From patchwork Tue Nov 12 12:03:26 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vincent Donnefort X-Patchwork-Id: 11239145 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 7F1CD1515 for ; Tue, 12 Nov 2019 12:03:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5F68F206BB for ; Tue, 12 Nov 2019 12:03:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726697AbfKLMDg (ORCPT ); Tue, 12 Nov 2019 07:03:36 -0500 Received: from foss.arm.com ([217.140.110.172]:32788 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725944AbfKLMDg (ORCPT ); Tue, 12 Nov 2019 07:03:36 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 9297231B; Tue, 12 Nov 2019 04:03:35 -0800 (PST) Received: from e120877-lin.cambridge.arm.com (e120877-lin.cambridge.arm.com [10.1.194.81]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 1B5143F6C4; Tue, 12 Nov 2019 04:03:34 -0800 (PST) From: vincent.donnefort@arm.com To: linux-trace-devel@vger.kernel.org Cc: Vincent Donnefort Subject: [PATCH v2 1/2] trace-cmd: Enable kptr_restrict Date: Tue, 12 Nov 2019 12:03:26 +0000 Message-Id: <1573560207-52550-1-git-send-email-vincent.donnefort@arm.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <20191111175203.252cc439@gandalf.local.home> References: <20191111175203.252cc439@gandalf.local.home> Sender: linux-trace-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-trace-devel@vger.kernel.org From: Vincent Donnefort kptr_restrict might prevent trace-cmd from accessing /proc/kallsyms, leading to a trace without the kernel function names resolved. Signed-off-by: Vincent Donnefort diff --git a/lib/trace-cmd/trace-output.c b/lib/trace-cmd/trace-output.c index 41932ee..be4d3f5 100644 --- a/lib/trace-cmd/trace-output.c +++ b/lib/trace-cmd/trace-output.c @@ -674,6 +674,46 @@ static int read_event_files(struct tracecmd_output *handle, return ret; } +#define KPTR_UNINITIALIZED 'X' + +static void set_proc_kptr_restrict(int reset) +{ + char *path = "/proc/sys/kernel/kptr_restrict"; + static char saved = KPTR_UNINITIALIZED; + int fd, ret = -1; + struct stat st; + char buf; + + if ((reset && saved == KPTR_UNINITIALIZED) || + (stat(path, &st) < 0)) + return; + + fd = open(path, O_RDONLY); + if (fd < 0) + goto err; + + if (reset) { + buf = saved; + } else { + if (read(fd, &buf, 1) < 0) + goto err; + saved = buf; + buf = '0'; + } + close(fd); + + fd = open(path, O_WRONLY); + if (fd < 0) + goto err; + if (write(fd, &buf, 1) > 0) + ret = 0; +err: + if (fd > 0) + close(fd); + if (ret) + warning("can't set kptr_restrict"); +} + static int read_proc_kallsyms(struct tracecmd_output *handle, const char *kallsyms) { @@ -698,12 +738,16 @@ static int read_proc_kallsyms(struct tracecmd_output *handle, endian4 = convert_endian_4(handle, size); if (do_write_check(handle, &endian4, 4)) return -1; + + set_proc_kptr_restrict(0); check_size = copy_file(handle, path); if (size != check_size) { errno = EINVAL; warning("error in size of file '%s'", path); + set_proc_kptr_restrict(1); return -1; } + set_proc_kptr_restrict(1); return 0; } From patchwork Tue Nov 12 12:03:27 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vincent Donnefort X-Patchwork-Id: 11239147 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 770A81515 for ; Tue, 12 Nov 2019 12:03:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 620ED21925 for ; Tue, 12 Nov 2019 12:03:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726725AbfKLMDh (ORCPT ); Tue, 12 Nov 2019 07:03:37 -0500 Received: from foss.arm.com ([217.140.110.172]:32794 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725944AbfKLMDh (ORCPT ); Tue, 12 Nov 2019 07:03:37 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 482AB328; Tue, 12 Nov 2019 04:03:36 -0800 (PST) Received: from e120877-lin.cambridge.arm.com (e120877-lin.cambridge.arm.com [10.1.194.81]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id C858F3F6C4; Tue, 12 Nov 2019 04:03:35 -0800 (PST) From: vincent.donnefort@arm.com To: linux-trace-devel@vger.kernel.org Cc: Vincent Donnefort Subject: [PATCH v2 2/2] trace-cmd: Add an option to set saved_cmdlines_size Date: Tue, 12 Nov 2019 12:03:27 +0000 Message-Id: <1573560207-52550-2-git-send-email-vincent.donnefort@arm.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1573560207-52550-1-git-send-email-vincent.donnefort@arm.com> References: <20191111175203.252cc439@gandalf.local.home> <1573560207-52550-1-git-send-email-vincent.donnefort@arm.com> Sender: linux-trace-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-trace-devel@vger.kernel.org From: Vincent Donnefort The tracing file saved_cmdlines_size allows setting the number of entries that saved_cmdlines will contain. The latter is then dumped into the trace.dat file to map PIDs with comm. The default value is 128. Signed-off-by: Vincent Donnefort diff --git a/Documentation/trace-cmd-record.1.txt b/Documentation/trace-cmd-record.1.txt index bb18e88..0d75e43 100644 --- a/Documentation/trace-cmd-record.1.txt +++ b/Documentation/trace-cmd-record.1.txt @@ -280,6 +280,12 @@ OPTIONS A value of one will only show where userspace enters the kernel but not any functions called in the kernel. The default is zero, which means no limit. +*--cmdlines-size* 'size':: + Set the number of entries the kernel tracing file "saved_cmdlines" can + contain. This file is a circular buffer which stores the mapping between + cmdlines and PIDs. If full, it leads to unresolved cmdlines ("<...>") within + the trace. The kernel default value is 128. + *--module* 'module':: Filter a module's name in function tracing. It is equivalent to adding ':mod:module' after all other functions being filtered. If no other function diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c index 7260d27..82556b0 100644 --- a/tracecmd/trace-record.c +++ b/tracecmd/trace-record.c @@ -229,6 +229,7 @@ struct common_record_context { int topt; int do_child; int run_command; + int saved_cmdlines_size; }; static void add_reset_file(const char *file, const char *val, int prio) @@ -1810,6 +1811,39 @@ static void set_options(void) } } +static void set_saved_cmdlines_size(struct common_record_context *ctx) +{ + char *path, *str; + int fd, len, ret; + + if (!ctx->saved_cmdlines_size) + return; + + path = tracecmd_get_tracing_file("saved_cmdlines_size"); + if (!path) + goto err; + + reset_save_file(path, RESET_DEFAULT_PRIO); + + fd = open(path, O_WRONLY); + tracecmd_put_tracing_file(path); + if (fd < 0) + goto err; + + len = asprintf(&str, "%d", ctx->saved_cmdlines_size); + if (len < 0) + die("%s couldn't allocate memory", __func__); + + if (write(fd, str, len) > 0) + ret = 0; + + close(fd); + free(str); +err: + if (ret) + warning("Couldn't set saved_cmdlines_size"); +} + static int trace_check_file_exists(struct buffer_instance *instance, char *file) { struct stat st; @@ -5190,6 +5224,7 @@ enum { OPT_date = 255, OPT_module = 256, OPT_nofifos = 257, + OPT_cmdlines_size = 258, }; void trace_stop(int argc, char **argv) @@ -5467,6 +5502,7 @@ static void parse_record_options(int argc, {"by-comm", no_argument, NULL, OPT_bycomm}, {"ts-offset", required_argument, NULL, OPT_tsoffset}, {"max-graph-depth", required_argument, NULL, OPT_max_graph_depth}, + {"cmdlines-size", required_argument, NULL, OPT_cmdlines_size}, {"no-filter", no_argument, NULL, OPT_no_filter}, {"debug", no_argument, NULL, OPT_debug}, {"quiet", no_argument, NULL, OPT_quiet}, @@ -5480,7 +5516,7 @@ static void parse_record_options(int argc, if (IS_EXTRACT(ctx)) opts = "+haf:Fp:co:O:sr:g:l:n:P:N:tb:B:ksiT"; else - opts = "+hae:f:FA:p:cC:dDGo:O:s:r:vg:l:n:P:N:tb:R:B:ksSiTm:M:H:q"; + opts = "+hae:f:FA:p:cC:dDGo:O:s:r:vg:l:n:P:N:tb:R:B:kK:sSiTm:M:H:qK"; c = getopt_long (argc-1, argv+1, opts, long_options, &option_index); if (c == -1) break; @@ -5795,6 +5831,9 @@ static void parse_record_options(int argc, if (!ctx->instance->max_graph_depth) die("Could not allocate option"); break; + case OPT_cmdlines_size: + ctx->saved_cmdlines_size = atoi(optarg); + break; case OPT_no_filter: no_filter = true; break; @@ -5990,6 +6029,7 @@ static void record_trace(int argc, char **argv, enable_events(instance); } + set_saved_cmdlines_size(ctx); set_buffer_size(); update_plugins(type); set_options(); diff --git a/tracecmd/trace-usage.c b/tracecmd/trace-usage.c index b5788f7..0080522 100644 --- a/tracecmd/trace-usage.c +++ b/tracecmd/trace-usage.c @@ -56,6 +56,7 @@ static struct usage_help usage_help[] = { " --func-stack perform a stack trace for function tracer\n" " (use with caution)\n" " --max-graph-depth limit function_graph depth\n" + " --cmdlines_size change kernel saved_cmdlines_size\n" " --no-filter include trace-cmd threads in the trace\n" " --proc-map save the traced processes address map into the trace.dat file\n" " --user execute the specified [command ...] as given user\n"