From 57faaa04804ccbf16582f7fc7a6b986fd0c0e78c Mon Sep 17 00:00:00 2001 From: "Masami Hiramatsu (Google)" Date: Thu, 27 Mar 2025 21:19:54 +0900 Subject: tracing: probe-events: Log error for exceeding the number of arguments Add error message when the number of arguments exceeds the limitation. Link: https://lore.kernel.org/all/174055075075.4079315.10916648136898316476.stgit@mhiramat.tok.corp.google.com/ Signed-off-by: Masami Hiramatsu (Google) Reviewed-by: Steven Rostedt (Google) --- kernel/trace/trace_eprobe.c | 2 ++ kernel/trace/trace_fprobe.c | 5 ++++- kernel/trace/trace_kprobe.c | 5 ++++- kernel/trace/trace_probe.h | 1 + kernel/trace/trace_uprobe.c | 9 +++++++-- 5 files changed, 18 insertions(+), 4 deletions(-) (limited to 'kernel/trace') diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c index 82fd637cfc19..af9fa0632b57 100644 --- a/kernel/trace/trace_eprobe.c +++ b/kernel/trace/trace_eprobe.c @@ -913,6 +913,8 @@ static int __trace_eprobe_create(int argc, const char *argv[]) } if (argc - 2 > MAX_TRACE_ARGS) { + trace_probe_log_set_index(2); + trace_probe_log_err(0, TOO_MANY_ARGS); ret = -E2BIG; goto error; } diff --git a/kernel/trace/trace_fprobe.c b/kernel/trace/trace_fprobe.c index 985ff98272da..5d7ca80173ea 100644 --- a/kernel/trace/trace_fprobe.c +++ b/kernel/trace/trace_fprobe.c @@ -1199,8 +1199,11 @@ static int trace_fprobe_create_internal(int argc, const char *argv[], argc = new_argc; argv = new_argv; } - if (argc > MAX_TRACE_ARGS) + if (argc > MAX_TRACE_ARGS) { + trace_probe_log_set_index(2); + trace_probe_log_err(0, TOO_MANY_ARGS); return -E2BIG; + } ret = traceprobe_expand_dentry_args(argc, argv, &dbuf); if (ret) diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index d8d5f18a141a..8287b175667f 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -1007,8 +1007,11 @@ static int trace_kprobe_create_internal(int argc, const char *argv[], argc = new_argc; argv = new_argv; } - if (argc > MAX_TRACE_ARGS) + if (argc > MAX_TRACE_ARGS) { + trace_probe_log_set_index(2); + trace_probe_log_err(0, TOO_MANY_ARGS); return -E2BIG; + } ret = traceprobe_expand_dentry_args(argc, argv, &dbuf); if (ret) diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h index 96792bc4b092..854e5668f5ee 100644 --- a/kernel/trace/trace_probe.h +++ b/kernel/trace/trace_probe.h @@ -545,6 +545,7 @@ extern int traceprobe_define_arg_fields(struct trace_event_call *event_call, C(BAD_BTF_TID, "Failed to get BTF type info."),\ C(BAD_TYPE4STR, "This type does not fit for string."),\ C(NEED_STRING_TYPE, "$comm and immediate-string only accepts string type"),\ + C(TOO_MANY_ARGS, "Too many arguments are specified"), \ C(TOO_MANY_EARGS, "Too many entry arguments specified"), #undef C diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c index ccc762fbb69c..3386439ec9f6 100644 --- a/kernel/trace/trace_uprobe.c +++ b/kernel/trace/trace_uprobe.c @@ -562,8 +562,14 @@ static int __trace_uprobe_create(int argc, const char **argv) if (argc < 2) return -ECANCELED; - if (argc - 2 > MAX_TRACE_ARGS) + + trace_probe_log_init("trace_uprobe", argc, argv); + + if (argc - 2 > MAX_TRACE_ARGS) { + trace_probe_log_set_index(2); + trace_probe_log_err(0, TOO_MANY_ARGS); return -E2BIG; + } if (argv[0][1] == ':') event = &argv[0][2]; @@ -582,7 +588,6 @@ static int __trace_uprobe_create(int argc, const char **argv) return -ECANCELED; } - trace_probe_log_init("trace_uprobe", argc, argv); trace_probe_log_set_index(1); /* filename is the 2nd argument */ *arg++ = '\0'; -- cgit v1.2.3 From bb9c6020f4c3a07a90dc36826cb5fbe83f09efd5 Mon Sep 17 00:00:00 2001 From: "Masami Hiramatsu (Google)" Date: Thu, 27 Mar 2025 21:19:54 +0900 Subject: tracing: probe-events: Add comments about entry data storing code Add comments about entry data storing code to __store_entry_arg() and traceprobe_get_entry_data_size(). These are a bit complicated because of building the entry data storing code and scanning it. This just add comments, no behavior change. Link: https://lore.kernel.org/all/174061715004.501424.333819546601401102.stgit@devnote2/ Reported-by: Steven Rostedt Closes: https://lore.kernel.org/all/20250226102223.586d7119@gandalf.local.home/ Reviewed-by: Steven Rostedt (Google) Signed-off-by: Masami Hiramatsu (Google) --- kernel/trace/trace_probe.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) (limited to 'kernel/trace') diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c index 8f58ee1e8858..2eeecb6c95ee 100644 --- a/kernel/trace/trace_probe.c +++ b/kernel/trace/trace_probe.c @@ -770,6 +770,10 @@ static int check_prepare_btf_string_fetch(char *typename, #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API +/* + * Add the entry code to store the 'argnum'th parameter and return the offset + * in the entry data buffer where the data will be stored. + */ static int __store_entry_arg(struct trace_probe *tp, int argnum) { struct probe_entry_arg *earg = tp->entry_arg; @@ -793,6 +797,20 @@ static int __store_entry_arg(struct trace_probe *tp, int argnum) tp->entry_arg = earg; } + /* + * The entry code array is repeating the pair of + * [FETCH_OP_ARG(argnum)][FETCH_OP_ST_EDATA(offset of entry data buffer)] + * and the rest of entries are filled with [FETCH_OP_END]. + * + * To reduce the redundant function parameter fetching, we scan the entry + * code array to find the FETCH_OP_ARG which already fetches the 'argnum' + * parameter. If it doesn't match, update 'offset' to find the last + * offset. + * If we find the FETCH_OP_END without matching FETCH_OP_ARG entry, we + * will save the entry with FETCH_OP_ARG and FETCH_OP_ST_EDATA, and + * return data offset so that caller can find the data offset in the entry + * data buffer. + */ offset = 0; for (i = 0; i < earg->size - 1; i++) { switch (earg->code[i].op) { @@ -826,6 +844,16 @@ int traceprobe_get_entry_data_size(struct trace_probe *tp) if (!earg) return 0; + /* + * earg->code[] array has an operation sequence which is run in + * the entry handler. + * The sequence stopped by FETCH_OP_END and each data stored in + * the entry data buffer by FETCH_OP_ST_EDATA. The FETCH_OP_ST_EDATA + * stores the data at the data buffer + its offset, and all data are + * "unsigned long" size. The offset must be increased when a data is + * stored. Thus we need to find the last FETCH_OP_ST_EDATA in the + * code array. + */ for (i = 0; i < earg->size; i++) { switch (earg->code[i].op) { case FETCH_OP_END: -- cgit v1.2.3