From: Andi Kleen <andi@firstfloor.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Bron Gondwana <brong@fastmail.fm>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Nick Piggin <npiggin@suse.de>,
Andrew Morton <akpm@linux-foundation.org>,
Rob Mueller <robm@fastmail.fm>, Ingo Molnar <mingo@elte.hu>
Subject: Re: BUG: mmapfile/writev spurious zero bytes (x86_64/not i386, bisected, reproducable)
Date: Tue, 17 Jun 2008 22:58:17 +0200 [thread overview]
Message-ID: <87od5zwzh2.fsf@basil.nowhere.org> (raw)
In-Reply-To: <alpine.LFD.1.10.0806171309130.2981@woody.linux-foundation.org> (Linus Torvalds's message of "Tue, 17 Jun 2008 13:16:39 -0700 (PDT)")
Linus Torvalds <torvalds@linux-foundation.org> writes:
>
> So I'm starting to think the bug is all in there, not in the VM itself.
> See arch/x86/lib/copy_user_nocache.S.
The x86-64 copy_*_user functions were always designed to return errors
both ways (as in both for load and for store). That's needed because
the loops are shared for copy_to_user and copy_from_user. That's normally
ok because when you do _to_user you shouldn't fault on the loads
and vice versa. If a caller does that it's buggy.
-Andi
next prev parent reply other threads:[~2008-06-17 21:00 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-06-17 6:00 BUG: mmapfile/writev spurious zero bytes (x86_64/not i386, bisected, reproducable) Bron Gondwana
2008-06-17 6:02 ` Bron Gondwana
2008-06-17 17:08 ` Linus Torvalds
2008-06-17 17:45 ` Linus Torvalds
2008-06-17 20:16 ` Linus Torvalds
2008-06-17 20:41 ` Linus Torvalds
2008-06-17 21:06 ` Linus Torvalds
2008-06-17 21:16 ` Andi Kleen
2008-06-17 21:24 ` Linus Torvalds
2008-06-17 21:30 ` Andi Kleen
2008-06-17 21:37 ` Linus Torvalds
2008-06-17 21:36 ` Al Viro
2008-06-17 21:42 ` Andi Kleen
2008-06-17 21:49 ` Linus Torvalds
2008-06-17 22:11 ` Al Viro
2008-06-17 22:21 ` Andi Kleen
2008-06-18 6:22 ` Nick Piggin
2008-06-17 21:20 ` Linus Torvalds
2008-06-18 2:27 ` Bron Gondwana
2008-06-18 3:14 ` Bron Gondwana
2008-06-18 4:03 ` Linus Torvalds
2008-06-18 5:11 ` Cyrus mmap vs lseek/write usage - (WAS: BUG: mmapfile/writev spurious zero bytes (x86_64/not i386, bisected, reproducable)) Bron Gondwana
2008-06-18 16:22 ` Linus Torvalds
2008-06-18 23:45 ` Robert Mueller
2008-06-19 0:20 ` Linus Torvalds
2008-10-03 11:44 ` BUG: mmapfile/writev spurious zero bytes still in the wild Bron Gondwana
2008-10-03 13:07 ` Andrew Morton
2008-10-04 0:13 ` Bron Gondwana
2008-06-17 21:15 ` BUG: mmapfile/writev spurious zero bytes (x86_64/not i386, bisected, reproducable) Andi Kleen
2008-06-17 20:58 ` Andi Kleen [this message]
2008-06-17 21:14 ` Linus Torvalds
2008-06-17 21:26 ` Andi Kleen
2008-06-17 21:31 ` Linus Torvalds
2008-06-17 21:34 ` Linus Torvalds
2008-06-17 21:34 ` Andi Kleen
2008-06-17 21:46 ` Linus Torvalds
2008-06-18 6:10 ` Nick Piggin
2008-06-18 2:21 ` Bron Gondwana
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