From: David Hildenbrand <david@redhat.com>
To: Liu Shixin <liushixin2@huawei.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Denys Vlasenko <dvlasenk@redhat.com>,
Kefeng Wang <wangkefeng.wang@huawei.com>,
Anshuman Khandual <anshuman.khandual@arm.com>,
David Hildenbrand <dhildenb@redhat.com>,
Rafael Aquini <raquini@redhat.com>,
Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] arm64/mm: fix incorrect file_map_count for invalid pmd/pud
Date: Wed, 16 Nov 2022 10:08:27 +0100 [thread overview]
Message-ID: <73189e81-08c2-bb18-dd4a-f717996ea819@redhat.com> (raw)
In-Reply-To: <20221116083811.464678-3-liushixin2@huawei.com>
On 16.11.22 09:38, Liu Shixin wrote:
> The page table check trigger BUG_ON() unexpectedly when split hugepage:
>
> ------------[ cut here ]------------
> kernel BUG at mm/page_table_check.c:119!
> Internal error: Oops - BUG: 00000000f2000800 [#1] SMP
> Dumping ftrace buffer:
> (ftrace buffer empty)
> Modules linked in:
> CPU: 7 PID: 210 Comm: transhuge-stres Not tainted 6.1.0-rc3+ #748
> Hardware name: linux,dummy-virt (DT)
> pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
> pc : page_table_check_set.isra.0+0x398/0x468
> lr : page_table_check_set.isra.0+0x1c0/0x468
> [...]
> Call trace:
> page_table_check_set.isra.0+0x398/0x468
> __page_table_check_pte_set+0x160/0x1c0
> __split_huge_pmd_locked+0x900/0x1648
> __split_huge_pmd+0x28c/0x3b8
> unmap_page_range+0x428/0x858
> unmap_single_vma+0xf4/0x1c8
> zap_page_range+0x2b0/0x410
> madvise_vma_behavior+0xc44/0xe78
> do_madvise+0x280/0x698
> __arm64_sys_madvise+0x90/0xe8
> invoke_syscall.constprop.0+0xdc/0x1d8
> do_el0_svc+0xf4/0x3f8
> el0_svc+0x58/0x120
> el0t_64_sync_handler+0xb8/0xc0
> el0t_64_sync+0x19c/0x1a0
> [...]
>
> On arm64, pmd_present() will return true even if the pmd is invalid.
I assume that's because of the pmd_present_invalid() check.
... I wonder why that behavior was chosen. Sounds error-prone to me.
Fix LGHTM, but I am not an arm64 pgtable expert.
--
Thanks,
David / dhildenb
WARNING: multiple messages have this Message-ID (diff)
From: David Hildenbrand <david@redhat.com>
To: Liu Shixin <liushixin2@huawei.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Denys Vlasenko <dvlasenk@redhat.com>,
Kefeng Wang <wangkefeng.wang@huawei.com>,
Anshuman Khandual <anshuman.khandual@arm.com>,
David Hildenbrand <dhildenb@redhat.com>,
Rafael Aquini <raquini@redhat.com>,
Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] arm64/mm: fix incorrect file_map_count for invalid pmd/pud
Date: Wed, 16 Nov 2022 10:08:27 +0100 [thread overview]
Message-ID: <73189e81-08c2-bb18-dd4a-f717996ea819@redhat.com> (raw)
In-Reply-To: <20221116083811.464678-3-liushixin2@huawei.com>
On 16.11.22 09:38, Liu Shixin wrote:
> The page table check trigger BUG_ON() unexpectedly when split hugepage:
>
> ------------[ cut here ]------------
> kernel BUG at mm/page_table_check.c:119!
> Internal error: Oops - BUG: 00000000f2000800 [#1] SMP
> Dumping ftrace buffer:
> (ftrace buffer empty)
> Modules linked in:
> CPU: 7 PID: 210 Comm: transhuge-stres Not tainted 6.1.0-rc3+ #748
> Hardware name: linux,dummy-virt (DT)
> pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
> pc : page_table_check_set.isra.0+0x398/0x468
> lr : page_table_check_set.isra.0+0x1c0/0x468
> [...]
> Call trace:
> page_table_check_set.isra.0+0x398/0x468
> __page_table_check_pte_set+0x160/0x1c0
> __split_huge_pmd_locked+0x900/0x1648
> __split_huge_pmd+0x28c/0x3b8
> unmap_page_range+0x428/0x858
> unmap_single_vma+0xf4/0x1c8
> zap_page_range+0x2b0/0x410
> madvise_vma_behavior+0xc44/0xe78
> do_madvise+0x280/0x698
> __arm64_sys_madvise+0x90/0xe8
> invoke_syscall.constprop.0+0xdc/0x1d8
> do_el0_svc+0xf4/0x3f8
> el0_svc+0x58/0x120
> el0t_64_sync_handler+0xb8/0xc0
> el0t_64_sync+0x19c/0x1a0
> [...]
>
> On arm64, pmd_present() will return true even if the pmd is invalid.
I assume that's because of the pmd_present_invalid() check.
... I wonder why that behavior was chosen. Sounds error-prone to me.
Fix LGHTM, but I am not an arm64 pgtable expert.
--
Thanks,
David / dhildenb
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linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2022-11-16 9:10 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-16 8:38 [PATCH 0/2] arm64: fix two bug about page table check Liu Shixin
2022-11-16 8:38 ` Liu Shixin
2022-11-16 8:38 ` [PATCH 1/2] arm64/mm: fix incorrect file_map_count for non-leaf pmd/pud Liu Shixin
2022-11-16 8:38 ` Liu Shixin
2022-11-16 9:04 ` David Hildenbrand
2022-11-16 9:04 ` David Hildenbrand
2022-11-16 14:59 ` Pasha Tatashin
2022-11-16 14:59 ` Pasha Tatashin
2022-11-17 4:09 ` Anshuman Khandual
2022-11-17 4:09 ` Anshuman Khandual
2022-11-17 6:59 ` Liu Shixin
2022-11-17 6:59 ` Liu Shixin
2022-11-21 15:57 ` Denys Vlasenko
2022-11-21 15:57 ` Denys Vlasenko
2022-11-16 8:38 ` [PATCH 2/2] arm64/mm: fix incorrect file_map_count for invalid pmd/pud Liu Shixin
2022-11-16 8:38 ` Liu Shixin
2022-11-16 9:08 ` David Hildenbrand [this message]
2022-11-16 9:08 ` David Hildenbrand
2022-11-16 15:46 ` Mark Rutland
2022-11-16 15:46 ` Mark Rutland
2022-11-17 4:24 ` Anshuman Khandual
2022-11-17 4:24 ` Anshuman Khandual
2022-11-16 15:18 ` Pasha Tatashin
2022-11-16 15:18 ` Pasha Tatashin
2022-11-16 15:52 ` Mark Rutland
2022-11-16 15:52 ` Mark Rutland
2022-11-17 3:15 ` Liu Shixin
2022-11-17 3:15 ` Liu Shixin
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