]> git.ipfire.org Git - thirdparty/kernel/linux.git/commit
perf trace: Skip internal syscall arguments
authorNamhyung Kim <namhyung@kernel.org>
Thu, 27 Nov 2025 04:44:18 +0000 (20:44 -0800)
committerNamhyung Kim <namhyung@kernel.org>
Sat, 29 Nov 2025 20:23:37 +0000 (12:23 -0800)
commit267c2e633af6e9461477bed91e428993f8b36ee8
tree1b7a9be787ffb8fa97c84d4d0f8fdfe0ffef6213
parent834ebb5678d75d844f5d4f44ede78724d8c96630
perf trace: Skip internal syscall arguments

Recent changes in the linux-next kernel will add new field for syscalls
to have contents in the userspace like below.

  # cat /sys/kernel/tracing/events/syscalls/sys_enter_write/format
  name: sys_enter_write
  ID: 758
  format:
          field:unsigned short common_type;       offset:0;       size:2; signed:0;
          field:unsigned char common_flags;       offset:2;       size:1; signed:0;
          field:unsigned char common_preempt_count;       offset:3;       size:1; signed:0;
          field:int common_pid;   offset:4;       size:4; signed:1;

          field:int __syscall_nr; offset:8;       size:4; signed:1;
          field:unsigned int fd;  offset:16;      size:8; signed:0;
          field:const char * buf; offset:24;      size:8; signed:0;
          field:size_t count;     offset:32;      size:8; signed:0;
          field:__data_loc char[] __buf_val;      offset:40;      size:4; signed:0;

  print fmt: "fd: 0x%08lx, buf: 0x%08lx (%s), count: 0x%08lx", ((unsigned long)(REC->fd)),
             ((unsigned long)(REC->buf)), __print_dynamic_array(__buf_val, 1),
             ((unsigned long)(REC->count))

We have a different way to handle those arguments and this change
confuses perf trace then make some tests failing.  Fix it by skipping
the new fields that have "__data_loc char[]" type.

Maybe we can switch to this instead of the BPF augmentation later.

Reviewed-by: Howard Chu <howardchu95@gmail.com>
Tested-by: Thomas Richter <tmricht@linux.ibm.com>
Tested-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Howard Chu <howardchu95@gmail.com>
Reported-by: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
tools/perf/builtin-trace.c