From patchwork Fri May 31 09:48:06 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Masami Hiramatsu (Google)" X-Patchwork-Id: 13681450 X-Patchwork-Delegate: mhiramat@kernel.org 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 F1AAA78C69; Fri, 31 May 2024 09:48:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717148890; cv=none; b=lDd082ix3BIVE/Vn2746V3IugdPGFMvDdZbx0jWCo5TPMQhfrHQnq41wZOaroTEveSPu1QkcwlCR7v8qjRBg0E9f/wWEipbIXL8FvFHqQSFuuP6S4ffoHUM/ALjDb4AnnbHNUT9wx843wjM/xMfBR2Oswj7nZBg60HbCV8RqjW8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717148890; c=relaxed/simple; bh=9emyVcHeEjih4DKqAaHmMJgrsFc11xb6jFw6hilqh6Q=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version:Content-Type; b=S50vtaiNz4rXlU325EpDb4Cd1Ua4MmqY55e+XOBKHyxozM5FX2aoGaUJHYmhgseq601Oifvcdo9AqD/vN2YD+3wEGxkucIKRVWXX2skyGgN2yLOjIphC1xnt+c+Qz73OQmK2l3lw0+X1fmqppu8BtzG7S8pkeiJVaITcaWWWSds= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ihS01GEb; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ihS01GEb" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 84323C116B1; Fri, 31 May 2024 09:48:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1717148889; bh=9emyVcHeEjih4DKqAaHmMJgrsFc11xb6jFw6hilqh6Q=; h=From:To:Cc:Subject:Date:From; b=ihS01GEbqeFL8vs00CWNTYO4XItYZgqUxwn0UhZHlggv20Y4y8bxDx9/Tmqw2fJJK u29IU4L/k8rrYANrHTK7MVlEeapqvAKO11SC3YM2oRhCDHv9zzyFrtzN6lrDIH+5k5 ELpgTzX8adQHhDCTPT7o93oBBQs52vu/a1fkbDQoDELzG3SL+SZ1OzIfq9Eo4tL5ae B/8FQIIxWPgJNytnEZ+GdJxwRSUhEafKVKVOVDAVoHHwSVuJpk/b5sii2hi0GltNM+ bjrpIxMmlH4SPyvdCMbQv3M78xVh4p9JMySYYaNz3bWpb098dzWNfSGkwDHN/UAFHv fpgR/2LJWu48g== From: "Masami Hiramatsu (Google)" To: Steven Rostedt Cc: don , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, mhiramat@kernel.org Subject: [PATCH] tracing/fprobe: Support raw tracepoint events on modules Date: Fri, 31 May 2024 18:48:06 +0900 Message-Id: <171714888633.198965.13093663631481169611.stgit@devnote2> X-Mailer: git-send-email 2.34.1 User-Agent: StGit/0.19 Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Masami Hiramatsu (Google) Support raw tracepoint event on module by fprobe events. Since it only uses for_each_kernel_tracepoint() to find a tracepoint, the tracepoints on modules are not handled. Thus if user specified a tracepoint on a module, it shows an error. This adds new for_each_module_tracepoint() API to tracepoint subsystem, and uses it to find tracepoints on modules. Reported-by: don Closes: https://lore.kernel.org/all/20240530215718.aeec973a1d0bf058d39cb1e3@kernel.org/ Signed-off-by: Masami Hiramatsu (Google) --- include/linux/tracepoint.h | 7 +++++++ kernel/trace/trace_fprobe.c | 46 ++++++++++++++++++++++++++++++++++++------- kernel/tracepoint.c | 19 ++++++++++++++++++ 3 files changed, 64 insertions(+), 8 deletions(-) diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h index 689b6d71590e..46e6a5e759fd 100644 --- a/include/linux/tracepoint.h +++ b/include/linux/tracepoint.h @@ -65,6 +65,8 @@ struct tp_module { bool trace_module_has_bad_taint(struct module *mod); extern int register_tracepoint_module_notifier(struct notifier_block *nb); extern int unregister_tracepoint_module_notifier(struct notifier_block *nb); +void for_each_module_tracepoint(void (*fct)(struct tracepoint *, void *), + void *priv); #else static inline bool trace_module_has_bad_taint(struct module *mod) { @@ -80,6 +82,11 @@ int unregister_tracepoint_module_notifier(struct notifier_block *nb) { return 0; } +static inline +void for_each_module_tracepoint(void (*fct)(struct tracepoint *, void *), + void *priv) +{ +} #endif /* CONFIG_MODULES */ /* diff --git a/kernel/trace/trace_fprobe.c b/kernel/trace/trace_fprobe.c index 62e6a8f4aae9..1d8a983e1edc 100644 --- a/kernel/trace/trace_fprobe.c +++ b/kernel/trace/trace_fprobe.c @@ -385,6 +385,7 @@ static struct trace_fprobe *alloc_trace_fprobe(const char *group, const char *event, const char *symbol, struct tracepoint *tpoint, + struct module *mod, int maxactive, int nargs, bool is_return) { @@ -405,6 +406,7 @@ static struct trace_fprobe *alloc_trace_fprobe(const char *group, tf->fp.entry_handler = fentry_dispatcher; tf->tpoint = tpoint; + tf->mod = mod; tf->fp.nr_maxactive = maxactive; ret = trace_probe_init(&tf->tp, event, group, false, nargs); @@ -895,8 +897,23 @@ static struct notifier_block tracepoint_module_nb = { struct __find_tracepoint_cb_data { const char *tp_name; struct tracepoint *tpoint; + struct module *mod; }; +static void __find_tracepoint_module_cb(struct tracepoint *tp, void *priv) +{ + struct __find_tracepoint_cb_data *data = priv; + + if (!data->tpoint && !strcmp(data->tp_name, tp->name)) { + data->tpoint = tp; + data->mod = __module_text_address((unsigned long)tp->probestub); + if (!try_module_get(data->mod)) { + data->tpoint = NULL; + data->mod = NULL; + } + } +} + static void __find_tracepoint_cb(struct tracepoint *tp, void *priv) { struct __find_tracepoint_cb_data *data = priv; @@ -905,14 +922,28 @@ static void __find_tracepoint_cb(struct tracepoint *tp, void *priv) data->tpoint = tp; } -static struct tracepoint *find_tracepoint(const char *tp_name) +/* + * Find a tracepoint from kernel and module. If the tracepoint is in a module, + * this increments the module refcount to prevent unloading until the + * trace_fprobe is registered to the list. After registering the trace_fprobe + * on the trace_fprobe list, the module refcount is decremented because + * tracepoint_probe_module_cb will handle it. + */ +static struct tracepoint *find_tracepoint(const char *tp_name, + struct module **tp_mod) { struct __find_tracepoint_cb_data data = { .tp_name = tp_name, + .mod = NULL, }; for_each_kernel_tracepoint(__find_tracepoint_cb, &data); + if (!data.tpoint && IS_ENABLED(CONFIG_MODULES)) { + for_each_module_tracepoint(__find_tracepoint_module_cb, &data); + *tp_mod = data.mod; + } + return data.tpoint; } @@ -996,6 +1027,7 @@ static int __trace_fprobe_create(int argc, const char *argv[]) char abuf[MAX_BTF_ARGS_LEN]; char *dbuf = NULL; bool is_tracepoint = false; + struct module *tp_mod = NULL; struct tracepoint *tpoint = NULL; struct traceprobe_parse_context ctx = { .flags = TPARG_FL_KERNEL | TPARG_FL_FPROBE, @@ -1080,7 +1112,7 @@ static int __trace_fprobe_create(int argc, const char *argv[]) if (is_tracepoint) { ctx.flags |= TPARG_FL_TPOINT; - tpoint = find_tracepoint(symbol); + tpoint = find_tracepoint(symbol, &tp_mod); if (!tpoint) { trace_probe_log_set_index(1); trace_probe_log_err(0, NO_TRACEPOINT); @@ -1110,8 +1142,8 @@ static int __trace_fprobe_create(int argc, const char *argv[]) goto out; /* setup a probe */ - tf = alloc_trace_fprobe(group, event, symbol, tpoint, maxactive, - argc, is_return); + tf = alloc_trace_fprobe(group, event, symbol, tpoint, tp_mod, + maxactive, argc, is_return); if (IS_ERR(tf)) { ret = PTR_ERR(tf); /* This must return -ENOMEM, else there is a bug */ @@ -1119,10 +1151,6 @@ static int __trace_fprobe_create(int argc, const char *argv[]) goto out; /* We know tf is not allocated */ } - if (is_tracepoint) - tf->mod = __module_text_address( - (unsigned long)tf->tpoint->probestub); - /* parse arguments */ for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) { trace_probe_log_set_index(i + 2); @@ -1155,6 +1183,8 @@ static int __trace_fprobe_create(int argc, const char *argv[]) } out: + if (tp_mod) + module_put(tp_mod); traceprobe_finish_parse(&ctx); trace_probe_log_clear(); kfree(new_argv); diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c index 8d1507dd0724..981b60199413 100644 --- a/kernel/tracepoint.c +++ b/kernel/tracepoint.c @@ -735,6 +735,25 @@ static __init int init_tracepoints(void) return ret; } __initcall(init_tracepoints); + +void for_each_module_tracepoint(void (*fct)(struct tracepoint *tp, void *priv), + void *priv) +{ + struct tp_module *tp_mod; + struct module *mod; + + if (!mod->num_tracepoints) + return; + + mutex_lock(&tracepoint_module_list_mutex); + list_for_each_entry(tp_mod, &tracepoint_module_list, list) { + mod = tp_mod->mod; + for_each_tracepoint_range(mod->__start___tracepoints_ptrs, + mod->tracepoints_ptrs + mod->num_tracepoints, + fct, priv); + } + mutex_unlock(&tracepoint_module_list_mutex); +} #endif /* CONFIG_MODULES */ /**