| Message ID | 22156.64847.849022.761752@mariner.uk.xensource.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
diff --git a/tools/blktap/drivers/block-qcow.c b/tools/blktap/drivers/block-qcow.c index 0e4e9cf..8fb6023 100644 --- a/tools/blktap/drivers/block-qcow.c +++ b/tools/blktap/drivers/block-qcow.c @@ -440,6 +440,7 @@ 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); @@ -613,6 +614,7 @@ 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);
Ian Campbell writes ("Re: [Xen-devel] [xen-4.4-testing test] 66583: regressions - FAIL"): > Aha, this failure is in tools/blktap/drivers/block-qcow.c and not > tools/blktap2/drivers/block-qcow.c. Well spotted. > 345e44a85d71 was writing after blktap1 was remove from the tree so > backporting it wouldn't have helped. Right. > $ git show 345e44a85d71a | patch tools/blktap/drivers/block-qcow.c > patching file tools/blktap/drivers/block-qcow.c > Hunk #1 succeeded at 440 (offset 13 lines). > Hunk #2 succeeded at 614 (offset 13 lines). > $ > > Seems like the way to go for all branches which still have blktap1 (4.5 and > back, although it was disabled by default in 76c66c689b85 which was in > 4.4.0-rc1. I have done roughly this, to 4.3-4.5 inclusive. Ian. commit a64bfae49ae845ba4cb8cb6923fa08c41439872a Author: Dario Faggioli <dario.faggioli@citrix.com> Date: Fri Jun 20 16:09:00 2014 +0200 blktap: Fix two 'maybe uninitialized' variables [ Cross-ported to blktap1 from 345e44a85d71a "blktap2: Fix two 'maybe uninitialized' variables" -iwj; Remainder of commit message is from blktap2's version. ] 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 <dario.faggioli@citrix.com> Acked-by: Ian Jackson <ian.jackson@eu.citrix.com> Backport-requested-by: Ian Campbell <ian.campbell@citrix.com> Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com> (cherry picked from commit 845e8c1653242bbd9b9de5a081182db0f3f39054) (cherry picked from commit e003d429d8c63523df40663b4586c572ce796659)