linux-kernel - [syzbot] [jfs?] INFO: task hung in diNewExt

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Message-ID: <68fc07a0.a70a0220.3bf6c6.01ac.GAE@google.com>
Date: Fri, 24 Oct 2025 16:11:28 -0700
From: syzbot <syzbot+b367cace420c21becba6@...kaller.appspotmail.com>
To: jfs-discussion@...ts.sourceforge.net, linux-kernel@...r.kernel.org, 
	shaggy@...nel.org, syzkaller-bugs@...glegroups.com
Subject: [syzbot] [jfs?] INFO: task hung in diNewExt

Hello,

syzbot found the following issue on:

HEAD commit:    aaa9c3550b60 Add linux-next specific files for 20251022
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=17ebcd2f980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=c8b911aebadf6410
dashboard link: https://syzkaller.appspot.com/bug?extid=b367cace420c21becba6
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=161adb04580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=123c9be2580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/44f7af9b7ca1/disk-aaa9c355.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/9d09b0a9994d/vmlinux-aaa9c355.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ae729ccb2c5c/bzImage-aaa9c355.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/41800c75cd89/mount_0.gz
  fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=156e6d42580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b367cace420c21becba6@...kaller.appspotmail.com

INFO: task syz.2.19:6098 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.19        state:D stack:24120 pid:6098  tgid:6097  ppid:5976   task_flags:0x400140 flags:0x00080003
Call Trace:
 context_switch kernel/sched/core.c:5254 [inline]
 __schedule+0x17c4/0x4d60 kernel/sched/core.c:6862
 __schedule_loop kernel/sched/core.c:6944 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6959
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7016
 rwsem_down_read_slowpath+0x5fd/0x8f0 kernel/locking/rwsem.c:1086
 __down_read_common kernel/locking/rwsem.c:1261 [inline]
 __down_read kernel/locking/rwsem.c:1274 [inline]
 down_read_nested+0x9a/0x2f0 kernel/locking/rwsem.c:1663
 diNewExt+0x9af/0x3150 fs/jfs/jfs_imap.c:2261
 diAllocExt fs/jfs/jfs_imap.c:1952 [inline]
 diAllocAG+0xe86/0x1df0 fs/jfs/jfs_imap.c:1669
 diAlloc+0x1d5/0x1680 fs/jfs/jfs_imap.c:1590
 ialloc+0x8c/0x8f0 fs/jfs/jfs_inode.c:56
 jfs_mkdir+0x193/0xa70 fs/jfs/namei.c:225
 vfs_mkdir+0x306/0x510 fs/namei.c:4453
 do_mkdirat+0x247/0x590 fs/namei.c:4486
 __do_sys_mkdirat fs/namei.c:4503 [inline]
 __se_sys_mkdirat fs/namei.c:4501 [inline]
 __x64_sys_mkdirat+0x87/0xa0 fs/namei.c:4501
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa19698efc9
RSP: 002b:00007fa197895038 EFLAGS: 00000246
RBP: 00007fa196a11f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
INFO: task syz.0.17:6103 blocked for more than 148 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.17        state:D
 stack:25592 pid:6103  tgid:6102  ppid:5971   task_flags:0x400140 flags:0x00080003
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5254 [inline]
 __schedule+0x17c4/0x4d60 kernel/sched/core.c:6862
 __schedule_loop kernel/sched/core.c:6944 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6959
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7016
 rwsem_down_read_slowpath+0x5fd/0x8f0 kernel/locking/rwsem.c:1086
 __down_read_common kernel/locking/rwsem.c:1261 [inline]
 __down_read kernel/locking/rwsem.c:1274 [inline]
 down_read_nested+0x9a/0x2f0 kernel/locking/rwsem.c:1663
 dbAlloc+0x3a7/0xba0 fs/jfs/jfs_dmap.c:790
 diNewExt+0x9af/0x3150 fs/jfs/jfs_imap.c:2261
 diAllocExt fs/jfs/jfs_imap.c:1952 [inline]
 diAllocAG+0xe86/0x1df0 fs/jfs/jfs_imap.c:1669
 diAlloc+0x1d5/0x1680 fs/jfs/jfs_imap.c:1590
 ialloc+0x8c/0x8f0 fs/jfs/jfs_inode.c:56
 jfs_mkdir+0x193/0xa70 fs/jfs/namei.c:225


---
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 syzkaller@...glegroups.com.

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

If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

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