Re: [syzbot] [jfs] general protection fault in txEnd

[syzbot]

Hello,

syzbot tried to test the proposed patch but the build/boot failed:

failed to apply patch:
checking file fs/jfs/namei.c
patch: **** unexpected end of file in patch



Tested on:

commit: 26df51ad Merge tag 'drm-fixes-2026-03-28-1' of https:/..
git tree: upstream
kernel config: https://syzkaller.appspot.com/x/.config?x=14b6a9313e132a6b
dashboard link: https://syzkaller.appspot.com/bug?extid=1d096d31de6a0491b55e
compiler:
patch: https://syzkaller.appspot.com/x/patch.diff?x=11dd6f72580000

[syzbot]

patch: https://syzkaller.appspot.com/x/patch.diff?x=13ef8102580000

[syzbot]

patch: https://syzkaller.appspot.com/x/patch.diff?x=10036f72580000

[Rafael Alejandro Díaz Cruz]

#syz test

diff --git a/fs/jfs/namei.c b/fs/jfs/namei.c
index 60c4a0e0fca5..25b303276b82 100644
--- a/fs/jfs/namei.c
+++ b/fs/jfs/namei.c
@@ -97,6 +97,10 @@ static int jfs_create(struct mnt_idmap *idmap,
struct inode *dip,
}
tid = txBegin(dip->i_sb, 0);
+ if (tid == 0) {
+ jfs_err("jfs_create: unable to create tblk due to read only filesystem");
+ return -EROFS;
+ }
mutex_lock_nested(&JFS_IP(dip)->commit_mutex, COMMIT_MUTEX_PARENT);
mutex_lock_nested(&JFS_IP(ip)->commit_mutex, COMMIT_MUTEX_CHILD);

On Fri, Mar 27, 2026 at 6:44 PM Rafael Alejandro Díaz Cruz
<rafa...@gmail.com> wrote:
>
> #syz test
>
> diff --git a/fs/jfs/namei.c b/fs/jfs/namei.c
> index 60c4a0e0fca5..25b303276b82 100644
> --- a/fs/jfs/namei.c
> +++ b/fs/jfs/namei.c
> @@ -97,6 +97,10 @@ static int jfs_create(struct mnt_idmap *idmap, struct inode *dip,
> }
> tid = txBegin(dip->i_sb, 0);
> + if (tid == 0) {
> + jfs_err("jfs_create: unable to create tblk due to read only filesystem");
> + return -EROFS;
> + }
> mutex_lock_nested(&JFS_IP(dip)->commit_mutex, COMMIT_MUTEX_PARENT);
> mutex_lock_nested(&JFS_IP(ip)->commit_mutex, COMMIT_MUTEX_CHILD);

[Rafael Alejandro Díaz Cruz]

[Rafael Alejandro Diaz Cruz]

#syz test

[Rafael Alejandro Díaz Cruz]

On Fri, Mar 27, 2026 at 6:33 PM syzbot <syzbot+1d096d...@syzkaller.appspotmail.com> wrote:

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
VFS: Busy inodes after unmount (use-after-free)

VFS: Busy inodes after unmount of loop0 (jfs)
------------[ cut here ]------------
kernel BUG at fs/super.c:656!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 6453 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:generic_shutdown_super+0x2c4/0x2d0 fs/super.c:654
Code: 03 42 80 3c 28 00 74 08 4c 89 f7 e8 06 7b ed ff 49 8b 16 48 81 c3 68 06 00 00 48 c7 c7 60 c1 b9 8b 48 89 de e8 ed 52 e8 fe 90 <0f> 0b 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc900036c7d00 EFLAGS: 00010246
RAX: 000000000000002d RBX: ffff888030f16668 RCX: fd47a21cb303a300
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 1ffff110061e2cf0 R08: ffffc900036c7a87 R09: 1ffff920006d8f50
R10: dffffc0000000000 R11: fffff520006d8f51 R12: 0000000000000000
R13: dffffc0000000000 R14: ffffffff8e99a160 R15: ffff888030f16780
FS: 0000555583959500(0000) GS:ffff88812576d000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fffe3d12ff0 CR3: 000000007abd2000 CR4: 0000000000350ef0
Call Trace:
<TASK>
kill_block_super+0x44/0x90 fs/super.c:1725
deactivate_locked_super+0xbc/0x130 fs/super.c:476
cleanup_mnt+0x437/0x4d0 fs/namespace.c:1312
task_work_run+0x1d9/0x270 kernel/task_work.c:233
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
__exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4217b9c157
Code: a2 c7 05 3c 84 23 00 00 00 00 00 eb 96 e8 e1 12 00 00 90 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007fffe3d13178 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f4217c2f33b RCX: 00007f4217b9c157
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007fffe3d13230
RBP: 00007fffe3d13230 R08: 00007fffe3d14230 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fffe3d142c0
R13: 00007f4217c2f33b R14: 0000000000021b21 R15: 00007fffe3d14300
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:generic_shutdown_super+0x2c4/0x2d0 fs/super.c:654
Code: 03 42 80 3c 28 00 74 08 4c 89 f7 e8 06 7b ed ff 49 8b 16 48 81 c3 68 06 00 00 48 c7 c7 60 c1 b9 8b 48 89 de e8 ed 52 e8 fe 90 <0f> 0b 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc900036c7d00 EFLAGS: 00010246
RAX: 000000000000002d RBX: ffff888030f16668 RCX: fd47a21cb303a300
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 1ffff110061e2cf0 R08: ffffc900036c7a87 R09: 1ffff920006d8f50
R10: dffffc0000000000 R11: fffff520006d8f51 R12: 0000000000000000
R13: dffffc0000000000 R14: ffffffff8e99a160 R15: ffff888030f16780
FS: 0000555583959500(0000) GS:ffff88812586d000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000563cc45995e0 CR3: 000000007abd2000 CR4: 0000000000350ef0


Tested on:

commit: cbfffcca Merge tag 'trace-v7.0-rc5' of git://git.kerne..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=156eceda580000
kernel config: https://syzkaller.appspot.com/x/.config?x=df6930c3610cf79
dashboard link: https://syzkaller.appspot.com/bug?extid=1d096d31de6a0491b55e
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
patch: https://syzkaller.appspot.com/x/patch.diff?x=1684f1f6580000

[Rafael Alejandro Diaz Cruz]

#syz test

[syzbot]

Hello,

syzbot tried to test the proposed patch but the build/boot failed:

failed to apply patch:
checking file fs/jfs/namei.c

Hunk #1 FAILED at 99.
1 out of 1 hunk FAILED



Tested on:

commit: d0c3bcd5 Merge tag 'libcrypto-for-linus' of git://git...

git tree: upstream
kernel config: https://syzkaller.appspot.com/x/.config?x=14b6a9313e132a6b

dashboard link: https://syzkaller.appspot.com/bug?extid=1d096d31de6a0491b55e
compiler:

patch: https://syzkaller.appspot.com/x/patch.diff?x=168d01ca580000

[Rafael Alejandro Diaz Cruz]

#syz test