ctrl
Status:
upstream: reported on 2026/08/04 00:43
Subsystems:
media
Labels:
prio:low
[Documentation on labels]
Reported-by: syzbot+ea047a32630b1f47da67@syzkaller.appspotmail.com
First crash: 4d20h, last: 5h41m
Sample crash report:
------------[ cut here ]------------
DEBUG_LOCKS_WARN_ON(lock->magic != lock)
WARNING: kernel/locking/mutex.c:625 at __mutex_lock_common kernel/locking/mutex.c:625 [inline], CPU#1: syz.0.1963/14166
WARNING: kernel/locking/mutex.c:625 at __mutex_lock+0x947/0x1bd0 kernel/locking/mutex.c:821, CPU#1: syz.0.1963/14166
Modules linked in:
CPU: 1 UID: 0 PID: 14166 Comm: syz.0.1963 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:__mutex_lock_common kernel/locking/mutex.c:625 [inline]
RIP: 0010:__mutex_lock+0x94e/0x1bd0 kernel/locking/mutex.c:821
Code: 0f b6 14 11 38 d0 7c 08 84 d2 0f 85 c6 10 00 00 44 8b 35 a5 31 67 05 45 85 f6 75 13 48 8d 3d 69 8f 6a 05 48 c7 c6 00 d9 cf 8b <67> 48 0f b9 3a 90 e9 18 f8 ff ff 4d 8d a7 e8 0a 00 00 4c 89 e7 e8
RSP: 0018:ffffc90005b57670 EFLAGS: 00010246
RAX: 0000000000000003 RBX: ffff88804fe4c010 RCX: 1ffffffff2245cb0
RDX: 0000000000000000 RSI: ffffffff8bcfd900 RDI: ffffffff91264350
RBP: ffffc90005b577e0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS: 00007f84be8366c0(0000) GS:ffff888123ed9000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f84be835ff8 CR3: 0000000033bf4000 CR4: 0000000000350ef0
Call Trace:
<TASK>
as102_stream_ctrl+0x28/0xd0 drivers/media/usb/as102/as102_drv.c:259
dvb_frontend_open+0x220/0x16d0 drivers/media/dvb-core/dvb_frontend.c:2825
dvb_device_open+0x270/0x3b0 drivers/media/dvb-core/dvbdev.c:109
chrdev_open+0x234/0x6a0 fs/char_dev.c:411
do_dentry_open+0x6ab/0x14d0 fs/open.c:947
vfs_open+0x82/0x3f0 fs/open.c:1052
do_open fs/namei.c:4700 [inline]
path_openat+0x2873/0x4280 fs/namei.c:4863
do_file_open+0x20e/0x430 fs/namei.c:4892
do_sys_openat2+0x10f/0x1e0 fs/open.c:1368
do_sys_open fs/open.c:1374 [inline]
__do_sys_openat fs/open.c:1390 [inline]
__se_sys_openat fs/open.c:1385 [inline]
__x64_sys_openat+0x12d/0x210 fs/open.c:1385
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f84bd95e84e
Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007f84be835b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f84be8366c0 RCX: 00007f84bd95e84e
RDX: 0000000000000802 RSI: 00007f84be835c00 RDI: ffffffffffffff9c
RBP: 00007f84be835c00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd
R13: 00007f84bdc263f8 R14: 00007f84bdc26360 R15: 00007fff78f26348
</TASK>
----------------
Code disassembly (best guess):
0: 0f b6 14 11 movzbl (%rcx,%rdx,1),%edx
4: 38 d0 cmp %dl,%al
6: 7c 08 jl 0x10
8: 84 d2 test %dl,%dl
a: 0f 85 c6 10 00 00 jne 0x10d6
10: 44 8b 35 a5 31 67 05 mov 0x56731a5(%rip),%r14d # 0x56731bc
17: 45 85 f6 test %r14d,%r14d
1a: 75 13 jne 0x2f
1c: 48 8d 3d 69 8f 6a 05 lea 0x56a8f69(%rip),%rdi # 0x56a8f8c
23: 48 c7 c6 00 d9 cf 8b mov $0xffffffff8bcfd900,%rsi
* 2a: 67 48 0f b9 3a ud1 (%edx),%rdi <-- trapping instruction
2f: 90 nop
30: e9 18 f8 ff ff jmp 0xfffff84d
35: 4d 8d a7 e8 0a 00 00 lea 0xae8(%r15),%r12
3c: 4c 89 e7 mov %r12,%rdi
3f: e8 .byte 0xe8
* Struck through repros no longer work on HEAD.