From: "Linus Torvalds" <torvalds@osdl.org>
To: <Administrator@smtp.paston.co.uk>
Cc: "Srivatsa Vaddagiri" <vatsa@in.ibm.com>,
"Kernel Mailing List" <linux-kernel@vger.kernel.org>,
<manfred@colorfullife.com>, <rusty@au1.ibm.com>,
"Andrew Morton" <akpm@osdl.org>
Subject: Re: BUG in x86 do_page_fault? [was Re: in_atomic doesn't count local_irq_disable?]
Date: Mon, 29 Mar 2004 16:43:08 +0100 [thread overview]
Message-ID: <023e01c415a4$88abd940$d100000a@sbs2003.local> (raw)
In-Reply-To: <20040104145736.GA11198@elf.ucw.cz>
On Sun, 4 Jan 2004, Pavel Machek wrote:
> >
> > Please don't do this, it will result in some _really_ nasty problems with
> > X and other programs that potentially disable interrupts in user
> > space.
>
> If user program causes page fault with interrupts disabled, it is
> certainly buggy, right?
No.
It may do a best-effort thing. It may also do a best-_performance_ thing,
in leaving interrupts disabled over a piece of code that doesn't care,
knowing that disabling interrupts is expensive. Or it may just be a
simple case of simplicity: disable interrupts over the whole region,
knowing that only a part of it matters.
It by no means is automatically a bug. And it unquestionably _does_
happen. We used to warn about it. We stopped.
Linus
next prev parent reply other threads:[~2004-03-29 15:43 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-12-29 15:13 in_atomic doesn't count local_irq_disable? Manfred Spraul
2003-12-30 13:26 ` Srivatsa Vaddagiri
2003-12-31 13:29 ` BUG in x86 do_page_fault? [was Re: in_atomic doesn't count local_irq_disable?] Srivatsa Vaddagiri
2003-12-31 19:08 ` Linus Torvalds
2004-01-04 14:57 ` Pavel Machek
2004-01-04 20:43 ` Linus Torvalds
2004-03-29 15:43 ` Linus Torvalds [this message]
2004-03-29 15:42 ` Pavel Machek
2003-12-31 13:35 ` [lhcs-devel] Re: in_atomic doesn't count local_irq_disable? Srivatsa Vaddagiri
2004-01-02 0:52 ` Manfred Spraul
2004-01-02 10:56 ` Srivatsa Vaddagiri
2004-01-02 14:00 ` Srivatsa Vaddagiri
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