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Commit 4983f0ab authored by Alexander Popov's avatar Alexander Popov Committed by Linus Torvalds
Browse files

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: default avatarAlexander 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus 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);

		}

	}