Re: [syzbot] [media?] BUG: corrupted list in az6007_i2c_xfer

[syzbot <syzbot+0192952caa411a3be209@syzkaller.appspotmail.com>]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
WARNING in az6007_i2c_xfer

az6007_i2c_xfer 8 : ffff88802743c880
------------[ cut here ]------------
DEBUG_LOCKS_WARN_ON(__owner_task(owner) != get_current())
WARNING: CPU: 1 PID: 7034 at kernel/locking/mutex.c:933 __mutex_unlock_slowpath+0x528/0x7b0 kernel/locking/mutex.c:933
Modules linked in:
CPU: 1 UID: 0 PID: 7034 Comm: syz.3.115 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:__mutex_unlock_slowpath+0x528/0x7b0 kernel/locking/mutex.c:933
Code: 08 84 c9 0f 85 78 02 00 00 44 8b 15 f2 ac 1a 05 45 85 d2 75 19 90 48 c7 c6 a0 5a ad 8b 48 c7 c7 60 56 ad 8b e8 79 29 ea f5 90 <0f> 0b 90 90 90 48 c7 c1 80 60 e3 9a 48 b8 00 00 00 00 00 fc ff df
RSP: 0018:ffffc9000420f918 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88802743c880 RCX: ffffffff817a2388
RDX: ffff888027188000 RSI: ffffffff817a2395 RDI: 0000000000000001
RBP: 1ffff92000841f28 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 205d313636365420 R12: 0000000000000003
R13: fffffbfff35c6c10 R14: ffffc9000420f9a0 R15: ffff888029d58000
FS:  00007f0406c336c0(0000) GS:ffff8881247e1000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000000025c0 CR3: 0000000062914000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 az6007_i2c_xfer+0x821/0xe50 drivers/media/usb/dvb-usb-v2/az6007.c:857
 __i2c_transfer+0x6b6/0x2190 drivers/i2c/i2c-core-base.c:2264
 i2c_transfer drivers/i2c/i2c-core-base.c:2320 [inline]
 i2c_transfer+0x1da/0x380 drivers/i2c/i2c-core-base.c:2296
 i2c_transfer_buffer_flags+0x10c/0x190 drivers/i2c/i2c-core-base.c:2348
 i2c_master_recv include/linux/i2c.h:79 [inline]
 i2cdev_read+0x111/0x280 drivers/i2c/i2c-dev.c:155
 do_loop_readv_writev fs/read_write.c:847 [inline]
 do_loop_readv_writev fs/read_write.c:835 [inline]
 vfs_readv+0x5c1/0x8b0 fs/read_write.c:1020
 do_preadv+0x1a6/0x270 fs/read_write.c:1132
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0405d8e169
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:00007f0406c33038 EFLAGS: 00000246
 ORIG_RAX: 0000000000000127
RAX: ffffffffffffffda RBX: 00007f0405fb5fa0 RCX: 00007f0405d8e169
RDX: 0000000000000001 RSI: 00002000000025c0 RDI: 0000000000000004
RBP: 00007f0405e10a68 R08: 000000000000007e R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f0405fb5fa0 R15: 00007ffdf15e6ff8
 </TASK>


Tested on:

commit:         d1d10cea Merge tag 'perf-tools-fixes-for-v6.17-2025-09..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15986962580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=bce5d4c1cf285a6c
dashboard link: https://syzkaller.appspot.com/bug?extid=0192952caa411a3be209
compiler:       gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=12cda87c580000