Below is the backport to 5.10 and 5.4.
-- Steve
------------------ original commit in Linus's tree ------------------
From ab8384442ee512fc0fc72deeb036110843d0e7ff Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (Google)" rostedt@goodmis.org Date: Sat, 20 Aug 2022 09:43:21 -0400 Subject: [PATCH] tracing/probes: Have kprobes and uprobes use $COMM too
Both $comm and $COMM can be used to get current->comm in eprobes and the filtering and histogram logic. Make kprobes and uprobes consistent in this regard and allow both $comm and $COMM as well. Currently kprobes and uprobes only handle $comm, which is inconsistent with the other utilities, and can be confusing to users.
Link: https://lkml.kernel.org/r/20220820134401.317014913@goodmis.org Link: https://lore.kernel.org/all/20220820220442.776e1ddaf8836e82edb34d01@kernel.o...
Cc: stable@vger.kernel.org Cc: Ingo Molnar mingo@kernel.org Cc: Andrew Morton akpm@linux-foundation.org Cc: Tzvetomir Stoyanov tz.stoyanov@gmail.com Cc: Tom Zanussi zanussi@kernel.org Fixes: 533059281ee5 ("tracing: probeevent: Introduce new argument fetching code") Suggested-by: Masami Hiramatsu (Google) mhiramat@kernel.org Acked-by: Masami Hiramatsu (Google) mhiramat@kernel.org Signed-off-by: Steven Rostedt (Google) rostedt@goodmis.org
--- kernel/trace/trace_probe.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
Index: linux-test.git/kernel/trace/trace_probe.c =================================================================== --- linux-test.git.orig/kernel/trace/trace_probe.c 2022-08-22 11:11:31.068828616 -0400 +++ linux-test.git/kernel/trace/trace_probe.c 2022-08-22 11:13:36.916829113 -0400 @@ -300,7 +300,7 @@ static int parse_probe_vars(char *arg, c } } else goto inval_var; - } else if (strcmp(arg, "comm") == 0) { + } else if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) { code->op = FETCH_OP_COMM; #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API } else if (((flags & TPARG_FL_MASK) == @@ -595,7 +595,8 @@ static int traceprobe_parse_probe_arg_bo * Since $comm and immediate string can not be dereferred, * we can find those by strcmp. */ - if (strcmp(arg, "$comm") == 0 || strncmp(arg, "\"", 2) == 0) { + if (strcmp(arg, "$comm") == 0 || strcmp(arg, "$COMM") == 0 || + strncmp(arg, "\"", 2) == 0) { /* The type of $comm must be "string", and not an array. */ if (parg->count || (t && strcmp(t, "string"))) return -EINVAL;