mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git/
synced 2026-04-17 22:23:45 -04:00
793c2579be
Currently kcsan_report() is used to handle three distinct cases: * The caller hit a watchpoint when attempting an access. Some information regarding the caller and access are recorded, but no output is produced. * A caller which previously setup a watchpoint detected that the watchpoint has been hit, and possibly detected a change to the location in memory being watched. This may result in output reporting the interaction between this caller and the caller which hit the watchpoint. * A caller detected a change to a modification to a memory location which wasn't detected by a watchpoint, for which there is no information on the other thread. This may result in output reporting the unexpected change. ... depending on the specific case the caller has distinct pieces of information available, but the prototype of kcsan_report() has to handle all three cases. This means that in some cases we pass redundant information, and in others we don't pass all the information we could pass. This also means that the report code has to demux these three cases. So that we can pass some additional information while also simplifying the callers and report code, add separate kcsan_report_*() functions for the distinct cases, updating callers accordingly. As the watchpoint_idx is unused in the case of kcsan_report_unknown_origin(), this passes a dummy value into kcsan_report(). Subsequent patches will refactor the report code to avoid this. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> [ elver@google.com: try to make kcsan_report_*() names more descriptive ] Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
148 lines
3.5 KiB
C
148 lines
3.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
/*
|
|
* The Kernel Concurrency Sanitizer (KCSAN) infrastructure. For more info please
|
|
* see Documentation/dev-tools/kcsan.rst.
|
|
*
|
|
* Copyright (C) 2019, Google LLC.
|
|
*/
|
|
|
|
#ifndef _KERNEL_KCSAN_KCSAN_H
|
|
#define _KERNEL_KCSAN_KCSAN_H
|
|
|
|
#include <linux/atomic.h>
|
|
#include <linux/kcsan.h>
|
|
#include <linux/sched.h>
|
|
|
|
/* The number of adjacent watchpoints to check. */
|
|
#define KCSAN_CHECK_ADJACENT 1
|
|
#define NUM_SLOTS (1 + 2*KCSAN_CHECK_ADJACENT)
|
|
|
|
extern unsigned int kcsan_udelay_task;
|
|
extern unsigned int kcsan_udelay_interrupt;
|
|
|
|
/*
|
|
* Globally enable and disable KCSAN.
|
|
*/
|
|
extern bool kcsan_enabled;
|
|
|
|
/*
|
|
* Save/restore IRQ flags state trace dirtied by KCSAN.
|
|
*/
|
|
void kcsan_save_irqtrace(struct task_struct *task);
|
|
void kcsan_restore_irqtrace(struct task_struct *task);
|
|
|
|
/*
|
|
* Statistics counters displayed via debugfs; should only be modified in
|
|
* slow-paths.
|
|
*/
|
|
enum kcsan_counter_id {
|
|
/*
|
|
* Number of watchpoints currently in use.
|
|
*/
|
|
KCSAN_COUNTER_USED_WATCHPOINTS,
|
|
|
|
/*
|
|
* Total number of watchpoints set up.
|
|
*/
|
|
KCSAN_COUNTER_SETUP_WATCHPOINTS,
|
|
|
|
/*
|
|
* Total number of data races.
|
|
*/
|
|
KCSAN_COUNTER_DATA_RACES,
|
|
|
|
/*
|
|
* Total number of ASSERT failures due to races. If the observed race is
|
|
* due to two conflicting ASSERT type accesses, then both will be
|
|
* counted.
|
|
*/
|
|
KCSAN_COUNTER_ASSERT_FAILURES,
|
|
|
|
/*
|
|
* Number of times no watchpoints were available.
|
|
*/
|
|
KCSAN_COUNTER_NO_CAPACITY,
|
|
|
|
/*
|
|
* A thread checking a watchpoint raced with another checking thread;
|
|
* only one will be reported.
|
|
*/
|
|
KCSAN_COUNTER_REPORT_RACES,
|
|
|
|
/*
|
|
* Observed data value change, but writer thread unknown.
|
|
*/
|
|
KCSAN_COUNTER_RACES_UNKNOWN_ORIGIN,
|
|
|
|
/*
|
|
* The access cannot be encoded to a valid watchpoint.
|
|
*/
|
|
KCSAN_COUNTER_UNENCODABLE_ACCESSES,
|
|
|
|
/*
|
|
* Watchpoint encoding caused a watchpoint to fire on mismatching
|
|
* accesses.
|
|
*/
|
|
KCSAN_COUNTER_ENCODING_FALSE_POSITIVES,
|
|
|
|
KCSAN_COUNTER_COUNT, /* number of counters */
|
|
};
|
|
extern atomic_long_t kcsan_counters[KCSAN_COUNTER_COUNT];
|
|
|
|
/*
|
|
* Returns true if data races in the function symbol that maps to func_addr
|
|
* (offsets are ignored) should *not* be reported.
|
|
*/
|
|
extern bool kcsan_skip_report_debugfs(unsigned long func_addr);
|
|
|
|
/*
|
|
* Value-change states.
|
|
*/
|
|
enum kcsan_value_change {
|
|
/*
|
|
* Did not observe a value-change, however, it is valid to report the
|
|
* race, depending on preferences.
|
|
*/
|
|
KCSAN_VALUE_CHANGE_MAYBE,
|
|
|
|
/*
|
|
* Did not observe a value-change, and it is invalid to report the race.
|
|
*/
|
|
KCSAN_VALUE_CHANGE_FALSE,
|
|
|
|
/*
|
|
* The value was observed to change, and the race should be reported.
|
|
*/
|
|
KCSAN_VALUE_CHANGE_TRUE,
|
|
};
|
|
|
|
enum kcsan_report_type {
|
|
/*
|
|
* The thread that set up the watchpoint and briefly stalled was
|
|
* signalled that another thread triggered the watchpoint.
|
|
*/
|
|
KCSAN_REPORT_RACE_SIGNAL,
|
|
|
|
/*
|
|
* A thread found and consumed a matching watchpoint.
|
|
*/
|
|
KCSAN_REPORT_CONSUMED_WATCHPOINT,
|
|
|
|
/*
|
|
* No other thread was observed to race with the access, but the data
|
|
* value before and after the stall differs.
|
|
*/
|
|
KCSAN_REPORT_RACE_UNKNOWN_ORIGIN,
|
|
};
|
|
|
|
/*
|
|
* Notify the report code that a race occurred.
|
|
*/
|
|
void kcsan_report_set_info(const volatile void *ptr, size_t size, int access_type,
|
|
int watchpoint_idx);
|
|
void kcsan_report_known_origin(const volatile void *ptr, size_t size, int access_type,
|
|
enum kcsan_value_change value_change, int watchpoint_idx);
|
|
void kcsan_report_unknown_origin(const volatile void *ptr, size_t size, int access_type);
|
|
|
|
#endif /* _KERNEL_KCSAN_KCSAN_H */
|