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authorMarco Elver <elver@google.com>2020-02-21 23:02:09 +0100
committerPaul E. McKenney <paulmck@kernel.org>2020-03-25 09:55:59 -0700
commit48b1fc190a180d971fb69217c88c7247f4f2ca19 (patch)
tree6b3408d62d095a068afc089cfbfd3f98d73cfaa5 /lib/Kconfig.kcsan
parentf5d2313bd3c540be405c4977a63840cd6d0167b5 (diff)
kcsan: Add option to allow watcher interruptions
Add option to allow interrupts while a watchpoint is set up. This can be enabled either via CONFIG_KCSAN_INTERRUPT_WATCHER or via the boot parameter 'kcsan.interrupt_watcher=1'. Note that, currently not all safe per-CPU access primitives and patterns are accounted for, which could result in false positives. For example, asm-generic/percpu.h uses plain operations, which by default are instrumented. On interrupts and subsequent accesses to the same variable, KCSAN would currently report a data race with this option. Therefore, this option should currently remain disabled by default, but may be enabled for specific test scenarios. To avoid new warnings, changes all uses of smp_processor_id() to use the raw version (as already done in kcsan_found_watchpoint()). The exact SMP processor id is for informational purposes in the report, and correctness is not affected. Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'lib/Kconfig.kcsan')
-rw-r--r--lib/Kconfig.kcsan11
1 files changed, 11 insertions, 0 deletions
diff --git a/lib/Kconfig.kcsan b/lib/Kconfig.kcsan
index f0b791143c6a..081ed2e1bf7b 100644
--- a/lib/Kconfig.kcsan
+++ b/lib/Kconfig.kcsan
@@ -88,6 +88,17 @@ config KCSAN_SKIP_WATCH_RANDOMIZE
KCSAN_WATCH_SKIP. If false, the chosen value is always
KCSAN_WATCH_SKIP.
+config KCSAN_INTERRUPT_WATCHER
+ bool "Interruptible watchers"
+ help
+ If enabled, a task that set up a watchpoint may be interrupted while
+ delayed. This option will allow KCSAN to detect races between
+ interrupted tasks and other threads of execution on the same CPU.
+
+ Currently disabled by default, because not all safe per-CPU access
+ primitives and patterns may be accounted for, and therefore could
+ result in false positives.
+
config KCSAN_REPORT_ONCE_IN_MS
int "Duration in milliseconds, in which any given race is only reported once"
default 3000