The patch titled
Subject: kernel/kcov.c: mark funcs in __sanitizer_cov_trace_pc() as notrace
has been added to the -mm tree. Its filename is
kernel-kcovc-mark-funcs-in-__sanitizer_cov_trace_pc-as-notrace.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/kernel-kcovc-mark-funcs-in-__sanitizer_cov_trace_pc-as-notrace.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/kernel-kcovc-mark-funcs-in-__sanitizer_cov_trace_pc-as-notrace.patch
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------------------------------------------------------
From: Anders Roxell <anders.roxell@xxxxxxxxxx>
Subject: kernel/kcov.c: mark funcs in __sanitizer_cov_trace_pc() as notrace
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@xxxxxxxxxx
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
Signen-off-by: Anders Roxell <anders.roxell@xxxxxxxxxx>
Co-developed-by: Arnd Bergmann <arnd@xxxxxxxx>
Acked-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/kcov.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/kernel/kcov.c~kernel-kcovc-mark-funcs-in-__sanitizer_cov_trace_pc-as-notrace
+++ a/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_mo
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();
_
Patches currently in -mm which might be from anders.roxell@xxxxxxxxxx are
kernel-kcovc-mark-funcs-in-__sanitizer_cov_trace_pc-as-notrace.patch
writeback-dont-decrement-wb-refcnt-if-wb-bdi.patch
