linux-kernel - [PATCH] media: atomisp: don't pass a pointer to a local variable

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Date:   Fri, 13 May 2022 10:23:43 +0200
From:   Mauro Carvalho Chehab <mchehab@...nel.org>
To:     unlisted-recipients:; (no To-header on input)
Cc:     Mauro Carvalho Chehab <mchehab@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Sakari Ailus <sakari.ailus@...ux.intel.com>,
        linux-kernel@...r.kernel.org, linux-media@...r.kernel.org,
        linux-staging@...ts.linux.dev
Subject: [PATCH] media: atomisp: don't pass a pointer to a local variable

As warned by gcc 12.1:

	drivers/staging/media/atomisp/pci/runtime/rmgr/src/rmgr_vbuf.c: In function 'ia_css_rmgr_acq_vbuf':
	drivers/staging/media/atomisp/pci/runtime/rmgr/src/rmgr_vbuf.c:275:33: error: storing the address of local variable 'h' in '*handle' [-Werror=dangling-pointer=]
	  275 |                         *handle = &h;
	      |                         ~~~~~~~~^~~~
	drivers/staging/media/atomisp/pci/runtime/rmgr/src/rmgr_vbuf.c:257:40: note: 'h' declared here
	  257 |         struct ia_css_rmgr_vbuf_handle h;
	      |                                        ^
	drivers/staging/media/atomisp/pci/runtime/rmgr/src/rmgr_vbuf.c:257:40: note: 'handle' declared here
	cc1: all warnings being treated as errors

The logic uses a temporary struct to update the handler, but,
instead of copying the value to the pointer sent by the caller, it
replaces it with the content with a local variable. That's wrong, and
may lead the caller to use a weird value.

Signed-off-by: Mauro Carvalho Chehab <mchehab@...nel.org>
---
 .../staging/media/atomisp/pci/runtime/rmgr/src/rmgr_vbuf.c    | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/media/atomisp/pci/runtime/rmgr/src/rmgr_vbuf.c b/drivers/staging/media/atomisp/pci/runtime/rmgr/src/rmgr_vbuf.c
index d96aaa4bc75d..39604752785b 100644
--- a/drivers/staging/media/atomisp/pci/runtime/rmgr/src/rmgr_vbuf.c
+++ b/drivers/staging/media/atomisp/pci/runtime/rmgr/src/rmgr_vbuf.c
@@ -254,7 +254,7 @@ void rmgr_pop_handle(struct ia_css_rmgr_vbuf_pool *pool,
 void ia_css_rmgr_acq_vbuf(struct ia_css_rmgr_vbuf_pool *pool,
 			  struct ia_css_rmgr_vbuf_handle **handle)
 {
-	struct ia_css_rmgr_vbuf_handle h;
+	struct ia_css_rmgr_vbuf_handle h = { 0 };
 
 	if ((!pool) || (!handle) || (!*handle)) {
 		IA_CSS_LOG("Invalid inputs");
@@ -272,7 +272,7 @@ void ia_css_rmgr_acq_vbuf(struct ia_css_rmgr_vbuf_pool *pool,
 			h.size = (*handle)->size;
 			/* release ref to current buffer */
 			ia_css_rmgr_refcount_release_vbuf(handle);
-			*handle = &h;
+			**handle = h;
 		}
 		/* get new buffer for needed size */
 		if ((*handle)->vptr == 0x0) {
-- 
2.36.1