[syzbot] [ext4?] WARNING in ext4_discard_allocated_blocks

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 7ba2090ca64e Merge tag 'ceph-for-6.6-rc1' of https://githu..
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=12c57f2fa80000
kernel config: https://syzkaller.appspot.com/x/.config?x=ed626705db308b2d
dashboard link: https://syzkaller.appspot.com/bug?extid=628e71e1cb809306030f
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=111acb20680000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=112d9f34680000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/7abbf7618c3a/disk-7ba2090c.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/694adc723518/vmlinux-7ba2090c.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3c5d9addc4e4/bzImage-7ba2090c.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/a4604150b51d/mount_0.gz

Bisection is inconclusive: the issue happens on the oldest tested release.

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=13e3dba8680000
final oops: https://syzkaller.appspot.com/x/report.txt?x=1013dba8680000
console output: https://syzkaller.appspot.com/x/log.txt?x=17e3dba8680000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+628e71...@syzkaller.appspotmail.com

ext4: mb_load_buddy failed (-117)
WARNING: CPU: 0 PID: 5538 at fs/ext4/mballoc.c:4620 ext4_discard_allocated_blocks+0x5d4/0x750 fs/ext4/mballoc.c:4619
Modules linked in:
CPU: 0 PID: 5538 Comm: syz-executor264 Not tainted 6.5.0-syzkaller-12107-g7ba2090ca64e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
RIP: 0010:ext4_discard_allocated_blocks+0x5d4/0x750 fs/ext4/mballoc.c:4619
Code: 00 0f 85 9a 01 00 00 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 eb 99 48 ff 48 c7 c7 00 42 1d 8b 44 89 fe e8 8c 14 0f ff <0f> 0b 49 bf 00 00 00 00 00 fc ff df eb 98 e8 c9 99 48 ff e9 19 fe
RSP: 0018:ffffc90005006cc0 EFLAGS: 00010246
RAX: da27be545f79de00 RBX: 0000000000000001 RCX: ffff888026741dc0
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90005006dd0 R08: ffffffff81541672 R09: 1ffff1101730516a
R10: dffffc0000000000 R11: ffffed101730516b R12: ffff888076b7a124
R13: 1ffff92000a00da0 R14: ffff888076b7a0d8 R15: 00000000ffffff8b
FS: 00007f095582f6c0(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020100000 CR3: 000000001c40b000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
ext4_mb_new_blocks+0x148f/0x4b30 fs/ext4/mballoc.c:6244
ext4_ext_map_blocks+0x1e13/0x7150 fs/ext4/extents.c:4285
ext4_map_blocks+0xa2f/0x1cb0 fs/ext4/inode.c:621
_ext4_get_block+0x238/0x6a0 fs/ext4/inode.c:763
ext4_block_write_begin+0x53d/0x1550 fs/ext4/inode.c:1043
ext4_write_begin+0x619/0x10b0
ext4_da_write_begin+0x300/0xa40 fs/ext4/inode.c:2865
generic_perform_write+0x31b/0x630 mm/filemap.c:3942
ext4_buffered_write_iter+0xc6/0x350 fs/ext4/file.c:299
ext4_file_write_iter+0x1d3/0x1ad0 fs/ext4/file.c:717
call_write_iter include/linux/fs.h:1985 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x782/0xaf0 fs/read_write.c:584
ksys_write+0x1a0/0x2c0 fs/read_write.c:637
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f0955872bd9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 b1 18 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f095582f218 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f09558fc6c8 RCX: 00007f0955872bd9
RDX: 000000000000a000 RSI: 0000000020000780 RDI: 0000000000000005
RBP: 00007f09558fc6c0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f09558c8a38
R13: 0000000000000000 R14: 6f6f6c2f7665642f R15: 0032656c69662f2e
</TASK>


---
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[syzbot]

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***

Subject: Test
Author: tinti...@gmail.com

#syz test:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

[syzbot]

syzbot suspects this issue was fixed by commit:

commit 6f861765464f43a71462d52026fbddfc858239a5
Author: Jan Kara <ja...@suse.cz>
Date: Wed Nov 1 17:43:10 2023 +0000

fs: Block writes to mounted block devices

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=13e72f42180000
start commit: 7ba2090ca64e Merge tag 'ceph-for-6.6-rc1' of https://githu..
git tree: upstream

kernel config: https://syzkaller.appspot.com/x/.config?x=ed626705db308b2d
dashboard link: https://syzkaller.appspot.com/bug?extid=628e71e1cb809306030f

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=111acb20680000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=112d9f34680000

If the result looks correct, please mark the issue as fixed by replying with:

#syz fix: fs: Block writes to mounted block devices

[Jan Kara]

On Thu 15-02-24 20:26:02, syzbot wrote:
> syzbot suspects this issue was fixed by commit:
>
> commit 6f861765464f43a71462d52026fbddfc858239a5
> Author: Jan Kara <ja...@suse.cz>
> Date: Wed Nov 1 17:43:10 2023 +0000
>
> fs: Block writes to mounted block devices
>
> bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=13e72f42180000
> start commit: 7ba2090ca64e Merge tag 'ceph-for-6.6-rc1' of https://githu..
> git tree: upstream
> kernel config: https://syzkaller.appspot.com/x/.config?x=ed626705db308b2d
> dashboard link: https://syzkaller.appspot.com/bug?extid=628e71e1cb809306030f
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=111acb20680000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=112d9f34680000
>
> If the result looks correct, please mark the issue as fixed by replying with:

Looks sensible.

#syz fix: fs: Block writes to mounted block devices

Honza
--
Jan Kara <ja...@suse.com>
SUSE Labs, CR