From: Chao Yu yuchao0@huawei.com
[ Upstream commit 6d7ab88a98c1b7a47c228f8ffb4f44d631eaf284 ]
As syzbot reported:
Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x21c/0x280 lib/dump_stack.c:118 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:122 __msan_warning+0x58/0xa0 mm/kmsan/kmsan_instr.c:219 f2fs_lookup+0xe05/0x1a80 fs/f2fs/namei.c:503 lookup_open fs/namei.c:3082 [inline] open_last_lookups fs/namei.c:3177 [inline] path_openat+0x2729/0x6a90 fs/namei.c:3365 do_filp_open+0x2b8/0x710 fs/namei.c:3395 do_sys_openat2+0xa88/0x1140 fs/open.c:1168 do_sys_open fs/open.c:1184 [inline] __do_compat_sys_openat fs/open.c:1242 [inline] __se_compat_sys_openat+0x2a4/0x310 fs/open.c:1240 __ia32_compat_sys_openat+0x56/0x70 fs/open.c:1240 do_syscall_32_irqs_on arch/x86/entry/common.c:80 [inline] __do_fast_syscall_32+0x129/0x180 arch/x86/entry/common.c:139 do_fast_syscall_32+0x6a/0xc0 arch/x86/entry/common.c:162 do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:205 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c
In f2fs_lookup(), @res_page could be used before being initialized, because in __f2fs_find_entry(), once F2FS_I(dir)->i_current_depth was been fuzzed to zero, then @res_page will never be initialized, causing this kmsan warning, relocating @res_page initialization place to fix this bug.
Reported-by: syzbot+0eac6f0bbd558fd866d7@syzkaller.appspotmail.com Signed-off-by: Chao Yu yuchao0@huawei.com Signed-off-by: Jaegeuk Kim jaegeuk@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- fs/f2fs/dir.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-)
diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c index e9af46dc06f72..78d041f9775a4 100644 --- a/fs/f2fs/dir.c +++ b/fs/f2fs/dir.c @@ -303,16 +303,15 @@ struct f2fs_dir_entry *__f2fs_find_entry(struct inode *dir, unsigned int max_depth; unsigned int level;
+ *res_page = NULL; + if (f2fs_has_inline_dentry(dir)) { - *res_page = NULL; de = f2fs_find_in_inline_dir(dir, fname, res_page); goto out; }
- if (npages == 0) { - *res_page = NULL; + if (npages == 0) goto out; - }
max_depth = F2FS_I(dir)->i_current_depth; if (unlikely(max_depth > MAX_DIR_HASH_DEPTH)) { @@ -323,7 +322,6 @@ struct f2fs_dir_entry *__f2fs_find_entry(struct inode *dir, }
for (level = 0; level < max_depth; level++) { - *res_page = NULL; de = find_in_level(dir, level, fname, res_page); if (de || IS_ERR(*res_page)) break;