Hi Rik, Thanks for the blazingly fast response :-) On 9 October 2017 at 21:08, Rik van Riel <riel@xxxxxxxxxx> wrote: > On Mon, 2017-10-09 at 21:06 +0200, Michael Kerrisk (man-pages) wrote: >> Hi Rik, >> >> I have a follow-up question re wipe-on-fork. What are the semantics >> for this setting with respect to fork() and exec()? That is, in the >> child of a fork(), does the flag remain set for the specified address >> range? (My quick read of the source suggests yes, but I have not >> tested.) And, when we do an exec(), my assumption is that the flag is >> cleared for the address range, but it would be good to have >> confirmation. > > Indeed, on exec() the flag is cleared, because all > memory regions get replaced on exec(). Thanks. > The flag remains across a fork(), so if a child task > were to fork, the memory would be empty of contents > again in its child. This seems to most closely match > the use case of discarding things like cryptographic > secrets at fork time. Thanks! I'll add this info to the madvise(2) page. Cheers, Michael -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/ -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
