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Add witness_is_owned(9)

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which returns an indicator if the current thread owns the specified
lock.

Reviewed by:	jah, markj
Tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Differential revision:	https://reviews.freebsd.org/D39477
This commit is contained in:
Konstantin Belousov 2023-04-10 18:54:58 +03:00
parent afa8f8971b
commit 75fc6f86c3
2 changed files with 49 additions and 10 deletions
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58
sys/kern/subr_witness.c
View File

@ -2429,6 +2429,32 @@ witness_restore(struct lock_object *lock, const char *file, int line)
instance->li_line = line;
}
static bool
witness_find_instance(const struct lock_object *lock,
struct lock_instance **instance)
{
#ifdef INVARIANT_SUPPORT
struct lock_class *class;
if (lock->lo_witness == NULL || witness_watch < 1 || KERNEL_PANICKED())
return (false);
class = LOCK_CLASS(lock);
if ((class->lc_flags & LC_SLEEPLOCK) != 0) {
*instance = find_instance(curthread->td_sleeplocks, lock);
return (true);
} else if ((class->lc_flags & LC_SPINLOCK) != 0) {
*instance = find_instance(PCPU_GET(spinlocks), lock);
return (true);
} else {
kassert_panic("Lock (%s) %s is not sleep or spin!",
class->lc_name, lock->lo_name);
return (false);
}
#else
return (false);
#endif
}
void
witness_assert(const struct lock_object *lock, int flags, const char *file,
int line)
@ -2437,18 +2463,9 @@ witness_assert(const struct lock_object *lock, int flags, const char *file,
struct lock_instance *instance;
struct lock_class *class;
if (lock->lo_witness == NULL || witness_watch < 1 || KERNEL_PANICKED())
if (!witness_find_instance(lock, &instance))
return;
class = LOCK_CLASS(lock);
if ((class->lc_flags & LC_SLEEPLOCK) != 0)
instance = find_instance(curthread->td_sleeplocks, lock);
else if ((class->lc_flags & LC_SPINLOCK) != 0)
instance = find_instance(PCPU_GET(spinlocks), lock);
else {
kassert_panic("Lock (%s) %s is not sleep or spin!",
class->lc_name, lock->lo_name);
return;
}
switch (flags) {
case LA_UNLOCKED:
if (instance != NULL)
@ -2501,6 +2518,27 @@ witness_assert(const struct lock_object *lock, int flags, const char *file,
#endif /* INVARIANT_SUPPORT */
}
/*
* Checks the ownership of the lock by curthread, consulting the witness list.
* Returns:
* 0 if witness is disabled or did not work
* -1 if not owned
* 1 if owned
*/
int
witness_is_owned(const struct lock_object *lock)
{
#ifdef INVARIANT_SUPPORT
struct lock_instance *instance;
if (!witness_find_instance(lock, &instance))
return (0);
return (instance == NULL ? -1 : 1);
#else
return (0);
#endif
}
static void
witness_setflag(struct lock_object *lock, int flag, int set)
{

1
sys/sys/lock.h
View File

@ -237,6 +237,7 @@ int witness_list_locks(struct lock_list_entry **,
int (*)(const char *, ...));
int witness_warn(int, struct lock_object *, const char *, ...);
void witness_assert(const struct lock_object *, int, const char *, int);
int witness_is_owned(const struct lock_object *lock);
void witness_display_spinlock(struct lock_object *, struct thread *,
int (*)(const char *, ...));
int witness_line(struct lock_object *);