Messages in this thread Patch in this message | | | Date | Wed, 8 Feb 2023 15:12:06 +0100 | From | David Hildenbrand <> | Subject | Re: [PATCH mm-unstable v1 04/26] arm/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE |
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On 07.02.23 01:32, Mark Brown wrote: > On Fri, Jan 13, 2023 at 06:10:04PM +0100, David Hildenbrand wrote: >> Let's support __HAVE_ARCH_PTE_SWP_EXCLUSIVE by stealing one bit from the >> offset. This reduces the maximum swap space per file to 64 GiB (was 128 >> GiB). >> >> While at it drop the PTE_TYPE_FAULT from __swp_entry_to_pte() which is >> defined to be 0 and is rather confusing because we should be dealing >> with "Linux PTEs" not "hardware PTEs". Also, properly mask the type in >> __swp_entry(). > > Today's -next (and at least back to Friday, older logs are unclear - I > only noticed -next issues today) fails to NFS boot on an AT91SAM9G20-EK > (an old ARMv5 platform) with multi_v5_defconfig, a bisect appears to > point to this patch (20aae9eff5acd8f5 in today's -next) as the culprit.
It's been in -next for quite a while, thanks for the report!
> > The failure happens at some point after starting userspace, the kernel > starts spamming the console with messages in the form: > > get_swap_device: Bad swap file entry 10120d20 >
_swap_info_get() tells us that the swp type seems to be bad. I assume we're dealing with a migration entry, if swap is disabled, and fail to detect is_migration_entry() correctly because the type is messed up.
Could you give the following a test?
From 8c4bdbd9862f85782d5919d044c172b584063e83 Mon Sep 17 00:00:00 2001 From: David Hildenbrand <david@redhat.com> Date: Wed, 8 Feb 2023 15:08:01 +0100 Subject: [PATCH] arm/mm: Fix swp type masking in __swp_entry()
We're masking with the number of type bits instead of the type mask, which is obviously wrong.
Fixes: 20aae9eff5ac ("arm/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE") Reported-by: Mark Brown <broonie@kernel.org> Signed-off-by: David Hildenbrand <david@redhat.com> --- arch/arm/include/asm/pgtable.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h index 2e626e6da9a3..a58ccbb406ad 100644 --- a/arch/arm/include/asm/pgtable.h +++ b/arch/arm/include/asm/pgtable.h @@ -292,7 +292,7 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot) #define __swp_type(x) (((x).val >> __SWP_TYPE_SHIFT) & __SWP_TYPE_MASK) #define __swp_offset(x) ((x).val >> __SWP_OFFSET_SHIFT) -#define __swp_entry(type, offset) ((swp_entry_t) { (((type) & __SWP_TYPE_BITS) << __SWP_TYPE_SHIFT) | \ +#define __swp_entry(type, offset) ((swp_entry_t) { (((type) & __SWP_TYPE_MASK) << __SWP_TYPE_SHIFT) | \ ((offset) << __SWP_OFFSET_SHIFT) }) #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) }) -- 2.39.1
-- Thanks,
David / dhildenb
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