From: Fengnan Chang <changfengnan@bytedance.com>
To: anatoly.burakov@intel.com, dev@dpdk.org, xuemingl@mellanox.com
Cc: Fengnan Chang <changfengnan@bytedance.com>
Subject: [PATCH] eal: fix modify data area after memset
Date: Tue, 12 Sep 2023 17:04:15 +0800 [thread overview]
Message-ID: <20230912090415.48709-1-changfengnan@bytedance.com> (raw)
Let's look at this path:
malloc_elem_free
->malloc_elem_join_adjacent_free
->join_elem(elem, elem->next)
0. cur elem's pad > 0
1. data area memset in malloc_elem_free first.
2. next elem is free, try to join cur elem and next.
3. in join_elem, try to modify inner->size, this address had
memset in step 1, it casue the content of addrees become non-zero.
If user call rte_zmalloc, and pick this elem, it can't get all
zero'd memory.
Fixes: 2808a12cc053 (malloc: fix memory element size in case of padding)
Signed-off-by: Fengnan Chang <changfengnan@bytedance.com>
---
lib/eal/common/malloc_elem.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/lib/eal/common/malloc_elem.c b/lib/eal/common/malloc_elem.c
index 619c040aa3..93a23fa8d4 100644
--- a/lib/eal/common/malloc_elem.c
+++ b/lib/eal/common/malloc_elem.c
@@ -492,7 +492,7 @@ malloc_elem_alloc(struct malloc_elem *elem, size_t size, unsigned align,
* be contiguous in memory.
*/
static inline void
-join_elem(struct malloc_elem *elem1, struct malloc_elem *elem2)
+join_elem(struct malloc_elem *elem1, struct malloc_elem *elem2, bool update_inner)
{
struct malloc_elem *next = elem2->next;
elem1->size += elem2->size;
@@ -502,7 +502,7 @@ join_elem(struct malloc_elem *elem1, struct malloc_elem *elem2)
elem1->heap->last = elem1;
elem1->next = next;
elem1->dirty |= elem2->dirty;
- if (elem1->pad) {
+ if (elem1->pad && update_inner) {
struct malloc_elem *inner = RTE_PTR_ADD(elem1, elem1->pad);
inner->size = elem1->size - elem1->pad;
}
@@ -526,7 +526,7 @@ malloc_elem_join_adjacent_free(struct malloc_elem *elem)
/* remove from free list, join to this one */
malloc_elem_free_list_remove(elem->next);
- join_elem(elem, elem->next);
+ join_elem(elem, elem->next, false);
/* erase header, trailer and pad */
memset(erase, MALLOC_POISON, erase_len);
@@ -550,7 +550,7 @@ malloc_elem_join_adjacent_free(struct malloc_elem *elem)
malloc_elem_free_list_remove(elem->prev);
new_elem = elem->prev;
- join_elem(new_elem, elem);
+ join_elem(new_elem, elem, false);
/* erase header, trailer and pad */
memset(erase, MALLOC_POISON, erase_len);
@@ -683,7 +683,7 @@ malloc_elem_resize(struct malloc_elem *elem, size_t size)
* join the two
*/
malloc_elem_free_list_remove(elem->next);
- join_elem(elem, elem->next);
+ join_elem(elem, elem->next, true);
if (elem->size - new_size >= MIN_DATA_SIZE + MALLOC_ELEM_OVERHEAD) {
/* now we have a big block together. Lets cut it down a bit, by splitting */
--
2.20.1
next reply other threads:[~2023-09-12 9:05 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-12 9:04 Fengnan Chang [this message]
2023-09-22 8:12 ` Fengnan Chang
2023-10-22 20:22 ` Dmitry Kozlyuk
2023-10-23 9:07 ` [External] " Fengnan Chang
2023-10-25 16:03 ` Stephen Hemminger
2023-10-30 12:31 ` Fengnan Chang
2023-10-17 13:32 ` Thomas Monjalon
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