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Re: [Qemu-block] [PATCH v4 7/7] block/nbd: NBDReply is used being uninit
From: |
Eric Blake |
Subject: |
Re: [Qemu-block] [PATCH v4 7/7] block/nbd: NBDReply is used being uninitialized |
Date: |
Fri, 19 Jul 2019 09:44:36 -0500 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 |
On 7/19/19 9:34 AM, Eric Blake wrote:
> On 7/19/19 4:40 AM, Andrey Shinkevich wrote:
>> In case nbd_co_receive_one_chunk() fails in
>> nbd_reply_chunk_iter_receive(), 'NBDReply reply' parameter is used in
>> the check nbd_reply_is_simple() without being initialized. The iotest
>> 083 does not pass under the Valgrind: $./check -nbd -valgrind 083.
>> The alternative solution is to swap the operands in the condition:
>> 'if (s->quit || nbd_reply_is_simple(reply))'
>>
>> Signed-off-by: Andrey Shinkevich <address@hidden>
>> ---
>> block/nbd.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> Huh. Very similar to
> https://lists.gnu.org/archive/html/qemu-devel/2019-07/msg03712.html, but
> affects a different function. I can queue this one through my NBD tree
> to get both in my rc2 pull request.
>
> Reviewed-by: Eric Blake <address@hidden>
Actually, since this is the second patch on the same topic, I'm
wondering if it's better to use the following one-liner to fix BOTH
issues and without relying on a gcc extension:
diff --git i/block/nbd.c w/block/nbd.c
index 8d565cc624ec..f751a8e633e5 100644
--- i/block/nbd.c
+++ w/block/nbd.c
@@ -640,6 +640,7 @@ static coroutine_fn int nbd_co_receive_one_chunk(
request_ret, qiov, payload,
errp);
if (ret < 0) {
+ memset(reply, 0, sizeof *reply);
s->quit = true;
} else {
/* For assert at loop start in nbd_connection_entry */
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3226
Virtualization: qemu.org | libvirt.org
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[Qemu-block] [PATCH v4 2/7] iotests: exclude killed processes from running under Valgrind, Andrey Shinkevich, 2019/07/19
[Qemu-block] [PATCH v4 4/7] iotests: Valgrind fails with nonexistent directory, Andrey Shinkevich, 2019/07/19
[Qemu-block] [PATCH v4 5/7] iotests: extended timeout under Valgrind, Andrey Shinkevich, 2019/07/19
[Qemu-block] [PATCH v4 1/7] iotests: allow Valgrind checking all QEMU processes, Andrey Shinkevich, 2019/07/19