From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
osth@freesurf.ch
Subject: [PATCH] xen: execve's error paths don't pin the mm before unpinning
Date: Tue, 25 Sep 2007 11:50:00 -0700 [thread overview]
Message-ID: <46F95858.40206@goop.org> (raw)
execve's error paths don't activate (and therefore pin) the mm before
calling exit_mmap to free it up, so don't try to unpin unless it is
actually pinned. This prevents a BUG_ON from triggering.
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: osth@freesurf.ch
---
arch/i386/xen/mmu.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
===================================================================
--- a/arch/i386/xen/mmu.c
+++ b/arch/i386/xen/mmu.c
@@ -558,6 +558,9 @@ void xen_exit_mmap(struct mm_struct *mm)
put_cpu();
spin_lock(&mm->page_table_lock);
- xen_pgd_unpin(mm->pgd);
+
+ /* pgd may not be pinned in the error exit path of execve */
+ if (PagePinned(virt_to_page(mm->pgd)))
+ xen_pgd_unpin(mm->pgd);
spin_unlock(&mm->page_table_lock);
}
reply other threads:[~2007-09-25 18:50 UTC|newest]
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