linux-kernel - [PATCH] dma-buf: st: fix error handling in test_get

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Date:   Tue, 26 Oct 2021 10:34:37 +0200
From:   Arnd Bergmann <arnd@...nel.org>
To:     Sumit Semwal <sumit.semwal@...aro.org>,
        Christian König <christian.koenig@....com>,
        Nathan Chancellor <nathan@...nel.org>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        Tvrtko Ursulin <tvrtko.ursulin@...el.com>,
        Daniel Vetter <daniel.vetter@...ll.ch>
Cc:     Arnd Bergmann <arnd@...db.de>, linux-media@...r.kernel.org,
        dri-devel@...ts.freedesktop.org, linaro-mm-sig@...ts.linaro.org,
        linux-kernel@...r.kernel.org, llvm@...ts.linux.dev
Subject: [PATCH] dma-buf: st: fix error handling in test_get_fences()

From: Arnd Bergmann <arnd@...db.de>

The new driver incorrectly unwinds after errors, as clang points out:

drivers/dma-buf/st-dma-resv.c:295:7: error: variable 'i' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized]
                if (r) {
                    ^
drivers/dma-buf/st-dma-resv.c:336:9: note: uninitialized use occurs here
        while (i--)
               ^
drivers/dma-buf/st-dma-resv.c:295:3: note: remove the 'if' if its condition is always false
                if (r) {
                ^~~~~~~~
drivers/dma-buf/st-dma-resv.c:288:6: error: variable 'i' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized]
        if (r) {
            ^
drivers/dma-buf/st-dma-resv.c:336:9: note: uninitialized use occurs here
        while (i--)
               ^
drivers/dma-buf/st-dma-resv.c:288:2: note: remove the 'if' if its condition is always false
        if (r) {
        ^~~~~~~~
drivers/dma-buf/st-dma-resv.c:280:10: note: initialize the variable 'i' to silence this warning
        int r, i;
                ^
                 = 0

Skip cleaning up the bits that have not been allocated at this point.

Fixes: 1d51775cd3f5 ("dma-buf: add dma_resv selftest v4")
Signed-off-by: Arnd Bergmann <arnd@...db.de>
---
I'm not familiar with these interfaces, so I'm just guessing where
we should jump after an error, please double-check and fix if necessary.
---
 drivers/dma-buf/st-dma-resv.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/dma-buf/st-dma-resv.c b/drivers/dma-buf/st-dma-resv.c
index 6f3ba756da3e..bc32b3eedcb6 100644
--- a/drivers/dma-buf/st-dma-resv.c
+++ b/drivers/dma-buf/st-dma-resv.c
@@ -287,7 +287,7 @@ static int test_get_fences(void *arg, bool shared)
 	r = dma_resv_lock(&resv, NULL);
 	if (r) {
 		pr_err("Resv locking failed\n");
-		goto err_free;
+		goto err_resv;
 	}
 
 	if (shared) {
@@ -295,7 +295,7 @@ static int test_get_fences(void *arg, bool shared)
 		if (r) {
 			pr_err("Resv shared slot allocation failed\n");
 			dma_resv_unlock(&resv);
-			goto err_free;
+			goto err_resv;
 		}
 
 		dma_resv_add_shared_fence(&resv, f);
@@ -336,6 +336,7 @@ static int test_get_fences(void *arg, bool shared)
 	while (i--)
 		dma_fence_put(fences[i]);
 	kfree(fences);
+err_resv:
 	dma_resv_fini(&resv);
 	dma_fence_put(f);
 	return r;
-- 
2.29.2