Re: [syzbot] [bcachefs?] WARNING in bchfs_truncate

[syzbot <syzbot+247ac87eabcb1f8fa990@syzkaller.appspotmail.com>]

syzbot has found a reproducer for the following issue on:

HEAD commit:    5f5673607153 Merge branch 'for-next/core' into for-kernelci
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
console output: https://syzkaller.appspot.com/x/log.txt?x=11e69c27980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=dedbcb1ff4387972
dashboard link: https://syzkaller.appspot.com/bug?extid=247ac87eabcb1f8fa990
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: arm64
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14a57480580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=15e69c27980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/40172aed5414/disk-5f567360.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/58372f305e9d/vmlinux-5f567360.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d2aae6fa798f/Image-5f567360.gz.xz
mounted in repro #1: https://storage.googleapis.com/syzbot-assets/b790e8eefcc7/mount_0.gz
mounted in repro #2: https://storage.googleapis.com/syzbot-assets/47201b805f63/mount_1.gz

The issue was bisected to:

commit 03ef80b469d5d83530ce1ce15be78a40e5300f9b
Author: Kent Overstreet <kent.overstreet@linux.dev>
Date:   Sat Sep 23 22:41:51 2023 +0000

    bcachefs: Ignore unknown mount options

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=1077cf8a980000
final oops:     https://syzkaller.appspot.com/x/report.txt?x=1277cf8a980000
console output: https://syzkaller.appspot.com/x/log.txt?x=1477cf8a980000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+247ac87eabcb1f8fa990@syzkaller.appspotmail.com
Fixes: 03ef80b469d5 ("bcachefs: Ignore unknown mount options")

------------[ cut here ]------------
truncate spotted in mem i_size < btree i_size: 1 < 57344
WARNING: CPU: 0 PID: 6420 at fs/bcachefs/fs-io.c:447 bchfs_truncate+0x988/0xab0 fs/bcachefs/fs-io.c:444
Modules linked in:
CPU: 0 UID: 0 PID: 6420 Comm: syz-executor335 Not tainted 6.11.0-rc7-syzkaller-g5f5673607153 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : bchfs_truncate+0x988/0xab0 fs/bcachefs/fs-io.c:444
lr : bchfs_truncate+0x988/0xab0 fs/bcachefs/fs-io.c:444
sp : ffff8000a4467300
x29: ffff8000a4467500 x28: ffff0000de380000 x27: 000000000000e000
x26: ffff0000de748da0 x25: dfff800000000000 x24: ffff70001488ce74
x23: 1fffe0001bce91b4 x22: ffff0000de748ca0 x21: ffff0000de3ca380
x20: ffff8000927b7000 x19: ffff0000de748760 x18: 0000000000000008
x17: 0000000000000000 x16: ffff800083032784 x15: 0000000000000001
x14: 1fffe000366d325a x13: 0000000000000000 x12: 0000000000000000
x11: 0000000000000002 x10: 0000000000ff0100 x9 : ab59bfad62359900
x8 : ab59bfad62359900 x7 : 0000000000000001 x6 : 0000000000000001
x5 : ffff8000a4466a58 x4 : ffff80008f65b620 x3 : ffff8000806051a0
x2 : 0000000000000001 x1 : 0000000100000000 x0 : 0000000000000000
Call trace:
 bchfs_truncate+0x988/0xab0 fs/bcachefs/fs-io.c:444
 bch2_setattr+0x198/0x230 fs/bcachefs/fs.c:942
 notify_change+0x9f0/0xca0 fs/attr.c:503
 do_truncate+0x1c0/0x28c fs/open.c:65
 handle_truncate fs/namei.c:3381 [inline]
 do_open fs/namei.c:3731 [inline]
 path_openat+0x2388/0x29f8 fs/namei.c:3886
 do_filp_open+0x1bc/0x3cc fs/namei.c:3913
 do_sys_openat2+0x124/0x1b8 fs/open.c:1416
 do_sys_open fs/open.c:1431 [inline]
 __do_sys_openat fs/open.c:1447 [inline]
 __se_sys_openat fs/open.c:1442 [inline]
 __arm64_sys_openat+0x1f0/0x240 fs/open.c:1442
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
 el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:712
 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730
 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598
irq event stamp: 140
hardirqs last  enabled at (139): [<ffff800080388420>] __up_console_sem kernel/printk/printk.c:341 [inline]
hardirqs last  enabled at (139): [<ffff800080388420>] __console_unlock kernel/printk/printk.c:2801 [inline]
hardirqs last  enabled at (139): [<ffff800080388420>] console_unlock+0x18c/0x3d4 kernel/printk/printk.c:3120
hardirqs last disabled at (140): [<ffff80008b3363f4>] el1_dbg+0x24/0x80 arch/arm64/kernel/entry-common.c:470
softirqs last  enabled at (8): [<ffff8000800307f8>] local_bh_enable+0x10/0x34 include/linux/bottom_half.h:32
softirqs last disabled at (6): [<ffff8000800307c4>] local_bh_disable+0x10/0x34 include/linux/bottom_half.h:19
---[ end trace 0000000000000000 ]---


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