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MFC r285522:

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Fix cleanup race between unp_dispose and unp_gc.

This change modifies the original commit to avoid changing the
domain_dispose KPI.

Tested by:	Oliver Pinter
This commit is contained in:
markj 2016-09-02 00:14:28 +00:00
parent a79616dbee
commit a80af232a4
4 changed files with 50 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

29
sys/kern/uipc_socket.c
View File

@ -741,8 +741,12 @@ sofree(struct socket *so)
ACCEPT_UNLOCK();
VNET_SO_ASSERT(so);
if (pr->pr_flags & PR_RIGHTS && pr->pr_domain->dom_dispose != NULL)
(*pr->pr_domain->dom_dispose)(so->so_rcv.sb_mb);
if (pr->pr_flags & PR_RIGHTS && pr->pr_domain->dom_dispose != NULL) {
if (pr->pr_domain->dom_family == AF_LOCAL)
unp_dispose_so(so);
else
(*pr->pr_domain->dom_dispose)(so->so_rcv.sb_mb);
}
if (pr->pr_usrreqs->pru_detach != NULL)
(*pr->pr_usrreqs->pru_detach)(so);
@ -2290,7 +2294,7 @@ sorflush(struct socket *so)
{
struct sockbuf *sb = &so->so_rcv;
struct protosw *pr = so->so_proto;
struct sockbuf asb;
struct socket aso;
VNET_SO_ASSERT(so);
@ -2315,8 +2319,9 @@ sorflush(struct socket *so)
* and mutex data unchanged.
*/
SOCKBUF_LOCK(sb);
bzero(&asb, offsetof(struct sockbuf, sb_startzero));
bcopy(&sb->sb_startzero, &asb.sb_startzero,
bzero(&aso, sizeof(aso));
aso.so_pcb = so->so_pcb;
bcopy(&sb->sb_startzero, &aso.so_rcv.sb_startzero,
sizeof(*sb) - offsetof(struct sockbuf, sb_startzero));
bzero(&sb->sb_startzero,
sizeof(*sb) - offsetof(struct sockbuf, sb_startzero));
@ -2324,12 +2329,16 @@ sorflush(struct socket *so)
sbunlock(sb);
/*
* Dispose of special rights and flush the socket buffer. Don't call
* any unsafe routines (that rely on locks being initialized) on asb.
* Dispose of special rights and flush the copied socket. Don't call
* any unsafe routines (that rely on locks being initialized) on aso.
*/
if (pr->pr_flags & PR_RIGHTS && pr->pr_domain->dom_dispose != NULL)
(*pr->pr_domain->dom_dispose)(asb.sb_mb);
sbrelease_internal(&asb, so);
if (pr->pr_flags & PR_RIGHTS && pr->pr_domain->dom_dispose != NULL) {
if (pr->pr_domain->dom_family == AF_LOCAL)
unp_dispose_so(&aso);
else
(*pr->pr_domain->dom_dispose)(aso.so_rcv.sb_mb);
}
sbrelease_internal(&aso.so_rcv, so);
}
/*

31
sys/kern/uipc_usrreq.c
View File

@ -2200,15 +2200,19 @@ unp_gc_process(struct unpcb *unp)
* Mark all sockets we reference with RIGHTS.
*/
so = unp->unp_socket;
SOCKBUF_LOCK(&so->so_rcv);
unp_scan(so->so_rcv.sb_mb, unp_accessable);
SOCKBUF_UNLOCK(&so->so_rcv);
if ((unp->unp_gcflag & UNPGC_IGNORE_RIGHTS) == 0) {
SOCKBUF_LOCK(&so->so_rcv);
unp_scan(so->so_rcv.sb_mb, unp_accessable);
SOCKBUF_UNLOCK(&so->so_rcv);
}
/*
* Mark all sockets in our accept queue.
*/
ACCEPT_LOCK();
TAILQ_FOREACH(soa, &so->so_comp, so_list) {
if ((sotounpcb(soa)->unp_gcflag & UNPGC_IGNORE_RIGHTS) != 0)
continue;
SOCKBUF_LOCK(&soa->so_rcv);
unp_scan(soa->so_rcv.sb_mb, unp_accessable);
SOCKBUF_UNLOCK(&soa->so_rcv);
@ -2238,11 +2242,13 @@ unp_gc(__unused void *arg, int pending)
unp_taskcount++;
UNP_LIST_LOCK();
/*
* First clear all gc flags from previous runs.
* First clear all gc flags from previous runs, apart from
* UNPGC_IGNORE_RIGHTS.
*/
for (head = heads; *head != NULL; head++)
LIST_FOREACH(unp, *head, unp_link)
unp->unp_gcflag = 0;
unp->unp_gcflag =
(unp->unp_gcflag & UNPGC_IGNORE_RIGHTS);
/*
* Scan marking all reachable sockets with UNPGC_REF. Once a socket
@ -2319,6 +2325,21 @@ unp_dispose(struct mbuf *m)
unp_scan(m, unp_freerights);
}
/*
* Synchronize against unp_gc, which can trip over data as we are freeing it.
*/
void
unp_dispose_so(struct socket *so)
{
struct unpcb *unp;
unp = sotounpcb(so);
UNP_LIST_LOCK();
unp->unp_gcflag |= UNPGC_IGNORE_RIGHTS;
UNP_LIST_UNLOCK();
unp_dispose(so->so_rcv.sb_mb);
}
static void
unp_scan(struct mbuf *m0, void (*op)(struct filedescent **, int))
{

4
sys/sys/domain.h
View File

@ -42,6 +42,7 @@
*/
struct mbuf;
struct ifnet;
struct socket;
struct domain {
int dom_family; /* AF_xxx */
@ -78,6 +79,9 @@ extern int domain_init_status;
extern struct domain *domains;
void domain_add(void *);
void domain_init(void *);
/* Hack to fix dom_dispose for unix domain sockets. */
void unp_dispose_so(struct socket *);
#ifdef VIMAGE
void vnet_domain_init(void *);
void vnet_domain_uninit(void *);

1
sys/sys/unpcb.h
View File

@ -118,6 +118,7 @@ struct unpcb {
#define UNPGC_REF 0x1 /* unpcb has external ref. */
#define UNPGC_DEAD 0x2 /* unpcb might be dead. */
#define UNPGC_SCANNED 0x4 /* Has been scanned. */
#define UNPGC_IGNORE_RIGHTS 0x8 /* Attached rights are freed */
#define sotounpcb(so) ((struct unpcb *)((so)->so_pcb))