[AUTOSEL,4.19,121/123] kernel/kcov.c: mark funcs in __sanitizer_cov_trace_pc() as notrace

Message ID 20181205093555.5386-121-sashal@kernel.org
State New
Headers show
Series
  • Untitled series #16937
Related show

Commit Message

Sasha Levin Dec. 5, 2018, 9:35 a.m.
From: Anders Roxell <anders.roxell@linaro.org>


[ Upstream commit 903e8ff86753e6f327bb92166a0665e4ecb8e2e7 ]

Since __sanitizer_cov_trace_pc() is marked as notrace, function calls in
__sanitizer_cov_trace_pc() shouldn't be traced either.
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 check_kcov_mode() and canonicalize_ip() that are called
from __sanitizer_cov_trace_pc() are also marked as notrace.

Link: http://lkml.kernel.org/r/20181128081239.18317-1-anders.roxell@linaro.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Signen-off-by: Anders Roxell <anders.roxell@linaro.org>
Co-developed-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: Sasha Levin <sashal@kernel.org>

---
 kernel/kcov.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

-- 
2.17.1

Patch

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();