| 113 | | <important> |
| 114 | | |
| 115 | | <para>When Udev is started by the LFS-Bootscripts, a replay of all kernel |
| 116 | | device events happens. These events tell Udev what devices exist. |
| 117 | | Sometimes the Udev bootscript doesn't wait long enough for |
| 118 | | <command>udevd</command> to process all of the replayed events and |
| 119 | | consequently the devices for those missed events are not created before the |
| 120 | | script exits. Since <command>udevd</command> is still running in the |
| 121 | | background, the devices will be created a few milliseconds later, but the |
| 122 | | next bootscript to run may require a device to exist before it has been |
| 123 | | created. To avoid such missed events, and to avoid hardcoding an overly |
| 124 | | long wait time, It is recommended that you run the following commands to |
| 125 | | aid the LFS development team in debugging these missed events and finding |
| 126 | | an acceptable solution more quickly.</para> |
| 127 | | |
| 128 | | <para>First, create a simple C file:</para> |
| 129 | | |
| 130 | | <screen><userinput>cat > bug.c << EOF |
| 131 | | <literal>/* Simple event recorder */ |
| 132 | | #define _GNU_SOURCE |
| 133 | | #include <sys/types.h> |
| 134 | | #include <sys/stat.h> |
| 135 | | #include <fcntl.h> |
| 136 | | #include <unistd.h> |
| 137 | | #include <stdlib.h> |
| 138 | | #include <argz.h> |
| 139 | | int main(int argc, char * argv[]) |
| 140 | | { |
| 141 | | char * envar; |
| 142 | | char * envz; |
| 143 | | size_t len; |
| 144 | | int bug; |
| 145 | | bug = open("/dev/bug", O_WRONLY | O_APPEND); |
| 146 | | if (bug == -1) |
| 147 | | return 0; |
| 148 | | |
| 149 | | /* Ignore everything USB-related to avoid spamming the list */ |
| 150 | | envar = getenv("PHYSDEVPATH"); |
| 151 | | if (envar && strstr(envar, "usb")) |
| 152 | | return 0; |
| 153 | | envar = getenv("DEVPATH"); |
| 154 | | if (envar && strstr(envar, "usb")) |
| 155 | | return 0; |
| 156 | | |
| 157 | | setenv("_SEPARATOR", "-------------------------------", 1); |
| 158 | | argz_create(environ, &envz, &len); |
| 159 | | argz_stringify(envz, len, '\n'); |
| 160 | | envz[len-1]='\n'; |
| 161 | | write(bug, envz, len); |
| 162 | | close(bug); |
| 163 | | free(envz); |
| 164 | | return 0; |
| 165 | | }</literal> |
| 166 | | EOF</userinput></screen> |
| 167 | | |
| 168 | | <para>Now compile it:</para> |
| 169 | | |
| 170 | | <screen><userinput>gcc -o /lib/udev/bug bug.c</userinput></screen> |
| 171 | | |
| 172 | | <para>When booting the new LFS system, if any events are missed, a warning |
| 173 | | message will appear and a <filename>/dev/bugreport</filename> file will be |
| 174 | | created. The warning message will tell you where to send feedback.</para> |
| 175 | | |
| 176 | | </important> |
| 177 | | |
