Messages in this thread Patch in this message | | | Date | Fri, 10 Oct 2008 12:21:28 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH RESEND] early_ioremap has a fencepost error |
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* Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:
> Can we get this into 2.6.27.x at some point as its a regression and a > crash on boot for some users moving from 2.6.26
yes, have your fix patch from yesterday in tip/x86/urgent already, with a stable@kernel.org tag included as well - see below. Thanks Alan!
Ingo
--------------> From dd5698f42a5f2b494c3e811598403f105b00f4f2 Mon Sep 17 00:00:00 2001 From: Alan Cox <alan@redhat.com> Date: Fri, 10 Oct 2008 10:46:45 +0100 Subject: [PATCH] x86, early_ioremap: fix fencepost error
The x86 implementation of early_ioremap has an off by one error. If we get an object which ends on the first byte of a page we undermap by one page and this causes a crash on boot with the ASUS P5QL whose DMI table happens to fit this alignment.
The size computation is currently
last_addr = phys_addr + size - 1; npages = (PAGE_ALIGN(last_addr) - phys_addr)
(Consider a request for 1 byte at alignment 0...)
Closes #11693
Debugging work by Ian Campbell/Felix Geyer
Signed-off-by: Alan Cox <alan@rehat.com> Cc: <stable@kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu> --- arch/x86/mm/ioremap.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c index d4b6e6a..d0975fc 100644 --- a/arch/x86/mm/ioremap.c +++ b/arch/x86/mm/ioremap.c @@ -595,7 +595,7 @@ void __init *early_ioremap(unsigned long phys_addr, unsigned long size) */ offset = phys_addr & ~PAGE_MASK; phys_addr &= PAGE_MASK; - size = PAGE_ALIGN(last_addr) - phys_addr; + size = PAGE_ALIGN(last_addr + 1) - phys_addr; /* * Mappings have to fit in the FIX_BTMAP area.
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