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From: Andi Kleen <ak@suse.de>
To: linux-arch@vger.kernel.org
Subject: You might need vmalloc_sync_all()
Date: Tue, 1 May 2007 06:26:55 +0200	[thread overview]
Message-ID: <20070501042655.GL25929@bingen.suse.de> (raw)


Since someone mentioned again.

Right now only x86 implements vmalloc_sync_all(). But iff:

- Your module mappings might require a page fault calling C 
code in kernel
- You got a pagefault notifier at the beginning of the page fault
handler

you risk a endless pagefault recursion with modular pagefault
notifiers. vmalloc_sync_all should sync all the available mappings 
on notifier register so that the C pf handler is not called for module 
faults.

Apparently at least ARM has this problem.

If the kernel module fault is only assembler code without notifier
(e.g. to reload a TLB) it is probably not needed.

-Andi


             reply	other threads:[~2007-05-01  3:29 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-05-01  4:26 Andi Kleen [this message]
2007-05-01  7:44 ` You might need vmalloc_sync_all() Russell King
2007-05-01 11:37   ` Andi Kleen
2007-05-01 19:20     ` Russell King

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