From e0f831836cead677fb07d54bd6bf499df35640c2 Mon Sep 17 00:00:00 2001 From: Yujie Liu Date: Fri, 27 Oct 2023 12:13:14 +0800 Subject: [PATCH 1/2] tracing/kprobes: Fix the description of variable length arguments Fix the following kernel-doc warnings: kernel/trace/trace_kprobe.c:1029: warning: Excess function parameter 'args' description in '__kprobe_event_gen_cmd_start' kernel/trace/trace_kprobe.c:1097: warning: Excess function parameter 'args' description in '__kprobe_event_add_fields' Refer to the usage of variable length arguments elsewhere in the kernel code, "@..." is the proper way to express it in the description. Link: https://lore.kernel.org/all/20231027041315.2613166-1-yujie.liu@intel.com/ Fixes: 2a588dd1d5d6 ("tracing: Add kprobe event command generation functions") Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202310190437.paI6LYJF-lkp@intel.com/ Signed-off-by: Yujie Liu Reviewed-by: Mukesh Ojha Acked-by: Masami Hiramatsu (Google) Signed-off-by: Masami Hiramatsu (Google) --- kernel/trace/trace_kprobe.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index a8fef6ab08727..95c5b0668cb7b 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -1007,7 +1007,7 @@ EXPORT_SYMBOL_GPL(kprobe_event_cmd_init); * @name: The name of the kprobe event * @loc: The location of the kprobe event * @kretprobe: Is this a return probe? - * @args: Variable number of arg (pairs), one pair for each field + * @...: Variable number of arg (pairs), one pair for each field * * NOTE: Users normally won't want to call this function directly, but * rather use the kprobe_event_gen_cmd_start() wrapper, which automatically @@ -1080,7 +1080,7 @@ EXPORT_SYMBOL_GPL(__kprobe_event_gen_cmd_start); /** * __kprobe_event_add_fields - Add probe fields to a kprobe command from arg list * @cmd: A pointer to the dynevent_cmd struct representing the new event - * @args: Variable number of arg (pairs), one pair for each field + * @...: Variable number of arg (pairs), one pair for each field * * NOTE: Users normally won't want to call this function directly, but * rather use the kprobe_event_add_fields() wrapper, which From 926fe783c8a64b33997fec405cf1af3e61aed441 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Fri, 27 Oct 2023 16:31:26 -0700 Subject: [PATCH 2/2] tracing/kprobes: Fix symbol counting logic by looking at modules as well Recent changes to count number of matching symbols when creating a kprobe event failed to take into account kernel modules. As such, it breaks kprobes on kernel module symbols, by assuming there is no match. Fix this my calling module_kallsyms_on_each_symbol() in addition to kallsyms_on_each_match_symbol() to perform a proper counting. Link: https://lore.kernel.org/all/20231027233126.2073148-1-andrii@kernel.org/ Cc: Francis Laniel Cc: stable@vger.kernel.org Cc: Masami Hiramatsu Cc: Steven Rostedt Fixes: b022f0c7e404 ("tracing/kprobes: Return EADDRNOTAVAIL when func matches several symbols") Signed-off-by: Andrii Nakryiko Acked-by: Song Liu Signed-off-by: Masami Hiramatsu (Google) --- kernel/trace/trace_kprobe.c | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-) diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 95c5b0668cb7b..e834f149695b7 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -714,14 +714,30 @@ static int count_symbols(void *data, unsigned long unused) return 0; } +struct sym_count_ctx { + unsigned int count; + const char *name; +}; + +static int count_mod_symbols(void *data, const char *name, unsigned long unused) +{ + struct sym_count_ctx *ctx = data; + + if (strcmp(name, ctx->name) == 0) + ctx->count++; + + return 0; +} + static unsigned int number_of_same_symbols(char *func_name) { - unsigned int count; + struct sym_count_ctx ctx = { .count = 0, .name = func_name }; + + kallsyms_on_each_match_symbol(count_symbols, func_name, &ctx.count); - count = 0; - kallsyms_on_each_match_symbol(count_symbols, func_name, &count); + module_kallsyms_on_each_symbol(NULL, count_mod_symbols, &ctx); - return count; + return ctx.count; } static int __trace_kprobe_create(int argc, const char *argv[])