linux-kernel - [syzbot] [bcachefs?] KMSAN: uninit-value in bch2_write

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Message-ID: <6794d5e3.050a0220.2eae65.0028.GAE@google.com>
Date: Sat, 25 Jan 2025 04:15:31 -0800
From: syzbot <syzbot+c17ad4b4367b72a853cb@...kaller.appspotmail.com>
To: kent.overstreet@...ux.dev, linux-bcachefs@...r.kernel.org, 
	linux-kernel@...r.kernel.org, syzkaller-bugs@...glegroups.com
Subject: [syzbot] [bcachefs?] KMSAN: uninit-value in bch2_write_inode

Hello,

syzbot found the following issue on:

HEAD commit:    95ec54a420b8 Merge tag 'powerpc-6.14-1' of git://git.kerne..
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=106f2ab0580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=94988d5f349cacd5
dashboard link: https://syzkaller.appspot.com/bug?extid=c17ad4b4367b72a853cb
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=13688ab0580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=140d89f8580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/df0d06cacc21/disk-95ec54a4.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/37dde637fea7/vmlinux-95ec54a4.xz
kernel image: https://storage.googleapis.com/syzbot-assets/f2689e46ad3d/bzImage-95ec54a4.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/75c69a8942c4/mount_2.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c17ad4b4367b72a853cb@...kaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in bch2_write_inode+0x9fa/0xf80 fs/bcachefs/fs.c:109
 bch2_write_inode+0x9fa/0xf80 fs/bcachefs/fs.c:109
 bch2_vfs_write_inode+0x8a/0x150 fs/bcachefs/fs.c:1835
 write_inode fs/fs-writeback.c:1525 [inline]
 __writeback_single_inode+0x8da/0x1290 fs/fs-writeback.c:1745
 writeback_sb_inodes+0xa34/0x1c20 fs/fs-writeback.c:1976
 __writeback_inodes_wb+0x14c/0x440 fs/fs-writeback.c:2047
 wb_writeback+0x50b/0xcb0 fs/fs-writeback.c:2158
 wb_check_old_data_flush fs/fs-writeback.c:2262 [inline]
 wb_do_writeback fs/fs-writeback.c:2315 [inline]
 wb_workfn+0x110c/0x1940 fs/fs-writeback.c:2343
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0xae0/0x1c40 kernel/workqueue.c:3317
 worker_thread+0xea7/0x14f0 kernel/workqueue.c:3398
 kthread+0x3e2/0x540 kernel/kthread.c:389
 ret_from_fork+0x6d/0x90 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Local variable io_opts.i117 created at:
 bch2_inode_rebalance_opts_get fs/bcachefs/inode.h:291 [inline]
 bch2_write_inode+0x696/0xf80 fs/bcachefs/fs.c:107
 bch2_vfs_write_inode+0x8a/0x150 fs/bcachefs/fs.c:1835

CPU: 0 UID: 0 PID: 3918 Comm: kworker/u8:17 Not tainted 6.13.0-syzkaller-00918-g95ec54a420b8 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Workqueue: writeback wb_workfn (flush-bcachefs-1)
=====================================================


---
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.

syzbot will keep track of this issue. See:
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If the report is already addressed, let syzbot know by replying with:
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