On Mon, May 19, 2025 at 10:39:14AM -0400, Steven Rostedt wrote: > On Thu, 15 May 2025 02:21:13 +0530 > Vishal Chourasia <vish...@linux.ibm.com> wrote: > > > When running trace-cmd record, I encounter multiple "No such device" > > errors due to the splice syscall failing with ENODEV for > > /sys/kernel/tracing/per_cpu/cpuX/trace_pipe_raw files corresponding to > > CPUs that are possible but not present. > > > > Environment: > > - Operating System: Red Hat Enterprise Linux 9.5 (Plow) > > - Kernel: Linux 6.12.0-55.9.1.el10_0.ppc64le > > - Architecture: ppc64le > > - Command Executed: trace-cmd record -o /dev/null -v -e sched_switch -- > > sleep 1 > > - System CPU Configuration: > > - /sys/devices/system/cpu/possible: 0-223 > > - /sys/devices/system/cpu/present: 0-63 > > - /sys/kernel/tracing/per_cpu/: Contains directories cpu0 to cpu223 > > Thanks for the report. Could you also submit a bug report here: > > > https://bugzilla.kernel.org/buglist.cgi?component=Trace-cmd%2FKernelshark&list_id=1152443&product=Tools&resolution=--- https://bugzilla.kernel.org/show_bug.cgi?id=220139 > > > > > > Steps to Reproduce: > > 1. On a system with a mismatch between possible and present CPUs (e.g., > > possible: 0-223, present: 0-63). > > 2. Ensure /sys/kernel/tracing/per_cpu/ contains directories for all > > possible > > CPUs (e.g., cpu0 to cpu223). > > 3. Run the command: > > strace --decode-fds -kk -o strace/trace-cmd -ff -- trace-cmd record -o > > /dev/null -v -e sched_switch -- sleep 1 > > 4. Observe the output and strace logs. > > > > Expected Behavior: trace-cmd should only attempt to access > > trace_pipe_raw files for CPUs that are present (e.g., cpu0 to cpu63), > > completing the recording without errors. > > Can you show me what you see in /sys/kernel/tracing/tracing_cpumask $ sudo cat /sys/kernel/tracing/tracing_cpumask ffffffff,ffffffff,ffffffff,ffffffff,ffffffff,ffffffff,ffffffff > > Thanks, > > -- Steve Thanks,
Vishal
