From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 717CE495D9; Thu, 30 Nov 2023 16:33:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="texp8yrM" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BA377C433C8; Thu, 30 Nov 2023 16:33:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1701361989; bh=/ktQrckJrDWcgfDwta6JMoKXEnq/ebQAv4POd/ypDAY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=texp8yrMtnVuSkPvg4zuXb3i5lNR2bTwT/1AQ/7FelntdE8r42HH/D4CH12Yd2oZU Qjk0kogPpwJ6x7yc9TNJndCfvnjKZi3CplEBMaw7YcmNqT09taiCZ92leuK0VJc7iN xFdQMYfvyC01uAx1Wv10E5KqgEJuyLsrE9s/Iw4M= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Masami Hiramatsu , Francis Laniel Subject: [PATCH 5.15 42/69] tracing/kprobes: Return EADDRNOTAVAIL when func matches several symbols Date: Thu, 30 Nov 2023 16:22:39 +0000 Message-ID: <20231130162134.460514886@linuxfoundation.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20231130162133.035359406@linuxfoundation.org> References: <20231130162133.035359406@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Francis Laniel commit b022f0c7e404887a7c5229788fc99eff9f9a80d5 upstream. When a kprobe is attached to a function that's name is not unique (is static and shares the name with other functions in the kernel), the kprobe is attached to the first function it finds. This is a bug as the function that it is attaching to is not necessarily the one that the user wants to attach to. Instead of blindly picking a function to attach to what is ambiguous, error with EADDRNOTAVAIL to let the user know that this function is not unique, and that the user must use another unique function with an address offset to get to the function they want to attach to. Link: https://lore.kernel.org/all/20231020104250.9537-2-flaniel@linux.microsoft.com/ Cc: stable@vger.kernel.org Fixes: 413d37d1eb69 ("tracing: Add kprobe-based event tracer") Suggested-by: Masami Hiramatsu Signed-off-by: Francis Laniel Link: https://lore.kernel.org/lkml/20230819101105.b0c104ae4494a7d1f2eea742@kernel.org/ Acked-by: Masami Hiramatsu (Google) Signed-off-by: Masami Hiramatsu (Google) Signed-off-by: Greg Kroah-Hartman --- kernel/trace/trace_kprobe.c | 74 ++++++++++++++++++++++++++++++++++++++++++++ kernel/trace/trace_probe.h | 1 2 files changed, 75 insertions(+) --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -708,6 +708,36 @@ static struct notifier_block trace_kprob .priority = 1 /* Invoked after kprobe module callback */ }; +struct count_symbols_struct { + const char *func_name; + unsigned int count; +}; + +static int count_symbols(void *data, const char *name, struct module *unused0, + unsigned long unused1) +{ + struct count_symbols_struct *args = data; + + if (strcmp(args->func_name, name)) + return 0; + + args->count++; + + return 0; +} + +static unsigned int number_of_same_symbols(char *func_name) +{ + struct count_symbols_struct args = { + .func_name = func_name, + .count = 0, + }; + + kallsyms_on_each_symbol(count_symbols, &args); + + return args.count; +} + static int __trace_kprobe_create(int argc, const char *argv[]) { /* @@ -836,6 +866,31 @@ static int __trace_kprobe_create(int arg } } + if (symbol && !strchr(symbol, ':')) { + unsigned int count; + + count = number_of_same_symbols(symbol); + if (count > 1) { + /* + * Users should use ADDR to remove the ambiguity of + * using KSYM only. + */ + trace_probe_log_err(0, NON_UNIQ_SYMBOL); + ret = -EADDRNOTAVAIL; + + goto error; + } else if (count == 0) { + /* + * We can return ENOENT earlier than when register the + * kprobe. + */ + trace_probe_log_err(0, BAD_PROBE_ADDR); + ret = -ENOENT; + + goto error; + } + } + trace_probe_log_set_index(0); if (event) { ret = traceprobe_parse_event_name(&event, &group, buf, @@ -1755,6 +1810,7 @@ static int unregister_kprobe_event(struc } #ifdef CONFIG_PERF_EVENTS + /* create a trace_kprobe, but don't add it to global lists */ struct trace_event_call * create_local_trace_kprobe(char *func, void *addr, unsigned long offs, @@ -1765,6 +1821,24 @@ create_local_trace_kprobe(char *func, vo int ret; char *event; + if (func) { + unsigned int count; + + count = number_of_same_symbols(func); + if (count > 1) + /* + * Users should use addr to remove the ambiguity of + * using func only. + */ + return ERR_PTR(-EADDRNOTAVAIL); + else if (count == 0) + /* + * We can return ENOENT earlier than when register the + * kprobe. + */ + return ERR_PTR(-ENOENT); + } + /* * local trace_kprobes are not added to dyn_event, so they are never * searched in find_trace_kprobe(). Therefore, there is no concern of --- a/kernel/trace/trace_probe.h +++ b/kernel/trace/trace_probe.h @@ -405,6 +405,7 @@ extern int traceprobe_define_arg_fields( C(BAD_MAXACT, "Invalid maxactive number"), \ C(MAXACT_TOO_BIG, "Maxactive is too big"), \ C(BAD_PROBE_ADDR, "Invalid probed address or symbol"), \ + C(NON_UNIQ_SYMBOL, "The symbol is not unique"), \ C(BAD_RETPROBE, "Retprobe address must be an function entry"), \ C(BAD_ADDR_SUFFIX, "Invalid probed address suffix"), \ C(NO_GROUP_NAME, "Group name is not specified"), \