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From: Michael Neuling on 7 Feb 2010 19:30
When reserving stack space for a new process, make sure we're not
attempting to allocate more than rlimit allows.

Also, reserve the same stack size independent of page size.

This fixes a bug cause by b6a2fea39318e43fee84fa7b0b90d68bed92d2ba
"mm: variable length argument support" and unmasked by
fc63cf237078c86214abcb2ee9926d8ad289da9b
"exec: setup_arg_pages() fails to return errors".

Signed-off-by: Michael Neuling <mikey(a)neuling.org>
Cc: Anton Blanchard <anton(a)samba.org>
Cc: stable(a)kernel.org
---
Update commit message to include patch name and SHA1 of related
patches.

fs/exec.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)

Index: clone1/fs/exec.c
===================================================================
--- clone1.orig/fs/exec.c
+++ clone1/fs/exec.c
@@ -554,7 +554,7 @@ static int shift_arg_pages(struct vm_are
return 0;
}

-#define EXTRA_STACK_VM_PAGES 20 /* random */
+#define EXTRA_STACK_VM_SIZE 81920UL /* randomly 20 4K pages */

/*
* Finalizes the stack vm_area_struct. The flags and permissions are updated,
@@ -627,10 +627,13 @@ int setup_arg_pages(struct linux_binprm
goto out_unlock;
}

+ stack_base = min(EXTRA_STACK_VM_SIZE,
+ current->signal->rlim[RLIMIT_STACK].rlim_cur) -
+ PAGE_SIZE;
#ifdef CONFIG_STACK_GROWSUP
- stack_base = vma->vm_end + EXTRA_STACK_VM_PAGES * PAGE_SIZE;
+ stack_base = vma->vm_end + stack_base;
#else
- stack_base = vma->vm_start - EXTRA_STACK_VM_PAGES * PAGE_SIZE;
+ stack_base = vma->vm_start - stack_base;
#endif
ret = expand_stack(vma, stack_base);
if (ret)
--
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Prev: [PATCH] compat_ioctl: add compat handler for TIOCGSID ioctl
Next: [Bug #15188] Graphic subsystem freeze