Ard Biesheuvel
24cc61d8cb
arm64: memblock: don't permit memblock resizing until linear mapping is up
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 <bhsharma@redhat.com> Acked-by: Will Deacon <will.deacon@arm.com> Tested-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Linux kernel ============ There are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. Please read Documentation/admin-guide/README.rst first. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. The formatted documentation can also be read online at: https://www.kernel.org/doc/html/latest/ There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.
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