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authorwanghanlin <wanghanlin@corp.netease.com>2020-12-28 16:19:05 +0800
committerFlorin Coras <florin.coras@gmail.com>2021-01-11 19:50:47 +0000
commitdcacdc4fd90d6cc71aaafccbca3ea91c7481ddbd (patch)
tree9b7abc60a57e8d0640027d15e3584fe413c79b79 /src/vcl
parent56177e64b620b93d3d935cd1f1663e2f7f1e5592 (diff)
vcl: fix deadlock in rpc
Worker thread A send rpc to worker thread B with vls_table_lock when worker thread B try to lock vls_table_lock, so unlock it temporarily. Add worker_rpc_lock to synchronize rpc message among workers to prevent waiting for each other deadly. Add timeout for rpc response to prevent hanging when VPP exit/crash. Type: fix Signed-off-by: wanghanlin <wanghanlin@corp.netease.com> Change-Id: I675f1fe76673ede09107f6eeaaa0eda8bbfc6e61
Diffstat (limited to 'src/vcl')
-rw-r--r--src/vcl/vcl_locked.c204
-rw-r--r--src/vcl/vcl_locked.h1
2 files changed, 134 insertions, 71 deletions
diff --git a/src/vcl/vcl_locked.c b/src/vcl/vcl_locked.c
index f3136f9d2ae..5011461596b 100644
--- a/src/vcl/vcl_locked.c
+++ b/src/vcl/vcl_locked.c
@@ -63,10 +63,19 @@ typedef struct vls_main_
/** Pool of data shared by sessions owned by different workers */
vls_shared_data_t *shared_data_pool;
clib_rwlock_t shared_data_lock;
+ /** Lock to protect rpc among workers */
+ clib_spinlock_t worker_rpc_lock;
} vls_main_t;
vls_main_t *vlsm;
+typedef enum
+{
+ VLS_RPC_STATE_INIT,
+ VLS_RPC_STATE_SUCCESS,
+ VLS_RPC_STATE_SESSION_NOT_EXIST,
+} vls_rpc_state_e;
+
typedef enum vls_rpc_msg_type_
{
VLS_RPC_CLONE_AND_SHARE,
@@ -97,13 +106,11 @@ typedef struct vls_sess_cleanup_msg_
void vls_send_session_cleanup_rpc (vcl_worker_t * wrk,
u32 dst_wrk_index, u32 dst_session_index);
-void vls_send_clone_and_share_rpc (vcl_worker_t * wrk,
- vcl_locked_session_t * vls,
+void vls_send_clone_and_share_rpc (vcl_worker_t *wrk, u32 origin_vls_index,
u32 session_index, u32 vls_wrk_index,
u32 dst_wrk_index, u32 dst_vls_index,
u32 dst_session_index);
-
static inline u32
vls_get_worker_index (void)
{
@@ -849,12 +856,12 @@ vls_mt_session_should_migrate (vcl_locked_session_t * vls)
&& vls->worker_index != vcl_get_worker_index ());
}
-static void
-vls_mt_session_migrate (vcl_locked_session_t * vls)
+static vcl_locked_session_t *
+vls_mt_session_migrate (vcl_locked_session_t *vls)
{
u32 wrk_index = vcl_get_worker_index ();
vcl_worker_t *wrk;
- u32 src_sid, sid;
+ u32 src_sid, sid, vls_index, own_vcl_wrk_index;
vcl_session_t *session;
uword *p;
@@ -868,7 +875,7 @@ vls_mt_session_migrate (vcl_locked_session_t * vls)
{
vls->worker_index = wrk_index;
vls->session_index = (u32) p[0];
- return;
+ return vls;
}
/*
@@ -881,40 +888,68 @@ vls_mt_session_migrate (vcl_locked_session_t * vls)
{
VERR ("session in owner worker(%u) is free", vls->owner_vcl_wrk_index);
ASSERT (0);
- return;
+ vls_unlock (vls);
+ vls_mt_table_runlock ();
+ return 0;
}
src_sid = (u32) p[0];
wrk = vcl_worker_get_current ();
session = vcl_session_alloc (wrk);
sid = session->session_index;
- vls_send_clone_and_share_rpc (wrk, vls, sid, vls_get_worker_index (),
- vls->owner_vcl_wrk_index, vls->vls_index,
- src_sid);
- session->session_index = sid;
- vls->worker_index = wrk_index;
- vls->session_index = sid;
- hash_set (vls->vcl_wrk_index_to_session_index, wrk_index, sid);
VDBG (1, "migrate session of worker (session): %u (%u) -> %u (%u)",
vls->owner_vcl_wrk_index, src_sid, wrk_index, sid);
- if (PREDICT_FALSE ((session->flags & VCL_SESSION_F_IS_VEP)
- && session->vep.next_sh != ~0))
+ /* Drop lock to prevent dead lock when dst wrk trying to get lock. */
+ vls_index = vls->vls_index;
+ own_vcl_wrk_index = vls->owner_vcl_wrk_index;
+ vls_unlock (vls);
+ vls_mt_table_runlock ();
+ vls_send_clone_and_share_rpc (wrk, vls_index, sid, vls_get_worker_index (),
+ own_vcl_wrk_index, vls_index, src_sid);
+
+ if (PREDICT_FALSE (wrk->rpc_done == VLS_RPC_STATE_SESSION_NOT_EXIST))
+ {
+ VWRN ("session %u not exist", src_sid);
+ goto err;
+ }
+ else if (PREDICT_FALSE (wrk->rpc_done == VLS_RPC_STATE_INIT))
+ {
+ VWRN ("failed to wait rpc response");
+ goto err;
+ }
+ else if (PREDICT_FALSE ((session->flags & VCL_SESSION_F_IS_VEP) &&
+ session->vep.next_sh != ~0))
{
- /* TODO: rollback? */
VERR ("can't migrate nonempty epoll session");
ASSERT (0);
- return;
+ goto err;
}
else if (PREDICT_FALSE (!(session->flags & VCL_SESSION_F_IS_VEP) &&
session->session_state != VCL_STATE_CLOSED))
{
- /* TODO: rollback? */
VERR ("migrate NOT supported, session_status (%u)",
session->session_state);
ASSERT (0);
- return;
+ goto err;
}
+
+ vls = vls_get_w_dlock (vls_index);
+ if (PREDICT_FALSE (!vls))
+ {
+ VWRN ("failed to get vls %u", vls_index);
+ goto err;
+ }
+
+ session->session_index = sid;
+ vls->worker_index = wrk_index;
+ vls->session_index = sid;
+ hash_set (vls->vcl_wrk_index_to_session_index, wrk_index, sid);
+ return vls;
+
+err:
+ vcl_session_free (wrk, session);
+ return 0;
}
static inline void
@@ -924,20 +959,24 @@ vls_mt_detect (void)
vls_mt_add ();
}
-#define vls_mt_guard(_vls, _op) \
- int _locks_acq = 0; \
- if (vls_mt_wrk_supported ()) \
- { \
- if (PREDICT_FALSE (_vls \
- && ((vcl_locked_session_t *)_vls)->worker_index != \
- vcl_get_worker_index ())) \
- vls_mt_session_migrate (_vls); \
- } \
- else \
- { \
- if (PREDICT_FALSE (vlsl->vls_mt_n_threads > 1)) \
- vls_mt_acq_locks (_vls, _op, &_locks_acq); \
- } \
+#define vls_mt_guard(_vls, _op) \
+ int _locks_acq = 0; \
+ if (vls_mt_wrk_supported ()) \
+ { \
+ if (PREDICT_FALSE (_vls && \
+ ((vcl_locked_session_t *) _vls)->worker_index != \
+ vcl_get_worker_index ())) \
+ { \
+ _vls = vls_mt_session_migrate (_vls); \
+ if (PREDICT_FALSE (!_vls)) \
+ return VPPCOM_EBADFD; \
+ } \
+ } \
+ else \
+ { \
+ if (PREDICT_FALSE (vlsl->vls_mt_n_threads > 1)) \
+ vls_mt_acq_locks (_vls, _op, &_locks_acq); \
+ }
#define vls_mt_unguard() \
if (PREDICT_FALSE (_locks_acq)) \
@@ -1037,7 +1076,11 @@ vls_attr (vls_handle_t vlsh, uint32_t op, void *buffer, uint32_t * buflen)
if (!(vls = vls_get_w_dlock (vlsh)))
return VPPCOM_EBADFD;
if (vls_mt_session_should_migrate (vls))
- vls_mt_session_migrate (vls);
+ {
+ vls = vls_mt_session_migrate (vls);
+ if (PREDICT_FALSE (!vls))
+ return VPPCOM_EBADFD;
+ }
rv = vppcom_session_attr (vls_to_sh_tu (vls), op, buffer, buflen);
vls_get_and_unlock (vlsh);
return rv;
@@ -1162,9 +1205,10 @@ vls_create (uint8_t proto, uint8_t is_nonblocking)
{
vcl_session_handle_t sh;
vls_handle_t vlsh;
+ vcl_locked_session_t *vls = NULL;
vls_mt_detect ();
- vls_mt_guard (0, VLS_MT_OP_SPOOL);
+ vls_mt_guard (vls, VLS_MT_OP_SPOOL);
sh = vppcom_session_create (proto, is_nonblocking);
vls_mt_unguard ();
if (sh == INVALID_SESSION_ID)
@@ -1277,12 +1321,16 @@ vls_epoll_ctl (vls_handle_t ep_vlsh, int op, vls_handle_t vlsh,
vls_mt_detect ();
vls_mt_table_rlock ();
ep_vls = vls_get_and_lock (ep_vlsh);
- vls = vls_get_and_lock (vlsh);
if (vls_mt_session_should_migrate (ep_vls))
- vls_mt_session_migrate (ep_vls);
+ {
+ ep_vls = vls_mt_session_migrate (ep_vls);
+ if (PREDICT_FALSE (!ep_vls))
+ return VPPCOM_EBADFD;
+ }
ep_sh = vls_to_sh (ep_vls);
+ vls = vls_get_and_lock (vlsh);
sh = vls_to_sh (vls);
if (PREDICT_FALSE (!vlsl->epoll_mp_check))
@@ -1305,13 +1353,13 @@ int
vls_epoll_wait (vls_handle_t ep_vlsh, struct epoll_event *events,
int maxevents, double wait_for_time)
{
- vcl_locked_session_t *vls;
+ vcl_locked_session_t *vls, *vls_tmp = NULL;
int rv;
vls_mt_detect ();
if (!(vls = vls_get_w_dlock (ep_vlsh)))
return VPPCOM_EBADFD;
- vls_mt_guard (0, VLS_MT_OP_XPOLL);
+ vls_mt_guard (vls_tmp, VLS_MT_OP_XPOLL);
rv = vppcom_epoll_wait (vls_to_sh_tu (vls), events, maxevents,
wait_for_time);
vls_mt_unguard ();
@@ -1356,9 +1404,10 @@ vls_select (int n_bits, vcl_si_set * read_map, vcl_si_set * write_map,
vcl_si_set * except_map, double wait_for_time)
{
int rv;
+ vcl_locked_session_t *vls = NULL;
vls_mt_detect ();
- vls_mt_guard (0, VLS_MT_OP_XPOLL);
+ vls_mt_guard (vls, VLS_MT_OP_XPOLL);
if (PREDICT_FALSE (!vlsl->select_mp_check))
vls_select_mp_checks (read_map);
rv = vppcom_select (n_bits, read_map, write_map, except_map, wait_for_time);
@@ -1560,24 +1609,33 @@ vls_clone_and_share_rpc_handler (void *args)
vcl_worker_t *vcl_wrk = vcl_worker_get_current (), *dst_vcl_wrk;
vcl_session_t *s, *dst_s;
- vls = vls_session_get (wrk, msg->vls_index);
-
- if (!vls_mt_wrk_supported ())
- vls_init_share_session (wrk, vls);
+ VDBG (1, "process session clone of worker (session): %u (%u) -> %u (%u)",
+ vcl_wrk->wrk_index, msg->session_index, msg->origin_vcl_wrk,
+ msg->origin_session_index);
- s = vcl_session_get (vcl_wrk, msg->session_index);
- dst_wrk = vls_worker_get (msg->origin_vls_wrk);
+ /* VCL locked session can't been protected, so DONT touch it.
+ * VCL session may been free, check it.
+ */
dst_vcl_wrk = vcl_worker_get (msg->origin_vcl_wrk);
- dst_vls = vls_session_get (dst_wrk, msg->origin_vls_index);
- dst_vls->shared_data_index = vls->shared_data_index;
+ s = vcl_session_get (vcl_wrk, msg->session_index);
+ if (PREDICT_FALSE (!s))
+ {
+ dst_vcl_wrk->rpc_done = VLS_RPC_STATE_SESSION_NOT_EXIST;
+ return;
+ }
+
+ if (!vls_mt_wrk_supported ())
+ {
+ vls = vls_session_get (wrk, msg->vls_index);
+ vls_init_share_session (wrk, vls);
+ dst_wrk = vls_worker_get (msg->origin_vls_wrk);
+ dst_vls = vls_session_get (dst_wrk, msg->origin_vls_index);
+ dst_vls->shared_data_index = vls->shared_data_index;
+ }
dst_s = vcl_session_get (dst_vcl_wrk, msg->origin_session_index);
clib_memcpy (dst_s, s, sizeof (*s));
- dst_vcl_wrk->rpc_done = 1;
-
- VDBG (1, "proces session clone of worker (session): %u (%u) -> %u (%u)",
- vcl_wrk->wrk_index, msg->session_index, dst_vcl_wrk->wrk_index,
- msg->origin_session_index);
+ dst_vcl_wrk->rpc_done = VLS_RPC_STATE_SUCCESS;
}
static void
@@ -1585,14 +1643,12 @@ vls_session_cleanup_rpc_handler (void *args)
{
vls_sess_cleanup_msg_t *msg = (vls_sess_cleanup_msg_t *) args;
vcl_worker_t *wrk = vcl_worker_get_current ();
- vcl_worker_t *dst_wrk = vcl_worker_get (msg->origin_vcl_wrk);
+ vcl_session_handle_t sh = vcl_session_handle_from_index (msg->session_index);
- vppcom_session_close (vcl_session_handle_from_index (msg->session_index));
+ VDBG (1, "process session cleanup of worker (session): %u (%u) from %u ()",
+ wrk->wrk_index, msg->session_index, msg->origin_vcl_wrk);
- dst_wrk->rpc_done = 1;
-
- VDBG (1, "proces session cleanup of worker (session): %u (%u) from %u ()",
- wrk->wrk_index, msg->session_index, dst_wrk->wrk_index);
+ vppcom_session_close (sh);
}
static void
@@ -1613,34 +1669,42 @@ vls_rpc_handler (void *args)
}
void
-vls_send_clone_and_share_rpc (vcl_worker_t * wrk,
- vcl_locked_session_t * vls, u32 session_index,
- u32 vls_wrk_index, u32 dst_wrk_index,
- u32 dst_vls_index, u32 dst_session_index)
+vls_send_clone_and_share_rpc (vcl_worker_t *wrk, u32 origin_vls_index,
+ u32 session_index, u32 vls_wrk_index,
+ u32 dst_wrk_index, u32 dst_vls_index,
+ u32 dst_session_index)
{
u8 data[sizeof (u8) + sizeof (vls_clone_and_share_msg_t)];
vls_clone_and_share_msg_t *msg;
vls_rpc_msg_t *rpc;
int ret;
+ f64 timeout = clib_time_now (&wrk->clib_time) + VLS_WORKER_RPC_TIMEOUT;
rpc = (vls_rpc_msg_t *) & data;
rpc->type = VLS_RPC_CLONE_AND_SHARE;
msg = (vls_clone_and_share_msg_t *) & rpc->data;
msg->origin_vls_wrk = vls_wrk_index;
- msg->origin_vls_index = vls->vls_index;
+ msg->origin_vls_index = origin_vls_index;
msg->origin_vcl_wrk = wrk->wrk_index;
msg->origin_session_index = session_index;
msg->vls_index = dst_vls_index;
msg->session_index = dst_session_index;
- wrk->rpc_done = 0;
+ /* Try lock and handle rpcs if two threads send each other
+ * clone requests at the same time.
+ */
+ wrk->rpc_done = VLS_RPC_STATE_INIT;
+ while (!clib_spinlock_trylock (&vlsm->worker_rpc_lock))
+ vcl_flush_mq_events ();
ret = vcl_send_worker_rpc (dst_wrk_index, rpc, sizeof (data));
VDBG (1, "send session clone to wrk (session): %u (%u) -> %u (%u), ret=%d",
dst_wrk_index, msg->session_index, msg->origin_vcl_wrk,
msg->origin_session_index, ret);
- while (!ret && !wrk->rpc_done)
+ while (!ret && wrk->rpc_done == VLS_RPC_STATE_INIT &&
+ clib_time_now (&wrk->clib_time) < timeout)
;
+ clib_spinlock_unlock (&vlsm->worker_rpc_lock);
}
void
@@ -1658,13 +1722,10 @@ vls_send_session_cleanup_rpc (vcl_worker_t * wrk,
msg->origin_vcl_wrk = wrk->wrk_index;
msg->session_index = dst_session_index;
- wrk->rpc_done = 0;
ret = vcl_send_worker_rpc (dst_wrk_index, rpc, sizeof (data));
VDBG (1, "send session cleanup to wrk (session): %u (%u) from %u, ret=%d",
dst_wrk_index, msg->session_index, msg->origin_vcl_wrk, ret);
- while (!ret && !wrk->rpc_done)
- ;
}
int
@@ -1679,6 +1740,7 @@ vls_app_create (char *app_name)
clib_memset (vlsm, 0, sizeof (*vlsm));
clib_rwlock_init (&vlsm->vls_table_lock);
clib_rwlock_init (&vlsm->shared_data_lock);
+ clib_spinlock_init (&vlsm->worker_rpc_lock);
pool_alloc (vlsm->workers, vcm->cfg.max_workers);
pthread_atfork (vls_app_pre_fork, vls_app_fork_parent_handler,
diff --git a/src/vcl/vcl_locked.h b/src/vcl/vcl_locked.h
index 7cfb3bdc522..11b71eee4af 100644
--- a/src/vcl/vcl_locked.h
+++ b/src/vcl/vcl_locked.h
@@ -21,6 +21,7 @@
#include <vcl/vppcom.h>
#define VLS_INVALID_HANDLE ((int)-1)
+#define VLS_WORKER_RPC_TIMEOUT 3 /* timeout to wait rpc response. */
typedef int vls_handle_t;