Re: [PATCH] misc: fastrpc: fix an incorrect NULL check on list iterator

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 





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@xxxxxxxxxxxxxxx
Fixes: 2419e55e532de ("misc: fastrpc: add mmap/unmap support")
Signed-off-by: Xiaomeng Tong <xiam0nd.tong@xxxxxxxxx>
LGTM,

Reviewed-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>

--- >   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);



[Index of Archives]     [Linux Kernel]     [Kernel Development Newbies]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite Hiking]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux