[syzbot] [bcachefs?] KMSAN: uninit-value in bch2_dirent_lookup_trans

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    614da38e2f7a Merge tag 'hid-for-linus-2024051401' of git:/..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12866ab2980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f5d2cbf33633f507
dashboard link: https://syzkaller.appspot.com/bug?extid=b09b7a89937134dc8f93
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/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

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b09b7a89937134dc8f93@xxxxxxxxxxxxxxxxxxxxxxxxx

bcachefs (loop4): snapshots_read... done
bcachefs (loop4): journal_replay... done
bcachefs (loop4): resume_logged_ops... done
bcachefs (loop4): going read-write
bcachefs (loop4): done starting filesystem
=====================================================
BUG: KMSAN: uninit-value in dirent_is_visible fs/bcachefs/dirent.c:85 [inline]
BUG: KMSAN: uninit-value in is_visible_key fs/bcachefs/str_hash.h:159 [inline]
BUG: KMSAN: uninit-value in bch2_hash_lookup_in_snapshot fs/bcachefs/str_hash.h:177 [inline]
BUG: KMSAN: uninit-value in bch2_hash_lookup fs/bcachefs/str_hash.h:202 [inline]
BUG: KMSAN: uninit-value in bch2_dirent_lookup_trans+0x652/0xfb0 fs/bcachefs/dirent.c:482
 dirent_is_visible fs/bcachefs/dirent.c:85 [inline]
 is_visible_key fs/bcachefs/str_hash.h:159 [inline]
 bch2_hash_lookup_in_snapshot fs/bcachefs/str_hash.h:177 [inline]
 bch2_hash_lookup fs/bcachefs/str_hash.h:202 [inline]
 bch2_dirent_lookup_trans+0x652/0xfb0 fs/bcachefs/dirent.c:482
 bch2_unlink_trans+0x505/0x2190 fs/bcachefs/fs-common.c:264
 __bch2_unlink+0x3e5/0x9c0 fs/bcachefs/fs.c:529
 bch2_unlink+0x128/0x1d0 fs/bcachefs/fs.c:563
 vfs_rmdir+0x5b1/0x790 fs/namei.c:4214
 do_rmdir+0x630/0x8b0 fs/namei.c:4273
 __do_sys_rmdir fs/namei.c:4292 [inline]
 __se_sys_rmdir fs/namei.c:4290 [inline]
 __x64_sys_rmdir+0x78/0xb0 fs/namei.c:4290
 x64_sys_call+0x3a8e/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:85
 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

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: 1 PID: 6831 Comm: syz-executor.4 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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