Messages in this thread | | | Date | Fri, 28 Jul 2006 19:52:58 -0400 | From | Neil Horman <> | Subject | Re: [KJ] audit return code handling for kernel_thread [1/11] |
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On Sat, Jul 29, 2006 at 09:49:01AM +1000, Nick Piggin wrote: > nhorman@tuxdriver.com wrote: > >Audit/Cleanup of kernel_thread calls, specifically checking of return > >codes. > > Problems seemed to fall into 3 main categories: > > > > Thanks for doing this. Nitpick: this should be all one patch, or at most 3 > patches (then each of the below 3 items would become individual changelogs). > You're welcome. I specifically split it into multiple little patches, as each file has a different maintainer, but if the consensus is for one patch (or three), so be it, I'll do that in the future.
> Each patch should have a unique changelog, each should have a unique subject > (sans the sequence number). > > cc'ing Andrew is also a good idea, if you want them to get merged ;) > I can do that :)
> One coding style comment: > if (...) > multi line > statement > > Could use braces around the outermost if statement, for clarity. > If you ack this, I'll post a follow on patch to clean that up next week. I've already received a suggestion to use the same failure to start thread warning message to save string table space, so I've got some extra clean up to do anyway.
Regards Neil
> > > 1) callers of kernel_thread were inconsistent about meaning of a zero > > return > > code. Some callers considered a zero return code to mean success, > > others took > > it to mean failure. a zero return code, while not actually possible > > in the > > current implementation, should be considered a success (pid 0 > > is/should be > > valid). fixed all callers to treat zero return as success > > > > 2) caller of kernel_thread saved return code of kernel_thread for > > later use > > without ever checking its value. Callers who did this tended to > > assume a > > non-zero return was success, and would often wait for a completion > > queue to be > > woken up, implying that an error (negative return code) from > > kernel_thread could > > lead to deadlock. Repaired by checking return code at call time, and > > setting > > saved return code to zero in the event of an error. > > > > 3) callers of kernel_thread never bothered to check the return code at > > all. > > This can lead to seemingly unrelated errors later in execution. Fixed > > by > > checking return code at call time and printing a warning message on > > failure. > > -- > SUSE Labs, Novell Inc. > Send instant messages to your online friends http://au.messenger.yahoo.com
-- /*************************************************** *Neil Horman *Software Engineer *gpg keyid: 1024D / 0x92A74FA1 - http://pgp.mit.edu ***************************************************/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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