fs/jfs/jfs_imap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
syzbot reports that hex_dump_to_buffer is using uninit-value:
=====================================================
BUG: KMSAN: uninit-value in hex_dump_to_buffer+0x888/0x1100 lib/hexdump.c:171
hex_dump_to_buffer+0x888/0x1100 lib/hexdump.c:171
print_hex_dump+0x13d/0x3e0 lib/hexdump.c:276
diFree+0x5ba/0x4350 fs/jfs/jfs_imap.c:876
jfs_evict_inode+0x510/0x550 fs/jfs/inode.c:156
evict+0x723/0xd10 fs/inode.c:796
iput_final fs/inode.c:1946 [inline]
iput+0x97b/0xdb0 fs/inode.c:1972
txUpdateMap+0xf3e/0x1150 fs/jfs/jfs_txnmgr.c:2367
txLazyCommit fs/jfs/jfs_txnmgr.c:2664 [inline]
jfs_lazycommit+0x627/0x11d0 fs/jfs/jfs_txnmgr.c:2733
kthread+0x6b9/0xef0 kernel/kthread.c:464
ret_from_fork+0x6d/0x90 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
Uninit was created at:
slab_post_alloc_hook mm/slub.c:4121 [inline]
slab_alloc_node mm/slub.c:4164 [inline]
__kmalloc_cache_noprof+0x8e3/0xdf0 mm/slub.c:4320
kmalloc_noprof include/linux/slab.h:901 [inline]
diMount+0x61/0x7f0 fs/jfs/jfs_imap.c:105
jfs_mount+0xa8e/0x11d0 fs/jfs/jfs_mount.c:176
jfs_fill_super+0xa47/0x17c0 fs/jfs/super.c:523
get_tree_bdev_flags+0x6ec/0x910 fs/super.c:1636
get_tree_bdev+0x37/0x50 fs/super.c:1659
jfs_get_tree+0x34/0x40 fs/jfs/super.c:635
vfs_get_tree+0xb1/0x5a0 fs/super.c:1814
do_new_mount+0x71f/0x15e0 fs/namespace.c:3560
path_mount+0x742/0x1f10 fs/namespace.c:3887
do_mount fs/namespace.c:3900 [inline]
__do_sys_mount fs/namespace.c:4111 [inline]
__se_sys_mount+0x71f/0x800 fs/namespace.c:4088
__x64_sys_mount+0xe4/0x150 fs/namespace.c:4088
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
=====================================================
The reason is that imap is not properly initialized after memory
allocation. It will cause the snprintf() function to write uninitialized
data into linebuf within hex_dump_to_buffer().
Fix this by using kzalloc instead of kmalloc to clear its content at the
beginning in diMount().
Signed-off-by: Zhongqiu Han <quic_zhonhan@quicinc.com>
Reported-by: syzbot+df6cdcb35904203d2b6d@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/lkml/67b5d07e.050a0220.14d86d.00e6.GAE@google.com/
---
fs/jfs/jfs_imap.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/jfs/jfs_imap.c b/fs/jfs/jfs_imap.c
index a360b24ed320..cf16655cd26b 100644
--- a/fs/jfs/jfs_imap.c
+++ b/fs/jfs/jfs_imap.c
@@ -102,7 +102,7 @@ int diMount(struct inode *ipimap)
* allocate/initialize the in-memory inode map control structure
*/
/* allocate the in-memory inode map control structure. */
- imap = kmalloc(sizeof(struct inomap), GFP_KERNEL);
+ imap = kzalloc(sizeof(struct inomap), GFP_KERNEL);
if (imap == NULL)
return -ENOMEM;
--
2.25.1On 2/19/25 8:02AM, Zhongqiu Han wrote: > syzbot reports that hex_dump_to_buffer is using uninit-value: > > ===================================================== > BUG: KMSAN: uninit-value in hex_dump_to_buffer+0x888/0x1100 lib/hexdump.c:171 > hex_dump_to_buffer+0x888/0x1100 lib/hexdump.c:171 > print_hex_dump+0x13d/0x3e0 lib/hexdump.c:276 > diFree+0x5ba/0x4350 fs/jfs/jfs_imap.c:876 > jfs_evict_inode+0x510/0x550 fs/jfs/inode.c:156 > evict+0x723/0xd10 fs/inode.c:796 > iput_final fs/inode.c:1946 [inline] > iput+0x97b/0xdb0 fs/inode.c:1972 > txUpdateMap+0xf3e/0x1150 fs/jfs/jfs_txnmgr.c:2367 > txLazyCommit fs/jfs/jfs_txnmgr.c:2664 [inline] > jfs_lazycommit+0x627/0x11d0 fs/jfs/jfs_txnmgr.c:2733 > kthread+0x6b9/0xef0 kernel/kthread.c:464 > ret_from_fork+0x6d/0x90 arch/x86/kernel/process.c:148 > ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 > > Uninit was created at: > slab_post_alloc_hook mm/slub.c:4121 [inline] > slab_alloc_node mm/slub.c:4164 [inline] > __kmalloc_cache_noprof+0x8e3/0xdf0 mm/slub.c:4320 > kmalloc_noprof include/linux/slab.h:901 [inline] > diMount+0x61/0x7f0 fs/jfs/jfs_imap.c:105 > jfs_mount+0xa8e/0x11d0 fs/jfs/jfs_mount.c:176 > jfs_fill_super+0xa47/0x17c0 fs/jfs/super.c:523 > get_tree_bdev_flags+0x6ec/0x910 fs/super.c:1636 > get_tree_bdev+0x37/0x50 fs/super.c:1659 > jfs_get_tree+0x34/0x40 fs/jfs/super.c:635 > vfs_get_tree+0xb1/0x5a0 fs/super.c:1814 > do_new_mount+0x71f/0x15e0 fs/namespace.c:3560 > path_mount+0x742/0x1f10 fs/namespace.c:3887 > do_mount fs/namespace.c:3900 [inline] > __do_sys_mount fs/namespace.c:4111 [inline] > __se_sys_mount+0x71f/0x800 fs/namespace.c:4088 > __x64_sys_mount+0xe4/0x150 fs/namespace.c:4088 > 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 > ===================================================== > > The reason is that imap is not properly initialized after memory > allocation. It will cause the snprintf() function to write uninitialized > data into linebuf within hex_dump_to_buffer(). > > Fix this by using kzalloc instead of kmalloc to clear its content at the > beginning in diMount(). Looks good. I'll add it to jfs-next. > > Signed-off-by: Zhongqiu Han <quic_zhonhan@quicinc.com> > Reported-by: syzbot+df6cdcb35904203d2b6d@syzkaller.appspotmail.com > Closes: https://lore.kernel.org/lkml/67b5d07e.050a0220.14d86d.00e6.GAE@google.com/ > --- > fs/jfs/jfs_imap.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/jfs/jfs_imap.c b/fs/jfs/jfs_imap.c > index a360b24ed320..cf16655cd26b 100644 > --- a/fs/jfs/jfs_imap.c > +++ b/fs/jfs/jfs_imap.c > @@ -102,7 +102,7 @@ int diMount(struct inode *ipimap) > * allocate/initialize the in-memory inode map control structure > */ > /* allocate the in-memory inode map control structure. */ > - imap = kmalloc(sizeof(struct inomap), GFP_KERNEL); > + imap = kzalloc(sizeof(struct inomap), GFP_KERNEL); > if (imap == NULL) > return -ENOMEM; >
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