Messages in this thread Patch in this message |  | | | Date | Thu, 16 Apr 2009 21:58:12 +0100 (BST) | | From | Hugh Dickins <> | | Subject | [PATCH] 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 --- Commoner in 2.6.30-rc, but needs fixing in 2.6.28.N and 2.6.29.N too. mm/mmap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- 2.6.30-rc2/mm/mmap.c 2009-04-08 18:20:25.000000000 +0100 +++ linux/mm/mmap.c 2009-04-16 20:31:17.000000000 +0100 @@ -1575,7 +1575,7 @@ static int acct_stack_growth(struct vm_a * Overcommit.. This must be the final test, as it will * update security statistics. */ - if (security_vm_enough_memory(grow)) + if (security_vm_enough_memory_mm(mm, grow)) return -ENOMEM; /* Ok, everything looks good - let it rip */
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