From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 72B5710E0 for ; Sun, 12 Jun 2022 16:06:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1655049978; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=A13Tgu0+0ldCSVdWWfytuoNL33R3vDWsMrOpJ8spRz0=; b=LZ1IerwS993rQhTLe83AwKGyzGI5LGkQst0rJkHG76hFSvdxgFnio57nHjgcQxOHN75vgw yE3ZK29TcJjf5OKe7bnrVCyW2UzYfuWL6V6ssLq9tANG2N6iTfvlOWKY2osZWqKuzQhLki ZwujGryLrjwqWEx9Vri/MrMsR1ySapI= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-252-er6C63x5PPejAU2D68HPYQ-1; Sun, 12 Jun 2022 12:06:12 -0400 X-MC-Unique: er6C63x5PPejAU2D68HPYQ-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 9AE2B801E67; Sun, 12 Jun 2022 16:06:11 +0000 (UTC) Received: from localhost.localdomain (unknown [10.39.192.31]) by smtp.corp.redhat.com (Postfix) with ESMTP id 219BD2166B26; Sun, 12 Jun 2022 16:06:10 +0000 (UTC) From: Hans de Goede To: Mauro Carvalho Chehab , Sakari Ailus Cc: Hans de Goede , Tsuchiya Yuto , Andy Shevchenko , Yury Luneff , Nable , andrey.i.trufanov@gmail.com, Fabio Aiuto , linux-media@vger.kernel.org, linux-staging@lists.linux.dev Subject: [PATCH 3/3] media: atomisp: fix -Wdangling-pointer warning Date: Sun, 12 Jun 2022 18:05:56 +0200 Message-Id: <20220612160556.108264-4-hdegoede@redhat.com> In-Reply-To: <20220612160556.108264-1-hdegoede@redhat.com> References: <20220612160556.108264-1-hdegoede@redhat.com> Precedence: bulk X-Mailing-List: linux-staging@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.78 on 10.11.54.6 ia_css_rmgr_acq_vbuf() uses a local on stack "struct ia_css_rmgr_vbuf_handle v" variable. When this path using this is hit, either the rmgr_pop_handle() call will make *handle point to another vbuf-handle, or because v.count == 0, ia_css_rmgr_refcount_retain_vbuf() will alloc a new vbuf-handle and make *handle point to it. So on leaving the function *handle will never point to the on stack vbuf-handle, but gcc does not know this and emits the following: 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:276:33: warning: storing the address of local variable ‘h’ in ‘*handle’ [-Wdangling-pointer=] 276 | *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 Rework the code using a new_handle helper to suppress this false-postive compiler warning. Signed-off-by: Hans de Goede --- .../atomisp/pci/runtime/rmgr/src/rmgr_vbuf.c | 22 +++++++++++++------ 1 file changed, 15 insertions(+), 7 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 afe2d22c603f..b84c6cff1499 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 @@ -254,14 +254,15 @@ 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 = { 0 }; - if ((!pool) || (!handle) || (!*handle)) { IA_CSS_LOG("Invalid inputs"); return; } if (pool->copy_on_write) { + struct ia_css_rmgr_vbuf_handle *new_handle; + struct ia_css_rmgr_vbuf_handle h = { 0 }; + /* only one reference, reuse (no new retain) */ if ((*handle)->count == 1) return; @@ -272,23 +273,30 @@ 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; + new_handle = &h; + } else { + new_handle = *handle; } /* get new buffer for needed size */ - if ((*handle)->vptr == 0x0) { + if (new_handle->vptr == 0x0) { if (pool->recycle) { /* try and pop from pool */ - rmgr_pop_handle(pool, handle); + rmgr_pop_handle(pool, &new_handle); } - if ((*handle)->vptr == 0x0) { + if (new_handle->vptr == 0x0) { /* we need to allocate */ - (*handle)->vptr = hmm_alloc((*handle)->size, + new_handle->vptr = hmm_alloc(new_handle->size, HMM_BO_PRIVATE, 0, NULL, 0); } else { /* we popped a buffer */ + *handle = new_handle; return; } } + /* Note that new_handle will change to an internally maintained one */ + ia_css_rmgr_refcount_retain_vbuf(&new_handle); + *handle = new_handle; + return; } /* Note that handle will change to an internally maintained one */ ia_css_rmgr_refcount_retain_vbuf(handle); -- 2.36.0