linux-stable.git/kernel/kcsan/selftest.c, branch v6.0 Linux kernel stable tree kcsan: Only test clear_bit_unlock_is_negative_byte if arch defines it 2021-12-10T00:42:29+00:00 Marco Elver elver@google.com 2021-12-06T06:41:51+00:00 b473a3891c46393e9c4ccb4e3197d7fb259c7100 Some architectures do not define clear_bit_unlock_is_negative_byte(). Only test it when it is actually defined (similar to other usage, such as in lib/test_kasan.c). Link: https://lkml.kernel.org/r/202112050757.x67rHnFU-lkp@intel.com Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> 
Some architectures do not define clear_bit_unlock_is_negative_byte().
Only test it when it is actually defined (similar to other usage, such
as in lib/test_kasan.c).

Link: https://lkml.kernel.org/r/202112050757.x67rHnFU-lkp@intel.com
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
kcsan: Make barrier tests compatible with lockdep 2021-12-10T00:42:28+00:00 Marco Elver elver@google.com 2021-12-03T23:38:17+00:00 a70d36e6a0bd867ef42dce8ef46eb9b5a1515fb0 The barrier tests in selftest and the kcsan_test module only need the spinlock and mutex to test correct barrier instrumentation. Therefore, these were initially placed on the stack. However, lockdep asserts that locks are in static storage, and will generate this warning: | INFO: trying to register non-static key. | The code is fine but needs lockdep annotation, or maybe | you didn't initialize this object before use? | turning off the locking correctness validator. | CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.16.0-rc1+ #3208 | Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-1ubuntu1.1 04/01/2014 | Call Trace: | <TASK> | dump_stack_lvl+0x88/0xd8 | dump_stack+0x15/0x1b | register_lock_class+0x6b3/0x840 | ... | test_barrier+0x490/0x14c7 | kcsan_selftest+0x47/0xa0 | ... To fix, move the test locks into static storage. Fixing the above also revealed that lock operations are strengthened on first use with lockdep enabled, due to lockdep calling out into non-instrumented files (recall that kernel/locking/lockdep.c is not instrumented with KCSAN). Only kcsan_test checks for over-instrumentation of *_lock() operations, where we can simply "warm up" the test locks to avoid the test case failing with lockdep. Reported-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> 
The barrier tests in selftest and the kcsan_test module only need the
spinlock and mutex to test correct barrier instrumentation. Therefore,
these were initially placed on the stack.

However, lockdep asserts that locks are in static storage, and will
generate this warning:

 | INFO: trying to register non-static key.
 | The code is fine but needs lockdep annotation, or maybe
 | you didn't initialize this object before use?
 | turning off the locking correctness validator.
 | CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.16.0-rc1+ #3208
 | Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-1ubuntu1.1 04/01/2014
 | Call Trace:
 |  <TASK>
 |  dump_stack_lvl+0x88/0xd8
 |  dump_stack+0x15/0x1b
 |  register_lock_class+0x6b3/0x840
 |  ...
 |  test_barrier+0x490/0x14c7
 |  kcsan_selftest+0x47/0xa0
 |  ...

To fix, move the test locks into static storage.

Fixing the above also revealed that lock operations are strengthened on
first use with lockdep enabled, due to lockdep calling out into
non-instrumented files (recall that kernel/locking/lockdep.c is not
instrumented with KCSAN).

Only kcsan_test checks for over-instrumentation of *_lock() operations,
where we can simply "warm up" the test locks to avoid the test case
failing with lockdep.

Reported-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
kcsan: selftest: Add test case to check memory barrier instrumentation 2021-12-10T00:42:27+00:00 Marco Elver elver@google.com 2021-11-30T11:44:21+00:00 71b0e3aeb28256712945d99ca67b3f5e3ed7e0b1 Memory barrier instrumentation is crucial to avoid false positives. To avoid surprises, run a simple test case in the boot-time selftest to ensure memory barriers are still instrumented correctly. Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> 
Memory barrier instrumentation is crucial to avoid false positives. To
avoid surprises, run a simple test case in the boot-time selftest to
ensure memory barriers are still instrumented correctly.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
kcsan: selftest: Cleanup and add missing __init 2021-09-13T23:41:20+00:00 Marco Elver elver@google.com 2021-08-13T08:10:55+00:00 ac20e39e8d254da3f82b5ed2afc7bb1e804d32c9 Make test_encode_decode() more readable and add missing __init. Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> 
Make test_encode_decode() more readable and add missing __init.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
kcsan: Add missing license and copyright headers 2021-03-08T22:27:43+00:00 Marco Elver elver@google.com 2021-01-15T17:09:53+00:00 bd0ccc4afca2d6ae0029cae35c4f1d2e2ade7579 Adds missing license and/or copyright headers for KCSAN source files. Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> 
Adds missing license and/or copyright headers for KCSAN source files.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
kcsan: selftest: Ensure that address is at least PAGE_SIZE 2020-11-03T01:08:50+00:00 Marco Elver elver@google.com 2020-10-22T11:45:52+00:00 4761612ffe3c1655e58f1ef9cf867c6f67d46fe2 In preparation of supporting only addresses not within the NULL page, change the selftest to never use addresses that are less than PAGE_SIZE. Reviewed-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> 
In preparation of supporting only addresses not within the NULL page,
change the selftest to never use addresses that are less than PAGE_SIZE.

Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
kcsan: Use pr_fmt for consistency 2020-08-24T22:10:23+00:00 Marco Elver elver@google.com 2020-07-31T08:17:23+00:00 178a1877d782c034f466edd80e30a107af5469df Use the same pr_fmt throughout for consistency. [ The only exception is report.c, where the format must be kept precisely as-is. ] Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> 
Use the same pr_fmt throughout for consistency. [ The only exception is
report.c, where the format must be kept precisely as-is. ]

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
kcsan: Rename test.c to selftest.c 2020-06-29T19:04:48+00:00 Marco Elver elver@google.com 2020-06-16T12:36:23+00:00 acfa087ccf2d2eff46186477f53e4c3ffbdb033d Rename 'test.c' to 'selftest.c' to better reflect its purpose (Kconfig variable and code inside already match this). This is to avoid confusion with the test suite module in 'kcsan-test.c'. No functional change. Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> 
Rename 'test.c' to 'selftest.c' to better reflect its purpose (Kconfig
variable and code inside already match this). This is to avoid confusion
with the test suite module in 'kcsan-test.c'.

No functional change.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>