From d157d7694460b9aa5b974c37b1ad5fb10c8f8b7c Mon Sep 17 00:00:00 2001 From: "Masami Hiramatsu (Google)" Date: Wed, 23 Aug 2023 01:26:22 +0900 Subject: tracing/probes: Support BTF field access from $retval Support BTF argument on '$retval' for function return events including kretprobe and fprobe for accessing the return value. This also allows user to access its fields if the return value is a pointer of a data structure. E.g. # echo 'f getname_flags%return +0($retval->name):string' \ > dynamic_events # echo 1 > events/fprobes/getname_flags__exit/enable # ls > /dev/null # head -n 40 trace | tail ls-87 [000] ...1. 8067.616101: getname_flags__exit: (vfs_fstatat+0x3c/0x70 <- getname_flags) arg1="./function_profile_enabled" ls-87 [000] ...1. 8067.616108: getname_flags__exit: (vfs_fstatat+0x3c/0x70 <- getname_flags) arg1="./trace_stat" ls-87 [000] ...1. 8067.616115: getname_flags__exit: (vfs_fstatat+0x3c/0x70 <- getname_flags) arg1="./set_graph_notrace" ls-87 [000] ...1. 8067.616122: getname_flags__exit: (vfs_fstatat+0x3c/0x70 <- getname_flags) arg1="./set_graph_function" ls-87 [000] ...1. 8067.616129: getname_flags__exit: (vfs_fstatat+0x3c/0x70 <- getname_flags) arg1="./set_ftrace_notrace" ls-87 [000] ...1. 8067.616135: getname_flags__exit: (vfs_fstatat+0x3c/0x70 <- getname_flags) arg1="./set_ftrace_filter" ls-87 [000] ...1. 8067.616143: getname_flags__exit: (vfs_fstatat+0x3c/0x70 <- getname_flags) arg1="./touched_functions" ls-87 [000] ...1. 8067.616237: getname_flags__exit: (vfs_fstatat+0x3c/0x70 <- getname_flags) arg1="./enabled_functions" ls-87 [000] ...1. 8067.616245: getname_flags__exit: (vfs_fstatat+0x3c/0x70 <- getname_flags) arg1="./available_filter_functions" ls-87 [000] ...1. 8067.616253: getname_flags__exit: (vfs_fstatat+0x3c/0x70 <- getname_flags) arg1="./set_ftrace_notrace_pid" Link: https://lore.kernel.org/all/169272158234.160970.2446691104240645205.stgit@devnote2/ Signed-off-by: Masami Hiramatsu (Google) Acked-by: Steven Rostedt (Google) --- kernel/trace/trace_probe.h | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel/trace/trace_probe.h') diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h index 6111f1ffca6c..9184c84833f8 100644 --- a/kernel/trace/trace_probe.h +++ b/kernel/trace/trace_probe.h @@ -385,6 +385,7 @@ struct traceprobe_parse_context { struct trace_event_call *event; /* BTF related parameters */ const char *funcname; /* Function name in BTF */ + const struct btf_type *proto; /* Prototype of the function */ const struct btf_param *params; /* Parameter of the function */ s32 nr_params; /* The number of the parameters */ struct btf *btf; /* The BTF to be used */ -- cgit v1.2.3