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Fixed buf #19168 based on patch by Dmitry Potapov

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This commit is contained in:
goldsimon 2007-03-04 12:45:58 +00:00
parent 1f544e087b
commit 9da7afb345
2 changed files with 21 additions and 11 deletions
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5
CHANGELOG
View File

@ -42,6 +42,11 @@ HISTORY
++ Bug fixes:
2007-03-04 Simon Goldschmidt (based on patch from Dmitry Potapov)
* pbuf.c: Fix BUG#19168 - pbuf_free can cause deadlock (if
SYS_LIGHTWEIGHT_PROT=1 & freeing PBUF_RAM when mem_sem is not available)
Also fixed cast warning in pbuf_alloc()
2007-03-04 Simon Goldschmidt
* etharp.c, etharp.h, memp.c, memp.h, opt.h: Fix BUG#11400 - don't corrupt
existing pbuf chain when enqueuing multiple pbufs to a pending ARP request

27
src/core/pbuf.c
View File

@ -216,7 +216,7 @@ pbuf_alloc(pbuf_layer l, u16_t length, pbuf_flag flag)
{
struct pbuf *p, *q, *r;
u16_t offset;
s32_t rem_len; /* remaining length */
u16_t rem_len; /* remaining length */
LWIP_DEBUGF(PBUF_DEBUG | DBG_TRACE | 3, ("pbuf_alloc(length=%"U16_F")\n", length));
/* determine header offset */
@ -270,6 +270,7 @@ pbuf_alloc(pbuf_layer l, u16_t length, pbuf_flag flag)
/* remember first pbuf for linkage in next iteration */
r = p;
/* remaining length to be allocated */
LWIP_ASSERT("length >= p->len", length >= p->len);
rem_len = length - p->len;
/* any remaining pbufs to be allocated? */
while (rem_len > 0) {
@ -296,7 +297,10 @@ pbuf_alloc(pbuf_layer l, u16_t length, pbuf_flag flag)
((mem_ptr_t)q->payload % MEM_ALIGNMENT) == 0);
q->ref = 1;
/* calculate remaining length to be allocated */
rem_len -= q->len;
if(q->len < rem_len)
rem_len -= q->len;
else
rem_len = 0;
/* remember this pbuf for linkage in next iteration */
r = q;
}
@ -567,7 +571,6 @@ pbuf_free(struct pbuf *p)
u16_t flags;
struct pbuf *q;
u8_t count;
SYS_ARCH_DECL_PROTECT(old_level);
LWIP_ASSERT("p != NULL", p != NULL);
/* if assertions are disabled, proceed with debug output */
@ -584,19 +587,22 @@ pbuf_free(struct pbuf *p)
p->flags == PBUF_FLAG_REF || p->flags == PBUF_FLAG_POOL);
count = 0;
/* Since decrementing ref cannot be guaranteed to be a single machine operation
* we must protect it. Also, the later test of ref must be protected.
*/
SYS_ARCH_PROTECT(old_level);
/* de-allocate all consecutive pbufs from the head of the chain that
* obtain a zero reference count after decrementing*/
while (p != NULL) {
u16_t ref;
SYS_ARCH_DECL_PROTECT(old_level);
/* Since decrementing ref cannot be guaranteed to be a single machine operation
* we must protect it. Also, the later test of ref must be protected.
*/
SYS_ARCH_PROTECT(old_level);
/* all pbufs in a chain are referenced at least once */
LWIP_ASSERT("pbuf_free: p->ref > 0", p->ref > 0);
/* decrease reference count (number of pointers to pbuf) */
p->ref--;
ref = p->ref--;
SYS_ARCH_UNPROTECT(old_level);
/* this pbuf is no longer referenced to? */
if (p->ref == 0) {
if (ref == 0) {
/* remember next pbuf in chain for next iteration */
q = p->next;
LWIP_DEBUGF( PBUF_DEBUG | 2, ("pbuf_free: deallocating %p\n", (void *)p));
@ -619,12 +625,11 @@ pbuf_free(struct pbuf *p)
/* p->ref > 0, this pbuf is still referenced to */
/* (and so the remaining pbufs in chain as well) */
} else {
LWIP_DEBUGF( PBUF_DEBUG | 2, ("pbuf_free: %p has ref %"U16_F", ending here.\n", (void *)p, (u16_t)p->ref));
LWIP_DEBUGF( PBUF_DEBUG | 2, ("pbuf_free: %p has ref %"U16_F", ending here.\n", (void *)p, ref));
/* stop walking through the chain */
p = NULL;
}
}
SYS_ARCH_UNPROTECT(old_level);
PERF_STOP("pbuf_free");
/* return number of de-allocated pbufs */
return count;