Re: [Qemu-devel] [PATCH for 2.10 04/35] ivshmem: fix incorrect error handling in ivshmem_recv_msg()

[Paolo Bonzini]

On 25/07/2017 10:18, Markus Armbruster wrote:
> Philippe Mathieu-Daudé <address@hidden> writes:
> 
>> If qemu_chr_fe_read_all() returns -EINTR the do {} statement continues and 
>> the
>> n accumulator used to complete reads upto sizeof(msg) is decremented by 4 
>> (the
>> value of EINTR on Linux).
>> To avoid that, use simpler if() statements and continue if EINTR occured.
>>
>> hw/misc/ivshmem.c:650:14: warning: Loss of sign in implicit conversion
>>     } while (n < sizeof(msg));
>>              ^
>>
> 
> Let's add "Screwed up in commit 3a55fc0f, v2.6.0."
> 
>> Reported-by: Clang Static Analyzer
>> Signed-off-by: Philippe Mathieu-Daudé <address@hidden>
>> ---
>> get_maintainer.pl: No maintainers found!
>>
>>  hw/misc/ivshmem.c | 5 ++++-
>>  1 file changed, 4 insertions(+), 1 deletion(-)
>>
>> diff --git a/hw/misc/ivshmem.c b/hw/misc/ivshmem.c
>> index a58f9ee579..47a015f072 100644
>> --- a/hw/misc/ivshmem.c
>> +++ b/hw/misc/ivshmem.c
>> @@ -642,7 +642,10 @@ static int64_t ivshmem_recv_msg(IVShmemState *s, int 
>> *pfd, Error **errp)
>>      do {
>>          ret = qemu_chr_fe_read_all(&s->server_chr, (uint8_t *)&msg + n,
>>                                     sizeof(msg) - n);
>> -        if (ret < 0 && ret != -EINTR) {
>> +        if (ret < 0) {
>> +            if (ret == -EINTR) {
>> +                continue;
>> +            }
>>              error_setg_errno(errp, -ret, "read from server failed");
>>              return INT64_MIN;
>>          }
> 
> Reviewed-by: Markus Armbruster <address@hidden>
> 
> Paolo, you taking this through your miscellaneous queue would save me
> (and possibly Peter) a bit of work.  Only if you have something queued
> already.  Let me know.

Fair enough, I'll pick this up.

Paolo