mm: pass correct mm when growing stack
authorHugh Dickins <hugh@veritas.com>
Thu, 16 Apr 2009 20:58:12 +0000 (21:58 +0100)
committerLinus Torvalds <torvalds@linux-foundation.org>
Thu, 16 Apr 2009 21:41:25 +0000 (14:41 -0700)
commit05fa199d45c54a9bda7aa3ae6537253d6f097aa9
treecfdcdd04bfcef7d0dcb47fad93ba8fa676349dd3
parent05f54c13cd0c33694eec39a265475c5d6cf223cf
mm: pass correct mm when growing stack

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>
mm/mmap.c