Re: [PATCH] mm: protect against concurrent vma expansion
From: Michel Lespinasse <hidden>
Date: 2012-12-20 03:07:28
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Hi Simon, On Wed, Dec 19, 2012 at 5:56 PM, Simon Jeons [off-list ref] wrote:
One question. I found that mainly callsite of expand_stack() is #PF, but it holds mmap_sem each time before call expand_stack(), how can hold a *shared* mmap_sem happen?
the #PF handler calls down_read(&mm->mmap_sem) before calling expand_stack. I think I'm just confusing you with my terminology; shared lock == read lock == several readers might hold it at once (I'd say they share it) -- Michel "Walken" Lespinasse A program is never fully debugged until the last user dies. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>