x86/mm: Do not reference phys addr beyond kernel
The new physical address randomized KASLR implementation can cause the kernel to be aligned close to the end of physical memory. In this case, _brk_end aligned to PMD will go beyond what is expected safe and hit the assert in __phys_addr_symbol(): VIRTUAL_BUG_ON(y >= KERNEL_IMAGE_SIZE); Instead, perform an inclusive range check to avoid incorrectly triggering the assert: kernel BUG at arch/x86/mm/physaddr.c:38! invalid opcode: 0000 [#1] SMP ... RIP: 0010:[<ffffffffbe055721>] __phys_addr_symbol+0x41/0x50 ... Call Trace: [<ffffffffbe052eb9>] cpa_process_alias+0xa9/0x210 [<ffffffffbe109011>] ? do_raw_spin_unlock+0xc1/0x100 [<ffffffffbe051eef>] __change_page_attr_set_clr+0x8cf/0xbd0 [<ffffffffbe201a4d>] ? vm_unmap_aliases+0x7d/0x210 [<ffffffffbe05237c>] change_page_attr_set_clr+0x18c/0x4e0 [<ffffffffbe0534ec>] set_memory_4k+0x2c/0x40 [<ffffffffbefb08b3>] check_bugs+0x28/0x2a [<ffffffffbefa4f52>] start_kernel+0x49d/0x4b9 [<ffffffffbefa4120>] ? early_idt_handler_array+0x120/0x120 [<ffffffffbefa4423>] x86_64_start_reservations+0x29/0x2b [<ffffffffbefa4568>] x86_64_start_kernel+0x143/0x152 Signed-off-by: NThomas Garnier <thgarnie@google.com> Signed-off-by: NKees Cook <keescook@chromium.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dexuan Cui <decui@microsoft.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sai Praneeth <sai.praneeth.prakhya@intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Toshi Kani <toshi.kani@hpe.com> Link: http://lkml.kernel.org/r/20160615190545.GA26071@www.outflux.netSigned-off-by: NIngo Molnar <mingo@kernel.org>
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