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mmap(MAP_32BIT) is broken due to the dependency on the TIF_ADDR32 thread flag. For 64bit applications MAP_32BIT will force legacy bottom-up allocations and the 1GB address space restriction even if the application issued a compat syscall, which should not be subject of these restrictions. For 32bit applications, which issue 64bit syscalls the newly introduced mmap base separation into 64-bit and compat bases changed the behaviour because now a 64-bit mapping is returned, but due to the TIF_ADDR32 dependency MAP_32BIT is ignored. Before the separation a 32-bit mapping was returned, so the MAP_32BIT handling was irrelevant. Replace the check for TIF_ADDR32 with a check for the compat syscall. That solves both the 64-bit issuing a compat syscall and the 32-bit issuing a 64-bit syscall problems. [ tglx: Massaged changelog ] Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com> Cc: 0x7f454c46@gmail.com Cc: linux-mm@kvack.org Cc: Andy Lutomirski <luto@kernel.org> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Borislav Petkov <bp@suse.de> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Link: http://lkml.kernel.org/r/20170306141721.9188-5-dsafonov@virtuozzo.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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.