Re: [syzbot] [v9fs?] KMSAN: uninit-value in v9fs_evict_inode

From: syzbot
Date: Tue Mar 19 2024 - 06:40:16 EST


Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KMSAN: uninit-value in v9fs_evict_inode

=====================================================
BUG: KMSAN: uninit-value in v9fs_evict_inode+0x109/0x130 fs/9p/vfs_inode.c:356
v9fs_evict_inode+0x109/0x130 fs/9p/vfs_inode.c:356
evict+0x3ae/0xa60 fs/inode.c:667
iput_final fs/inode.c:1741 [inline]
iput+0x9ca/0xe10 fs/inode.c:1767
iget_failed+0x15e/0x180 fs/bad_inode.c:248
v9fs_fid_iget_dotl+0x375/0x570 fs/9p/vfs_inode_dotl.c:96
v9fs_get_inode_from_fid fs/9p/v9fs.h:230 [inline]
v9fs_mount+0xc02/0x12b0 fs/9p/vfs_super.c:142
legacy_get_tree+0x114/0x290 fs/fs_context.c:662
vfs_get_tree+0xa7/0x570 fs/super.c:1797
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
do_syscall_64+0xd5/0x1f0
entry_SYSCALL_64_after_hwframe+0x6d/0x75

Uninit was created at:
__alloc_pages+0x9d6/0xe70 mm/page_alloc.c:4598
__alloc_pages_node include/linux/gfp.h:238 [inline]
alloc_pages_node include/linux/gfp.h:261 [inline]
alloc_slab_page mm/slub.c:2175 [inline]
allocate_slab mm/slub.c:2338 [inline]
new_slab+0x2de/0x1400 mm/slub.c:2391
___slab_alloc+0x1184/0x33d0 mm/slub.c:3525
__slab_alloc mm/slub.c:3610 [inline]
__slab_alloc_node mm/slub.c:3663 [inline]
slab_alloc_node mm/slub.c:3835 [inline]
kmem_cache_alloc_lru+0x6d7/0xbe0 mm/slub.c:3864
alloc_inode_sb include/linux/fs.h:3089 [inline]
v9fs_alloc_inode+0x62/0x130 fs/9p/vfs_inode.c:228
alloc_inode+0x86/0x460 fs/inode.c:261
iget_locked+0x2bf/0xee0 fs/inode.c:1280
v9fs_fid_iget_dotl+0x7f/0x570 fs/9p/vfs_inode_dotl.c:62
v9fs_get_inode_from_fid fs/9p/v9fs.h:230 [inline]
v9fs_mount+0xc02/0x12b0 fs/9p/vfs_super.c:142
legacy_get_tree+0x114/0x290 fs/fs_context.c:662
vfs_get_tree+0xa7/0x570 fs/super.c:1797
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
do_syscall_64+0xd5/0x1f0
entry_SYSCALL_64_after_hwframe+0x6d/0x75

CPU: 1 PID: 5499 Comm: syz-executor.0 Not tainted 6.8.0-syzkaller-11567-gb3603fcb79b1-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
=====================================================


Tested on:

commit: b3603fcb Merge tag 'dlm-6.9' of git://git.kernel.org/p..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=175f8006180000
kernel config: https://syzkaller.appspot.com/x/.config?x=d08e4cfe8c38e605
dashboard link: https://syzkaller.appspot.com/bug?extid=eb83fe1cce5833cd66a0
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
patch: https://syzkaller.appspot.com/x/patch.diff?x=1250b481180000