[BUG] two missing states in sepoll transition matrix

Two states were missing in the speculative epoll state transition
matrix. This could cause some timeouts and unhandled events. The
problem showed up in TCP mode with a fast server at high session
rates, but could in theory also affect HTTP mode.

diff --git a/src/ev_sepoll.c b/src/ev_sepoll.c
index 74917add8e9c0d83650d94a77f8d921bced75b36..c3b777647e265ce4789152a5ce759a4860166729 100644 (file)
--- a/src/ev_sepoll.c
+++ b/src/ev_sepoll.c
@@ -232,10 +232,16 @@ REGPRM1 static void __fd_clo(int fd)
        fd_list[fd].e &= ~(FD_EV_MASK);
 }
 
+/*
+ * operations to perform when reaching _do_poll() for some FDs in the spec
+ * queue depending on their state. This is mainly used to cleanup some FDs
+ * which are in STOP state. It is also used to compute EPOLL* flags when
+ * switching from SPEC to WAIT.
+ */
 static struct ev_to_epoll {
        char op;        // epoll opcode to switch from spec to wait, 0 if none
        char m;         // inverted mask for existing events
-       char ev;        // remainint epoll events after change
+       char ev;        // remaining epoll events after change
        char pad;
 } ev_to_epoll[16] = {
        [FD_EV_IDLE_W | FD_EV_STOP_R] = { .op=EPOLL_CTL_DEL, .m=FD_EV_MASK_R },
@@ -245,6 +251,8 @@ static struct ev_to_epoll {
        [FD_EV_WAIT_W | FD_EV_STOP_R] = { .op=EPOLL_CTL_MOD, .m=FD_EV_MASK_R, .ev=EPOLLOUT },
        [FD_EV_STOP_W | FD_EV_WAIT_R] = { .op=EPOLL_CTL_MOD, .m=FD_EV_MASK_W, .ev=EPOLLIN },
        [FD_EV_STOP_W | FD_EV_STOP_R] = { .op=EPOLL_CTL_DEL, .m=FD_EV_MASK_R|FD_EV_MASK_W },
+       [FD_EV_SPEC_W | FD_EV_WAIT_R] = { .ev=EPOLLIN },
+       [FD_EV_WAIT_W | FD_EV_SPEC_R] = { .ev=EPOLLOUT },
        [FD_EV_WAIT_W | FD_EV_WAIT_R] = { .ev=EPOLLIN|EPOLLOUT },
 };
 
@@ -274,10 +282,10 @@ REGPRM2 static void _do_poll(struct poller *p, int wait_time)
 
                opcode = ev_to_epoll[fd_list[fd].e].op;
                if (opcode) {
-                       ev.events  = ev_to_epoll[fd_list[fd].e].ev;
                        ev.data.fd = fd;
-                       epoll_ctl(epoll_fd, opcode, fd, &ev);
+                       ev.events  = ev_to_epoll[fd_list[fd].e].ev;
                        fd_list[fd].e &= ~(unsigned int)ev_to_epoll[fd_list[fd].e].m;
+                       epoll_ctl(epoll_fd, opcode, fd, &ev);
                }
 
                if (!(fd_list[fd].e & FD_EV_RW_SL)) {