Re: [PATCH v13 12/22] mm: pagewalk: Allow walking without vma

From: Steven Price <steven.price@arm.com>
To: kbuild test robot <lkp@intel.com>
Cc: "Mark Rutland" <Mark.Rutland@arm.com>,
	"Peter Zijlstra" <peterz@infradead.org>,
	"Catalin Marinas" <catalin.marinas@arm.com>,
	"Dave Hansen" <dave.hansen@linux.intel.com>,
	linux-mm@kvack.org, "H. Peter Anvin" <hpa@zytor.com>,
	"Will Deacon" <will@kernel.org>,
	"Liang, Kan" <kan.liang@linux.intel.com>,
	x86@kernel.org, "Ingo Molnar" <mingo@redhat.com>,
	"Arnd Bergmann" <arnd@arndb.de>,
	"Jérôme Glisse" <jglisse@redhat.com>,
	"Borislav Petkov" <bp@alien8.de>,
	"Andy Lutomirski" <luto@kernel.org>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	linux-arm-kernel@lists.infradead.org, kbuild-all@lists.01.org,
	"Ard Biesheuvel" <ard.biesheuvel@linaro.org>,
	linux-kernel@vger.kernel.org, "James Morse" <james.morse@arm.com>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Vineet Gupta" <vgupta@synopsys.com>
Subject: Re: [PATCH v13 12/22] mm: pagewalk: Allow walking without vma
Date: Mon, 28 Oct 2019 10:46:55 +0000	[thread overview]
Message-ID: <14bd3b3c-268b-4a4f-2ee7-17ba6f10f31d@arm.com> (raw)
In-Reply-To: <201910271514.G7Dilhf7%lkp@intel.com>

On 27/10/2019 07:59, kbuild test robot wrote:
> Hi Steven,
> 
> Thank you for the patch! Yet something to improve:
> 
> [auto build test ERROR on linus/master]
> [also build test ERROR on v5.4-rc4 next-20191025]
> [if your patch is applied to the wrong git tree, please drop us a note to help
> improve the system. BTW, we also suggest to use '--base' option to specify the
> base tree in git format-patch, please see https://stackoverflow.com/a/37406982]
> 
> url:    https://github.com/0day-ci/linux/commits/Steven-Price/Generic-page-walk-and-ptdump/20191027-140322
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 5a1e843c66fa6438f389045981c37e4073917641
> config: arc-defconfig (attached as .config)
> compiler: arc-elf-gcc (GCC) 7.4.0
> reproduce:
>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>         chmod +x ~/bin/make.cross
>         # save the attached .config to linux build tree
>         GCC_VERSION=7.4.0 make.cross ARCH=arc 

First off, these instructions don't work! make.cross attempts to
download a sparc toolchain.

However, the issue is actually quite easy to see if you look more
closely at patch 2:

> +#define pmd_leaf(x)                    (pmd_val(pmd) & _PAGE_HW_SZ)

That 'pmd' variable should really have been 'x'!

Below diff should fix this up - I'll repost with this squashed in shortly:

----8<----

diff --git a/arch/arc/include/asm/pgtable.h b/arch/arc/include/asm/pgtable.h
index 5ec798e50836..b4a0cf27ac1c 100644
--- a/arch/arc/include/asm/pgtable.h
+++ b/arch/arc/include/asm/pgtable.h
@@ -274,7 +274,7 @@ static inline void pmd_set(pmd_t *pmdp, pte_t *ptep)
 #define pmd_none(x)                    (!pmd_val(x))
 #define        pmd_bad(x)                      ((pmd_val(x) & ~PAGE_MASK))
 #define pmd_present(x)                 (pmd_val(x))
-#define pmd_leaf(x)                    (pmd_val(pmd) & _PAGE_HW_SZ)
+#define pmd_leaf(x)                    (pmd_val(x) & _PAGE_HW_SZ)
 #define pmd_clear(xp)                  do { pmd_val(*(xp)) = 0; } while (0)

 #define pte_page(pte)          pfn_to_page(pte_pfn(pte))
