pm24.git/kernel/kcsan, branch v5.16

kcsan: selftest: Cleanup and add missing __init

2021-09-13T23:41:20Z

Make test_encode_decode() more readable and add missing __init. Signed-off-by: Marco Elver Signed-off-by: Paul E. McKenney

kcsan: Move ctx to start of argument list

2021-09-13T23:41:19Z

It is clearer if ctx is at the start of the function argument list; it'll be more consistent when adding functions with varying arguments but all requiring ctx. No functional change intended. Signed-off-by: Marco Elver Signed-off-by: Paul E. McKenney

kcsan: Support reporting scoped read-write access type

2021-09-13T23:41:19Z

Support generating the string representation of scoped read-write accesses for completeness. They will become required in planned changes. Signed-off-by: Marco Elver Signed-off-by: Paul E. McKenney

kcsan: Start stack trace with explicit location if provided

2021-09-13T23:41:19Z

If an explicit access address is set, as is done for scoped accesses, always start the stack trace from that location. get_stack_skipnr() is changed into sanitize_stack_entries(), which if given an address, scans the stack trace for a matching function and then replaces that entry with the explicitly provided address. The previous reports for scoped accesses were all over the place, which could be quite confusing. We now always point at the start of the scope. Signed-off-by: Marco Elver Signed-off-by: Paul E. McKenney

kcsan: Save instruction pointer for scoped accesses

2021-09-13T23:41:19Z

Save the instruction pointer for scoped accesses, so that it becomes possible for the reporting code to construct more accurate stack traces that will show the start of the scope. Signed-off-by: Marco Elver Signed-off-by: Paul E. McKenney

kcsan: Add ability to pass instruction pointer of access to reporting

2021-09-13T23:41:19Z

Add the ability to pass an explicitly set instruction pointer of access from check_access() all the way through to reporting. In preparation of using it in reporting. Signed-off-by: Marco Elver Signed-off-by: Paul E. McKenney

kcsan: test: Fix flaky test case

2021-09-13T23:41:19Z

If CONFIG_KCSAN_REPORT_VALUE_CHANGE_ONLY=n, then we may also see data races between the writers only. If we get unlucky and never capture a read-write data race, but only the write-write data races, then the test_no_value_change* test cases may incorrectly fail. The second problem is that the initial value needs to be reset, as otherwise we might actually observe a value change at the start. Fix it by also looking for the write-write data races, and resetting the value to what will be written. Signed-off-by: Marco Elver Signed-off-by: Paul E. McKenney

kcsan: test: Use kunit_skip() to skip tests

2021-09-13T23:41:19Z

Use the new kunit_skip() to skip tests if requirements were not met. Signed-off-by: Marco Elver Signed-off-by: Paul E. McKenney

kcsan: test: Defer kcsan_test_init() after kunit initialization

2021-09-13T23:41:19Z

When the test is built into the kernel (not a module), kcsan_test_init() and kunit_init() both use late_initcall(), which means kcsan_test_init() might see a NULL debugfs_rootdir as parent dentry, resulting in kcsan_test_init() and kcsan_debugfs_init() both trying to create a debugfs node named "kcsan" in debugfs root. One of them will show an error and be unsuccessful. Defer kcsan_test_init() until we're sure kunit was initialized. Signed-off-by: Marco Elver Signed-off-by: Paul E. McKenney

Merge tag 'locking-debug-2021-09-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2021-09-02T20:00:15Z

Pull memory model updates from Ingo Molnar: "LKMM updates: - Update documentation and code example KCSAN updates: - Introduce CONFIG_KCSAN_STRICT (which RCU uses) - Optimize use of get_ctx() by kcsan_found_watchpoint() - Rework atomic.h into permissive.h - Add the ability to ignore writes that change only one bit of a given data-racy variable. - Improve comments" * tag 'locking-debug-2021-09-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: tools/memory-model: Document data_race(READ_ONCE()) tools/memory-model: Heuristics using data_race() must handle all values tools/memory-model: Add example for heuristic lockless reads tools/memory-model: Make read_foo_diagnostic() more clearly diagnostic kcsan: Make strict mode imply interruptible watchers kcsan: permissive: Ignore data-racy 1-bit value changes kcsan: Print if strict or non-strict during init kcsan: Rework atomic.h into permissive.h kcsan: Reduce get_ctx() uses in kcsan_found_watchpoint() kcsan: Introduce CONFIG_KCSAN_STRICT kcsan: Remove CONFIG_KCSAN_DEBUG kcsan: Improve some Kconfig comments