Re: [PATCH] dma-buf: st: fix error handling in test_get_fences()

[Christian König]

Am 26.10.21 um 10:34 schrieb Arnd Bergmann:

From: Arnd Bergmann <a...@arndb.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 <a...@arndb.de>

I already send out a patch to fix this up, but forgot to fix both gotos.

Going to add my rb and using that one here instead.

Thanks,
Christian.

---
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;