linux-kernel - [syzbot] [bcachefs?] KMSAN: uninit-value in bch2_trans_start_alloc_update

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [day] [month] [year] [list]
Message-ID: <677743ce.050a0220.178762.0036.GAE@google.com>
Date: Thu, 02 Jan 2025 17:56:30 -0800
From: syzbot <syzbot+3304ecaea706d3a6524c@...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_trans_start_alloc_update_noupdate

Hello,

syzbot found the following issue on:

HEAD commit:    4099a71718b0 Merge tag 'sched-urgent-2024-12-29' of git://..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=103e70b0580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f9048090d7bb0d06
dashboard link: https://syzkaller.appspot.com/bug?extid=3304ecaea706d3a6524c
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/62835b60de83/disk-4099a717.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/9262b999e6be/vmlinux-4099a717.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3fc8cec4d596/bzImage-4099a717.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+3304ecaea706d3a6524c@...kaller.appspotmail.com

bcachefs (loop3): starting version 1.7: mi_btree_bitmap opts=errors=continue,metadata_checksum=none,data_checksum=none,compression=lz4,nojournal_transaction_names
bcachefs (loop3): initializing new filesystem
bcachefs (loop3): going read-write
bcachefs (loop3): marking superblocks
=====================================================
BUG: KMSAN: uninit-value in bch2_alloc_to_v4_mut_inlined fs/bcachefs/alloc_background.c:447 [inline]
BUG: KMSAN: uninit-value in bch2_trans_start_alloc_update_noupdate+0x61b/0x12f0 fs/bcachefs/alloc_background.c:472
 bch2_alloc_to_v4_mut_inlined fs/bcachefs/alloc_background.c:447 [inline]
 bch2_trans_start_alloc_update_noupdate+0x61b/0x12f0 fs/bcachefs/alloc_background.c:472
 __bch2_trans_mark_metadata_bucket fs/bcachefs/buckets.c:958 [inline]
 bch2_trans_mark_metadata_bucket+0x2e6/0x2430 fs/bcachefs/buckets.c:1048
 __bch2_trans_mark_dev_sb fs/bcachefs/buckets.c:1120 [inline]
 bch2_trans_mark_dev_sb+0xcf7/0x10e0 fs/bcachefs/buckets.c:1133
 bch2_trans_mark_dev_sbs_flags+0x3e5/0x9f0 fs/bcachefs/buckets.c:1143
 bch2_trans_mark_dev_sbs+0x32/0x40 fs/bcachefs/buckets.c:1155
 bch2_fs_initialize+0x19bd/0x35d0 fs/bcachefs/recovery.c:1074
 bch2_fs_start+0x77d/0xbd0 fs/bcachefs/super.c:1038
 bch2_fs_get_tree+0x13ea/0x22d0 fs/bcachefs/fs.c:2170
 vfs_get_tree+0xb1/0x5a0 fs/super.c:1814
 do_new_mount+0x71f/0x15e0 fs/namespace.c:3507
 path_mount+0x742/0x1f10 fs/namespace.c:3834
 do_mount fs/namespace.c:3847 [inline]
 __do_sys_mount fs/namespace.c:4057 [inline]
 __se_sys_mount+0x722/0x810 fs/namespace.c:4034
 __x64_sys_mount+0xe4/0x150 fs/namespace.c:4034
 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

Uninit was stored to memory at:
 memcpy_u64s_small fs/bcachefs/util.h:393 [inline]
 bkey_reassemble fs/bcachefs/bkey.h:513 [inline]
 btree_key_cache_create fs/bcachefs/btree_key_cache.c:259 [inline]
 btree_key_cache_fill+0x13da/0x3d60 fs/bcachefs/btree_key_cache.c:309
 bch2_btree_path_traverse_cached+0x988/0xe20 fs/bcachefs/btree_key_cache.c:361
 bch2_btree_path_traverse_one+0x749/0x47b0 fs/bcachefs/btree_iter.c:1159
 bch2_btree_path_traverse fs/bcachefs/btree_iter.h:247 [inline]
 bch2_btree_iter_peek_slot+0x10b7/0x3950 fs/bcachefs/btree_iter.c:2629
 __bch2_bkey_get_iter fs/bcachefs/btree_iter.h:575 [inline]
 bch2_bkey_get_iter fs/bcachefs/btree_iter.h:589 [inline]
 bch2_trans_start_alloc_update_noupdate+0x390/0x12f0 fs/bcachefs/alloc_background.c:464
 __bch2_trans_mark_metadata_bucket fs/bcachefs/buckets.c:958 [inline]
 bch2_trans_mark_metadata_bucket+0x2e6/0x2430 fs/bcachefs/buckets.c:1048
 __bch2_trans_mark_dev_sb fs/bcachefs/buckets.c:1120 [inline]
 bch2_trans_mark_dev_sb+0xcf7/0x10e0 fs/bcachefs/buckets.c:1133
 bch2_trans_mark_dev_sbs_flags+0x3e5/0x9f0 fs/bcachefs/buckets.c:1143
 bch2_trans_mark_dev_sbs+0x32/0x40 fs/bcachefs/buckets.c:1155
 bch2_fs_initialize+0x19bd/0x35d0 fs/bcachefs/recovery.c:1074
 bch2_fs_start+0x77d/0xbd0 fs/bcachefs/super.c:1038
 bch2_fs_get_tree+0x13ea/0x22d0 fs/bcachefs/fs.c:2170
 vfs_get_tree+0xb1/0x5a0 fs/super.c:1814
 do_new_mount+0x71f/0x15e0 fs/namespace.c:3507
 path_mount+0x742/0x1f10 fs/namespace.c:3834
 do_mount fs/namespace.c:3847 [inline]
 __do_sys_mount fs/namespace.c:4057 [inline]
 __se_sys_mount+0x722/0x810 fs/namespace.c:4034
 __x64_sys_mount+0xe4/0x150 fs/namespace.c:4034
 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

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:650
 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+0x4e4/0xb50 fs/bcachefs/btree_cache.c:653
 bch2_fs_alloc fs/bcachefs/super.c:917 [inline]
 bch2_fs_open+0x4d3a/0x5b40 fs/bcachefs/super.c:2065
 bch2_fs_get_tree+0x983/0x22d0 fs/bcachefs/fs.c:2157
 vfs_get_tree+0xb1/0x5a0 fs/super.c:1814
 do_new_mount+0x71f/0x15e0 fs/namespace.c:3507
 path_mount+0x742/0x1f10 fs/namespace.c:3834
 do_mount fs/namespace.c:3847 [inline]
 __do_sys_mount fs/namespace.c:4057 [inline]
 __se_sys_mount+0x722/0x810 fs/namespace.c:4034
 __x64_sys_mount+0xe4/0x150 fs/namespace.c:4034
 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: 10842 Comm: syz.3.1345 Not tainted 6.13.0-rc4-syzkaller-00110-g4099a71718b0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
=====================================================


---
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:
#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