Date: Sat, 09 Feb 2002 10:50:42 -0500 (EST) From: John Baldwin <jhb@FreeBSD.org> To: Julian Elischer <julian@elischer.org> Cc: current@freebsd.org Subject: RE: cred stuff.. Message-ID: <XFMail.020209105042.jhb@FreeBSD.org> In-Reply-To: <Pine.BSF.4.21.0202082246100.5404-100000@InterJet.elischer.org>
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On 09-Feb-02 Julian Elischer wrote: > John, (peter? others?) > > How is it that getting a ucred reference is guarded by PROC_LOCK(p) > but freeing it is guarded by mtx_lock(&Giant); > ? > > Call me naive, but shouldn't they be guarded by the same thing? Naive, maybe. :-P The actual refcount for a ucred is protected by an internal mutex. The PROC_LOCK is to ensure that the value of p_ucred is up to date and doesn't change so that the cred doesn't get free'd out from under us. Giant is needed for crfree() since it can call free(). > Julian > > > On Fri, 8 Feb 2002, Julian Elischer wrote: > >> I'm a little worried about invariants because the behaviour when >> INVARIANTS is set wil be different to teh behaviour when it is off, which >> is 'strange' to say the least. Normally the behaviour si the same but you >> just check for invariant conditions. >> >> >> On Fri, 8 Feb 2002, John Baldwin wrote: >> >> > >> > On 08-Feb-02 Julian Elischer wrote: >> > > >> > > I'd like to commit the code to keep the ucred across userland, >> > > with the code to clear it to NULL kept under DEBUG ifdefs. >> > >> > Use INVARIANTS for the ifdef macro name, but sure. >> > >> > -- >> > >> > John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ >> > "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/ >> > >> >> >> To Unsubscribe: send mail to majordomo@FreeBSD.org >> with "unsubscribe freebsd-current" in the body of the message >> > -- John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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