fs: ecryptfs: remove BUG_ON from crypt_scatterlist

crypt_stat memory itself is allocated when inode is created, in
ecryptfs_alloc_inode, which returns NULL on failure and is handled
by callers, which would prevent us getting to this point. It then
calls ecryptfs_init_crypt_stat which allocates crypt_stat->tfm
checking for and likewise handling allocation failure. Finally,
crypt_stat->flags has ECRYPTFS_STRUCT_INITIALIZED merged into it
in ecryptfs_init_crypt_stat as well.

Simply put, the conditions that the BUG_ON checks for will never
be triggered, as to even get to this function, the relevant conditions
will have already been fulfilled (or the inode allocation would fail in
the first place and thus no call to this function or those above it).

Cc: Tyler Hicks <code@tyhicks.com>
Signed-off-by: Phillip Potter <phil@philpotter.co.uk>
Link: https://lore.kernel.org/r/20210503115736.2104747-50-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fs/ecryptfs/crypto.c

@@ -296,8 +296,6 @@ static int crypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
 	struct extent_crypt_result ecr;
 	int rc = 0;
 
-	BUG_ON(!crypt_stat || !crypt_stat->tfm
-	       || !(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED));
 	if (unlikely(ecryptfs_verbosity > 0)) {
 		ecryptfs_printk(KERN_DEBUG, "Key size [%zd]; key:\n",
 				crypt_stat->key_size);