From 4983f0ab7ffaad1e534b21975367429736475205 Mon Sep 17 00:00:00 2001 From: Alexander Popov <alex.popov@linux.com> Date: Mon, 19 Dec 2016 16:23:09 -0800 Subject: [PATCH] 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> --- kernel/kcov.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/kernel/kcov.c b/kernel/kcov.c index cc2fa35ca480..85e5546cd791 100644 --- a/kernel/kcov.c +++ b/kernel/kcov.c @@ -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); } } -- GitLab