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Code Issues Releases Activity

Assert socket buffer lock in sb_lock() to protect socket buffer sleep

Browse Source 
lock state.  Convert tsleep() into msleep() with socket buffer mutex
as argument.  Hold socket buffer lock over sbunlock() to protect sleep
lock state.

Assert socket buffer lock in sbwait() to protect the socket buffer
wait state.  Convert tsleep() into msleep() with socket buffer mutex
as argument.

Modify sofree(), sosend(), and soreceive() to acquire SOCKBUF_LOCK()
in order to call into these functions with the lock, as well as to
start protecting other socket buffer use in their implementation.  Drop
the socket buffer mutexes around calls into the protocol layer, around
potentially blocking operations, for copying to/from user space, and
VM operations relating to zero-copy.  Assert the socket buffer mutex
strategically after code sections or at the beginning of loops.  In
some cases, modify return code to ensure locks are properly dropped.

Convert the potentially blocking allocation of storage for the remote
address in soreceive() into a non-blocking allocation; we may wish to
move the allocation earlier so that it can block prior to acquisition
of the socket buffer lock.

Drop some spl use.

NOTE: Some races exist in the current structuring of sosend() and
soreceive().  This commit only merges basic socket locking in this
code; follow-up commits will close additional races.  As merged,
these changes are not sufficient to run without Giant safely.

Reviewed by:	juli, tjr
This commit is contained in:
Robert Watson 2004-06-19 03:23:14 +00:00
parent 3e7fa136ea
commit 31f555a1c5
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=130705
4 changed files with 93 additions and 29 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
sys/kern/uipc_sockbuf.c
View File

@ -323,8 +323,10 @@ sbwait(sb)
struct sockbuf *sb;
{
SOCKBUF_LOCK_ASSERT(sb);
sb->sb_flags |= SB_WAIT;
return (tsleep(&sb->sb_cc,
return (msleep(&sb->sb_cc, &sb->sb_mtx,
(sb->sb_flags & SB_NOINTR) ? PSOCK : PSOCK | PCATCH, "sbwait",
sb->sb_timeo));
}
@ -339,9 +341,11 @@ sb_lock(sb)
{
int error;
SOCKBUF_LOCK_ASSERT(sb);
while (sb->sb_flags & SB_LOCK) {
sb->sb_flags |= SB_WANT;
error = tsleep(&sb->sb_flags,
error = msleep(&sb->sb_flags, &sb->sb_mtx,
(sb->sb_flags & SB_NOINTR) ? PSOCK : PSOCK|PCATCH,
"sblock", 0);
if (error)

85
sys/kern/uipc_socket.c
View File

@ -295,7 +295,6 @@ sofree(so)
struct socket *so;
{
struct socket *head;
int s;
KASSERT(so->so_count == 0, ("socket %p so_count not 0", so));
SOCK_LOCK_ASSERT(so);
@ -341,13 +340,13 @@ sofree(so)
("sofree: so_head == NULL, but still SQ_COMP(%d) or SQ_INCOMP(%d)",
so->so_qstate & SQ_COMP, so->so_qstate & SQ_INCOMP));
ACCEPT_UNLOCK();
SOCKBUF_LOCK(&so->so_snd);
so->so_snd.sb_flags |= SB_NOINTR;
(void)sblock(&so->so_snd, M_WAITOK);
s = splimp();
socantsendmore(so);
splx(s);
sbunlock(&so->so_snd);
sbrelease(&so->so_snd, so);
SOCKBUF_UNLOCK(&so->so_snd);
sorflush(so);
sodealloc(so);
}
@ -597,11 +596,14 @@ sosend(so, addr, uio, top, control, flags, td)
clen = control->m_len;
#define snderr(errno) { error = (errno); splx(s); goto release; }
SOCKBUF_LOCK(&so->so_snd);
restart:
SOCKBUF_LOCK_ASSERT(&so->so_snd);
error = sblock(&so->so_snd, SBLOCKWAIT(flags));
if (error)
goto out;
goto out_locked;
do {
SOCKBUF_LOCK_ASSERT(&so->so_snd);
s = splnet();
if (so->so_snd.sb_state & SBS_CANTSENDMORE)
snderr(EPIPE);
@ -641,9 +643,10 @@ sosend(so, addr, uio, top, control, flags, td)
error = sbwait(&so->so_snd);
splx(s);
if (error)
goto out;
goto out_locked;
goto restart;
}
SOCKBUF_UNLOCK(&so->so_snd);
splx(s);
mp = ⊤
space -= clen;
@ -665,6 +668,7 @@ sosend(so, addr, uio, top, control, flags, td)
MGETHDR(m, M_TRYWAIT, MT_DATA);
if (m == NULL) {
error = ENOBUFS;
SOCKBUF_LOCK(&so->so_snd);
goto release;
}
m->m_pkthdr.len = 0;
@ -673,6 +677,7 @@ sosend(so, addr, uio, top, control, flags, td)
MGET(m, M_TRYWAIT, MT_DATA);
if (m == NULL) {
error = ENOBUFS;
SOCKBUF_LOCK(&so->so_snd);
goto release;
}
}
@ -726,6 +731,7 @@ sosend(so, addr, uio, top, control, flags, td)
}
if (m == NULL) {
error = ENOBUFS;
SOCKBUF_LOCK(&so->so_snd);
goto release;
}
@ -740,8 +746,10 @@ sosend(so, addr, uio, top, control, flags, td)
m->m_len = len;
*mp = m;
top->m_pkthdr.len += len;
if (error)
if (error) {
SOCKBUF_LOCK(&so->so_snd);
goto release;
}
mp = &m->m_next;
if (resid <= 0) {
if (flags & MSG_EOR)
@ -787,13 +795,20 @@ sosend(so, addr, uio, top, control, flags, td)
control = NULL;
top = NULL;
mp = &top;
if (error)
if (error) {
SOCKBUF_LOCK(&so->so_snd);
goto release;
}
} while (resid && space > 0);
SOCKBUF_LOCK(&so->so_snd);
} while (resid);
release:
SOCKBUF_LOCK_ASSERT(&so->so_snd);
sbunlock(&so->so_snd);
out_locked:
SOCKBUF_LOCK_ASSERT(&so->so_snd);
SOCKBUF_UNLOCK(&so->so_snd);
out:
if (top != NULL)
m_freem(top);
@ -886,10 +901,12 @@ soreceive(so, psa, uio, mp0, controlp, flagsp)
if (so->so_state & SS_ISCONFIRMING && uio->uio_resid)
(*pr->pr_usrreqs->pru_rcvd)(so, 0);
SOCKBUF_LOCK(&so->so_rcv);
restart:
SOCKBUF_LOCK_ASSERT(&so->so_rcv);
error = sblock(&so->so_rcv, SBLOCKWAIT(flags));
if (error)
return (error);
goto out;
s = splnet();
m = so->so_rcv.sb_mb;
@ -949,10 +966,11 @@ soreceive(so, psa, uio, mp0, controlp, flagsp)
error = sbwait(&so->so_rcv);
splx(s);
if (error)
return (error);
goto out;
goto restart;
}
dontblock:
SOCKBUF_LOCK_ASSERT(&so->so_rcv);
if (uio->uio_td)
uio->uio_td->td_proc->p_stats->p_ru.ru_msgrcv++;
SBLASTRECORDCHK(&so->so_rcv);
@ -964,7 +982,7 @@ soreceive(so, psa, uio, mp0, controlp, flagsp)
orig_resid = 0;
if (psa != NULL)
*psa = sodupsockaddr(mtod(m, struct sockaddr *),
mp0 == NULL ? M_WAITOK : M_NOWAIT);
M_NOWAIT);
if (flags & MSG_PEEK) {
m = m->m_next;
} else {
@ -982,10 +1000,12 @@ soreceive(so, psa, uio, mp0, controlp, flagsp)
sbfree(&so->so_rcv, m);
so->so_rcv.sb_mb = m->m_next;
m->m_next = NULL;
if (pr->pr_domain->dom_externalize)
error =
(*pr->pr_domain->dom_externalize)(m, controlp);
else if (controlp != NULL)
if (pr->pr_domain->dom_externalize) {
SOCKBUF_UNLOCK(&so->so_rcv);
error = (*pr->pr_domain->dom_externalize)
(m, controlp);
SOCKBUF_LOCK(&so->so_rcv);
} else if (controlp != NULL)
*controlp = m;
else
m_freem(m);
@ -1021,12 +1041,14 @@ soreceive(so, psa, uio, mp0, controlp, flagsp)
SB_EMPTY_FIXUP(&so->so_rcv);
}
}
SOCKBUF_LOCK_ASSERT(&so->so_rcv);
SBLASTRECORDCHK(&so->so_rcv);
SBLASTMBUFCHK(&so->so_rcv);
moff = 0;
offset = 0;
while (m != NULL && uio->uio_resid > 0 && error == 0) {
SOCKBUF_LOCK_ASSERT(&so->so_rcv);
if (m->m_type == MT_OOBDATA) {
if (type != MT_OOBDATA)
break;
@ -1050,8 +1072,10 @@ soreceive(so, psa, uio, mp0, controlp, flagsp)
* block interrupts again.
*/
if (mp == NULL) {
SOCKBUF_LOCK_ASSERT(&so->so_rcv);
SBLASTRECORDCHK(&so->so_rcv);
SBLASTMBUFCHK(&so->so_rcv);
SOCKBUF_UNLOCK(&so->so_rcv);
splx(s);
#ifdef ZERO_COPY_SOCKETS
if (so_zero_copy_receive) {
@ -1076,6 +1100,7 @@ soreceive(so, psa, uio, mp0, controlp, flagsp)
} else
#endif /* ZERO_COPY_SOCKETS */
error = uiomove(mtod(m, char *) + moff, (int)len, uio);
SOCKBUF_LOCK(&so->so_rcv);
s = splnet();
if (error)
goto release;
@ -1125,6 +1150,7 @@ soreceive(so, psa, uio, mp0, controlp, flagsp)
if ((flags & MSG_PEEK) == 0) {
so->so_oobmark -= len;
if (so->so_oobmark == 0) {
SOCKBUF_LOCK_ASSERT(&so->so_rcv);
so->so_rcv.sb_state |= SBS_RCVATMARK;
break;
}
@ -1145,22 +1171,23 @@ soreceive(so, psa, uio, mp0, controlp, flagsp)
*/
while (flags & MSG_WAITALL && m == NULL && uio->uio_resid > 0 &&
!sosendallatonce(so) && nextrecord == NULL) {
SOCKBUF_LOCK_ASSERT(&so->so_rcv);
if (so->so_error || so->so_rcv.sb_state & SBS_CANTRCVMORE)
break;
/*
* Notify the protocol that some data has been
* drained before blocking.
*/
if (pr->pr_flags & PR_WANTRCVD && so->so_pcb != NULL)
if (pr->pr_flags & PR_WANTRCVD && so->so_pcb != NULL) {
SOCKBUF_UNLOCK(&so->so_rcv);
(*pr->pr_usrreqs->pru_rcvd)(so, flags);
SOCKBUF_LOCK(&so->so_rcv);
}
SBLASTRECORDCHK(&so->so_rcv);
SBLASTMBUFCHK(&so->so_rcv);
error = sbwait(&so->so_rcv);
if (error) {
sbunlock(&so->so_rcv);
splx(s);
return (0);
}
if (error)
goto release;
m = so->so_rcv.sb_mb;
if (m != NULL)
nextrecord = m->m_nextpkt;
@ -1169,8 +1196,10 @@ soreceive(so, psa, uio, mp0, controlp, flagsp)
if (m != NULL && pr->pr_flags & PR_ATOMIC) {
flags |= MSG_TRUNC;
if ((flags & MSG_PEEK) == 0)
if ((flags & MSG_PEEK) == 0) {
SOCKBUF_LOCK_ASSERT(&so->so_rcv);
(void) sbdroprecord(&so->so_rcv);
}
}
if ((flags & MSG_PEEK) == 0) {
if (m == NULL) {
@ -1188,9 +1217,13 @@ soreceive(so, psa, uio, mp0, controlp, flagsp)
}
SBLASTRECORDCHK(&so->so_rcv);
SBLASTMBUFCHK(&so->so_rcv);
if (pr->pr_flags & PR_WANTRCVD && so->so_pcb)
if (pr->pr_flags & PR_WANTRCVD && so->so_pcb) {
SOCKBUF_UNLOCK(&so->so_rcv);
(*pr->pr_usrreqs->pru_rcvd)(so, flags);
SOCKBUF_LOCK(&so->so_rcv);
}
}
SOCKBUF_LOCK_ASSERT(&so->so_rcv);
if (orig_resid == uio->uio_resid && orig_resid &&
(flags & MSG_EOR) == 0 && (so->so_rcv.sb_state & SBS_CANTRCVMORE) == 0) {
sbunlock(&so->so_rcv);
@ -1201,7 +1234,10 @@ soreceive(so, psa, uio, mp0, controlp, flagsp)
if (flagsp != NULL)
*flagsp |= flags;
release:
SOCKBUF_LOCK_ASSERT(&so->so_rcv);
sbunlock(&so->so_rcv);
out:
SOCKBUF_UNLOCK(&so->so_rcv);
splx(s);
return (error);
}
@ -1229,12 +1265,11 @@ sorflush(so)
{
struct sockbuf *sb = &so->so_rcv;
struct protosw *pr = so->so_proto;
int s;
struct sockbuf asb;
SOCKBUF_LOCK(sb);
sb->sb_flags |= SB_NOINTR;
(void) sblock(sb, M_WAITOK);
s = splimp();
socantrcvmore(so);
sbunlock(sb);
asb = *sb;
@ -1244,7 +1279,7 @@ sorflush(so)
*/
bzero(&sb->sb_startzero,
sizeof(*sb) - offsetof(struct sockbuf, sb_startzero));
splx(s);
SOCKBUF_UNLOCK(sb);
if (pr->pr_flags & PR_RIGHTS && pr->pr_domain->dom_dispose != NULL)
(*pr->pr_domain->dom_dispose)(asb.sb_mb);

8
sys/kern/uipc_socket2.c
View File

@ -323,8 +323,10 @@ sbwait(sb)
struct sockbuf *sb;
{
SOCKBUF_LOCK_ASSERT(sb);
sb->sb_flags |= SB_WAIT;
return (tsleep(&sb->sb_cc,
return (msleep(&sb->sb_cc, &sb->sb_mtx,
(sb->sb_flags & SB_NOINTR) ? PSOCK : PSOCK | PCATCH, "sbwait",
sb->sb_timeo));
}
@ -339,9 +341,11 @@ sb_lock(sb)
{
int error;
SOCKBUF_LOCK_ASSERT(sb);
while (sb->sb_flags & SB_LOCK) {
sb->sb_flags |= SB_WANT;
error = tsleep(&sb->sb_flags,
error = msleep(&sb->sb_flags, &sb->sb_mtx,
(sb->sb_flags & SB_NOINTR) ? PSOCK : PSOCK|PCATCH,
"sblock", 0);
if (error)

21
sys/kern/uipc_syscalls.c
View File

@ -1801,7 +1801,9 @@ do_sendfile(struct thread *td, struct sendfile_args *uap, int compat)
/*
* Protect against multiple writers to the socket.
*/
SOCKBUF_LOCK(&so->so_snd);
(void) sblock(&so->so_snd, M_WAITOK);
SOCKBUF_UNLOCK(&so->so_snd);
/*
* Loop through the pages in the file, starting with the requested
@ -1841,14 +1843,17 @@ do_sendfile(struct thread *td, struct sendfile_args *uap, int compat)
* Optimize the non-blocking case by looking at the socket space
* before going to the extra work of constituting the sf_buf.
*/
SOCKBUF_LOCK(&so->so_snd);
if ((so->so_state & SS_NBIO) && sbspace(&so->so_snd) <= 0) {
if (so->so_snd.sb_state & SBS_CANTSENDMORE)
error = EPIPE;
else
error = EAGAIN;
sbunlock(&so->so_snd);
SOCKBUF_UNLOCK(&so->so_snd);
goto done;
}
SOCKBUF_UNLOCK(&so->so_snd);
VM_OBJECT_LOCK(obj);
/*
* Attempt to look up the page.
@ -1936,7 +1941,9 @@ do_sendfile(struct thread *td, struct sendfile_args *uap, int compat)
}
vm_page_unlock_queues();
VM_OBJECT_UNLOCK(obj);
SOCKBUF_LOCK(&so->so_snd);
sbunlock(&so->so_snd);
SOCKBUF_UNLOCK(&so->so_snd);
goto done;
}
vm_page_unlock_queues();
@ -1952,7 +1959,9 @@ do_sendfile(struct thread *td, struct sendfile_args *uap, int compat)
if (pg->wire_count == 0 && pg->object == NULL)
vm_page_free(pg);
vm_page_unlock_queues();
SOCKBUF_LOCK(&so->so_snd);
sbunlock(&so->so_snd);
SOCKBUF_UNLOCK(&so->so_snd);
error = EINTR;
goto done;
}
@ -1967,7 +1976,9 @@ do_sendfile(struct thread *td, struct sendfile_args *uap, int compat)
if (m == NULL) {
error = ENOBUFS;
sf_buf_mext((void *)sf_buf_kva(sf), sf);
SOCKBUF_LOCK(&so->so_snd);
sbunlock(&so->so_snd);
SOCKBUF_UNLOCK(&so->so_snd);
goto done;
}
/*
@ -1989,6 +2000,7 @@ do_sendfile(struct thread *td, struct sendfile_args *uap, int compat)
* Add the buffer to the socket buffer chain.
*/
s = splnet();
SOCKBUF_LOCK(&so->so_snd);
retry_space:
/*
* Make sure that the socket is still able to take more data.
@ -2001,6 +2013,7 @@ do_sendfile(struct thread *td, struct sendfile_args *uap, int compat)
* blocks before the pru_send (or more accurately, any blocking
* results in a loop back to here to re-check).
*/
SOCKBUF_LOCK_ASSERT(&so->so_snd);
if ((so->so_snd.sb_state & SBS_CANTSENDMORE) || so->so_error) {
if (so->so_snd.sb_state & SBS_CANTSENDMORE) {
error = EPIPE;
@ -2010,6 +2023,7 @@ do_sendfile(struct thread *td, struct sendfile_args *uap, int compat)
}
m_freem(m);
sbunlock(&so->so_snd);
SOCKBUF_UNLOCK(&so->so_snd);
splx(s);
goto done;
}
@ -2022,6 +2036,7 @@ do_sendfile(struct thread *td, struct sendfile_args *uap, int compat)
if (so->so_state & SS_NBIO) {
m_freem(m);
sbunlock(&so->so_snd);
SOCKBUF_UNLOCK(&so->so_snd);
splx(s);
error = EAGAIN;
goto done;
@ -2035,20 +2050,26 @@ do_sendfile(struct thread *td, struct sendfile_args *uap, int compat)
if (error) {
m_freem(m);
sbunlock(&so->so_snd);
SOCKBUF_UNLOCK(&so->so_snd);
splx(s);
goto done;
}
goto retry_space;
}
SOCKBUF_UNLOCK(&so->so_snd);
error = (*so->so_proto->pr_usrreqs->pru_send)(so, 0, m, 0, 0, td);
splx(s);
if (error) {
SOCKBUF_LOCK(&so->so_snd);
sbunlock(&so->so_snd);
SOCKBUF_UNLOCK(&so->so_snd);
goto done;
}
headersent = 1;
}
SOCKBUF_LOCK(&so->so_snd);
sbunlock(&so->so_snd);
SOCKBUF_UNLOCK(&so->so_snd);
/*
* Send trailers. Wimp out and use writev(2).