arm64: hibernate: handle allocation failures
In create_safe_exec_page(), we create a copy of the hibernate exit text, along with some page tables to map this via TTBR0. We then install the new tables in TTBR0. In swsusp_arch_resume() we call create_safe_exec_page() before trying a number of operations which may fail (e.g. copying the linear map page tables). If these fail, we bail out of swsusp_arch_resume() and return an error code, but leave TTBR0 as-is. Subsequently, the core hibernate code will call free_basic_memory_bitmaps(), which will free all of the memory allocations we made, including the page tables installed in TTBR0. Thus, we may have TTBR0 pointing at dangling freed memory for some period of time. If the hibernate attempt was triggered by a user requesting a hibernate test via the reboot syscall, we may return to userspace with the clobbered TTBR0 value. Avoid these issues by reorganising swsusp_arch_resume() such that we have no failure paths after create_safe_exec_page(). We also add a check that the zero page allocation succeeded, matching what we have for other allocations. Fixes: 82869ac5 ("arm64: kernel: Add support for hibernate/suspend-to-disk") Signed-off-by:Mark Rutland <mark.rutland@arm.com> Acked-by:
James Morse <james.morse@arm.com> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: <stable@vger.kernel.org> # 4.7+ Signed-off-by:
Catalin Marinas <catalin.marinas@arm.com>
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