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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-04 01:49:36 +00:00
![Masami Hiramatsu](/assets/img/avatar_default.png)
Disable ftrace selftests when any tracer (kernel command line options
like ftrace=, trace_events=, kprobe_events=, and boot-time tracing)
starts running because selftest can disturb it.
Currently ftrace= and trace_events= are checked, but kprobe_events
has a different flag, and boot-time tracing didn't checked. This unifies
the disabled flag and all of those boot-time tracing features sets
the flag.
This also fixes warnings on kprobe-event selftest
(CONFIG_FTRACE_STARTUP_TEST=y and CONFIG_KPROBE_EVENTS=y) with boot-time
tracing (ftrace.event.kprobes.EVENT.probes) like below;
[ 59.803496] trace_kprobe: Testing kprobe tracing:
[ 59.804258] ------------[ cut here ]------------
[ 59.805682] WARNING: CPU: 3 PID: 1 at kernel/trace/trace_kprobe.c:1987 kprobe_trace_self_tests_ib
[ 59.806944] Modules linked in:
[ 59.807335] CPU: 3 PID: 1 Comm: swapper/0 Not tainted 5.10.0-rc7+ #172
[ 59.808029] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1 04/01/204
[ 59.808999] RIP: 0010:kprobe_trace_self_tests_init+0x5f/0x42b
[ 59.809696] Code: e8 03 00 00 48 c7 c7 30 8e 07 82 e8 6d 3c 46 ff 48 c7 c6 00 b2 1a 81 48 c7 c7 7
[ 59.812439] RSP: 0018:ffffc90000013e78 EFLAGS: 00010282
[ 59.813038] RAX: 00000000ffffffef RBX: 0000000000000000 RCX: 0000000000049443
[ 59.813780] RDX: 0000000000049403 RSI: 0000000000049403 RDI: 000000000002deb0
[ 59.814589] RBP: ffffc90000013e90 R08: 0000000000000001 R09: 0000000000000001
[ 59.815349] R10: 0000000000000001 R11: 0000000000000000 R12: 00000000ffffffef
[ 59.816138] R13: ffff888004613d80 R14: ffffffff82696940 R15: ffff888004429138
[ 59.816877] FS: 0000000000000000(0000) GS:ffff88807dcc0000(0000) knlGS:0000000000000000
[ 59.817772] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 59.818395] CR2: 0000000001a8dd38 CR3: 0000000002222000 CR4: 00000000000006a0
[ 59.819144] Call Trace:
[ 59.819469] ? init_kprobe_trace+0x6b/0x6b
[ 59.819948] do_one_initcall+0x5f/0x300
[ 59.820392] ? rcu_read_lock_sched_held+0x4f/0x80
[ 59.820916] kernel_init_freeable+0x22a/0x271
[ 59.821416] ? rest_init+0x241/0x241
[ 59.821841] kernel_init+0xe/0x10f
[ 59.822251] ret_from_fork+0x22/0x30
[ 59.822683] irq event stamp: 16403349
[ 59.823121] hardirqs last enabled at (16403359): [<ffffffff810db81e>] console_unlock+0x48e/0x580
[ 59.824074] hardirqs last disabled at (16403368): [<ffffffff810db786>] console_unlock+0x3f6/0x580
[ 59.825036] softirqs last enabled at (16403200): [<ffffffff81c0033a>] __do_softirq+0x33a/0x484
[ 59.825982] softirqs last disabled at (16403087): [<ffffffff81a00f02>] asm_call_irq_on_stack+0x10
[ 59.827034] ---[ end trace 200c544775cdfeb3 ]---
[ 59.827635] trace_kprobe: error on probing function entry.
Link: https://lkml.kernel.org/r/160741764955.3448999.3347769358299456915.stgit@devnote2
Fixes: 4d655281eb
("tracing/boot Add kprobe event support")
Cc: Ingo Molnar <mingo@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
355 lines
8.4 KiB
C
355 lines
8.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* trace_boot.c
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* Tracing kernel boot-time
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*/
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#define pr_fmt(fmt) "trace_boot: " fmt
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#include <linux/bootconfig.h>
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#include <linux/cpumask.h>
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#include <linux/ftrace.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/mutex.h>
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#include <linux/string.h>
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#include <linux/slab.h>
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#include <linux/trace.h>
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#include <linux/trace_events.h>
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#include "trace.h"
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#define MAX_BUF_LEN 256
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static void __init
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trace_boot_set_instance_options(struct trace_array *tr, struct xbc_node *node)
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{
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struct xbc_node *anode;
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const char *p;
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char buf[MAX_BUF_LEN];
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unsigned long v = 0;
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/* Common ftrace options */
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xbc_node_for_each_array_value(node, "options", anode, p) {
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if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf)) {
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pr_err("String is too long: %s\n", p);
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continue;
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}
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if (trace_set_options(tr, buf) < 0)
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pr_err("Failed to set option: %s\n", buf);
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}
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p = xbc_node_find_value(node, "tracing_on", NULL);
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if (p && *p != '\0') {
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if (kstrtoul(p, 10, &v))
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pr_err("Failed to set tracing on: %s\n", p);
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if (v)
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tracer_tracing_on(tr);
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else
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tracer_tracing_off(tr);
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}
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p = xbc_node_find_value(node, "trace_clock", NULL);
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if (p && *p != '\0') {
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if (tracing_set_clock(tr, p) < 0)
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pr_err("Failed to set trace clock: %s\n", p);
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}
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p = xbc_node_find_value(node, "buffer_size", NULL);
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if (p && *p != '\0') {
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v = memparse(p, NULL);
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if (v < PAGE_SIZE)
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pr_err("Buffer size is too small: %s\n", p);
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if (tracing_resize_ring_buffer(tr, v, RING_BUFFER_ALL_CPUS) < 0)
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pr_err("Failed to resize trace buffer to %s\n", p);
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}
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p = xbc_node_find_value(node, "cpumask", NULL);
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if (p && *p != '\0') {
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cpumask_var_t new_mask;
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if (alloc_cpumask_var(&new_mask, GFP_KERNEL)) {
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if (cpumask_parse(p, new_mask) < 0 ||
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tracing_set_cpumask(tr, new_mask) < 0)
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pr_err("Failed to set new CPU mask %s\n", p);
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free_cpumask_var(new_mask);
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}
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}
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}
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#ifdef CONFIG_EVENT_TRACING
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static void __init
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trace_boot_enable_events(struct trace_array *tr, struct xbc_node *node)
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{
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struct xbc_node *anode;
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char buf[MAX_BUF_LEN];
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const char *p;
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xbc_node_for_each_array_value(node, "events", anode, p) {
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if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf)) {
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pr_err("String is too long: %s\n", p);
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continue;
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}
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if (ftrace_set_clr_event(tr, buf, 1) < 0)
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pr_err("Failed to enable event: %s\n", p);
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}
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}
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#ifdef CONFIG_KPROBE_EVENTS
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static int __init
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trace_boot_add_kprobe_event(struct xbc_node *node, const char *event)
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{
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struct dynevent_cmd cmd;
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struct xbc_node *anode;
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char buf[MAX_BUF_LEN];
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const char *val;
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int ret = 0;
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xbc_node_for_each_array_value(node, "probes", anode, val) {
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kprobe_event_cmd_init(&cmd, buf, MAX_BUF_LEN);
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ret = kprobe_event_gen_cmd_start(&cmd, event, val);
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if (ret) {
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pr_err("Failed to generate probe: %s\n", buf);
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break;
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}
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ret = kprobe_event_gen_cmd_end(&cmd);
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if (ret) {
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pr_err("Failed to add probe: %s\n", buf);
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break;
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}
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}
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return ret;
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}
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#else
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static inline int __init
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trace_boot_add_kprobe_event(struct xbc_node *node, const char *event)
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{
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pr_err("Kprobe event is not supported.\n");
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return -ENOTSUPP;
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}
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#endif
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#ifdef CONFIG_SYNTH_EVENTS
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static int __init
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trace_boot_add_synth_event(struct xbc_node *node, const char *event)
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{
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struct dynevent_cmd cmd;
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struct xbc_node *anode;
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char buf[MAX_BUF_LEN];
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const char *p;
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int ret;
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synth_event_cmd_init(&cmd, buf, MAX_BUF_LEN);
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ret = synth_event_gen_cmd_start(&cmd, event, NULL);
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if (ret)
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return ret;
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xbc_node_for_each_array_value(node, "fields", anode, p) {
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ret = synth_event_add_field_str(&cmd, p);
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if (ret)
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return ret;
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}
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ret = synth_event_gen_cmd_end(&cmd);
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if (ret < 0)
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pr_err("Failed to add synthetic event: %s\n", buf);
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return ret;
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}
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#else
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static inline int __init
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trace_boot_add_synth_event(struct xbc_node *node, const char *event)
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{
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pr_err("Synthetic event is not supported.\n");
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return -ENOTSUPP;
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}
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#endif
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static void __init
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trace_boot_init_one_event(struct trace_array *tr, struct xbc_node *gnode,
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struct xbc_node *enode)
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{
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struct trace_event_file *file;
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struct xbc_node *anode;
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char buf[MAX_BUF_LEN];
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const char *p, *group, *event;
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group = xbc_node_get_data(gnode);
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event = xbc_node_get_data(enode);
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if (!strcmp(group, "kprobes"))
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if (trace_boot_add_kprobe_event(enode, event) < 0)
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return;
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if (!strcmp(group, "synthetic"))
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if (trace_boot_add_synth_event(enode, event) < 0)
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return;
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mutex_lock(&event_mutex);
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file = find_event_file(tr, group, event);
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if (!file) {
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pr_err("Failed to find event: %s:%s\n", group, event);
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goto out;
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}
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p = xbc_node_find_value(enode, "filter", NULL);
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if (p && *p != '\0') {
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if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf))
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pr_err("filter string is too long: %s\n", p);
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else if (apply_event_filter(file, buf) < 0)
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pr_err("Failed to apply filter: %s\n", buf);
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}
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xbc_node_for_each_array_value(enode, "actions", anode, p) {
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if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf))
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pr_err("action string is too long: %s\n", p);
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else if (trigger_process_regex(file, buf) < 0)
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pr_err("Failed to apply an action: %s\n", buf);
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}
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if (xbc_node_find_value(enode, "enable", NULL)) {
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if (trace_event_enable_disable(file, 1, 0) < 0)
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pr_err("Failed to enable event node: %s:%s\n",
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group, event);
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}
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out:
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mutex_unlock(&event_mutex);
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}
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static void __init
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trace_boot_init_events(struct trace_array *tr, struct xbc_node *node)
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{
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struct xbc_node *gnode, *enode;
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node = xbc_node_find_child(node, "event");
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if (!node)
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return;
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/* per-event key starts with "event.GROUP.EVENT" */
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xbc_node_for_each_child(node, gnode)
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xbc_node_for_each_child(gnode, enode)
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trace_boot_init_one_event(tr, gnode, enode);
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}
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#else
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#define trace_boot_enable_events(tr, node) do {} while (0)
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#define trace_boot_init_events(tr, node) do {} while (0)
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#endif
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#ifdef CONFIG_DYNAMIC_FTRACE
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static void __init
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trace_boot_set_ftrace_filter(struct trace_array *tr, struct xbc_node *node)
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{
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struct xbc_node *anode;
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const char *p;
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char *q;
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xbc_node_for_each_array_value(node, "ftrace.filters", anode, p) {
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q = kstrdup(p, GFP_KERNEL);
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if (!q)
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return;
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if (ftrace_set_filter(tr->ops, q, strlen(q), 0) < 0)
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pr_err("Failed to add %s to ftrace filter\n", p);
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else
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ftrace_filter_param = true;
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kfree(q);
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}
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xbc_node_for_each_array_value(node, "ftrace.notraces", anode, p) {
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q = kstrdup(p, GFP_KERNEL);
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if (!q)
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return;
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if (ftrace_set_notrace(tr->ops, q, strlen(q), 0) < 0)
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pr_err("Failed to add %s to ftrace filter\n", p);
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else
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ftrace_filter_param = true;
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kfree(q);
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}
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}
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#else
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#define trace_boot_set_ftrace_filter(tr, node) do {} while (0)
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#endif
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static void __init
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trace_boot_enable_tracer(struct trace_array *tr, struct xbc_node *node)
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{
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const char *p;
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trace_boot_set_ftrace_filter(tr, node);
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p = xbc_node_find_value(node, "tracer", NULL);
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if (p && *p != '\0') {
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if (tracing_set_tracer(tr, p) < 0)
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pr_err("Failed to set given tracer: %s\n", p);
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}
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/* Since tracer can free snapshot buffer, allocate snapshot here.*/
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if (xbc_node_find_value(node, "alloc_snapshot", NULL)) {
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if (tracing_alloc_snapshot_instance(tr) < 0)
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pr_err("Failed to allocate snapshot buffer\n");
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}
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}
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static void __init
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trace_boot_init_one_instance(struct trace_array *tr, struct xbc_node *node)
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{
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trace_boot_set_instance_options(tr, node);
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trace_boot_init_events(tr, node);
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trace_boot_enable_events(tr, node);
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trace_boot_enable_tracer(tr, node);
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}
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static void __init
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trace_boot_init_instances(struct xbc_node *node)
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{
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struct xbc_node *inode;
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struct trace_array *tr;
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const char *p;
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node = xbc_node_find_child(node, "instance");
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if (!node)
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return;
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xbc_node_for_each_child(node, inode) {
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p = xbc_node_get_data(inode);
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if (!p || *p == '\0')
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continue;
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tr = trace_array_get_by_name(p);
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if (!tr) {
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pr_err("Failed to get trace instance %s\n", p);
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continue;
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}
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trace_boot_init_one_instance(tr, inode);
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trace_array_put(tr);
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}
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}
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static int __init trace_boot_init(void)
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{
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struct xbc_node *trace_node;
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struct trace_array *tr;
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trace_node = xbc_find_node("ftrace");
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if (!trace_node)
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return 0;
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tr = top_trace_array();
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if (!tr)
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return 0;
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/* Global trace array is also one instance */
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trace_boot_init_one_instance(tr, trace_node);
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trace_boot_init_instances(trace_node);
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disable_tracing_selftest("running boot-time tracing");
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return 0;
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}
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/*
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* Start tracing at the end of core-initcall, so that it starts tracing
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* from the beginning of postcore_initcall.
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*/
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core_initcall_sync(trace_boot_init);
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