From c971b9f61f5b143dd36d8afc322d1b0bedbbb1a7 Mon Sep 17 00:00:00 2001 From: Dario Faggioli Date: Fri, 20 Jun 2014 16:09:00 +0200 Subject: [PATCH] blktap2: Fix two 'maybe uninitialized' variables for which gcc 4.9.0 complains about, like this: block-qcow.c: In function `get_cluster_offset': block-qcow.c:431:3: error: `tmp_ptr' may be used uninitialized in this function [-Werror=maybe-uninitialized] memcpy(tmp_ptr, l1_ptr, 4096); ^ block-qcow.c:606:7: error: `tmp_ptr2' may be used uninitialized in this function [-Werror=maybe-uninitialized] if (write(s->fd, tmp_ptr2, 4096) != 4096) { ^ cc1: all warnings being treated as errors /home/dario/Sources/xen/xen/xen.git/tools/blktap2/drivers/../../../tools/Rules.mk:89: recipe for target 'block-qcow.o' failed make[5]: *** [block-qcow.o] Error 1 The proper behavior is to return upon allocation failure. About what to return, 0 seems the best option, looking at both the function and the call sites. Signed-off-by: Dario Faggioli Acked-by: Ian Jackson (cherry picked from commit 345e44a85d71a1a910385f33c7f1ba3683026d18) (cherry picked from commit 5e39eb05aa2a6d9bfa6c3b3e299b071422498625) (cherry picked from commit c591613f8c629f18a521269d67240d532f2c27d1) --- tools/blktap2/drivers/block-qcow.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/tools/blktap2/drivers/block-qcow.c b/tools/blktap2/drivers/block-qcow.c index d5053d4174..b45bcaa077 100644 --- a/tools/blktap2/drivers/block-qcow.c +++ b/tools/blktap2/drivers/block-qcow.c @@ -427,6 +427,7 @@ static uint64_t get_cluster_offset(struct tdqcow_state *s, if (posix_memalign((void **)&tmp_ptr, 4096, 4096) != 0) { DPRINTF("ERROR allocating memory for L1 table\n"); + return 0; } memcpy(tmp_ptr, l1_ptr, 4096); @@ -600,6 +601,7 @@ found: if (posix_memalign((void **)&tmp_ptr2, 4096, 4096) != 0) { DPRINTF("ERROR allocating memory for L1 table\n"); + return 0; } memcpy(tmp_ptr2, l2_ptr, 4096); lseek(s->fd, l2_offset + (l2_sector << 12), SEEK_SET); -- 2.39.5