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Add sanity checking for QUEUE(3) TAILQs under INVARIANTS (similar to

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the LIST checks).  Races may lead to list corruption, which can be
difficult to unravel in a post-mortem analysis.  These checks verify
that the prev and next pointers are consistent when inserting or
removing elements, thus catching any corruption earlier.
This commit is contained in:
Ed Maste 2006-05-26 18:17:53 +00:00
parent becc5c626d
commit af8d1678e1
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=158963
1 changed files with 37 additions and 0 deletions
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37
sys/sys/queue.h
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@ -430,6 +430,37 @@ struct { \
/*
* Tail queue functions.
*/
#if (defined(_KERNEL) && defined(INVARIANTS))
#define QMD_TAILQ_CHECK_HEAD(head, field) do { \
if (!TAILQ_EMPTY(head) && \
TAILQ_FIRST((head))->field.tqe_prev != \
&TAILQ_FIRST((head))) \
panic("Bad tailq head %p first->prev != head", (head)); \
} while (0)
#define QMD_TAILQ_CHECK_TAIL(head, field) do { \
if (*(head)->tqh_last != NULL) \
panic("Bad tailq NEXT(%p->tqh_last) != NULL", (head)); \
} while (0)
#define QMD_TAILQ_CHECK_NEXT(elm, field) do { \
if (TAILQ_NEXT((elm), field) != NULL && \
TAILQ_NEXT((elm), field)->field.tqe_prev != \
&((elm)->field.tqe_next)) \
panic("Bad link elm %p next->prev != elm", (elm)); \
} while (0)
#define QMD_TAILQ_CHECK_PREV(elm, field) do { \
if (*(elm)->field.tqe_prev != (elm)) \
panic("Bad link elm %p prev->next != elm", (elm)); \
} while (0)
#else
#define QMD_TAILQ_CHECK_HEAD(head, field)
#define QMD_TAILQ_CHECK_TAIL(head, headname)
#define QMD_TAILQ_CHECK_NEXT(elm, field)
#define QMD_TAILQ_CHECK_PREV(elm, field)
#endif /* (_KERNEL && INVARIANTS) */
#define TAILQ_CONCAT(head1, head2, field) do { \
if (!TAILQ_EMPTY(head2)) { \
*(head1)->tqh_last = (head2)->tqh_first; \
@ -472,6 +503,7 @@ struct { \
} while (0)
#define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \
QMD_TAILQ_CHECK_NEXT(listelm, field); \
if ((TAILQ_NEXT((elm), field) = TAILQ_NEXT((listelm), field)) != NULL)\
TAILQ_NEXT((elm), field)->field.tqe_prev = \
&TAILQ_NEXT((elm), field); \
@ -486,6 +518,7 @@ struct { \
} while (0)
#define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \
QMD_TAILQ_CHECK_PREV(listelm, field); \
(elm)->field.tqe_prev = (listelm)->field.tqe_prev; \
TAILQ_NEXT((elm), field) = (listelm); \
*(listelm)->field.tqe_prev = (elm); \
@ -495,6 +528,7 @@ struct { \
} while (0)
#define TAILQ_INSERT_HEAD(head, elm, field) do { \
QMD_TAILQ_CHECK_HEAD(head, field); \
if ((TAILQ_NEXT((elm), field) = TAILQ_FIRST((head))) != NULL) \
TAILQ_FIRST((head))->field.tqe_prev = \
&TAILQ_NEXT((elm), field); \
@ -507,6 +541,7 @@ struct { \
} while (0)
#define TAILQ_INSERT_TAIL(head, elm, field) do { \
QMD_TAILQ_CHECK_TAIL(head, field); \
TAILQ_NEXT((elm), field) = NULL; \
(elm)->field.tqe_prev = (head)->tqh_last; \
*(head)->tqh_last = (elm); \
@ -524,6 +559,8 @@ struct { \
(*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
#define TAILQ_REMOVE(head, elm, field) do { \
QMD_TAILQ_CHECK_NEXT(elm, field); \
QMD_TAILQ_CHECK_PREV(elm, field); \
if ((TAILQ_NEXT((elm), field)) != NULL) \
TAILQ_NEXT((elm), field)->field.tqe_prev = \
(elm)->field.tqe_prev; \