Hi, Any thoughts: I observe the same issue even with CONFIG_PREEMPT and CONFIG_PREEMPT_COUNT -Vineet On 03/30/2013 06:05 PM, Vineet Gupta wrote: > Hi, > > I've been stress testing ARC Linux 3.8 (same happens for 3.9-rc3 as well). The > setup has 3 telnet sessions, each running find . -name "*" in a loop. > The platform is a FPGA @ 80 MHz, running a single core ARC700 so kernel .config > has !SMP and PREEMPT_NONE. > > After ~10 mins of run, I see that one of the telnet session gets stuck (and later > the 2nd one as well), while system is still alive, 3rd telnet is running find merrily. > > [ARCLinux]$ ps > .... > 7 root 0:00 inetd > 62 root 0:00 -/bin/sh > 64 root 1:34 telnetd -i -l /bin/sh > 65 root 0:00 /bin/sh > 75 root 1:47 telnetd -i -l /bin/sh > 76 root 0:00 /bin/sh > 79 root 0:53 telnetd -i -l /bin/sh > 80 root 0:00 /bin/sh > 281 root 0:00 find / -name * <--- stuck > 358 root 0:03 find / -name * <--- stuck > 377 root 0:00 find / -name * > 378 root 0:00 ps > > Hung find task is sitting in the schedule() call in n_tty_write() > > [ARCLinux]$ cat /proc/281/stack > [<8065945e>] n_tty_write+0x23a/0x424 > [<80655cd4>] tty_write+0x1ac/0x2d4 > [<805976ba>] vfs_write+0x92/0x110 > [<80597816>] sys_write+0x4e/0x88 > [<8050e780>] ret_from_system_call+0x0/0x4 > > This task never resumes out of schedule() - verified by putting a hardware > breakpoint on next insn - using a JTAG host debugger. > > Attached are .config, /proc/281/sched, /proc/schedstat, /proc/sched_debug > > My knowledge of schedular is close to none, hence any tips to debug this further > would be much appreciated. > > > TIA, > -Vineet > -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
