From: Anders Roxell <anders.roxell@linaro.org>
To: akpm@linux-foundation.org, dvyukov@google.com
Cc: rostedt@goodmis.org, mingo@redhat.com,
linux-kernel@vger.kernel.org,
Anders Roxell <anders.roxell@linaro.org>,
Arnd Bergmann <arnd@arndb.de>
Subject: [PATCH 1/2] kernel/kcov.c: mark funcs in __sanitizer_cov_trace_pc as notrace
Date: Wed, 28 Nov 2018 09:12:39 +0100 [thread overview]
Message-ID: <20181128081239.18317-1-anders.roxell@linaro.org> (raw)
Since __sanitizer_cov_trace_pc is marked as notrace, function calls in
__sanitizer_cov_trace_pc shouldn't be traced either. The function
ftrace_graph_caller() gets called for each function that isn't marked
'notrace', like canonicalize_ip(). This is the call trace from a run:
[ 139.644550] ftrace_graph_caller+0x1c/0x24
[ 139.648352] canonicalize_ip+0x18/0x28
[ 139.652313] __sanitizer_cov_trace_pc+0x14/0x58
[ 139.656184] sched_clock+0x34/0x1e8
[ 139.659759] trace_clock_local+0x40/0x88
[ 139.663722] ftrace_push_return_trace+0x8c/0x1f0
[ 139.667767] prepare_ftrace_return+0xa8/0x100
[ 139.671709] ftrace_graph_caller+0x1c/0x24
Rework so that the functions check_kcov_mode and canonicalize_ip that is
callef from __sanitizer_cov_trace_pc also is marked as notrace.
Co-developed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signen-off-by: Anders Roxell <anders.roxell@linaro.org>
---
kernel/kcov.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/kcov.c b/kernel/kcov.c
index 3ebd09efe72a..97959d7b77e2 100644
--- a/kernel/kcov.c
+++ b/kernel/kcov.c
@@ -56,7 +56,7 @@ struct kcov {
struct task_struct *t;
};
-static bool check_kcov_mode(enum kcov_mode needed_mode, struct task_struct *t)
+static notrace bool check_kcov_mode(enum kcov_mode needed_mode, struct task_struct *t)
{
unsigned int mode;
@@ -78,7 +78,7 @@ static bool check_kcov_mode(enum kcov_mode needed_mode, struct task_struct *t)
return mode == needed_mode;
}
-static unsigned long canonicalize_ip(unsigned long ip)
+static notrace unsigned long canonicalize_ip(unsigned long ip)
{
#ifdef CONFIG_RANDOMIZE_BASE
ip -= kaslr_offset();
--
2.19.2
next reply other threads:[~2018-11-28 8:13 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-28 8:12 Anders Roxell [this message]
2018-11-28 14:05 ` [PATCH 1/2] kernel/kcov.c: mark funcs in __sanitizer_cov_trace_pc as notrace Steven Rostedt
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