From patchwork Wed Feb 5 22:50:38 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Rostedt X-Patchwork-Id: 13961995 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 0F0EB21CA15; Wed, 5 Feb 2025 22:50:24 +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=1738795824; cv=none; b=mSfKjoOAPFnGWuthZZeLHM23UaajzwOZbEozqiRjffmUllxFA2aQtA/urDztbdUZ9WAE9wPM29apUqRm69ULKtLZt+vDOYP4WzHT5MaHZxIzAWjAe+hjVFXMTMaqKLTb0O3qQSt+8jcLNzkTGC3gLbnbAobVydpwM90pRSpX+mg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738795824; c=relaxed/simple; bh=1sdF2NBoWm5Mamd9+JN7fxCR634ZF4plAOnnC3jjZ2s=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=cB348aAOXaIACqW/14jcg6Wy76/+Gu0bXisZqirIHXIBLGR9n/Uw+2DYjnFLt+1CVoE3EVf/Xk1KC5raxLzmT8Z1faq97HFF14ipETHVvGIlBfbRu3UWK4DvZxE2pECUOO7pLRIRR+GzmKl7ncsZOxXGv7RORsGmTgjMsGigYyU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 Received: by smtp.kernel.org (Postfix) with ESMTPSA id E753DC4CEE4; Wed, 5 Feb 2025 22:50:23 +0000 (UTC) Received: from rostedt by gandalf with local (Exim 4.98) (envelope-from ) id 1tfoEa-00000007gWZ-11TE; Wed, 05 Feb 2025 17:51:04 -0500 Message-ID: <20250205225104.096389081@goodmis.org> User-Agent: quilt/0.68 Date: Wed, 05 Feb 2025 17:50:38 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , Andrew Morton Subject: [PATCH 7/8] tracing: Show module names and addresses of last boot References: <20250205225031.799739376@goodmis.org> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Steven Rostedt Add the last boot module's names and addresses to the last_boot_info file. This only shows the module information from a previous boot. If the buffer is started and is recording the current boot, this file still will only show "current". # cat instances/boot_mapped/last_boot_info Offset: 10c00000 ffffffffc00ca000 usb_serial_simple ffffffffc00ae000 usbserial ffffffffc008b000 bfq # echo function > instances/boot_mapped/current_tracer # cat instances/boot_mapped/last_boot_info Offset: current Signed-off-by: Steven Rostedt (Google) --- kernel/trace/trace.c | 103 +++++++++++++++++++++++++++++++++++++------ 1 file changed, 90 insertions(+), 13 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index a8e5f7ac2193..7b4027804cd4 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -6005,6 +6005,8 @@ struct trace_scratch { struct trace_mod_entry entries[]; }; +static DEFINE_MUTEX(scratch_mutex); + static int save_mod(struct module *mod, void *data) { struct trace_array *tr = data; @@ -6012,6 +6014,8 @@ static int save_mod(struct module *mod, void *data) struct trace_mod_entry *entry; unsigned int size; + guard(mutex)(&scratch_mutex); + tscratch = tr->scratch; if (!tscratch) return -1; @@ -6882,15 +6886,47 @@ tracing_total_entries_read(struct file *filp, char __user *ubuf, return simple_read_from_buffer(ubuf, cnt, ppos, buf, r); } -static ssize_t -tracing_last_boot_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) +#define LAST_BOOT_HEADER ((void *)1) + +static void *l_next(struct seq_file *m, void *v, loff_t *pos) { - struct trace_array *tr = filp->private_data; + struct trace_array *tr = m->private; struct trace_scratch *tscratch = tr->scratch; - struct seq_buf seq; - char buf[64]; + unsigned int index = *pos; + + (*pos)++; + + if (*pos == 1) + return LAST_BOOT_HEADER; + + /* Only show offsets of the last boot data */ + if (!tscratch || !(tr->flags & TRACE_ARRAY_FL_LAST_BOOT)) + return NULL; + + /* *pos 0 is for the header, 1 is for the first module */ + index--; + + if (index >= tscratch->nr_entries) + return NULL; - seq_buf_init(&seq, buf, 64); + return &tscratch->entries[index]; +} + +static void *l_start(struct seq_file *m, loff_t *pos) +{ + mutex_lock(&scratch_mutex); + + return l_next(m, NULL, pos); +} + +static void l_stop(struct seq_file *m, void *p) +{ + mutex_unlock(&scratch_mutex); +} + +static void show_last_boot_header(struct seq_file *m, struct trace_array *tr) +{ + struct trace_scratch *tscratch = tr->scratch; /* * Do not leak KASLR address. This only shows the KASLR address of @@ -6900,11 +6936,52 @@ tracing_last_boot_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t * should not be the same as the current boot. */ if (!tscratch || !(tr->flags & TRACE_ARRAY_FL_LAST_BOOT)) - seq_buf_puts(&seq, "Offset: current\n"); + seq_puts(m, "Offset: current\n"); else - seq_buf_printf(&seq, "Offset: %lx\n", tscratch->kaslr_addr); + seq_printf(m, "Offset: %lx\n", tscratch->kaslr_addr); +} - return simple_read_from_buffer(ubuf, cnt, ppos, buf, seq_buf_used(&seq)); +static int l_show(struct seq_file *m, void *v) +{ + struct trace_array *tr = m->private; + struct trace_mod_entry *entry = v; + + if (v == LAST_BOOT_HEADER) { + show_last_boot_header(m, tr); + return 0; + } + + seq_printf(m, "%lx %s\n", entry->mod_addr, entry->mod_name); + return 0; +} + +static const struct seq_operations last_boot_seq_ops = { + .start = l_start, + .next = l_next, + .stop = l_stop, + .show = l_show, +}; + +static int tracing_last_boot_open(struct inode *inode, struct file *file) +{ + struct trace_array *tr = inode->i_private; + struct seq_file *m; + int ret; + + ret = tracing_check_open_get_tr(tr); + if (ret) + return ret; + + ret = seq_open(file, &last_boot_seq_ops); + if (ret) { + trace_array_put(tr); + return ret; + } + + m = file->private_data; + m->private = tr; + + return 0; } static int tracing_buffer_meta_open(struct inode *inode, struct file *filp) @@ -7533,10 +7610,10 @@ static const struct file_operations trace_time_stamp_mode_fops = { }; static const struct file_operations last_boot_fops = { - .open = tracing_open_generic_tr, - .read = tracing_last_boot_read, - .llseek = generic_file_llseek, - .release = tracing_release_generic_tr, + .open = tracing_last_boot_open, + .read = seq_read, + .llseek = seq_lseek, + .release = tracing_seq_release, }; #ifdef CONFIG_TRACER_SNAPSHOT