On 6/6/24 6:32 AM, Jeff Moyer wrote:
> Hi, Eric,
>
> This looks like a repost? I mentioned that we should also set done = 1
> for a failed setup_tracer_devpaths() call, and I was hoping you'd
> include that in a new version (or at least comment on whether you
> thought it was a good idea). Sorry if that wasn't clear!
The first one was a question, this one was a patch :)
I'm sorry, I have not had time to look into or test for failed
setup_tracer_devpaths() calls, and hoped to just fix the bug
I had encountered.
> The change here looks good to me.
Thanks,
-Eric
> -Jeff
>
> Eric Sandeen <sandeen@xxxxxxxxxx> writes:
>
>> # blktrace -o - /dev/sda /dev/sdb /dev/sdc
>>
>> has to be SIGKILLed if BLKTRACESETUP fails for any or all of the devices
>> listed. (I simulated this by just catching one of the devices in
>> setup_buts(), skipping the ioctl, and doing ret++).
>>
>> This seems to be because with "-o -" on the command line, use_tracer_devpaths()
>> sees piped_output set, so we call process_trace_bufs which ends up waiting on
>> (!done) and "done" is never set. i.e.
>>
>> atexit(exit_tracing)
>> wait_tracers
>> if (use_tracer_devpaths()) // true because "-o -"
>> process_trace_bufs
>> while (wait_empty_entries())
>> wait_empty_entries
>> while (!done ... )
>> <loop forever>
>>
>> I think this can be avoided by just setting "done = 1" before returning
>> when setup_buts() fails in run_tracers().
>>
>> Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx>
>> ---
>>
>> diff --git a/blktrace.c b/blktrace.c
>> index 3444fbb..038b2cb 100644
>> --- a/blktrace.c
>> +++ b/blktrace.c
>> @@ -2684,8 +2684,10 @@ static int run_tracers(void)
>> if (net_mode == Net_client)
>> printf("blktrace: connecting to %s\n", hostname);
>>
>> - if (setup_buts())
>> + if (setup_buts()) {
>> + done = 1;
>> return 1;
>> + }
>>
>> if (use_tracer_devpaths()) {
>> if (setup_tracer_devpaths())
>
>
