Re: [syzbot] [media?] KASAN: slab-use-after-free Read in dvb_frontend_release (3)

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
BUG: corrupted list in dvb_remove_device

 non-paged memory
list_del corruption, ffff88802b938400->next is LIST_POISON1 (dead000000000100)
------------[ cut here ]------------
kernel BUG at lib/list_debug.c:58!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 1 UID: 0 PID: 6584 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:__list_del_entry_valid_or_report+0x10e/0x190 lib/list_debug.c:56
Code: a0 47 a6 8b 48 89 de e8 20 01 80 fc 90 0f 0b 4c 89 e7 e8 b5 c4 61 fd 48 c7 c7 00 48 a6 8b 48 89 de 4c 89 e2 e8 03 01 80 fc 90 <0f> 0b 4c 89 e7 e8 98 c4 61 fd 48 c7 c7 60 48 a6 8b 48 89 de 4c 89
RSP: 0018:ffffc90003b6fa88 EFLAGS: 00010246
RAX: 000000000000004e RBX: ffff88802b938400 RCX: 70c5d03fc278f600
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed1017124923 R12: dead000000000100
R13: dffffc0000000000 R14: dead000000000100 R15: dead000000000122
FS:  000055556ef5d500(0000) GS:ffff888126442000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f467ca4efeb CR3: 0000000025052000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 __list_del_entry_valid include/linux/list.h:132 [inline]
 __list_del_entry include/linux/list.h:223 [inline]
 list_del include/linux/list.h:237 [inline]
 dvb_remove_device+0x131/0x280 drivers/media/dvb-core/dvbdev.c:611
 dvb_frontend_release+0x3e6/0x510 drivers/media/dvb-core/dvb_frontend.c:2936
 __fput+0x461/0xa90 fs/file_table.c:469
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 get_signal+0x11c3/0x1310 kernel/signal.c:2807
 arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop+0x86/0x480 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
 do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe67637bf79
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc7f8caa78 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007ffc7f8cab60 RCX: 00007fe67637bf79
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 0000000000023360 R08: 0000000000000001 R09: 0000000000000000
R10: 0000001b30020000 R11: 0000000000000246 R12: 00007ffc7f8caba0
R13: 00007fe6765f5fac R14: 00000000000233c3 R15: 00007fe6765f5fa0
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__list_del_entry_valid_or_report+0x10e/0x190 lib/list_debug.c:56
Code: a0 47 a6 8b 48 89 de e8 20 01 80 fc 90 0f 0b 4c 89 e7 e8 b5 c4 61 fd 48 c7 c7 00 48 a6 8b 48 89 de 4c 89 e2 e8 03 01 80 fc 90 <0f> 0b 4c 89 e7 e8 98 c4 61 fd 48 c7 c7 60 48 a6 8b 48 89 de 4c 89
RSP: 0018:ffffc90003b6fa88 EFLAGS: 00010246
RAX: 000000000000004e RBX: ffff88802b938400 RCX: 70c5d03fc278f600
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed1017124923 R12: dead000000000100
R13: dffffc0000000000 R14: dead000000000100 R15: dead000000000122
FS:  000055556ef5d500(0000) GS:ffff888126442000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f467ca4efeb CR3: 0000000025052000 CR4: 00000000003526f0


Tested on:

commit:         d79526b8 Merge tag 'spi-fix-v7.0-merge-window' of git:..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=143a8152580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=4b084d82ac8e0fbd
dashboard link: https://syzkaller.appspot.com/bug?extid=ae466a728017ec940b41
compiler:       Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1572f95a580000