From 4983f0ab7ffaad1e534b21975367429736475205 Mon Sep 17 00:00:00 2001 From: Alexander Popov Date: Mon, 19 Dec 2016 16:23:09 -0800 Subject: 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 Cc: Catalin Marinas Cc: Will Deacon Cc: Ard Biesheuvel Cc: Mark Rutland Cc: Rob Herring Cc: Kefeng Wang Cc: AKASHI Takahiro Cc: Jon Masters Cc: David Daney Cc: Ganapatrao Kulkarni Cc: Dmitry Vyukov Cc: Nicolai Stange Cc: James Morse Cc: Andrey Ryabinin Cc: Andrey Konovalov Cc: Alexander Popov Cc: syzkaller Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/kcov.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'kernel/kcov.c') 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 #include #include +#include /* * 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); } } -- cgit v1.2.3