From: Jeff Moyer <jmoyer@redhat.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: dan.j.williams@intel.com, Ingo Molnar <mingo@redhat.com>,
"H. Peter Anvin" <hpa@zytor.com>, Tony Luck <tony.luck@intel.com>,
Borislav Petkov <bp@alien8.de>,
linux-edac@vger.kernel.org, x86@kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [patch] x86/pat: pass correct address to sanitize_phys
Date: Tue, 10 Aug 2021 15:22:19 -0400 [thread overview]
Message-ID: <x49k0ktm7f8.fsf@segfault.boston.devel.redhat.com> (raw)
In-Reply-To: <87wnotst1l.ffs@tglx> (Thomas Gleixner's message of "Tue, 10 Aug 2021 08:38:46 +0200")
Thomas Gleixner <tglx@linutronix.de> writes:
> Jeff,
>
> On Wed, Jul 21 2021 at 15:48, Jeff Moyer wrote:
>
> Please write function names with brackets, i.e. sanitize_phys().
OK, will do.
>> memtype_reserve takes an address range of the form [start, end). It
>
> [start, end]
Start is inclusive, end is exclusive, so start <= x < end. I used the
notation found here:
https://en.wikipedia.org/wiki/Interval_(mathematics)
If that's too confusing, I can stick to inclusive vs exclusive verbiage.
>> then passes the start and end addresses to sanitize_phys, which is meant
>> to operate on the inclusive addresses. If end falls at the end of the
>> physical address space, sanitize_phys will return 0. This can result in
>> drivers failing to load:
>>
>> [ 10.000087] mpt3sas_cm0: unable to map adapter memory! or resource not found
>> [ 10.000334] mpt3sas_cm0: failure at drivers/scsi/mpt3sas/mpt3sas_scsih.c:10597/_scsih_probe()!
>
> Doesn't this trigger the WARN() right below that offending line?
It does. I'll include the warning message in the v2 posting.
>> Fix this by passing the inclusive end address to sanitize_phys.
>>
>> Fixes: 510ee090abc3 ("x86/mm/pat: Prepare {reserve, free}_memtype() for "decoy" addresses")
>> Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
>> --
>> It might be worth adding a comment, here. If there are any suggestions
>> on what a sane wording would be, I'm all ears.
>
> See below.
>
>> diff --git a/arch/x86/mm/pat/memtype.c b/arch/x86/mm/pat/memtype.c
>> index 3112ca7786ed..482557905294 100644
>> --- a/arch/x86/mm/pat/memtype.c
>> +++ b/arch/x86/mm/pat/memtype.c
>> @@ -583,7 +583,7 @@ int memtype_reserve(u64 start, u64 end, enum page_cache_mode req_type,
>> int err = 0;
>>
>> start = sanitize_phys(start);
>> - end = sanitize_phys(end);
>
> /*
> * [start, end] is an exclusive address range, but
> * sanitize_phys() expects an inclusive end address
> */
That works for me (modulo the interval notation), thanks for the
suggestion.
Thanks!
Jeff
prev parent reply other threads:[~2021-08-10 19:21 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-21 19:48 [patch] x86/pat: pass correct address to sanitize_phys Jeff Moyer
2021-08-09 15:58 ` Jeff Moyer
2021-08-09 17:25 ` David Hildenbrand
2021-08-10 6:38 ` Thomas Gleixner
2021-08-10 19:22 ` Jeff Moyer [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=x49k0ktm7f8.fsf@segfault.boston.devel.redhat.com \
--to=jmoyer@redhat.com \
--cc=bp@alien8.de \
--cc=dan.j.williams@intel.com \
--cc=hpa@zytor.com \
--cc=linux-edac@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mingo@redhat.com \
--cc=tglx@linutronix.de \
--cc=tony.luck@intel.com \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).