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uma_zalloc: assert M_NOWAIT ^ M_WAITOK

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The uma_zalloc functions expect exactly one of [M_NOWAIT, M_WAITOK].
If neither or both are passed, print an error and a stack dump.
Only do this ten times, to prevent livelock.  In the future, after
this exposes enough bad callers, this will be changed to a KASSERT().

Reviewed by:	rstone, markj
MFC after:	1 month
Sponsored by:	Dell EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D34452
This commit is contained in:
Eric van Gyzen 2022-03-04 05:23:08 -06:00
parent 863070bbf6
commit a8cbb835bf
1 changed files with 28 additions and 0 deletions
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28
sys/vm/uma_core.c
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@ -3494,6 +3494,9 @@ item_domain(void *item)
#endif
#if defined(INVARIANTS) || defined(DEBUG_MEMGUARD) || defined(WITNESS)
#if defined(INVARIANTS) && (defined(DDB) || defined(STACK))
#include <sys/stack.h>
#endif
#define UMA_ZALLOC_DEBUG
static int
uma_zalloc_debug(uma_zone_t zone, void **itemp, void *udata, int flags)
@ -3515,6 +3518,31 @@ uma_zalloc_debug(uma_zone_t zone, void **itemp, void *udata, int flags)
("uma_zalloc_debug: called within spinlock or critical section"));
KASSERT((zone->uz_flags & UMA_ZONE_PCPU) == 0 || (flags & M_ZERO) == 0,
("uma_zalloc_debug: allocating from a pcpu zone with M_ZERO"));
_Static_assert(M_NOWAIT != 0 && M_WAITOK != 0,
"M_NOWAIT and M_WAITOK must be non-zero for this assertion:");
#if 0
/*
* Give the #elif clause time to find problems, then remove it
* and enable this. (Remove <sys/stack.h> above, too.)
*/
KASSERT((flags & (M_NOWAIT|M_WAITOK)) == M_NOWAIT ||
(flags & (M_NOWAIT|M_WAITOK)) == M_WAITOK,
("uma_zalloc_debug: must pass one of M_NOWAIT or M_WAITOK"));
#elif defined(DDB) || defined(STACK)
if (__predict_false((flags & (M_NOWAIT|M_WAITOK)) != M_NOWAIT &&
(flags & (M_NOWAIT|M_WAITOK)) != M_WAITOK)) {
static int stack_count;
struct stack st;
if (stack_count < 10) {
++stack_count;
printf("uma_zalloc* called with bad WAIT flags:\n");
stack_save(&st);
stack_print(&st);
}
}
#endif
#endif
#ifdef DEBUG_MEMGUARD