[syzbot] [trace?] BUG: corrupted list in ring_buffer_subbuf_order_set

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: cd2e103d57e5 Merge tag 'hardening-v6.16-rc1-fix1-take2' of..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17f0680c580000
kernel config: https://syzkaller.appspot.com/x/.config?x=d97b092471e3ab82
dashboard link: https://syzkaller.appspot.com/bug?extid=05d673e83ec640f0ced9
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1795b970580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13b281d4580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/14cc036168b8/disk-cd2e103d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/1ce688b4cfd5/vmlinux-cd2e103d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/62da26310dac/bzImage-cd2e103d.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+05d673...@syzkaller.appspotmail.com

slab kmalloc-1k start ffff88801b488800 pointer offset 576 size 1024
list_del corruption. prev->next should be ffff88802a7d3180, but was ffff88801b488a40. (prev=ffff88801b488a40)
------------[ cut here ]------------
kernel BUG at lib/list_debug.c:62!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 1 UID: 0 PID: 5851 Comm: syz-executor420 Not tainted 6.15.0-syzkaller-10820-gcd2e103d57e5 #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:__list_del_entry_valid_or_report+0x17a/0x200 lib/list_debug.c:62
Code: 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 0f 85 8d 00 00 00 48 8b 55 00 48 89 e9 48 89 de 48 c7 c7 40 33 f5 8b e8 f7 0d be fc 90 <0f> 0b 4c 89 e7 e8 1c aa 21 fd 48 89 ea 48 b8 00 00 00 00 00 fc ff
RSP: 0018:ffffc9000436fb70 EFLAGS: 00010286
RAX: 000000000000006d RBX: ffff88802a7d3180 RCX: ffffffff819a75b9
RDX: 0000000000000000 RSI: ffffffff819af446 RDI: 0000000000000005
RBP: ffff88801b488a40 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000080000000 R11: 0000000000000001 R12: ffff88802a7d3e00
R13: ffff88802a7d3180 R14: ffff88802a7d3e00 R15: 0000000000000001
FS: 0000555580420380(0000) GS:ffff888124a75000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1e1bcb9130 CR3: 0000000075590000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
__list_del_entry_valid include/linux/list.h:124 [inline]
__list_del_entry include/linux/list.h:215 [inline]
list_del_init include/linux/list.h:287 [inline]
ring_buffer_subbuf_order_set+0x92e/0x18f0 kernel/trace/ring_buffer.c:6921
buffer_subbuf_size_write+0x182/0x280 kernel/trace/trace.c:9546
vfs_write+0x2a0/0x1150 fs/read_write.c:684
ksys_write+0x12a/0x250 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0x490 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1e1bc3eca9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 c1 17 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fffe8f63c48 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f1e1bc3eca9
RDX: 000000000000fdef RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00000000000f4240 R08: 00000000000000a0 R09: 00000000000000a0
R10: 00000000000000a0 R11: 0000000000000246 R12: 00000000000175b3
R13: 00007fffe8f63c5c R14: 00007fffe8f63c70 R15: 00007fffe8f63c60
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__list_del_entry_valid_or_report+0x17a/0x200 lib/list_debug.c:62
Code: 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 0f 85 8d 00 00 00 48 8b 55 00 48 89 e9 48 89 de 48 c7 c7 40 33 f5 8b e8 f7 0d be fc 90 <0f> 0b 4c 89 e7 e8 1c aa 21 fd 48 89 ea 48 b8 00 00 00 00 00 fc ff
RSP: 0018:ffffc9000436fb70 EFLAGS: 00010286
RAX: 000000000000006d RBX: ffff88802a7d3180 RCX: ffffffff819a75b9
RDX: 0000000000000000 RSI: ffffffff819af446 RDI: 0000000000000005
RBP: ffff88801b488a40 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000080000000 R11: 0000000000000001 R12: ffff88802a7d3e00
R13: ffff88802a7d3180 R14: ffff88802a7d3e00 R15: 0000000000000001
FS: 0000555580420380(0000) GS:ffff888124a75000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1e1bcb60d0 CR3: 0000000075590000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


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***

Subject: #syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git e271ed52b344ac02d4581286961d0c40acc54c03
Author: dman...@yandex.ru

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git e271ed52b344ac02d4581286961d0c40acc54c03

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+05d673...@syzkaller.appspotmail.com
Tested-by: syzbot+05d673...@syzkaller.appspotmail.com

Tested on:

commit: e271ed52 Merge tag 'pm-6.16-rc1-3' of git://git.kernel..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=16d93c0c580000
kernel config: https://syzkaller.appspot.com/x/.config?x=6ede24871858ac52

dashboard link: https://syzkaller.appspot.com/bug?extid=05d673e83ec640f0ced9
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=17893c0c580000

Note: testing is done by a robot and is best-effort only.

[Hillf Danton]

> Date: Fri, 06 Jun 2025 00:29:28 -0700

> syzbot found the following issue on:
>
> HEAD commit: cd2e103d57e5 Merge tag 'hardening-v6.16-rc1-fix1-take2' of..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=17f0680c580000
> kernel config: https://syzkaller.appspot.com/x/.config?x=d97b092471e3ab82
> dashboard link: https://syzkaller.appspot.com/bug?extid=05d673e83ec640f0ced9
> compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1795b970580000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13b281d4580000

#syz test

--- x/kernel/trace/ring_buffer.c
+++ y/kernel/trace/ring_buffer.c
@@ -6909,7 +6909,6 @@ error:
buffer->subbuf_size = old_size;

atomic_dec(&buffer->record_disabled);
- mutex_unlock(&buffer->mutex);

for_each_buffer_cpu(buffer, cpu) {
cpu_buffer = buffer->buffers[cpu];
@@ -6922,6 +6921,7 @@ error:
free_buffer_page(bpage);
}
}
+ mutex_unlock(&buffer->mutex);

return err;
}
--

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+05d673...@syzkaller.appspotmail.com
Tested-by: syzbot+05d673...@syzkaller.appspotmail.com

Tested on:

commit: e271ed52 Merge tag 'pm-6.16-rc1-3' of git://git.kernel..

git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14499570580000
kernel config: https://syzkaller.appspot.com/x/.config?x=6ede24871858ac52

dashboard link: https://syzkaller.appspot.com/bug?extid=05d673e83ec640f0ced9
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=15e19570580000