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

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Message-ID: <6799f224.050a0220.ac840.02cb.GAE@google.com>
Date: Wed, 29 Jan 2025 01:17:24 -0800
From: syzbot <syzbot+de02219c78c082fe2f21@...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 btree_interior_update_work

Hello,

syzbot found the following issue on:

HEAD commit:    ab18b8fff124 Merge tag 'auxdisplay-v6.14-1' of git://git.k..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13a47564580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=ac8df499d47c7efd
dashboard link: https://syzkaller.appspot.com/bug?extid=de02219c78c082fe2f21
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/366f413714ce/disk-ab18b8ff.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/5270d59ecedc/vmlinux-ab18b8ff.xz
kernel image: https://storage.googleapis.com/syzbot-assets/43d7aec7a24c/bzImage-ab18b8ff.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+de02219c78c082fe2f21@...kaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in btree_update_nodes_written fs/bcachefs/btree_update_interior.c:688 [inline]
BUG: KMSAN: uninit-value in btree_interior_update_work+0xcef/0x4820 fs/bcachefs/btree_update_interior.c:844
 btree_update_nodes_written fs/bcachefs/btree_update_interior.c:688 [inline]
 btree_interior_update_work+0xcef/0x4820 fs/bcachefs/btree_update_interior.c:844
 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+0x6b9/0xef0 kernel/kthread.c:464
 ret_from_fork+0x6d/0x90 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Uninit was created at:
 ___kmalloc_large_node+0x22c/0x370 mm/slub.c:4253
 __kmalloc_large_node_noprof+0x3f/0x1e0 mm/slub.c:4270
 __do_kmalloc_node mm/slub.c:4286 [inline]
 __kmalloc_node_noprof+0xc96/0x1250 mm/slub.c:4304
 __kvmalloc_node_noprof+0xc0/0x2d0 mm/util.c:645
 btree_node_data_alloc fs/bcachefs/btree_cache.c:153 [inline]
 __bch2_btree_node_mem_alloc+0x2be/0xa80 fs/bcachefs/btree_cache.c:198
 bch2_fs_btree_cache_init+0x4f0/0xb60 fs/bcachefs/btree_cache.c:652
 bch2_fs_alloc fs/bcachefs/super.c:908 [inline]
 bch2_fs_open+0x4b24/0x59c0 fs/bcachefs/super.c:2053
 bch2_fs_get_tree+0x986/0x2330 fs/bcachefs/fs.c:2190
 vfs_get_tree+0xb1/0x5a0 fs/super.c:1814
 do_new_mount+0x71f/0x15e0 fs/namespace.c:3560
 path_mount+0x742/0x1f10 fs/namespace.c:3887
 do_mount fs/namespace.c:3900 [inline]
 __do_sys_mount fs/namespace.c:4111 [inline]
 __se_sys_mount+0x71f/0x800 fs/namespace.c:4088
 __x64_sys_mount+0xe4/0x150 fs/namespace.c:4088
 x64_sys_call+0x39bf/0x3c30 arch/x86/include/generated/asm/syscalls_64.h:166
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 0 UID: 0 PID: 5856 Comm: kworker/u8:4 Not tainted 6.13.0-syzkaller-06077-gab18b8fff124 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Workqueue: btree_update btree_interior_update_work
=====================================================


---
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:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

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

If you want to overwrite report's subsystems, reply with:
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(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