[PATCH 1/1] perf trace: Mark the 'head' arg in the set_robust_list syscall as coming from user space

[Arnaldo Carvalho de Melo]

With that it uses the generic BTF based pretty printer:

This one we need to think about, not being acquainted with this syscall,
should we _traverse_ that list somehow? Would that be useful?

  root@number:~# perf trace -e set_robust_list sleep 1
       0.000 ( 0.004 ms): sleep/1206493 set_robust_list(head: (struct robust_list_head){.list = (struct robust_list){.next = (struct robust_list *)0x7f48a9a02a20,},.futex_offset = (long int)-32,}, len: 24) =
  root@number:~#

strace prints the default integer args:

  root@number:~# strace -e set_robust_list sleep 1
  set_robust_list(0x7efd99559a20, 24)     = 0
  +++ exited with 0 +++
  root@number:~#

Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Alan Maguire <alan.maguire@xxxxxxxxxx>
Cc: Howard Chu <howardchu95@xxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/perf/builtin-trace.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 27084ae38bc480c9..f6e8475290739a10 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -1351,6 +1351,8 @@ static const struct syscall_fmt syscall_fmts[] = {
 	{ .name	    = "sendto",
 	  .arg = { [3] = { .scnprintf = SCA_MSG_FLAGS, /* flags */ },
 		   [4] = SCA_SOCKADDR_FROM_USER(addr), }, },
+	{ .name	    = "set_robust_list",	    .errpid = true,
+	  .arg = { [0] = { .from_user = true /* head */, }, }, },
 	{ .name	    = "set_tid_address", .errpid = true, },
 	{ .name	    = "setitimer",
 	  .arg = { [0] = STRARRAY(which, itimers), }, },
-- 
2.46.0