This is a note to let you know that I've just added the patch titled
ARM: missing ->mmap_sem around find_vma() in swp_emulate.c
to the 3.0-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
arm-missing-mmap_sem-around-find_vma-in-swp_emulate.c.patch
and it can be found in the queue-3.0 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 7bf9b7bef881aac820bf1f2e9951a17b09bd7e04 Mon Sep 17 00:00:00 2001
From: Al Viro <[email protected]>
Date: Sun, 16 Dec 2012 00:25:57 +0000
Subject: ARM: missing ->mmap_sem around find_vma() in swp_emulate.c
From: Al Viro <[email protected]>
commit 7bf9b7bef881aac820bf1f2e9951a17b09bd7e04 upstream.
find_vma() is *not* safe when somebody else is removing vmas. Not just
the return value might get bogus just as you are getting it (this instance
doesn't try to dereference the resulting vma), the search itself can get
buggered in rather spectacular ways. IOW, ->mmap_sem really, really is
not optional here.
Signed-off-by: Al Viro <[email protected]>
Signed-off-by: Russell King <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/arm/kernel/swp_emulate.c | 2 ++
1 file changed, 2 insertions(+)
--- a/arch/arm/kernel/swp_emulate.c
+++ b/arch/arm/kernel/swp_emulate.c
@@ -108,10 +108,12 @@ static void set_segfault(struct pt_regs
{
siginfo_t info;
+ down_read(¤t->mm->mmap_sem);
if (find_vma(current->mm, addr) == NULL)
info.si_code = SEGV_MAPERR;
else
info.si_code = SEGV_ACCERR;
+ up_read(¤t->mm->mmap_sem);
info.si_signo = SIGSEGV;
info.si_errno = 0;
Patches currently in stable-queue which might be from [email protected]
are
queue-3.0/arm-missing-mmap_sem-around-find_vma-in-swp_emulate.c.patch
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