Commit 4983f0ab authored Dec 19, 2016 by Alexander Popov Committed by Linus Torvalds Dec 20, 2016

kcov: make kcov work properly with KASLR enabled

Subtract KASLR offset from the kernel addresses reported by kcov.
Tested on x86_64 and AArch64 (Hikey LeMaker).

Link: http://lkml.kernel.org/r/1481417456-28826-3-git-send-email-alex.popov@linux.com


Signed-off-by: Alexander Popov <alex.popov@linux.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: Jon Masters <jcm@redhat.com>
Cc: David Daney <david.daney@cavium.com>
Cc: Ganapatrao Kulkarni <gkulkarni@caviumnetworks.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Nicolai Stange <nicstange@gmail.com>
Cc: James Morse <james.morse@arm.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Popov <alex.popov@linux.com>
Cc: syzkaller <syzkaller@googlegroups.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 7ede8665

kernel/kcov.c

+7 −1

Original line number	Diff line number	Diff line
		@@ -19,6 +19,7 @@
		#include <linux/debugfs.h>
		#include <linux/uaccess.h>
		#include <linux/kcov.h>
		#include <asm/setup.h>

		/*
		* kcov descriptor (one per opened debugfs file).
		@@ -73,6 +74,11 @@ void notrace __sanitizer_cov_trace_pc(void)
		if (mode == KCOV_MODE_TRACE) {
		unsigned long *area;
		unsigned long pos;
		unsigned long ip = _RET_IP_;

		#ifdef CONFIG_RANDOMIZE_BASE
		ip -= kaslr_offset();
		#endif

		/*
		* There is some code that runs in interrupts but for which
		@@ -86,7 +92,7 @@ void notrace __sanitizer_cov_trace_pc(void)
		/* The first word is number of subsequent PCs. */
		pos = READ_ONCE(area[0]) + 1;
		if (likely(pos < t->kcov_size)) {
		area[pos] = _RET_IP_;
		area[pos] = ip;
		WRITE_ONCE(area[0], pos);
		}
		}

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