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vDSO VMA address is saved in mm_context for the purpose of using restorer from vDSO page to return to userspace after signal handling. In Checkpoint Restore in Userspace (CRIU) project we place vDSO VMA on restore back to the place where it was on the dump. With the exception for x86 (where there is API to map vDSO with arch_prctl()), we move vDSO inherited from CRIU task to restoree position by mremap(). CRIU does support arm64 architecture, but kernel doesn't update context.vdso pointer after mremap(). Which results in translation fault after signal handling on restored application: https://github.com/xemul/criu/issues/288 Make vDSO code track the VMA address by supplying .mremap() fops the same way it's done for x86 and arm32 by: commit b059a453b1cf ("x86/vdso: Add mremap hook to vm_special_mapping") commit 280e87e98c09 ("ARM: 8683/1: ARM32: Support mremap() for sigpage/vDSO"). Cc: Russell King <rmk+kernel@armlinux.org.uk> Cc: linux-arm-kernel@lists.infradead.org Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Cc: Christopher Covington <cov@codeaurora.org> Reviewed-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.