Author: hselasky Date: Fri May 8 16:19:01 2015 New Revision: 282645 URL: https://svnweb.freebsd.org/changeset/base/282645
Log: Prevent switching to NULL or own window in the "vt_proc_window_switch" function. This fixes an issue where X11 keyboard input can appear stuck. The cause of the problem is a duplicate TTY device window switch IOCTL during boot, which leaves the "vt_switch_timer" running, because the current window is already selected. While at it factor out some NULL checks. PR: 200032 Differential Revision: https://reviews.freebsd.org/D2480 Reported by: several people MFC after: 1 week Reviewed by: emaste Modified: head/sys/dev/vt/vt_core.c Modified: head/sys/dev/vt/vt_core.c ============================================================================== --- head/sys/dev/vt/vt_core.c Fri May 8 16:18:11 2015 (r282644) +++ head/sys/dev/vt/vt_core.c Fri May 8 16:19:01 2015 (r282645) @@ -451,12 +451,35 @@ vt_proc_window_switch(struct vt_window * struct vt_device *vd; int ret; + /* Prevent switching to NULL */ + if (vw == NULL) { + DPRINTF(30, "%s: Cannot switch: vw is NULL.", __func__); + return (EINVAL); + } vd = vw->vw_device; curvw = vd->vd_curwindow; + /* Check if virtual terminal is locked */ if (curvw->vw_flags & VWF_VTYLOCK) return (EBUSY); + /* Check if switch already in progress */ + if (curvw->vw_flags & VWF_SWWAIT_REL) { + /* Check if switching to same window */ + if (curvw->vw_switch_to == vw) { + DPRINTF(30, "%s: Switch in progress to same vw.", __func__); + return (0); /* success */ + } + DPRINTF(30, "%s: Switch in progress to different vw.", __func__); + return (EBUSY); + } + + /* Avoid switching to already selected window */ + if (vw == curvw) { + DPRINTF(30, "%s: Cannot switch: vw == curvw.", __func__); + return (0); /* success */ + } + /* Ask current process permission to switch away. */ if (curvw->vw_smode.mode == VT_PROCESS) { DPRINTF(30, "%s: VT_PROCESS ", __func__); @@ -664,8 +687,7 @@ vt_scrollmode_kbdevent(struct vt_window if (console == 0) { if (c >= F_SCR && c <= MIN(L_SCR, F_SCR + VT_MAXWINDOWS - 1)) { vw = vd->vd_windows[c - F_SCR]; - if (vw != NULL) - vt_proc_window_switch(vw); + vt_proc_window_switch(vw); return; } VT_LOCK(vd); @@ -750,8 +772,7 @@ vt_processkey(keyboard_t *kbd, struct vt if (c >= F_SCR && c <= MIN(L_SCR, F_SCR + VT_MAXWINDOWS - 1)) { vw = vd->vd_windows[c - F_SCR]; - if (vw != NULL) - vt_proc_window_switch(vw); + vt_proc_window_switch(vw); return (0); } @@ -760,15 +781,13 @@ vt_processkey(keyboard_t *kbd, struct vt /* Switch to next VT. */ c = (vw->vw_number + 1) % VT_MAXWINDOWS; vw = vd->vd_windows[c]; - if (vw != NULL) - vt_proc_window_switch(vw); + vt_proc_window_switch(vw); return (0); case PREV: /* Switch to previous VT. */ c = (vw->vw_number - 1) % VT_MAXWINDOWS; vw = vd->vd_windows[c]; - if (vw != NULL) - vt_proc_window_switch(vw); + vt_proc_window_switch(vw); return (0); case SLK: { vt_save_kbd_state(vw, kbd); @@ -2774,8 +2793,7 @@ vt_resume(struct vt_device *vd) if (vt_suspendswitch == 0) return; - /* Switch back to saved window */ - if (vd->vd_savedwindow != NULL) - vt_proc_window_switch(vd->vd_savedwindow); + /* Switch back to saved window, if any */ + vt_proc_window_switch(vd->vd_savedwindow); vd->vd_savedwindow = NULL; } _______________________________________________ [email protected] mailing list http://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "[email protected]"
