Re: [PATCH] tracing: Fix missing errno when zero parser->idx in trace_pid_write

[kernel test robot <oliver.sang@intel.com>]

Hello,

kernel test robot noticed "perf-sanity-tests.perf_ftrace_tests.fail" on:

commit: cebdd2c9a622becc41349f32ace1795d750beda8 ("[PATCH] tracing: Fix missing errno when zero parser->idx in trace_pid_write")
url: https://github.com/intel-lab-lkp/linux/commits/Pu-Lehui/tracing-Fix-missing-errno-when-zero-parser-idx-in-trace_pid_write/20250821-151736
base: https://git.kernel.org/cgit/linux/kernel/git/trace/linux-trace for-next
patch link: https://lore.kernel.org/all/20250821071721.3609109-1-pulehui@huaweicloud.com/
patch subject: [PATCH] tracing: Fix missing errno when zero parser->idx in trace_pid_write

in testcase: perf-sanity-tests
version: 
with following parameters:

	perf_compiler: gcc
	group: group-01


config: x86_64-rhel-9.4-bpf
compiler: gcc-12
test machine: 20 threads 1 sockets (Commet Lake) with 16G memory

(please refer to attached dmesg/kmsg for entire log/backtrace)



If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <oliver.sang@intel.com>
| Closes: https://lore.kernel.org/oe-lkp/202509022339.ae20a8bb-lkp@intel.com


The kernel config and materials to reproduce are available at:
https://download.01.org/0day-ci/archive/20250902/202509022339.ae20a8bb-lkp@intel.com


2025-08-31 21:12:04 sudo /usr/src/linux-perf-x86_64-rhel-9.4-bpf-cebdd2c9a622becc41349f32ace1795d750beda8/tools/perf/perf test 83 -v
 83: perf ftrace tests                                               : Running (1 active)
--- start ---
test child forked, pid 10325
perf ftrace list test
syscalls for sleep:
__ia32_sys_nanosleep
__x64_sys_nanosleep
__x64_sys_clock_nanosleep
__ia32_sys_clock_nanosleep
perf ftrace list test  [Success]
perf ftrace trace test
failed to reset ftrace
---- end(-1) ----
 83: perf ftrace tests                                               : FAILED!

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