From mboxrd@z Thu Jan 1 00:00:00 1970 From: ard.biesheuvel@linaro.org (Ard Biesheuvel) Date: Wed, 7 Nov 2018 15:16:06 +0100 Subject: [PATCH v2 1/6] arm64: memblock: don't permit memblock resizing until linear mapping is up In-Reply-To: <20181107141611.12076-1-ard.biesheuvel@linaro.org> References: <20181107141611.12076-1-ard.biesheuvel@linaro.org> Message-ID: <20181107141611.12076-2-ard.biesheuvel@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Bhupesh reports that having numerous memblock reservations at early boot may result in the following crash: Unable to handle kernel paging request at virtual address ffff80003ffe0000 ... Call trace: __memcpy+0x110/0x180 memblock_add_range+0x134/0x2e8 memblock_reserve+0x70/0xb8 memblock_alloc_base_nid+0x6c/0x88 __memblock_alloc_base+0x3c/0x4c memblock_alloc_base+0x28/0x4c memblock_alloc+0x2c/0x38 early_pgtable_alloc+0x20/0xb0 paging_init+0x28/0x7f8 This is caused by the fact that we permit memblock resizing before the linear mapping is up, and so the memblock_reserved() array is moved into memory that is not mapped yet. So let's ensure that this crash can no longer occur, by deferring to call to memblock_allow_resize() to after the linear mapping has been created. Reported-by: Bhupesh Sharma Acked-by: Will Deacon Tested-by: Marc Zyngier Signed-off-by: Ard Biesheuvel --- arch/arm64/mm/init.c | 2 -- arch/arm64/mm/mmu.c | 2 ++ 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index 9d9582cac6c4..9b432d9fcada 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -483,8 +483,6 @@ void __init arm64_memblock_init(void) high_memory = __va(memblock_end_of_DRAM() - 1) + 1; dma_contiguous_reserve(arm64_dma_phys_limit); - - memblock_allow_resize(); } void __init bootmem_init(void) diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index d6d05c8c5c52..e1b2d58a311a 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -671,6 +671,8 @@ void __init paging_init(void) memblock_free(__pa_symbol(init_pg_dir), __pa_symbol(init_pg_end) - __pa_symbol(init_pg_dir)); + + memblock_allow_resize(); } /* -- 2.19.1