kcsan: Add option to allow watcher interruptions

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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>

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This commit is contained in:

Marco Elver 2020-02-21 23:02:09 +01:00 • committed by Paul E. McKenney

parent f5d2313bd3

commit 48b1fc190a

2 changed files with 21 additions and 24 deletions

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34

kernel/kcsan/core.c

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11

lib/Kconfig.kcsan

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