On 12/07/2018 18:30, Stefan Hajnoczi wrote: > On Wed, Jul 11, 2018 at 03:33:21PM +0200, Cornelia Huck wrote: >> The other qemu-nbds (the inet and the unix socket ones from the first >> run, the second inet one from the second run) have a single thread with >> the same backtrace I posted above. > > We just discussed this on IRC, but for the record: > > qemu-nbd --fork will fork the process after the simpletrace write-out > thread has been spawned. The child process lacks this thread (due to > how fork(2) handles multithreading). Either qemu-nbd needs to > initialize tracing later (but that means we cannot trace early init) or > simpletrace needs a way to respawn the write-out thread.
You can use pthread_atfork for this. Paolo
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