Is remount racy?
Is remount racy?
jfs_dirty_inode called on read-only volume
Is remount racy?
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000105: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000828-0x000000000000082f]
CPU: 1 UID: 0 PID: 6308 Comm: syz.0.97 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:JFS_SBI fs/jfs/jfs_incore.h:217 [inline]
RIP: 0010:txEnd+0xb4/0x530 fs/jfs/jfs_txnmgr.c:508
Code: 49 8d 5e 20 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 ac ca ce fe 41 bf 28 08 00 00 4c 03 3b 4c 89 f8 48 c1 e8 03 <42> 80 3c 28 00 74 08 4c 89 ff e8 8d ca ce fe 49 8b 1f 48 83 c3 30
RSP: 0018:ffffc90005737ae0 EFLAGS: 00010206
RAX: 0000000000000105 RBX: ffffc900030e9020 RCX: 0000000000000046
RDX: 0000000000000006 RSI: ffffffff8dafa05e RDI: ffff88805df15d00
RBP: ffffc90005737d68 R08: ffffffff8fafb037 R09: 1ffffffff1f5f606
R10: dffffc0000000000 R11: fffffbfff1f5f607 R12: 00000000ffffffe2
R13: dffffc0000000000 R14: ffffc900030e9000 R15: 0000000000000828
FS:  00007f14f4ac66c0(0000) GS:ffff888125d32000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1e71dcc000 CR3: 000000005e01a000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 jfs_mkdir+0x2ee/0xaf0 fs/jfs/namei.c:294
 vfs_mkdir+0x408/0x620 fs/namei.c:5410
 filename_mkdirat+0x289/0x520 fs/namei.c:5443
 __do_sys_mkdirat fs/namei.c:5464 [inline]
 __se_sys_mkdirat+0x35/0x150 fs/namei.c:5461
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f14f686e0d9
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:00007f14f4ac6028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007f14f6af5fa0 RCX: 00007f14f686e0d9
RDX: 00000000000001ed RSI: 0000200000000100 RDI: ffffffffffffff9c
RBP: 00007f14f6905024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f14f6af6038 R14: 00007f14f6af5fa0 R15: 00007fffce8a1378
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:JFS_SBI fs/jfs/jfs_incore.h:217 [inline]
RIP: 0010:txEnd+0xb4/0x530 fs/jfs/jfs_txnmgr.c:508
Code: 49 8d 5e 20 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 ac ca ce fe 41 bf 28 08 00 00 4c 03 3b 4c 89 f8 48 c1 e8 03 <42> 80 3c 28 00 74 08 4c 89 ff e8 8d ca ce fe 49 8b 1f 48 83 c3 30
RSP: 0018:ffffc90005737ae0 EFLAGS: 00010206
RAX: 0000000000000105 RBX: ffffc900030e9020 RCX: 0000000000000046
RDX: 0000000000000006 RSI: ffffffff8dafa05e RDI: ffff88805df15d00
RBP: ffffc90005737d68 R08: ffffffff8fafb037 R09: 1ffffffff1f5f606
R10: dffffc0000000000 R11: fffffbfff1f5f607 R12: 00000000ffffffe2
R13: dffffc0000000000 R14: ffffc900030e9000 R15: 0000000000000828
FS:  00007f14f4ac66c0(0000) GS:ffff888125d32000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1e71dcc000 CR3: 000000005e01a000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
   0:	49 8d 5e 20          	lea    0x20(%r14),%rbx
   4:	48 89 d8             	mov    %rbx,%rax
   7:	48 c1 e8 03          	shr    $0x3,%rax
   b:	42 80 3c 28 00       	cmpb   $0x0,(%rax,%r13,1)
  10:	74 08                	je     0x1a
  12:	48 89 df             	mov    %rbx,%rdi
  15:	e8 ac ca ce fe       	call   0xfececac6
  1a:	41 bf 28 08 00 00    	mov    $0x828,%r15d
  20:	4c 03 3b             	add    (%rbx),%r15
  23:	4c 89 f8             	mov    %r15,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 80 3c 28 00       	cmpb   $0x0,(%rax,%r13,1) <-- trapping instruction
  2f:	74 08                	je     0x39
  31:	4c 89 ff             	mov    %r15,%rdi
  34:	e8 8d ca ce fe       	call   0xfececac6
  39:	49 8b 1f             	mov    (%r15),%rbx
  3c:	48 83 c3 30          	add    $0x30,%rbx