Hi, I found a bug on CPU hotplug. If oprofile is running, CPU hot remove causes system hang. I only confirm that this problem occurs on my ia64 box. I'm glad if someone report about other arch.
How to reproduce ================ 1) start oprofile # opcontrol --start 2) offline a CPU. # echo 0 >/sys/devices/system/cpu/cpu1/online Expected Result =============== Succeed to remove CPU Actual Result ============= See the following console log. # opcontrol --start Detected stale lock file. Removing. Using 2.6+ OProfile kernel interface. Reading module info. Running perfmon child on CPU0. Waiting on CPU0 Perfmon child up on CPU0 Running perfmon child on CPU1. Waiting on CPU1 Perfmon child up on CPU1 Running perfmon child on CPU2. Waiting on CPU2 Perfmon child up on CPU2 Running perfmon child on CPU3. Waiting on CPU3 Perfmon child up on CPU3 Running perfmon child on CPU4. Waiting on CPU4 Perfmon child up on CPU4 Running perfmon child on CPU5. Waiting on CPU5 Perfmon child up on CPU5 Running perfmon child on CPU6. Waiting on CPU6 Perfmon child up on CPU6 Running perfmon child on CPU7. Waiting on CPU7 Perfmon child up on CPU7 Using log file /var/lib/oprofile/oprofiled.log Daemon started. PFM_START on CPU1 PFM_START on CPU4 PFM_START on CPU0 Profiler running. PFM_START on CPU3 PFM_START on CPU5 PFM_START on CPU2 PFM_START on CPU7 PFM_START on CPU6 # echo 0 >/sys/devices/system/cpu/cpu1/online <SYSTEM HANG UP here!> Thanks, Satoru - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
