xemu/util
Michal Privoznik a760715095 qemu_opts_append: Play nicely with QemuOptsList's head
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>
2014-06-26 15:53:52 +02:00
..
acl.c acl: acl_add can't insert before last list element, fix 2013-06-21 22:52:50 +04:00
aes.c util: Add InvMixColumns 2014-06-16 13:24:33 +02:00
bitmap.c bitmap: use long as index 2014-01-13 14:04:53 +01:00
bitops.c bitops: unroll while loop in find_next_bit() 2013-03-26 13:32:32 +01:00
compatfd.c Add a 'name' parameter to qemu_thread_create 2014-03-09 21:09:38 +02:00
crc32c.c qemu: add castagnoli crc32c checksum algorithm 2013-05-03 10:31:58 +02:00
cutils.c cutils: tighten qemu_parse_fd() 2014-05-08 14:19:58 -04:00
envlist.c
error.c error: error_is_set() is finally unused; remove 2014-05-21 11:57:58 +02:00
event_notifier-posix.c sysemu: avoid proliferation of include/ subdirectories 2013-04-15 18:19:25 +02:00
event_notifier-win32.c
fifo8.c savevm: Remove all the unneeded version_minimum_id_old (arm) 2014-05-13 16:09:35 +01:00
getauxval.c qemu/osdep: Remove the need for qemu_init_auxval 2014-06-23 07:32:27 -07:00
hbitmap.c util/hbitmap.c: Use ctpopl rather than reimplementing a local equivalent 2014-06-11 00:25:06 +01:00
hexdump.c Rename hexdump to avoid FreeBSD libutil conflict 2013-05-20 08:20:08 -05:00
host-utils.c target-ppc: Add ISA2.06 divde[o] Instructions 2014-03-05 03:06:39 +01:00
iov.c util: add return value to qemu_iovec_concat_iov 2014-06-18 08:47:10 +02:00
Makefile.objs tcg-ppc: Merge cache-utils into the backend 2014-06-23 07:32:30 -07:00
module.c util: Add 'static' attribute to function implementation 2014-03-27 19:22:48 +04:00
notify.c notify: add NotiferWithReturn so notifier list can abort 2013-06-28 09:20:26 +02:00
osdep.c do not call g_thread_init() for glib >= 2.31 2014-05-07 21:00:43 +04:00
oslib-posix.c memory: move preallocation code out of exec.c 2014-06-19 18:44:19 +03:00
oslib-win32.c pc,pci,virtio,hotplug fixes, enhancements 2014-06-20 18:01:24 +01:00
path.c init_paths: fix minor memory leak 2014-04-28 08:55:32 +04:00
qemu-config.c qapi: output def_value_str when query command line options 2014-06-16 17:23:20 +08:00
qemu-error.c error: Print error_report() to stderr if using qmp 2014-04-25 09:19:58 -04:00
qemu-openpty.c util/qemu-openpty: fix build with musl libc by include termios.h as fallback 2014-06-11 00:25:06 +01:00
qemu-option.c qemu_opts_append: Play nicely with QemuOptsList's head 2014-06-26 15:53:52 +02:00
qemu-progress.c qemu-progress: Fix progress printing on SIGUSR1 2014-01-24 14:33:00 +01:00
qemu-sockets.c qapi event: convert SPICE events 2014-06-23 11:12:28 -04:00
qemu-thread-posix.c Detect pthread_setname_np at configure time 2014-03-27 17:48:11 +02:00
qemu-thread-win32.c Detect pthread_setname_np at configure time 2014-03-27 17:48:11 +02:00
qemu-timer-common.c Allow clock_gettime() monotonic clock to be utilized on more OS's 2013-04-04 20:22:45 -05:00
readline.c readline: Clear screen on form feed. 2014-06-11 10:10:29 -04:00
rfifolock.c rfifolock: add recursive FIFO lock 2014-03-13 14:42:21 +01:00
throttle.c throttle: add throttle_detach/attach_aio_context() 2014-06-04 09:56:12 +02:00
unicode.c unicode: New mod_utf8_codepoint() 2013-04-13 19:39:59 +00:00
uri.c clean unnecessary code: don't check g_strdup arg for NULL 2013-05-12 13:25:55 +04:00