Re: [syzbot] [bcachefs?] KMSAN: uninit-value in bch2_alloc_v4_invalid

syzbot
2024-06-01T16:53:25Z

syzbot has found a reproducer for the following issue on:

HEAD commit: 614da38e2f7a Merge tag 'hid-for-linus-2024051401' of git:/..
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=15e19bd2980000
kernel config: https://syzkaller.appspot.com/x/.config?x=f5d2cbf33633f507
dashboard link: https://syzkaller.appspot.com/bug?extid=3b2968fa4953885dd66a
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=17a7d616980000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14cfabd6980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/89eafb874b71/disk-614da38e.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/356000512ad9/vmlinux-614da38e.xz
kernel image: https://storage.googleapis.com/syzbot-assets/839c73939115/bzImage-614da38e.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/f1976dcc68c4/mount_2.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+3b2968fa4953885dd66a@syzkaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in bch2_alloc_v4_invalid+0x625/0x10f0 fs/bcachefs/alloc_background.c:247
bch2_alloc_v4_invalid+0x625/0x10f0 fs/bcachefs/alloc_background.c:247
bch2_bkey_val_invalid+0x24f/0x380 fs/bcachefs/bkey_methods.c:140
bset_key_invalid fs/bcachefs/btree_io.c:831 [inline]
validate_bset_keys+0x12d8/0x25d0 fs/bcachefs/btree_io.c:904
validate_bset_for_write+0x1dd/0x340 fs/bcachefs/btree_io.c:1945
__bch2_btree_node_write+0x4777/0x67c0 fs/bcachefs/btree_io.c:2138
bch2_btree_node_write+0xa5/0x2e0 fs/bcachefs/btree_io.c:2288
btree_node_write_if_need fs/bcachefs/btree_io.h:153 [inline]
__btree_node_flush+0x4d0/0x640 fs/bcachefs/btree_trans_commit.c:229
bch2_btree_node_flush0+0x35/0x60 fs/bcachefs/btree_trans_commit.c:238
journal_flush_pins+0xce6/0x1780 fs/bcachefs/journal_reclaim.c:553
__bch2_journal_reclaim+0xd88/0x1610 fs/bcachefs/journal_reclaim.c:685
bch2_journal_reclaim_thread+0x18e/0x760 fs/bcachefs/journal_reclaim.c:727
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

Uninit was stored to memory at:
memcpy_u64s_small fs/bcachefs/util.h:511 [inline]
bkey_p_copy fs/bcachefs/bkey.h:46 [inline]
bch2_sort_keys+0x1f34/0x2cb0 fs/bcachefs/bkey_sort.c:194
__bch2_btree_node_write+0x3acd/0x67c0 fs/bcachefs/btree_io.c:2100
bch2_btree_node_write+0xa5/0x2e0 fs/bcachefs/btree_io.c:2288
btree_node_write_if_need fs/bcachefs/btree_io.h:153 [inline]
__btree_node_flush+0x4d0/0x640 fs/bcachefs/btree_trans_commit.c:229
bch2_btree_node_flush0+0x35/0x60 fs/bcachefs/btree_trans_commit.c:238
journal_flush_pins+0xce6/0x1780 fs/bcachefs/journal_reclaim.c:553
__bch2_journal_reclaim+0xd88/0x1610 fs/bcachefs/journal_reclaim.c:685
bch2_journal_reclaim_thread+0x18e/0x760 fs/bcachefs/journal_reclaim.c:727
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

Uninit was created at:
__kmalloc_large_node+0x231/0x370 mm/slub.c:3994
__do_kmalloc_node mm/slub.c:4027 [inline]
__kmalloc_node+0xb10/0x10c0 mm/slub.c:4046
kmalloc_node include/linux/slab.h:648 [inline]
kvmalloc_node+0xc0/0x2d0 mm/util.c:634
kvmalloc include/linux/slab.h:766 [inline]
btree_bounce_alloc fs/bcachefs/btree_io.c:118 [inline]
bch2_btree_node_read_done+0x4e68/0x75e0 fs/bcachefs/btree_io.c:1185
btree_node_read_work+0x8a5/0x1eb0 fs/bcachefs/btree_io.c:1324
bch2_btree_node_read+0x3d42/0x4b50
__bch2_btree_root_read fs/bcachefs/btree_io.c:1748 [inline]
bch2_btree_root_read+0xa6c/0x13d0 fs/bcachefs/btree_io.c:1772
read_btree_roots+0x454/0xee0 fs/bcachefs/recovery.c:457
bch2_fs_recovery+0x7b6a/0x93e0 fs/bcachefs/recovery.c:785
bch2_fs_start+0x7b2/0xbd0 fs/bcachefs/super.c:1043
bch2_fs_open+0x152a/0x15f0 fs/bcachefs/super.c:2105
bch2_mount+0x90d/0x1d90 fs/bcachefs/fs.c:1906
legacy_get_tree+0x114/0x290 fs/fs_context.c:662
vfs_get_tree+0xa7/0x570 fs/super.c:1779
do_new_mount+0x71f/0x15e0 fs/namespace.c:3352
path_mount+0x742/0x1f20 fs/namespace.c:3679
do_mount fs/namespace.c:3692 [inline]
__do_sys_mount fs/namespace.c:3898 [inline]
__se_sys_mount+0x725/0x810 fs/namespace.c:3875
__x64_sys_mount+0xe4/0x150 fs/namespace.c:3875
x64_sys_call+0x2bf4/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:166
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 0 PID: 5053 Comm: bch-reclaim/loo Not tainted 6.9.0-syzkaller-02707-g614da38e2f7a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
=====================================================

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#syz test: git://repo/address.git branch-or-commit-hash
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