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Don't panic if a spin lock is initialized that isn't in our static order

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list.  Just warn about it instead.

Requested by:	scottl
MFC after:	1 day
This commit is contained in:
John Baldwin 2005-10-24 20:14:24 +00:00
parent 33a00fc0b1
commit cf23efc12a
1 changed files with 16 additions and 7 deletions
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23
sys/kern/subr_witness.c
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@ -450,6 +450,12 @@ static struct mtx all_mtx = {
*/
static int witness_cold = 1;
/*
* This global is set to 1 once the static lock orders have been enrolled
* so that a warning can be issued for any spin locks enrolled later.
*/
static int witness_spin_warn = 0;
/*
* Global variables for book keeping.
*/
@ -501,6 +507,7 @@ witness_initialize(void *dummy __unused)
w = w1;
}
}
witness_spin_warn = 1;
/* Iterate through all locks and add them to witness. */
mtx_lock(&all_mtx);
@ -514,7 +521,7 @@ witness_initialize(void *dummy __unused)
mtx_unlock(&all_mtx);
/* Mark the witness code as being ready for use. */
atomic_store_rel_int(&witness_cold, 0);
witness_cold = 0;
mtx_lock(&Giant);
}
@ -1404,13 +1411,15 @@ enroll(const char *description, struct lock_class *lock_class)
}
}
/*
* This isn't quite right, as witness_cold is still 0 while we
* enroll all the locks initialized before witness_initialize().
* We issue a warning for any spin locks not defined in the static
* order list as a way to discourage their use (folks should really
* be using non-spin mutexes most of the time). However, several
* 3rd part device drivers use spin locks because that is all they
* have available on Windows and Linux and they think that normal
* mutexes are insufficient.
*/
if ((lock_class->lc_flags & LC_SPINLOCK) && !witness_cold) {
mtx_unlock_spin(&w_mtx);
panic("spin lock %s not in order list", description);
}
if ((lock_class->lc_flags & LC_SPINLOCK) && witness_spin_warn)
printf("WITNESS: spin lock %s not in order list", description);
if ((w = witness_get()) == NULL)
return (NULL);
w->w_name = description;