From 57faaa04804ccbf16582f7fc7a6b986fd0c0e78c Mon Sep 17 00:00:00 2001 From: "Masami Hiramatsu (Google)" Date: Thu, 27 Mar 2025 21:19:54 +0900 Subject: [PATCH 1/5] 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(-) 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'; From 381af2ab916669e1b25648ccfd0b2a7c228662f7 Mon Sep 17 00:00:00 2001 From: "Masami Hiramatsu (Google)" Date: Thu, 27 Mar 2025 21:19:54 +0900 Subject: [PATCH 2/5] selftests/ftrace: Expand the tprobe event test to check wrong format Expand the tprobe event test case to check wrong tracepoint format. Link: https://lore.kernel.org/all/174055076681.4079315.16941322116874021804.stgit@mhiramat.tok.corp.google.com/ Signed-off-by: Masami Hiramatsu (Google) --- .../ftrace/test.d/dynevent/add_remove_tprobe.tc | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_tprobe.tc b/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_tprobe.tc index 155792eaeee5..f271c4238b72 100644 --- a/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_tprobe.tc +++ b/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_tprobe.tc @@ -6,6 +6,7 @@ echo 0 > events/enable echo > dynamic_events +SUBSYSTEM=kmem TRACEPOINT1=kmem_cache_alloc TRACEPOINT2=kmem_cache_free @@ -24,4 +25,17 @@ grep -q myevent1 dynamic_events echo > dynamic_events +# auto naming check +echo "t $TRACEPOINT1" >> dynamic_events + +test -d events/tracepoints/$TRACEPOINT1 + +echo > dynamic_events + +# SUBSYSTEM is not supported +echo "t $SUBSYSTEM/$TRACEPOINT1" >> dynamic_events && exit_fail ||: +echo "t $SUBSYSTEM:$TRACEPOINT1" >> dynamic_events && exit_fail ||: +echo "t:myevent3 $SUBSYSTEM/$TRACEPOINT1" >> dynamic_events && exit_fail ||: +echo "t:myevent3 $SUBSYSTEM:$TRACEPOINT1" >> dynamic_events && exit_fail ||: + clear_trace From 168ccc9b9938d07e71e6e25b82826f8ea11172fc Mon Sep 17 00:00:00 2001 From: "Masami Hiramatsu (Google)" Date: Thu, 27 Mar 2025 21:19:54 +0900 Subject: [PATCH 3/5] selftests/ftrace: Add new syntax error test Add BAD_TP_NAME syntax error message check. Link: https://lore.kernel.org/all/174055077485.4079315.3624012056141021755.stgit@mhiramat.tok.corp.google.com/ Signed-off-by: Masami Hiramatsu (Google) --- .../selftests/ftrace/test.d/dynevent/fprobe_syntax_errors.tc | 1 + 1 file changed, 1 insertion(+) diff --git a/tools/testing/selftests/ftrace/test.d/dynevent/fprobe_syntax_errors.tc b/tools/testing/selftests/ftrace/test.d/dynevent/fprobe_syntax_errors.tc index c9425a34fae3..fee479295e2f 100644 --- a/tools/testing/selftests/ftrace/test.d/dynevent/fprobe_syntax_errors.tc +++ b/tools/testing/selftests/ftrace/test.d/dynevent/fprobe_syntax_errors.tc @@ -27,6 +27,7 @@ check_error 'f:^foo.1/bar vfs_read' # BAD_GROUP_NAME check_error 'f:^ vfs_read' # NO_EVENT_NAME check_error 'f:foo/^12345678901234567890123456789012345678901234567890123456789012345 vfs_read' # EVENT_TOO_LONG check_error 'f:foo/^bar.1 vfs_read' # BAD_EVENT_NAME +check_error 't kmem^/kfree' # BAD_TP_NAME check_error 'f vfs_read ^$stack10000' # BAD_STACK_NUM From 581a7b26ab364410c260df1eb5941e70722d25fc Mon Sep 17 00:00:00 2001 From: "Masami Hiramatsu (Google)" Date: Thu, 27 Mar 2025 21:19:54 +0900 Subject: [PATCH 4/5] selftests/ftrace: Add dynamic events argument limitation test case Add argument limitation test case for dynamic events. This is a boudary check for the maximum number of the probe event arguments. Link: https://lore.kernel.org/all/174055078295.4079315.14702008939511417359.stgit@mhiramat.tok.corp.google.com/ Signed-off-by: Masami Hiramatsu (Google) --- .../test.d/dynevent/dynevent_limitations.tc | 42 +++++++++++++++++++ 1 file changed, 42 insertions(+) create mode 100644 tools/testing/selftests/ftrace/test.d/dynevent/dynevent_limitations.tc diff --git a/tools/testing/selftests/ftrace/test.d/dynevent/dynevent_limitations.tc b/tools/testing/selftests/ftrace/test.d/dynevent/dynevent_limitations.tc new file mode 100644 index 000000000000..6b94b678741a --- /dev/null +++ b/tools/testing/selftests/ftrace/test.d/dynevent/dynevent_limitations.tc @@ -0,0 +1,42 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 +# description: Checking dynamic events limitations +# requires: dynamic_events "imm-value":README + +# Max arguments limitation +MAX_ARGS=128 +EXCEED_ARGS=$((MAX_ARGS + 1)) + +check_max_args() { # event_header + TEST_STRING=$1 + # Acceptable + for i in `seq 1 $MAX_ARGS`; do + TEST_STRING="$TEST_STRING \\$i" + done + echo "$TEST_STRING" >> dynamic_events + echo > dynamic_events + # Error + TEST_STRING="$TEST_STRING \\$EXCEED_ARGS" + ! echo "$TEST_STRING" >> dynamic_events + return 0 +} + +# Kprobe max args limitation +if grep -q "kprobe_events" README; then + check_max_args "p vfs_read" +fi + +# Fprobe max args limitation +if grep -q "f[:[/][]] [%return] []" README; then + check_max_args "f vfs_read" +fi + +# Tprobe max args limitation +if grep -q "t[:[/][]] []" README; then + check_max_args "t kfree" +fi + +# Uprobe max args limitation +if grep -q "uprobe_events" README; then + check_max_args "p /bin/sh:10" +fi From bb9c6020f4c3a07a90dc36826cb5fbe83f09efd5 Mon Sep 17 00:00:00 2001 From: "Masami Hiramatsu (Google)" Date: Thu, 27 Mar 2025 21:19:54 +0900 Subject: [PATCH 5/5] 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(+) 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: