From: Hugh Dickins <hugh@veritas.com>
To: Petr Vandrovec <VANDROVE@vc.cvut.cz>
Cc: Andrew Morton <akpm@digeo.com>,
Christoph Hellwig <hch@infradead.org>,
<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] Re: Shared memory shmat/dt not working well in
Date: Tue, 1 Oct 2002 18:14:04 +0100 (BST) [thread overview]
Message-ID: <Pine.LNX.4.44.0210011804001.1783-100000@localhost.localdomain> (raw)
In-Reply-To: <35FD2132190@vcnet.vc.cvut.cz>
On Tue, 1 Oct 2002, Petr Vandrovec wrote:
>
> You are my hero!
Aww, shucks! I guess I'd better have a go at your next problem...
> Unfortunately it did not fixed another problem I have with sys_mprotect.
> If I start X, system stops to do anything useful. After SAK I could
> do remote connect and running 'w' and 'ps axf' moved them to 'D' state.
> Oct 1 17:47:55 vana kernel: [<c0107ec9>]error_code+0x2d/0x38
> Oct 1 17:47:55 vana kernel: [<c011216f>]flush_tlb_mm+0x1b/0x70
> Oct 1 17:47:55 vana kernel: [<c0133ed1>]change_protection+0x1a1/0x1dc
> Oct 1 17:47:55 vana kernel: [<c01341ed>]mprotect_fixup+0x16d/0x188
Looks to me like flush_tlb_mm is faulting on the vma->vm_mm given it.
And looks to me like mprotect_fixup, in the merge case, may be passing
an already freed vma to change_protection. I'm not as confident about
this patch as the earlier one, but I believe it's correct: please
give it a try, and maybe Christoph will confirm or deny it.
Hugh
--- 2.5.40/mm/mprotect.c Fri Sep 27 23:56:45 2002
+++ linux/mm/mprotect.c Tue Oct 1 18:00:31 2002
@@ -186,8 +186,10 @@
/*
* Try to merge with the previous vma.
*/
- if (mprotect_attempt_merge(vma, *pprev, end, newflags))
+ if (mprotect_attempt_merge(vma, *pprev, end, newflags)) {
+ vma = *pprev;
goto success;
+ }
} else {
error = split_vma(mm, vma, start, 1);
if (error)
next prev parent reply other threads:[~2002-10-01 17:10 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-10-01 16:02 [PATCH] Re: Shared memory shmat/dt not working well in Petr Vandrovec
2002-10-01 17:14 ` Hugh Dickins [this message]
2002-10-01 17:56 ` Petr Vandrovec
2002-10-01 19:01 ` Christoph Hellwig
2002-10-01 19:15 ` Andrew Morton
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