Re: [PATCH] MIPS: Fix HIGHMEM crash in __update_cache().

From: Lars Persson
Date: Fri Apr 10 2015 - 10:31:17 EST


I came to think that also non-executable mappings for highmem pages could reach the flushing code in __update_cache() and trigger an OOPS.

Until the highmem patches are merged we should block highmem pages in __update_cache(). Could you add this to the patch ?

Sent from my iPhone

> 10 apr 2015 kl. 15:47 skrev Ralf Baechle <ralf@xxxxxxxxxxxxxx>:
>> On Fri, Apr 10, 2015 at 03:21:24PM +0200, Lars Persson wrote:
>> Commit 8b5fe5e54b47 ("MIPS: Fix race condition in lazy cache flushing.")
>> triggered NULL pointer dereferences on systems with HIGHMEM.
>> The problem was caused by not clearing the PG_dcache_dirty flag in
>> flush_icache_page() and thus we enter __update_cache() that lacks
>> support for HIGHMEM.
> Thanks, I've folded this patch into the original 8b5fe5e54b47 commit.
> Ralf
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