On 27/03/2022 07:22, Xiaomeng Tong wrote:

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.

Cc: stable@vger.kernel.org Fixes: 2419e55e532de ("misc: fastrpc: add mmap/unmap support") Signed-off-by: Xiaomeng Tong xiam0nd.tong@gmail.com

LGTM,

Reviewed-by: Srinivas Kandagatla srinivas.kandagatla@linaro.org

--- > drivers/misc/fastrpc.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c index aa1682b94a23..45aaf54a7560 100644 --- a/drivers/misc/fastrpc.c +++ b/drivers/misc/fastrpc.c @@ -1353,17 +1353,18 @@ 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);