syzbot


BUG: unable to handle kernel paging request in txAllocPMap

Status: moderation: reported on 2025/12/17 16:11
Subsystems: jfs
[Documentation on labels]
Reported-by: syzbot+3cb326afc4692d993f88@syzkaller.appspotmail.com
First crash: 47d, last: 30d

Sample crash report:
blkno = c78e735740, nblocks = c74800
ERROR: (device loop0): dbUpdatePMap: blocks are outside the map
ERROR: (device loop0): remounting filesystem as read-only
BUG: unable to handle page fault for address: ffff888001215190
#PF: supervisor write access in kernel mode
#PF: error_code(0x0003) - permissions violation
PGD 1a001067 P4D 1a001067 PUD 1a002067 PMD 80000000012001a1 
Oops: Oops: 0003 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 103 Comm: jfsCommit Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:txAllocPMap+0x3d4/0x6b0 fs/jfs/jfs_txnmgr.c:2417
Code: 81 e5 ff ff ff 00 48 8b 7c 24 18 31 f6 48 89 ea 4c 89 e9 4c 8b 44 24 20 e8 b9 16 fb ff 42 0f b6 04 33 84 c0 0f 85 f7 00 00 00 <41> 80 24 24 fc 48 8b 44 24 28 42 0f b6 04 30 84 c0 0f 85 fb 00 00
RSP: 0018:ffffc9000189fb78 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 1ffff11000242a32 RCX: 3c37c5e3d1d24900
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 000000c78e735740 R08: ffffc9000189f6e7 R09: 1ffff92000313edc
R10: dffffc0000000000 R11: fffff52000313edd R12: ffff888001215190
R13: 0000000000c74800 R14: dffffc0000000000 R15: ffff888001215190
FS:  0000000000000000(0000) GS:ffff88808d416000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffff888001215190 CR3: 0000000033199000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 txUpdateMap+0x2a2/0x9c0 fs/jfs/jfs_txnmgr.c:2309
 txLazyCommit fs/jfs/jfs_txnmgr.c:2665 [inline]
 jfs_lazycommit+0x43f/0xa90 fs/jfs/jfs_txnmgr.c:2734
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
Modules linked in:
CR2: ffff888001215190
---[ end trace 0000000000000000 ]---
RIP: 0010:txAllocPMap+0x3d4/0x6b0 fs/jfs/jfs_txnmgr.c:2417
Code: 81 e5 ff ff ff 00 48 8b 7c 24 18 31 f6 48 89 ea 4c 89 e9 4c 8b 44 24 20 e8 b9 16 fb ff 42 0f b6 04 33 84 c0 0f 85 f7 00 00 00 <41> 80 24 24 fc 48 8b 44 24 28 42 0f b6 04 30 84 c0 0f 85 fb 00 00
RSP: 0018:ffffc9000189fb78 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 1ffff11000242a32 RCX: 3c37c5e3d1d24900
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 000000c78e735740 R08: ffffc9000189f6e7 R09: 1ffff92000313edc
R10: dffffc0000000000 R11: fffff52000313edd R12: ffff888001215190
R13: 0000000000c74800 R14: dffffc0000000000 R15: ffff888001215190
FS:  0000000000000000(0000) GS:ffff88808d416000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffff888001215190 CR3: 0000000033199000 CR4: 0000000000352ef0
----------------
Code disassembly (best guess):
   0:	81 e5 ff ff ff 00    	and    $0xffffff,%ebp
   6:	48 8b 7c 24 18       	mov    0x18(%rsp),%rdi
   b:	31 f6                	xor    %esi,%esi
   d:	48 89 ea             	mov    %rbp,%rdx
  10:	4c 89 e9             	mov    %r13,%rcx
  13:	4c 8b 44 24 20       	mov    0x20(%rsp),%r8
  18:	e8 b9 16 fb ff       	call   0xfffb16d6
  1d:	42 0f b6 04 33       	movzbl (%rbx,%r14,1),%eax
  22:	84 c0                	test   %al,%al
  24:	0f 85 f7 00 00 00    	jne    0x121
* 2a:	41 80 24 24 fc       	andb   $0xfc,(%r12) <-- trapping instruction
  2f:	48 8b 44 24 28       	mov    0x28(%rsp),%rax
  34:	42 0f b6 04 30       	movzbl (%rax,%r14,1),%eax
  39:	84 c0                	test   %al,%al
  3b:	0f                   	.byte 0xf
  3c:	85 fb                	test   %edi,%ebx

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/12/30 21:02 upstream dbf8fe85a16a d1b870e1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root BUG: unable to handle kernel paging request in txAllocPMap
2025/12/17 01:16 upstream 40fbbd64bba6 d1b870e1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root BUG: unable to handle kernel paging request in txAllocPMap
2025/12/13 16:07 upstream 9551a26f17d9 d1b870e1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root BUG: unable to handle kernel paging request in txAllocPMap
2025/12/15 04:09 upstream 8f0b4cce4481 d1b870e1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: vmalloc-out-of-bounds Read in txAllocPMap
* Struck through repros no longer work on HEAD.