diff options
| author | Stefan Hajnoczi <stefanha@redhat.com> | 2020-02-24 10:34:05 +0000 |
|---|---|---|
| committer | Stefan Hajnoczi <stefanha@redhat.com> | 2020-03-09 16:39:20 +0000 |
| commit | a31ca6801c027dbee2c589da85814b56eec563f6 (patch) | |
| tree | 6ca6c52710b3b4b7fb7d6594eebc01b752347f42 | |
| parent | 67f17e23baca5dd545fe98b01169cc351a70fe35 (diff) | |
qemu/queue.h: clear linked list pointers on remove
Do not leave stale linked list pointers around after removal. It's
safer to set them to NULL so that use-after-removal results in an
immediate segfault.
The RCU queue removal macros are unchanged since nodes may still be
traversed after removal.
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Link: https://lore.kernel.org/r/20200224103406.1894923-2-stefanha@redhat.com
Message-Id: <20200224103406.1894923-2-stefanha@redhat.com>
| -rw-r--r-- | include/qemu/queue.h | 19 |
1 files changed, 15 insertions, 4 deletions
diff --git a/include/qemu/queue.h b/include/qemu/queue.h index 294db54eb1..456a5b01ee 100644 --- a/include/qemu/queue.h +++ b/include/qemu/queue.h @@ -142,6 +142,8 @@ struct { \ (elm)->field.le_next->field.le_prev = \ (elm)->field.le_prev; \ *(elm)->field.le_prev = (elm)->field.le_next; \ + (elm)->field.le_next = NULL; \ + (elm)->field.le_prev = NULL; \ } while (/*CONSTCOND*/0) /* @@ -225,12 +227,15 @@ struct { \ } while (/*CONSTCOND*/0) #define QSLIST_REMOVE_HEAD(head, field) do { \ - (head)->slh_first = (head)->slh_first->field.sle_next; \ + typeof((head)->slh_first) elm = (head)->slh_first; \ + (head)->slh_first = elm->field.sle_next; \ + elm->field.sle_next = NULL; \ } while (/*CONSTCOND*/0) #define QSLIST_REMOVE_AFTER(slistelm, field) do { \ - (slistelm)->field.sle_next = \ - QSLIST_NEXT(QSLIST_NEXT((slistelm), field), field); \ + typeof(slistelm) next = (slistelm)->field.sle_next; \ + (slistelm)->field.sle_next = next->field.sle_next; \ + next->field.sle_next = NULL; \ } while (/*CONSTCOND*/0) #define QSLIST_REMOVE(head, elm, type, field) do { \ @@ -241,6 +246,7 @@ struct { \ while (curelm->field.sle_next != (elm)) \ curelm = curelm->field.sle_next; \ curelm->field.sle_next = curelm->field.sle_next->field.sle_next; \ + (elm)->field.sle_next = NULL; \ } \ } while (/*CONSTCOND*/0) @@ -304,8 +310,10 @@ struct { \ } while (/*CONSTCOND*/0) #define QSIMPLEQ_REMOVE_HEAD(head, field) do { \ - if (((head)->sqh_first = (head)->sqh_first->field.sqe_next) == NULL)\ + typeof((head)->sqh_first) elm = (head)->sqh_first; \ + if (((head)->sqh_first = elm->field.sqe_next) == NULL) \ (head)->sqh_last = &(head)->sqh_first; \ + elm->field.sqe_next = NULL; \ } while (/*CONSTCOND*/0) #define QSIMPLEQ_SPLIT_AFTER(head, elm, field, removed) do { \ @@ -329,6 +337,7 @@ struct { \ if ((curelm->field.sqe_next = \ curelm->field.sqe_next->field.sqe_next) == NULL) \ (head)->sqh_last = &(curelm)->field.sqe_next; \ + (elm)->field.sqe_next = NULL; \ } \ } while (/*CONSTCOND*/0) @@ -446,6 +455,8 @@ union { \ (head)->tqh_circ.tql_prev = (elm)->field.tqe_circ.tql_prev; \ (elm)->field.tqe_circ.tql_prev->tql_next = (elm)->field.tqe_next; \ (elm)->field.tqe_circ.tql_prev = NULL; \ + (elm)->field.tqe_circ.tql_next = NULL; \ + (elm)->field.tqe_next = NULL; \ } while (/*CONSTCOND*/0) /* remove @left, @right and all elements in between from @head */ |