Description of problem: SCHED_FIFO program that is in a constant loop seems to freeze the system till it is done, or if it is infinite loop system has to be rebotted even when running the shell at the highest priority. Version-Release number of selected component (if applicable): I am using glibc-2.3.2-27.9 on readhat 9, kernel version 2.4.20-18.9 How reproducible: Always Steps to Reproduce: 1. get schedutils package if you don't have already to get chrt program to change real time priority 2.gcc sched_test.c -o sched_test 4. run the shell at highest priority chrt -f -p 99 pidofshell 3.chrt -f 10 sched_test time_to_sleep& /sched_test.c/ #include <sys/time.h> #include <time.h> #include <stdlib.h> #include <stdio.h> #include <unistd.h> int main(int argc, char *argv[]) { int end_time; struct timeval now; if (argc < 2) { end_time = 1; } else { end_time = atoi(argv[1]); } gettimeofday(&now, NULL); end_time += now.tv_sec + 1; do{ gettimeofday(&now, NULL); }while (now.tv_sec < end_time); printf("bye now.\n"); return 0; } Actual results: system freezes till the sleep_time is done in the sched_test program. Expected results: be able to stop program as the shell is running at high priority Additional info: No keyboard input is displayed though it will be displayed once the program is done, showing that the keyboard interrupts handlers are working but some kind of priority inversion seems to be in effect as X is somehow involved. And based on the discussion I found at this site http://www.ussg.iu.edu/hypermail/linux/kernel/0306.2/0635.html I tried to raise the priority of the keventd to 99 , sched_fifo but still I get no change. Books and man pages on real time scheduling just mention that running a shell of max priority will take care of lower priority real time threads that have run wild. I have also tried it with Fedora test2 distribution based on kernel 2.6 with the same effect. Also the kernel fix that was mentioned in the http://www.ussg.iu.edu/hypermail/linux/kernel/0306.2/0986.html doesn't seem to help.
Thanks for the bug report. However, Red Hat no longer maintains this version of the product. Please upgrade to the latest version and open a new bug if the problem persists. The Fedora Legacy project (http://fedoralegacy.org/) maintains some older releases, and if you believe this bug is interesting to them, please report the problem in the bug tracker at: http://bugzilla.fedora.us/