[v6.6] general protection fault in btrfs_encoded_read_endio

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 9760bf04666d Linux 6.6.135
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=168852d2580000
kernel config: https://syzkaller.appspot.com/x/.config?x=c5b35c4db8465904
dashboard link: https://syzkaller.appspot.com/bug?extid=687ff8c95070d957cb3f
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/a685913d05a7/disk-9760bf04.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a3c1d21d4bca/vmlinux-9760bf04.xz
kernel image: https://storage.googleapis.com/syzbot-assets/09178887ef0d/bzImage-9760bf04.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+687ff8...@syzkaller.appspotmail.com

general protection fault, probably for non-canonical address 0xdffffc0021790f08: 0000 [#1] PREEMPT SMP KASAN
KASAN: probably user-memory-access in range [0x000000010bc87840-0x000000010bc87847]
CPU: 1 PID: 11 Comm: kworker/u4:0 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: btrfs-endio btrfs_end_bio_work
RIP: 0010:__wake_up_common+0x23c/0x4e0 kernel/sched/wait.c:100
Code: 24 00 00 00 00 49 83 c5 40 4d 39 ef 0f 84 ed 01 00 00 45 31 f6 eb 09 4d 39 ef 0f 84 df 01 00 00 4c 89 fd 4c 89 f8 48 c1 e8 03 <80> 3c 10 00 74 12 48 89 ef e8 36 ca 79 00 48 ba 00 00 00 00 00 fc
RSP: 0018:ffffc90000107898 EFLAGS: 00010002
RAX: 0000000021790f08 RBX: 0000000000000001 RCX: f8eda4d6cde3a300
RDX: dffffc0000000000 RSI: ffffffff8acadb60 RDI: ffffffff8b1c8e60
RBP: 000000010bc87840 R08: 0000000000000000 R09: ffffc90000107940
R10: dffffc0000000000 R11: fffff52000020efc R12: ffffc9000bc87800
R13: ffffc9000bc87840 R14: 0000000000000000 R15: 000000010bc87840
FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2d61eff8 CR3: 00000000601c9000 CR4: 00000000003506e0
Call Trace:
<TASK>
__wake_up_common_lock kernel/sched/wait.c:138 [inline]
__wake_up+0x125/0x1a0 kernel/sched/wait.c:160
btrfs_encoded_read_endio+0xd1/0x130 fs/btrfs/inode.c:10060
btrfs_check_read_bio+0xf08/0x1500 fs/btrfs/bio.c:325
process_one_work kernel/workqueue.c:2653 [inline]
process_scheduled_works+0xa5d/0x15d0 kernel/workqueue.c:2730
worker_thread+0xa55/0xfc0 kernel/workqueue.c:2811
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__wake_up_common+0x23c/0x4e0 kernel/sched/wait.c:100
Code: 24 00 00 00 00 49 83 c5 40 4d 39 ef 0f 84 ed 01 00 00 45 31 f6 eb 09 4d 39 ef 0f 84 df 01 00 00 4c 89 fd 4c 89 f8 48 c1 e8 03 <80> 3c 10 00 74 12 48 89 ef e8 36 ca 79 00 48 ba 00 00 00 00 00 fc
RSP: 0018:ffffc90000107898 EFLAGS: 00010002
RAX: 0000000021790f08 RBX: 0000000000000001 RCX: f8eda4d6cde3a300
RDX: dffffc0000000000 RSI: ffffffff8acadb60 RDI: ffffffff8b1c8e60
RBP: 000000010bc87840 R08: 0000000000000000 R09: ffffc90000107940
R10: dffffc0000000000 R11: fffff52000020efc R12: ffffc9000bc87800
R13: ffffc9000bc87840 R14: 0000000000000000 R15: 000000010bc87840
FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2d61eff8 CR3: 00000000601c9000 CR4: 00000000003506e0
----------------
Code disassembly (best guess), 1 bytes skipped:
0: 00 00 add %al,(%rax)
2: 00 00 add %al,(%rax)
4: 49 83 c5 40 add $0x40,%r13
8: 4d 39 ef cmp %r13,%r15
b: 0f 84 ed 01 00 00 je 0x1fe
11: 45 31 f6 xor %r14d,%r14d
14: eb 09 jmp 0x1f
16: 4d 39 ef cmp %r13,%r15
19: 0f 84 df 01 00 00 je 0x1fe
1f: 4c 89 fd mov %r15,%rbp
22: 4c 89 f8 mov %r15,%rax
25: 48 c1 e8 03 shr $0x3,%rax
* 29: 80 3c 10 00 cmpb $0x0,(%rax,%rdx,1) <-- trapping instruction
2d: 74 12 je 0x41
2f: 48 89 ef mov %rbp,%rdi
32: e8 36 ca 79 00 call 0x79ca6d
37: 48 rex.W
38: ba 00 00 00 00 mov $0x0,%edx
3d: 00 fc add %bh,%ah


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup