Attachment 27628 Details for Bug 64652

[patch] fix-smp-race-2.4

smprace-2.4.patch (text/plain), 1.10 KB, created by Marcus Meissner on 2005-01-14 00:42:16 UTC

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Creator: Marcus Meissner

Created: 2005-01-14 00:42:16 UTC

Size: 1.10 KB

patch

obsolete

>--- linux-2.4.21/include/linux/mm.h.orig	2005-01-13 17:27:18.000000000 +0100
>+++ linux-2.4.21/include/linux/mm.h	2005-01-13 17:37:00.000000000 +0100
>@@ -728,14 +728,21 @@
> 	int err = -ENOMEM;
> 
> 	/*
>-	 * vma->vm_start/vm_end cannot change under us because the caller is required
>-	 * to hold the mmap_sem in write mode. We need to get the spinlock only
>-	 * before relocating the vma range ourself.
>+	 * vma->vm_start/vm_end cannot change under us because the caller
>+	 * is required to hold the mmap_sem in read mode.  We need the
>+	 * page_table_lock lock to serialize against concurrent expand_stacks.
> 	 */
> 	address &= PAGE_MASK;
> 	if (prev_vma && prev_vma->vm_end + (heap_stack_gap << PAGE_SHIFT) > address)
> 		goto out;
> 	spin_lock(&vma->vm_mm->page_table_lock);
>+
>+	/* already expanded while we were spinning? */
>+	if (vma->vm_start <= address) {
>+		spin_unlock(&vma->vm_mm->page_table_lock);
>+		return 0;
>+	}
>+
> 	grow = (vma->vm_start - address) >> PAGE_SHIFT;
> 	if (vma->vm_end - address > current->rlim[RLIMIT_STACK].rlim_cur ||
> 	    ((vma->vm_mm->total_vm + grow) << PAGE_SHIFT) > current->rlim[RLIMIT_AS].rlim_cur)

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