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When running a libvirt test suite I've noticed the qemu-img is crashing occasionally. Tracing the problem down led me to the following valgrind output: qemu.git $ valgrind -q ./qemu-img create -f qed -obacking_file=/dev/null,backing_fmt=raw qed ==14881== Invalid write of size 8 ==14881== at 0x1D263F: qemu_opts_create (qemu-option.c:692) ==14881== by 0x130782: bdrv_img_create (block.c:5531) ==14881== by 0x118DE0: img_create (qemu-img.c:462) ==14881== by 0x11E7E4: main (qemu-img.c:2830) ==14881== Address 0x11fedd38 is 24 bytes inside a block of size 232 free'd ==14881== at 0x4C2CA5E: realloc (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so) ==14881== by 0x592D35E: g_realloc (in /usr/lib64/libglib-2.0.so.0.3800.2) ==14881== by 0x1D38D8: qemu_opts_append (qemu-option.c:1129) ==14881== by 0x13075E: bdrv_img_create (block.c:5528) ==14881== by 0x118DE0: img_create (qemu-img.c:462) ==14881== by 0x11E7E4: main (qemu-img.c:2830) ==14881== Formatting 'qed', fmt=qed size=0 backing_file='/dev/null' backing_fmt='raw' cluster_size=65536 ==14881== Invalid write of size 8 ==14881== at 0x1D28BE: qemu_opts_del (qemu-option.c:750) ==14881== by 0x130BF3: bdrv_img_create (block.c:5638) ==14881== by 0x118DE0: img_create (qemu-img.c:462) ==14881== by 0x11E7E4: main (qemu-img.c:2830) ==14881== Address 0x11fedd38 is 24 bytes inside a block of size 232 free'd ==14881== at 0x4C2CA5E: realloc (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so) ==14881== by 0x592D35E: g_realloc (in /usr/lib64/libglib-2.0.so.0.3800.2) ==14881== by 0x1D38D8: qemu_opts_append (qemu-option.c:1129) ==14881== by 0x13075E: bdrv_img_create (block.c:5528) ==14881== by 0x118DE0: img_create (qemu-img.c:462) ==14881== by 0x11E7E4: main (qemu-img.c:2830) ==14881== The problem is apparently in the qemu_opts_append(). Well, if it gets called twice or more. On the first call, when @dst is NULL some initialization is done during which @dst->head list gets initialized. The list is initialized in a way, so that the list tail points at the list head. However, the next time qemu_opts_append() is called for new options to be added, g_realloc() may move @dst to a new address making the old list tail point at an invalid address. If that's the case, we must update the list pointers. Signed-off-by: Michal Privoznik <mprivozn@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> |
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| .. | ||
| acl.c | ||
| aes.c | ||
| bitmap.c | ||
| bitops.c | ||
| compatfd.c | ||
| crc32c.c | ||
| cutils.c | ||
| envlist.c | ||
| error.c | ||
| event_notifier-posix.c | ||
| event_notifier-win32.c | ||
| fifo8.c | ||
| getauxval.c | ||
| hbitmap.c | ||
| hexdump.c | ||
| host-utils.c | ||
| iov.c | ||
| Makefile.objs | ||
| module.c | ||
| notify.c | ||
| osdep.c | ||
| oslib-posix.c | ||
| oslib-win32.c | ||
| path.c | ||
| qemu-config.c | ||
| qemu-error.c | ||
| qemu-openpty.c | ||
| qemu-option.c | ||
| qemu-progress.c | ||
| qemu-sockets.c | ||
| qemu-thread-posix.c | ||
| qemu-thread-win32.c | ||
| qemu-timer-common.c | ||
| readline.c | ||
| rfifolock.c | ||
| throttle.c | ||
| unicode.c | ||
| uri.c | ||