This is a note to let you know that I've just added the patch titled hostfs: fix memory handling in follow_link() to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: hostfs-fix-memory-handling-in-follow_link.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 54979138fe7141e097f89dd20525382a4ac0647b Author: Al Viro <viro@xxxxxxxxxxxxxxxxxx> Date: Thu Mar 25 14:12:34 2021 -0400 hostfs: fix memory handling in follow_link() [ Upstream commit 7f6c411c9b50cfab41cc798e003eff27608c7016 ] 1) argument should not be freed in any case - the caller already has it as ->s_fs_info (and uses it a lot afterwards) 2) allocate readlink buffer with kmalloc() - the caller has no way to tell if it's got that (on absolute symlink) or a result of kasprintf(). Sure, for SLAB and SLUB kfree() works on results of kmem_cache_alloc(), but that's not documented anywhere, might change in the future *and* is already not true for SLOB. Fixes: 52b209f7b848 ("get rid of hostfs_read_inode()") Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/fs/hostfs/hostfs_kern.c b/fs/hostfs/hostfs_kern.c index 4f5d857f6ecb..58a972667bf8 100644 --- a/fs/hostfs/hostfs_kern.c +++ b/fs/hostfs/hostfs_kern.c @@ -142,7 +142,7 @@ static char *follow_link(char *link) char *name, *resolved, *end; int n; - name = __getname(); + name = kmalloc(PATH_MAX, GFP_KERNEL); if (!name) { n = -ENOMEM; goto out_free; @@ -171,12 +171,11 @@ static char *follow_link(char *link) goto out_free; } - __putname(name); - kfree(link); + kfree(name); return resolved; out_free: - __putname(name); + kfree(name); return ERR_PTR(n); }