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From:   Mauro Carvalho Chehab <mchehab@kernel.org>
Cc:     Mauro Carvalho Chehab <mchehab@kernel.org>,
        Aline Santana Cordeiro <alinesantanacordeiro@gmail.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Hans Verkuil <hverkuil-cisco@xs4all.nl>,
        Sakari Ailus <sakari.ailus@linux.intel.com>,
        linux-kernel@vger.kernel.org, linux-media@vger.kernel.org,
        linux-staging@lists.linux.dev, Hans Verkuil <hverkuil@xs4all.nl>
Subject: [PATCH] media: atomisp: fix bad usage at error handling logic
Date:   Mon, 14 Mar 2022 18:15:31 +0100
Message-Id: <7c6071ba016b58206fc1f731f02c67ea0ae3c758.1647278119.git.mchehab@kernel.org>
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As warned by sparse:
	atomisp: drivers/staging/media/atomisp/pci/atomisp_acc.c:508 atomisp_acc_load_extensions() warn: iterator used outside loop: 'acc_fw'

The acc_fw interactor is used outside the loop, at the error handling
logic. On most cases, this is actually safe there, but, if
atomisp_css_set_acc_parameters() has an error, an attempt to use it
will pick an invalid value for acc_fw.

Reported-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
---
 .../staging/media/atomisp/pci/atomisp_acc.c   | 28 +++++++++++++------
 1 file changed, 19 insertions(+), 9 deletions(-)

diff --git a/drivers/staging/media/atomisp/pci/atomisp_acc.c b/drivers/staging/media/atomisp/pci/atomisp_acc.c
index 9a1751895ab0..28cb271663c4 100644
--- a/drivers/staging/media/atomisp/pci/atomisp_acc.c
+++ b/drivers/staging/media/atomisp/pci/atomisp_acc.c
@@ -439,6 +439,18 @@ int atomisp_acc_s_mapped_arg(struct atomisp_sub_device *asd,
 	return 0;
 }
 
+static void atomisp_acc_unload_some_extensions(struct atomisp_sub_device *asd,
+					      int i,
+					      struct atomisp_acc_fw *acc_fw)
+{
+	while (--i >= 0) {
+		if (acc_fw->flags & acc_flag_to_pipe[i].flag) {
+			atomisp_css_unload_acc_extension(asd, acc_fw->fw,
+							 acc_flag_to_pipe[i].pipe_id);
+		}
+	}
+}
+
 /*
  * Appends the loaded acceleration binary extensions to the
  * current ISP mode. Must be called just before sh_css_start().
@@ -479,16 +491,20 @@ int atomisp_acc_load_extensions(struct atomisp_sub_device *asd)
 								     acc_fw->fw,
 								     acc_flag_to_pipe[i].pipe_id,
 								     acc_fw->type);
-				if (ret)
+				if (ret) {
+					atomisp_acc_unload_some_extensions(asd, i, acc_fw);
 					goto error;
+				}
 
 				ext_loaded = true;
 			}
 		}
 
 		ret = atomisp_css_set_acc_parameters(acc_fw);
-		if (ret < 0)
+		if (ret < 0) {
+			atomisp_acc_unload_some_extensions(asd, i, acc_fw);
 			goto error;
+		}
 	}
 
 	if (!ext_loaded)
@@ -497,6 +513,7 @@ int atomisp_acc_load_extensions(struct atomisp_sub_device *asd)
 	ret = atomisp_css_update_stream(asd);
 	if (ret) {
 		dev_err(isp->dev, "%s: update stream failed.\n", __func__);
+		atomisp_acc_unload_extensions(asd);
 		goto error;
 	}
 
@@ -504,13 +521,6 @@ int atomisp_acc_load_extensions(struct atomisp_sub_device *asd)
 	return 0;
 
 error:
-	while (--i >= 0) {
-		if (acc_fw->flags & acc_flag_to_pipe[i].flag) {
-			atomisp_css_unload_acc_extension(asd, acc_fw->fw,
-							 acc_flag_to_pipe[i].pipe_id);
-		}
-	}
-
 	list_for_each_entry_continue_reverse(acc_fw, &asd->acc.fw, list) {
 		if (acc_fw->type != ATOMISP_ACC_FW_LOAD_TYPE_OUTPUT &&
 		    acc_fw->type != ATOMISP_ACC_FW_LOAD_TYPE_VIEWFINDER)
-- 
2.35.1