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authorLinus Torvalds <torvalds@linux-foundation.org>2022-01-11 09:51:26 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2022-01-11 09:51:26 -0800
commit1be5bdf8cd5a194d981e65687367b0828c839c37 (patch)
treed6560826c211fd7a4ddcc1d45040dab123271df8 /scripts
parent1c824bf768d69fce36de748c60c7197a2b838944 (diff)
parentb473a3891c46393e9c4ccb4e3197d7fb259c7100 (diff)
downloadlinux-1be5bdf8cd5a194d981e65687367b0828c839c37.tar.bz2
Merge tag 'kcsan.2022.01.09a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu
Pull KCSAN updates from Paul McKenney: "This provides KCSAN fixes and also the ability to take memory barriers into account for weakly-ordered systems. This last can increase the probability of detecting certain types of data races" * tag 'kcsan.2022.01.09a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu: (29 commits) kcsan: Only test clear_bit_unlock_is_negative_byte if arch defines it kcsan: Avoid nested contexts reading inconsistent reorder_access kcsan: Turn barrier instrumentation into macros kcsan: Make barrier tests compatible with lockdep kcsan: Support WEAK_MEMORY with Clang where no objtool support exists compiler_attributes.h: Add __disable_sanitizer_instrumentation objtool, kcsan: Remove memory barrier instrumentation from noinstr objtool, kcsan: Add memory barrier instrumentation to whitelist sched, kcsan: Enable memory barrier instrumentation mm, kcsan: Enable barrier instrumentation x86/qspinlock, kcsan: Instrument barrier of pv_queued_spin_unlock() x86/barriers, kcsan: Use generic instrumentation for non-smp barriers asm-generic/bitops, kcsan: Add instrumentation for barriers locking/atomics, kcsan: Add instrumentation for barriers locking/barriers, kcsan: Support generic instrumentation locking/barriers, kcsan: Add instrumentation for barriers kcsan: selftest: Add test case to check memory barrier instrumentation kcsan: Ignore GCC 11+ warnings about TSan runtime support kcsan: test: Add test cases for memory barrier instrumentation kcsan: test: Match reordered or normal accesses ...
Diffstat (limited to 'scripts')
-rw-r--r--scripts/Makefile.kcsan15
-rw-r--r--scripts/Makefile.lib5
-rwxr-xr-xscripts/atomic/gen-atomic-instrumented.sh41
3 files changed, 50 insertions, 11 deletions
diff --git a/scripts/Makefile.kcsan b/scripts/Makefile.kcsan
index 37cb504c77e1..19f693b68a96 100644
--- a/scripts/Makefile.kcsan
+++ b/scripts/Makefile.kcsan
@@ -9,7 +9,18 @@ endif
# Keep most options here optional, to allow enabling more compilers if absence
# of some options does not break KCSAN nor causes false positive reports.
-export CFLAGS_KCSAN := -fsanitize=thread \
- $(call cc-option,$(call cc-param,tsan-instrument-func-entry-exit=0) -fno-optimize-sibling-calls) \
+kcsan-cflags := -fsanitize=thread -fno-optimize-sibling-calls \
$(call cc-option,$(call cc-param,tsan-compound-read-before-write=1),$(call cc-option,$(call cc-param,tsan-instrument-read-before-write=1))) \
$(call cc-param,tsan-distinguish-volatile=1)
+
+ifdef CONFIG_CC_IS_GCC
+# GCC started warning about operations unsupported by the TSan runtime. But
+# KCSAN != TSan, so just ignore these warnings.
+kcsan-cflags += -Wno-tsan
+endif
+
+ifndef CONFIG_KCSAN_WEAK_MEMORY
+kcsan-cflags += $(call cc-option,$(call cc-param,tsan-instrument-func-entry-exit=0))
+endif
+
+export CFLAGS_KCSAN := $(kcsan-cflags)
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index d1f865b8c0cb..ab17f7b2e33c 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -182,6 +182,11 @@ ifeq ($(CONFIG_KCSAN),y)
_c_flags += $(if $(patsubst n%,, \
$(KCSAN_SANITIZE_$(basetarget).o)$(KCSAN_SANITIZE)y), \
$(CFLAGS_KCSAN))
+# Some uninstrumented files provide implied barriers required to avoid false
+# positives: set KCSAN_INSTRUMENT_BARRIERS for barrier instrumentation only.
+_c_flags += $(if $(patsubst n%,, \
+ $(KCSAN_INSTRUMENT_BARRIERS_$(basetarget).o)$(KCSAN_INSTRUMENT_BARRIERS)n), \
+ -D__KCSAN_INSTRUMENT_BARRIERS__)
endif
# $(srctree)/$(src) for including checkin headers from generated source files
diff --git a/scripts/atomic/gen-atomic-instrumented.sh b/scripts/atomic/gen-atomic-instrumented.sh
index 035ceb4ee85c..68f902731d01 100755
--- a/scripts/atomic/gen-atomic-instrumented.sh
+++ b/scripts/atomic/gen-atomic-instrumented.sh
@@ -34,6 +34,14 @@ gen_param_check()
gen_params_checks()
{
local meta="$1"; shift
+ local order="$1"; shift
+
+ if [ "${order}" = "_release" ]; then
+ printf "\tkcsan_release();\n"
+ elif [ -z "${order}" ] && ! meta_in "$meta" "slv"; then
+ # RMW with return value is fully ordered
+ printf "\tkcsan_mb();\n"
+ fi
while [ "$#" -gt 0 ]; do
gen_param_check "$meta" "$1"
@@ -56,7 +64,7 @@ gen_proto_order_variant()
local ret="$(gen_ret_type "${meta}" "${int}")"
local params="$(gen_params "${int}" "${atomic}" "$@")"
- local checks="$(gen_params_checks "${meta}" "$@")"
+ local checks="$(gen_params_checks "${meta}" "${order}" "$@")"
local args="$(gen_args "$@")"
local retstmt="$(gen_ret_stmt "${meta}")"
@@ -75,29 +83,44 @@ EOF
gen_xchg()
{
local xchg="$1"; shift
+ local order="$1"; shift
local mult="$1"; shift
+ kcsan_barrier=""
+ if [ "${xchg%_local}" = "${xchg}" ]; then
+ case "$order" in
+ _release) kcsan_barrier="kcsan_release()" ;;
+ "") kcsan_barrier="kcsan_mb()" ;;
+ esac
+ fi
+
if [ "${xchg%${xchg#try_cmpxchg}}" = "try_cmpxchg" ] ; then
cat <<EOF
-#define ${xchg}(ptr, oldp, ...) \\
+#define ${xchg}${order}(ptr, oldp, ...) \\
({ \\
typeof(ptr) __ai_ptr = (ptr); \\
typeof(oldp) __ai_oldp = (oldp); \\
+EOF
+[ -n "$kcsan_barrier" ] && printf "\t${kcsan_barrier}; \\\\\n"
+cat <<EOF
instrument_atomic_write(__ai_ptr, ${mult}sizeof(*__ai_ptr)); \\
instrument_atomic_write(__ai_oldp, ${mult}sizeof(*__ai_oldp)); \\
- arch_${xchg}(__ai_ptr, __ai_oldp, __VA_ARGS__); \\
+ arch_${xchg}${order}(__ai_ptr, __ai_oldp, __VA_ARGS__); \\
})
EOF
else
cat <<EOF
-#define ${xchg}(ptr, ...) \\
+#define ${xchg}${order}(ptr, ...) \\
({ \\
typeof(ptr) __ai_ptr = (ptr); \\
+EOF
+[ -n "$kcsan_barrier" ] && printf "\t${kcsan_barrier}; \\\\\n"
+cat <<EOF
instrument_atomic_write(__ai_ptr, ${mult}sizeof(*__ai_ptr)); \\
- arch_${xchg}(__ai_ptr, __VA_ARGS__); \\
+ arch_${xchg}${order}(__ai_ptr, __VA_ARGS__); \\
})
EOF
@@ -145,21 +168,21 @@ done
for xchg in "xchg" "cmpxchg" "cmpxchg64" "try_cmpxchg"; do
for order in "" "_acquire" "_release" "_relaxed"; do
- gen_xchg "${xchg}${order}" ""
+ gen_xchg "${xchg}" "${order}" ""
printf "\n"
done
done
for xchg in "cmpxchg_local" "cmpxchg64_local" "sync_cmpxchg"; do
- gen_xchg "${xchg}" ""
+ gen_xchg "${xchg}" "" ""
printf "\n"
done
-gen_xchg "cmpxchg_double" "2 * "
+gen_xchg "cmpxchg_double" "" "2 * "
printf "\n\n"
-gen_xchg "cmpxchg_double_local" "2 * "
+gen_xchg "cmpxchg_double_local" "" "2 * "
cat <<EOF