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mm: pass correct mm when growing stack

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Tetsuo Handa reports seeing the WARN_ON(current->mm == NULL) in
security_vm_enough_memory(), when do_execve() is touching the
target mm's stack, to set up its args and environment.

Yes, a UMH_NO_WAIT or UMH_WAIT_PROC call_usermodehelper() spawns
an mm-less kernel thread to do the exec.  And in any case, that
vm_enough_memory check when growing stack ought to be done on the
target mm, not on the execer's mm (though apart from the warning,
it only makes a slight tweak to OVERCOMMIT_NEVER behaviour).

Reported-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Hugh Dickins 2009-04-16 21:58:12 +01:00 committed by Linus Torvalds
parent 05f54c13cd
commit 05fa199d45
1 changed files with 1 additions and 1 deletions
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2
mm/mmap.c
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@ -1575,7 +1575,7 @@ static int acct_stack_growth(struct vm_area_struct *vma, unsigned long size, uns
* Overcommit.. This must be the final test, as it will * Overcommit.. This must be the final test, as it will
* update security statistics. * update security statistics.
*/ */
if (security_vm_enough_memory(grow)) if (security_vm_enough_memory_mm(mm, grow))
return -ENOMEM; return -ENOMEM;
/* Ok, everything looks good - let it rip */ /* Ok, everything looks good - let it rip */