Hi! I crashed my RedHat Linux 7.1 box once when viewing one of my handwritten web pages, and after some debugging is seems that bad html on Mozilla starts xfs font server spinning out of control. xfs eats all CPU time and memory after opening the page with Mozilla, which seems to be asking for larger and larger fonts.
Perhaps someone from xfree or mozilla lists can debug the details. There is a bug in Mozilla when viewing this kind of page, but xfs still should not go crazy. I did not have time to install newer versions of Xfree, but at least http://www.xfree.org/security/ does not show a fix for this. Linux setup: $ uname -a Linux lnx 2.4.2-2 #1 Sun Apr 8 20:41:30 EDT 2001 i686 unknown $ X -version XFree86 Version 4.0.3 / X Window System (protocol Version 11, revision 0, vendor release 6400) Release Date: 16 March 2001 If the server is older than 6-12 months, or if your card is newer than the above date, look for a newer version before reporting problems. (See http://www.XFree86.Org/FAQ) Operating System: Linux 2.2.17-8smp i686 [ELF] Module Loader present $ mozilla -version Mozilla/5.0 (X11; U; Linux i686; en-US; rv:0.9.6) Gecko/20011120, build 2001112012 $ mozilla -version Mozilla/5.0 (X11; N; Linux 2.4.2-2 i686), build 2001031614 The 'not-that-bad' html page: $ perl -e 'print "<HTML>" x 1; print "<BODY>" x 1;print "<CENTER><P><H3>A" x 100; print "</BODY>" x 1;print "</HTML>" x 1' top log: <snip> 4:07pm up 23:08, 6 users, load average: 0.02, 0.06, 0.02 1 processes: 1 sleeping, 0 running, 0 zombie, 0 stopped CPU states: 2.7% user, 0.8% system, 0.0% nice, 44.8% idle Mem: 125640K av, 122956K used, 2684K free, 0K shrd, 1604K buff Swap: 208804K av, 99844K used, 108960K free 64972K cached PID USER PRI NI SIZE RSS SHARE STAT %CPU %MEM TIME COMMAND 1208 xfs 9 0 73100 27M 20948 S 0.0 22.4 17:18 xfs 1208 xfs 9 0 73100 27M 20948 S 0.0 22.4 17:18 xfs 1208 xfs 17 0 73100 30M 23816 D 45.3 24.5 17:19 xfs 1208 xfs 17 0 73100 27M 24080 D 30.0 22.1 17:20 xfs 1208 xfs 15 0 73056 31M 29092 D 15.1 25.7 17:20 xfs 1208 xfs 15 0 73056 34M 32284 D 12.1 28.3 17:20 xfs 1208 xfs 17 0 73056 39M 37056 D 6.6 32.1 17:20 xfs 1208 xfs 17 0 73056 42M 39852 D 2.4 34.3 17:20 xfs 4:08pm up 23:09, 6 users, load average: 0.54, 0.16, 0.05 1 processes: 1 sleeping, 0 running, 0 zombie, 0 stopped CPU states: 4.3% user, 7.1% system, 0.0% nice, 88.5% idle Mem: 125640K av, 122436K used, 3204K free, 0K shrd, 404K buff Swap: 208804K av, 114312K used, 94492K free 63136K cached PID USER PRI NI SIZE RSS SHARE STAT %CPU %MEM TIME COMMAND 1208 xfs 17 0 73056 45M 43728 D 5.7 37.4 17:21 xfs <had to killall mozilla-bin to avoid out-of-mem, snip> It seems that neither xfs nor Mozilla have any real security holes, since Mozilla only asks for larger and larger fonts. However, this is way too easy to reproduce, and when the xfs dies the whole X session becomes unstable... Regards, -Mikko
