In the last episode (Jan 29), Murat Balaban said:
> Are there any issues that i should now about memcpy and
> multithreading in FreeBSD? I've got a code which reads:
>
> memcpy(&(h.req), req, sizeof(struct request));
What are the values of h and req at the time of segfault? You might
want to try running with MALLOC_OPTIONS=J, which makes sure you don't
accidentally use free'd memory, or assume that malloced memory is
zeroed. If you see pointers with values near 0xD0D0D0D0, you have
found a bug in your code...
> and I keep getting SIGSEGV there in FreeBSD but not in Linux.
>
> PS: Of course, I protect the write operation with a mutex.
Mutexes will protect you from someone stepping on your memory while
you're copying. They don't protect you from seg faults if you have the
wrong pointers in the first place.
--
Dan Nelson
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