Steven Sistare <steven.sist...@oracle.com> writes:
> On 2/5/2025 4:52 PM, Steven Sistare wrote:
>> On 2/5/2025 4:28 PM, Peter Xu wrote:
>>> On Wed, Feb 05, 2025 at 12:54:01PM -0800, Steve Sistare wrote:
>>>> qmp_migrate guarantees that cpr_channel is not null for
>>>> MIG_MODE_CPR_TRANSFER when cpr_state_save is called:
>>>>
>>>> qmp_migrate()
>>>> if (s->parameters.mode == MIG_MODE_CPR_TRANSFER && !cpr_channel) {
>>>> return;
>>>> }
>>>> cpr_state_save(cpr_channel)
>>>>
>>>> but cpr_state_save checks for mode differently before using channel,
>>>> and Coverity cannot infer that they are equivalent in outgoing QEMU,
>>>> and warns that channel may be NULL:
>>>>
>>>> cpr_state_save(channel)
>>>> MigMode mode = migrate_mode();
>>>> if (mode == MIG_MODE_CPR_TRANSFER) {
>>>> f = cpr_transfer_output(channel, errp);
>>>>
>>>> To make Coverity happy, use parameters.mode in cpr_state_save.
>>>>
>>>> Resolves: Coverity CID 1590980
>>>> Reported-by: Peter Maydell <peter.mayd...@linaro.org>
>>>> Signed-off-by: Steve Sistare <steven.sist...@oracle.com>
>>>> ---
>>>> migration/cpr.c | 3 ++-
>>>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/migration/cpr.c b/migration/cpr.c
>>>> index 584b0b9..7f20bd5 100644
>>>> --- a/migration/cpr.c
>>>> +++ b/migration/cpr.c
>>>> @@ -8,6 +8,7 @@
>>>> #include "qemu/osdep.h"
>>>> #include "qapi/error.h"
>>>> #include "migration/cpr.h"
>>>> +#include "migration/migration.h"
>>>> #include "migration/misc.h"
>>>> #include "migration/options.h"
>>>> #include "migration/qemu-file.h"
>>>> @@ -132,7 +133,7 @@ int cpr_state_save(MigrationChannel *channel, Error
>>>> **errp)
>>>> {
>>>> int ret;
>>>> QEMUFile *f;
>>>> - MigMode mode = migrate_mode();
>>>> + MigMode mode = migrate_get_current()->parameters.mode;
>>>
>>> Are we sure this can make coverity happy?
>>
>> It should, based on Peter Maydell's analysis, but I would appreciate
>> if he could apply and test the fix.
>>
>>> Another more straightforward change is caching migrate mode in
>>> qmp_migrate() and also check that before invoking cpr_state_save().
>>
>> Surely anyone would consider my one-line change to be straight forward.
>
>
> Given that Coverity complains about channel, and not mode, this is the
> most direct fix:
>
> ----------------------------------------
> diff --git a/migration/cpr.c b/migration/cpr.c
> index 59644e8..224b6ff 100644
> --- a/migration/cpr.c
> +++ b/migration/cpr.c
> @@ -160,6 +160,7 @@ int cpr_state_save(MigrationChannel *channel, Error
> **errp)
> trace_cpr_state_save(MigMode_str(mode));
>
> if (mode == MIG_MODE_CPR_TRANSFER) {
> + g_assert(channel);
> f = cpr_transfer_output(channel, errp);
> } else {
> return 0;
> -------------------------------
>
> - Steve
Queueing this^ version. Thanks
