forked from luck/tmp_suning_uos_patched
d591ec3db7
The KCSAN_ACCESS_ASSERT access type may be used to introduce dummy reads
and writes to assert certain properties of concurrent code, where bugs
could not be detected as normal data races.
For example, a variable that is only meant to be written by a single
CPU, but may be read (without locking) by other CPUs must still be
marked properly to avoid data races. However, concurrent writes,
regardless if WRITE_ONCE() or not, would be a bug. Using
kcsan_check_access(&x, sizeof(x), KCSAN_ACCESS_ASSERT) would allow
catching such bugs.
To support KCSAN_ACCESS_ASSERT the following notable changes were made:
* If an access is of type KCSAN_ASSERT_ACCESS, disable various filters
that only apply to data races, so that all races that KCSAN observes are
reported.
* Bug reports that involve an ASSERT access type will be reported as
"KCSAN: assert: race in ..." instead of "data-race"; this will help
more easily distinguish them.
* Update a few comments to just mention 'races' where we do not always
mean pure data races.
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
117 lines
2.6 KiB
C
117 lines
2.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* The Kernel Concurrency Sanitizer (KCSAN) infrastructure. For more info please
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* see Documentation/dev-tools/kcsan.rst.
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*/
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#ifndef _KERNEL_KCSAN_KCSAN_H
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#define _KERNEL_KCSAN_KCSAN_H
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#include <linux/kcsan.h>
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/* The number of adjacent watchpoints to check. */
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#define KCSAN_CHECK_ADJACENT 1
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/*
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* Globally enable and disable KCSAN.
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*/
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extern bool kcsan_enabled;
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/*
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* Initialize debugfs file.
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*/
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void kcsan_debugfs_init(void);
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enum kcsan_counter_id {
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/*
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* Number of watchpoints currently in use.
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*/
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KCSAN_COUNTER_USED_WATCHPOINTS,
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/*
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* Total number of watchpoints set up.
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*/
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KCSAN_COUNTER_SETUP_WATCHPOINTS,
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/*
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* Total number of data races.
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*/
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KCSAN_COUNTER_DATA_RACES,
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/*
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* Total number of ASSERT failures due to races. If the observed race is
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* due to two conflicting ASSERT type accesses, then both will be
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* counted.
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*/
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KCSAN_COUNTER_ASSERT_FAILURES,
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/*
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* Number of times no watchpoints were available.
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*/
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KCSAN_COUNTER_NO_CAPACITY,
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/*
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* A thread checking a watchpoint raced with another checking thread;
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* only one will be reported.
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*/
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KCSAN_COUNTER_REPORT_RACES,
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/*
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* Observed data value change, but writer thread unknown.
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*/
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KCSAN_COUNTER_RACES_UNKNOWN_ORIGIN,
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/*
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* The access cannot be encoded to a valid watchpoint.
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*/
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KCSAN_COUNTER_UNENCODABLE_ACCESSES,
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/*
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* Watchpoint encoding caused a watchpoint to fire on mismatching
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* accesses.
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*/
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KCSAN_COUNTER_ENCODING_FALSE_POSITIVES,
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KCSAN_COUNTER_COUNT, /* number of counters */
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};
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/*
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* Increment/decrement counter with given id; avoid calling these in fast-path.
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*/
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extern void kcsan_counter_inc(enum kcsan_counter_id id);
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extern void kcsan_counter_dec(enum kcsan_counter_id id);
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/*
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* Returns true if data races in the function symbol that maps to func_addr
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* (offsets are ignored) should *not* be reported.
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*/
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extern bool kcsan_skip_report_debugfs(unsigned long func_addr);
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enum kcsan_report_type {
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/*
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* The thread that set up the watchpoint and briefly stalled was
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* signalled that another thread triggered the watchpoint.
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*/
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KCSAN_REPORT_RACE_SIGNAL,
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/*
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* A thread found and consumed a matching watchpoint.
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*/
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KCSAN_REPORT_CONSUMED_WATCHPOINT,
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/*
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* No other thread was observed to race with the access, but the data
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* value before and after the stall differs.
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*/
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KCSAN_REPORT_RACE_UNKNOWN_ORIGIN,
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};
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/*
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* Print a race report from thread that encountered the race.
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*/
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extern void kcsan_report(const volatile void *ptr, size_t size, int access_type,
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bool value_change, int cpu_id, enum kcsan_report_type type);
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#endif /* _KERNEL_KCSAN_KCSAN_H */
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