Re: [syzbot] [reiserfs?] KMSAN: uninit-value in reiserfs_new_inode (2)

Re: [syzbot] [reiserfs?] KMSAN: uninit-value in reiserfs_new_inode (2)

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit:    861deac3b092 Linux 6.7-rc7
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=12057ecee80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=e0c7078a6b901aa3
dashboard link: https://syzkaller.appspot.com/bug?extid=6450929faa7a97cd42d1
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=14836ca1e80000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=159e1e16e80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/0ea60ee8ed32/disk-861deac3.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/6d69fdc33021/vmlinux-861deac3.xz
kernel image: https://storage.googleapis.com/syzbot-assets/f0158750d452/bzImage-861deac3.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/dcd887118b46/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+6450929faa7a97cd42d1@syzkaller.appspotmail.com

REISERFS warning (device loop0): vs-13060 reiserfs_update_sd_size: stat data of object [1 2 0x0 SD] (nlink == 1) not found (pos 2)
REISERFS (device loop0): Created .reiserfs_priv - reserved for xattr storage.
=====================================================
BUG: KMSAN: uninit-value in reiserfs_new_inode+0x16cd/0x20f0 fs/reiserfs/inode.c:2044
 reiserfs_new_inode+0x16cd/0x20f0 fs/reiserfs/inode.c:2044
 reiserfs_create+0x674/0xcb0 fs/reiserfs/namei.c:666
 xattr_create fs/reiserfs/xattr.c:70 [inline]
 xattr_lookup+0x3ee/0x5e0 fs/reiserfs/xattr.c:413
 reiserfs_xattr_set_handle+0xe7/0x21b0 fs/reiserfs/xattr.c:535
 reiserfs_xattr_set+0x670/0x7f0 fs/reiserfs/xattr.c:635
 trusted_set+0x112/0x190 fs/reiserfs/xattr_trusted.c:31
 __vfs_setxattr+0x7aa/0x8b0 fs/xattr.c:201
 __vfs_setxattr_noperm+0x24f/0xa30 fs/xattr.c:235
 __vfs_setxattr_locked+0x441/0x480 fs/xattr.c:296
 vfs_setxattr+0x294/0x650 fs/xattr.c:322
 do_setxattr fs/xattr.c:630 [inline]
 setxattr+0x45f/0x540 fs/xattr.c:653
 path_setxattr+0x1f5/0x3c0 fs/xattr.c:672
 __do_sys_setxattr fs/xattr.c:688 [inline]
 __se_sys_setxattr fs/xattr.c:684 [inline]
 __x64_sys_setxattr+0xf7/0x180 fs/xattr.c:684
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

Uninit was created at:
 __alloc_pages+0x9a4/0xe00 mm/page_alloc.c:4591
 alloc_pages_mpol+0x62b/0x9d0 mm/mempolicy.c:2133
 alloc_pages+0x1be/0x1e0 mm/mempolicy.c:2204
 alloc_slab_page mm/slub.c:1870 [inline]
 allocate_slab mm/slub.c:2017 [inline]
 new_slab+0x421/0x1570 mm/slub.c:2070
 ___slab_alloc+0x13db/0x33d0 mm/slub.c:3223
 __slab_alloc mm/slub.c:3322 [inline]
 __slab_alloc_node mm/slub.c:3375 [inline]
 slab_alloc_node mm/slub.c:3468 [inline]
 slab_alloc mm/slub.c:3486 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3493 [inline]
 kmem_cache_alloc_lru+0x552/0x970 mm/slub.c:3509
 alloc_inode_sb include/linux/fs.h:2937 [inline]
 reiserfs_alloc_inode+0x62/0x150 fs/reiserfs/super.c:642
 alloc_inode+0x83/0x440 fs/inode.c:261
 iget5_locked+0xa9/0x210 fs/inode.c:1271
 reiserfs_fill_super+0x2109/0x39d0 fs/reiserfs/super.c:2053
 mount_bdev+0x3d7/0x560 fs/super.c:1650
 get_super_block+0x4d/0x60 fs/reiserfs/super.c:2601
 legacy_get_tree+0x110/0x290 fs/fs_context.c:662
 vfs_get_tree+0xa5/0x520 fs/super.c:1771
 do_new_mount+0x68d/0x1550 fs/namespace.c:3337
 path_mount+0x73d/0x1f20 fs/namespace.c:3664
 do_mount fs/namespace.c:3677 [inline]
 __do_sys_mount fs/namespace.c:3886 [inline]
 __se_sys_mount+0x725/0x810 fs/namespace.c:3863
 __x64_sys_mount+0xe4/0x140 fs/namespace.c:3863
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

CPU: 1 PID: 5006 Comm: syz-executor185 Not tainted 6.7.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
=====================================================


---
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#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

[PATCH] reiserfs: fix uninit-value in reiserfs_new_inode

[Edward Adam Davis]

Before creating a new inode, it is necessary to initialize the "new packing
locality" tag of the dir.

Signed-off-by: Edward Adam Davis <eadavis@qq.com>
---
 fs/reiserfs/namei.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/fs/reiserfs/namei.c b/fs/reiserfs/namei.c
index 994d6e6995ab..3a824fb170d5 100644
--- a/fs/reiserfs/namei.c
+++ b/fs/reiserfs/namei.c
@@ -638,6 +638,10 @@ static int reiserfs_create(struct mnt_idmap *idmap, struct inode *dir,
 	if (retval)
 		return retval;
 
+#ifdef DISPLACE_NEW_PACKING_LOCALITIES
+	REISERFS_I(dir)->new_packing_locality = 0;
+#endif
+
 	if (!(inode = new_inode(dir->i_sb))) {
 		return -ENOMEM;
 	}
-- 
2.43.0