general protection fault in btrfs_encoded_read_endio (2)

Status: upstream: reported on 2026/11/01 07:57
Reported-by: syzbot+b48fc6d2672c1f1f8b9e@syzkaller.appspotmail.com
First crash: 8d07h, last: 8d07h
▶ ▼ Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.6 general protection fault in btrfs_encoded_read_endio 2 2 171d 198d 0/2 auto-obsoleted due to no activity on 2026/08/30 04:58

Sample crash report:
general protection fault, probably for non-canonical address 0xdffffc0000003fff: 0000 [#1] PREEMPT SMP KASAN
KASAN: probably user-memory-access in range [0x000000000001fff8-0x000000000001ffff]
CPU: 0 PID: 2937 Comm: kworker/u4:9 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
Workqueue: btrfs-endio btrfs_end_bio_work
RIP: 0010:__wake_up_common+0x227/0x4d0 kernel/sched/wait.c:100
Code: 07 00 00 00 00 49 83 c5 40 4c 39 ed 0f 84 f2 01 00 00 45 31 f6 eb 09 4c 39 ed 0f 84 e4 01 00 00 49 89 ef 48 89 e8 48 c1 e8 03 <80> 3c 10 00 74 12 4c 89 ff e8 3b a2 7a 00 48 ba 00 00 00 00 00 fc
RSP: 0018:ffffc9000bda78a0 EFLAGS: 00010007
RAX: 0000000000003fff RBX: 0000000000000001 RCX: 20e4a74db42b0b00
RDX: dffffc0000000000 RSI: ffffffff8aeae2c0 RDI: ffffffff8b3c5260
RBP: 000000000001ffff R08: 0000000000000000 R09: ffffc9000bda7940
R10: dffffc0000000000 R11: fffff520017b4efc R12: ffffc90004d478a0
R13: ffffc90004d478e0 R14: 0000000000000000 R15: 000000000001ffff
FS:  0000000000000000(0000) GS:ffff8880b8c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f25a3a3b250 CR3: 000000005f6a6000 CR4: 00000000003506f0
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:10245
 btrfs_check_read_bio+0xf63/0x1610 fs/btrfs/bio.c:320
 process_one_work kernel/workqueue.c:2657 [inline]
 process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2734
 worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2815
 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+0x227/0x4d0 kernel/sched/wait.c:100
Code: 07 00 00 00 00 49 83 c5 40 4c 39 ed 0f 84 f2 01 00 00 45 31 f6 eb 09 4c 39 ed 0f 84 e4 01 00 00 49 89 ef 48 89 e8 48 c1 e8 03 <80> 3c 10 00 74 12 4c 89 ff e8 3b a2 7a 00 48 ba 00 00 00 00 00 fc
RSP: 0018:ffffc9000bda78a0 EFLAGS: 00010007
RAX: 0000000000003fff RBX: 0000000000000001 RCX: 20e4a74db42b0b00
RDX: dffffc0000000000 RSI: ffffffff8aeae2c0 RDI: ffffffff8b3c5260
RBP: 000000000001ffff R08: 0000000000000000 R09: ffffc9000bda7940
R10: dffffc0000000000 R11: fffff520017b4efc R12: ffffc90004d478a0
R13: ffffc90004d478e0 R14: 0000000000000000 R15: 000000000001ffff
FS:  0000000000000000(0000) GS:ffff8880b8c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f25a3a3b250 CR3: 000000005f6a6000 CR4: 00000000003506f0
----------------
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:	4c 39 ed             	cmp    %r13,%rbp
   b:	0f 84 f2 01 00 00    	je     0x203
  11:	45 31 f6             	xor    %r14d,%r14d
  14:	eb 09                	jmp    0x1f
  16:	4c 39 ed             	cmp    %r13,%rbp
  19:	0f 84 e4 01 00 00    	je     0x203
  1f:	49 89 ef             	mov    %rbp,%r15
  22:	48 89 e8             	mov    %rbp,%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:	4c 89 ff             	mov    %r15,%rdi
  32:	e8 3b a2 7a 00       	call   0x7aa272
  37:	48                   	rex.W
  38:	ba 00 00 00 00       	mov    $0x0,%edx
  3d:	00 fc                	add    %bh,%ah

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/11/01 07:56 linux-6.6.y b5a1dc3ad482 25a0ae84 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in btrfs_encoded_read_endio
* Struck through repros no longer work on HEAD.