Commit 5ac11fe0 authored by Xiaomeng Tong's avatar Xiaomeng Tong Committed by Greg Kroah-Hartman
Browse files

misc: fastrpc: fix an incorrect NULL check on list iterator 



The bug is here:
	if (!buf) {

The list iterator value 'buf' will *always* be set and non-NULL
by list_for_each_entry(), so it is incorrect to assume that the
iterator value will be NULL if the list is empty (in this case, the
check 'if (!buf) {' will always be false and never exit expectly).

To fix the bug, use a new variable 'iter' as the list iterator,
while use the original variable 'buf' as a dedicated pointer to
point to the found element.

Fixes: 2419e55e ("misc: fastrpc: add mmap/unmap support")
Signed-off-by: default avatarXiaomeng Tong <xiam0nd.tong@gmail.com>
Link: https://lore.kernel.org/r/20220327062202.5720-1-xiam0nd.tong@gmail.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 4834f989

drivers/misc/fastrpc.c

+5 −4
Original line number Diff line number Diff line
@@ -1606,17 +1606,18 @@ static int fastrpc_req_munmap_impl(struct fastrpc_user *fl, 
				   struct fastrpc_req_munmap *req)

{

	struct fastrpc_invoke_args args[1] = { [0] = { 0 } };

	struct fastrpc_buf *buf, *b;

	struct fastrpc_buf *buf = NULL, *iter, *b;

	struct fastrpc_munmap_req_msg req_msg;

	struct device *dev = fl->sctx->dev;

	int err;

	u32 sc;



	spin_lock(&fl->lock);

	list_for_each_entry_safe(buf, b, &fl->mmaps, node) {

		if ((buf->raddr == req->vaddrout) && (buf->size == req->size))

	list_for_each_entry_safe(iter, b, &fl->mmaps, node) {

		if ((iter->raddr == req->vaddrout) && (iter->size == req->size)) {

			buf = iter;

			break;

		buf = NULL;

		}

	}

	spin_unlock(&fl->lock);