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ksym_tracer: Remove trace_stat
trace_stat is problematic. Don't use it, use seqfile instead. This fixes a race that reading the stat file is not protected by any lock, which can lead to use after free. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: K.Prasad <prasad@linux.vnet.ibm.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <4B3AF203.40200@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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parent
e6d9491bf8
commit
53ab668064
1 changed files with 56 additions and 83 deletions
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@ -26,7 +26,6 @@
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#include <linux/fs.h>
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#include "trace_output.h"
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#include "trace_stat.h"
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#include "trace.h"
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#include <linux/hw_breakpoint.h>
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@ -444,103 +443,77 @@ struct tracer ksym_tracer __read_mostly =
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.print_line = ksym_trace_output
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};
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__init static int init_ksym_trace(void)
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{
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struct dentry *d_tracer;
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struct dentry *entry;
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d_tracer = tracing_init_dentry();
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ksym_filter_entry_count = 0;
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entry = debugfs_create_file("ksym_trace_filter", 0644, d_tracer,
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NULL, &ksym_tracing_fops);
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if (!entry)
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pr_warning("Could not create debugfs "
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"'ksym_trace_filter' file\n");
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return register_tracer(&ksym_tracer);
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}
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device_initcall(init_ksym_trace);
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#ifdef CONFIG_PROFILE_KSYM_TRACER
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static int ksym_tracer_stat_headers(struct seq_file *m)
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static int ksym_profile_show(struct seq_file *m, void *v)
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{
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seq_puts(m, " Access Type ");
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seq_puts(m, " Symbol Counter\n");
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seq_puts(m, " ----------- ");
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seq_puts(m, " ------ -------\n");
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return 0;
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}
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static int ksym_tracer_stat_show(struct seq_file *m, void *v)
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{
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struct hlist_node *stat = v;
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struct hlist_node *node;
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struct trace_ksym *entry;
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int access_type = 0;
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char fn_name[KSYM_NAME_LEN];
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entry = hlist_entry(stat, struct trace_ksym, ksym_hlist);
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seq_puts(m, " Access Type ");
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seq_puts(m, " Symbol Counter\n");
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seq_puts(m, " ----------- ");
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seq_puts(m, " ------ -------\n");
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access_type = entry->attr.bp_type;
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rcu_read_lock();
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hlist_for_each_entry_rcu(entry, node, &ksym_filter_head, ksym_hlist) {
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switch (access_type) {
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case HW_BREAKPOINT_R:
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seq_puts(m, " R ");
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break;
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case HW_BREAKPOINT_W:
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seq_puts(m, " W ");
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break;
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case HW_BREAKPOINT_R | HW_BREAKPOINT_W:
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seq_puts(m, " RW ");
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break;
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default:
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seq_puts(m, " NA ");
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access_type = entry->attr.bp_type;
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switch (access_type) {
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case HW_BREAKPOINT_R:
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seq_puts(m, " R ");
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break;
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case HW_BREAKPOINT_W:
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seq_puts(m, " W ");
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break;
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case HW_BREAKPOINT_R | HW_BREAKPOINT_W:
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seq_puts(m, " RW ");
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break;
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default:
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seq_puts(m, " NA ");
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}
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if (lookup_symbol_name(entry->attr.bp_addr, fn_name) >= 0)
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seq_printf(m, " %-36s", fn_name);
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else
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seq_printf(m, " %-36s", "<NA>");
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seq_printf(m, " %15llu\n",
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(unsigned long long)atomic64_read(&entry->counter));
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}
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if (lookup_symbol_name(entry->attr.bp_addr, fn_name) >= 0)
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seq_printf(m, " %-36s", fn_name);
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else
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seq_printf(m, " %-36s", "<NA>");
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seq_printf(m, " %15llu\n",
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(unsigned long long)atomic64_read(&entry->counter));
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rcu_read_unlock();
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return 0;
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}
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static void *ksym_tracer_stat_start(struct tracer_stat *trace)
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static int ksym_profile_open(struct inode *node, struct file *file)
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{
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return ksym_filter_head.first;
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return single_open(file, ksym_profile_show, NULL);
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}
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static void *
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ksym_tracer_stat_next(void *v, int idx)
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{
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struct hlist_node *stat = v;
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return stat->next;
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}
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static struct tracer_stat ksym_tracer_stats = {
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.name = "ksym_tracer",
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.stat_start = ksym_tracer_stat_start,
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.stat_next = ksym_tracer_stat_next,
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.stat_headers = ksym_tracer_stat_headers,
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.stat_show = ksym_tracer_stat_show
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static const struct file_operations ksym_profile_fops = {
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.open = ksym_profile_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = single_release,
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};
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__init static int ksym_tracer_stat_init(void)
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{
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int ret;
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ret = register_stat_tracer(&ksym_tracer_stats);
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if (ret) {
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printk(KERN_WARNING "Warning: could not register "
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"ksym tracer stats\n");
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return 1;
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}
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return 0;
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}
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fs_initcall(ksym_tracer_stat_init);
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#endif /* CONFIG_PROFILE_KSYM_TRACER */
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__init static int init_ksym_trace(void)
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{
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struct dentry *d_tracer;
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d_tracer = tracing_init_dentry();
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trace_create_file("ksym_trace_filter", 0644, d_tracer,
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NULL, &ksym_tracing_fops);
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#ifdef CONFIG_PROFILE_KSYM_TRACER
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trace_create_file("ksym_profile", 0444, d_tracer,
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NULL, &ksym_profile_fops);
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#endif
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return register_tracer(&ksym_tracer);
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}
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device_initcall(init_ksym_trace);
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