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| author | Marco Elver <elver@google.com> | 2020-02-14 22:10:35 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2020-03-21 09:44:41 +0100 |
| commit | f5d2313bd3c540be405c4977a63840cd6d0167b5 (patch) | |
| tree | 25a8bfd1f857fc11aab179fb67ac36071e9c1503 /kernel/kcsan | |
| parent | 703b321501c95c658275fd76775282fe45989641 (diff) | |
| download | lwn-f5d2313bd3c540be405c4977a63840cd6d0167b5.tar.gz lwn-f5d2313bd3c540be405c4977a63840cd6d0167b5.zip | |
kcsan, trace: Make KCSAN compatible with tracing
Previously the system would lock up if ftrace was enabled together with
KCSAN. This is due to recursion on reporting if the tracer code is
instrumented with KCSAN.
To avoid this for all types of tracing, disable KCSAN instrumentation
for all of kernel/trace.
Furthermore, since KCSAN relies on udelay() to introduce delay, we have
to disable ftrace for udelay() (currently done for x86) in case KCSAN is
used together with lockdep and ftrace. The reason is that it may corrupt
lockdep IRQ flags tracing state due to a peculiar case of recursion
(details in Makefile comment).
Reported-by: Qian Cai <cai@lca.pw>
Tested-by: Qian Cai <cai@lca.pw>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/kcsan')
| -rw-r--r-- | kernel/kcsan/Makefile | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/kcsan/Makefile b/kernel/kcsan/Makefile index df6b7799e492..d4999b38d1be 100644 --- a/kernel/kcsan/Makefile +++ b/kernel/kcsan/Makefile @@ -4,6 +4,8 @@ KCOV_INSTRUMENT := n UBSAN_SANITIZE := n CFLAGS_REMOVE_core.o = $(CC_FLAGS_FTRACE) +CFLAGS_REMOVE_debugfs.o = $(CC_FLAGS_FTRACE) +CFLAGS_REMOVE_report.o = $(CC_FLAGS_FTRACE) CFLAGS_core.o := $(call cc-option,-fno-conserve-stack,) \ $(call cc-option,-fno-stack-protector,) |