Messages in this thread | | | Date | Thu, 4 Sep 2003 18:16:09 +0100 | From | Jamie Lokier <> | Subject | Re: [PATCH] Alternate futex non-page-pinning and COW fix |
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Linus Torvalds wrote: > Actually: the VM_SHARED flag will never change, so testing VM_SHARED is > actually the _right_ thing from a mm perspective.
Yes it can. See sys_mprotect(). If that's not intended, it's a bug in mprotect(). What does PROT_SEM mean for Linux, btw?
See: if (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC | PROT_SEM)) return -EINVAL;
and: newflags = prot | (vma->vm_flags & ~(PROT_READ | PROT_WRITE | PROT_EXEC)); if ((newflags & ~(newflags >> 4)) & 0xf) { error = -EACCES; goto out; }
newflags is than used to index protection_map[], like this: newprot = protection_map[newflags & 0xf];
and that is stored in the page tables.
-- Jamie - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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