From: Li Zetao lizetao1@huawei.com
mainline inclusion from mainline-v6.1-rc1 commit d08af40340cad0e025d643c3982781a8f99d5032 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I4KIAO
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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kmemleak reported a sequence of memory leaks, and one of them indicated we failed to free a pointer: comm "mount", pid 19610, jiffies 4297086464 (age 60.635s) hex dump (first 8 bytes): 73 64 61 00 81 88 ff ff sda..... backtrace: [<00000000d77f3e04>] kstrdup_const+0x46/0x70 [<00000000e51fa804>] kobject_set_name_vargs+0x2f/0xb0 [<00000000247cd595>] kobject_init_and_add+0xb0/0x120 [<00000000f9139aaf>] xfs_mountfs+0x367/0xfc0 [<00000000250d3caf>] xfs_fs_fill_super+0xa16/0xdc0 [<000000008d873d38>] get_tree_bdev+0x256/0x390 [<000000004881f3fa>] vfs_get_tree+0x41/0xf0 [<000000008291ab52>] path_mount+0x9b3/0xdd0 [<0000000022ba8f2d>] __x64_sys_mount+0x190/0x1d0
As mentioned in kobject_init_and_add() comment, if this function returns an error, kobject_put() must be called to properly clean up the memory associated with the object. Apparently, xfs_sysfs_init() does not follow such a requirement. When kobject_init_and_add() returns an error, the space of kobj->kobject.name alloced by kstrdup_const() is unfree, which will cause the above stack.
Fix it by adding kobject_put() when kobject_init_and_add returns an error.
Fixes: a31b1d3d89e4 ("xfs: add xfs_mount sysfs kobject") Signed-off-by: Li Zetao lizetao1@huawei.com Reviewed-by: Darrick J. Wong djwong@kernel.org Signed-off-by: Darrick J. Wong djwong@kernel.org Signed-off-by: Guo Xuenan guoxuenan@huawei.com Reviewed-by: Zhang Yi yi.zhang@huawei.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- fs/xfs/xfs_sysfs.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/fs/xfs/xfs_sysfs.h b/fs/xfs/xfs_sysfs.h index 43585850f154..513095e353a5 100644 --- a/fs/xfs/xfs_sysfs.h +++ b/fs/xfs/xfs_sysfs.h @@ -33,10 +33,15 @@ xfs_sysfs_init( const char *name) { struct kobject *parent; + int err;
parent = parent_kobj ? &parent_kobj->kobject : NULL; init_completion(&kobj->complete); - return kobject_init_and_add(&kobj->kobject, ktype, parent, "%s", name); + err = kobject_init_and_add(&kobj->kobject, ktype, parent, "%s", name); + if (err) + kobject_put(&kobj->kobject); + + return err; }
static inline void