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authorSoeren Sandmann <sandmann@daimi.au.dk>2008-05-11 23:28:50 -0400
committerThomas Gleixner <tglx@linutronix.de>2008-05-23 17:59:12 -0400
commitcf3271a73b612a03da00681ecd9bfefab37c74c9 (patch)
treefa4423bf262449aedea54a1145e6b10deefc3bf7 /kernel/trace
parent8a9e94c1fbfdac45a3b6811b880777c4116aa309 (diff)
ftrace/sysprof: don't trace the user stack if we are a kernel thread.
Check that current->mm is non-NULL before attempting to trace the user stack. Also take depth of the kernel stack into account when comparing against sample_max_depth. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/trace')
-rw-r--r--kernel/trace/trace_sysprof.c50
1 files changed, 29 insertions, 21 deletions
diff --git a/kernel/trace/trace_sysprof.c b/kernel/trace/trace_sysprof.c
index fe23d6dba7f1..2301e1e7c606 100644
--- a/kernel/trace/trace_sysprof.c
+++ b/kernel/trace/trace_sysprof.c
@@ -95,13 +95,12 @@ const static struct stacktrace_ops backtrace_ops = {
95 .address = backtrace_address, 95 .address = backtrace_address,
96}; 96};
97 97
98static struct pt_regs * 98static int
99trace_kernel(struct pt_regs *regs, struct trace_array *tr, 99trace_kernel(struct pt_regs *regs, struct trace_array *tr,
100 struct trace_array_cpu *data) 100 struct trace_array_cpu *data)
101{ 101{
102 struct backtrace_info info; 102 struct backtrace_info info;
103 unsigned long bp; 103 unsigned long bp;
104 char *user_stack;
105 char *stack; 104 char *stack;
106 105
107 info.tr = tr; 106 info.tr = tr;
@@ -119,10 +118,7 @@ trace_kernel(struct pt_regs *regs, struct trace_array *tr,
119 118
120 dump_trace(NULL, regs, (void *)stack, bp, &backtrace_ops, &info); 119 dump_trace(NULL, regs, (void *)stack, bp, &backtrace_ops, &info);
121 120
122 /* Now trace the user stack */ 121 return info.pos;
123 user_stack = ((char *)current->thread.sp0 - sizeof(struct pt_regs));
124
125 return (struct pt_regs *)user_stack;
126} 122}
127 123
128static void timer_notify(struct pt_regs *regs, int cpu) 124static void timer_notify(struct pt_regs *regs, int cpu)
@@ -150,32 +146,44 @@ static void timer_notify(struct pt_regs *regs, int cpu)
150 __trace_special(tr, data, 0, 0, current->pid); 146 __trace_special(tr, data, 0, 0, current->pid);
151 147
152 if (!is_user) 148 if (!is_user)
153 regs = trace_kernel(regs, tr, data); 149 i = trace_kernel(regs, tr, data);
150 else
151 i = 0;
154 152
155 fp = (void __user *)regs->bp; 153 /*
154 * Trace user stack if we are not a kernel thread
155 */
156 if (current->mm && i < sample_max_depth) {
157 regs = (struct pt_regs *)current->thread.sp0 - 1;
156 158
157 __trace_special(tr, data, 2, regs->ip, 0); 159 fp = (void __user *)regs->bp;
158 160
159 for (i = 0; i < sample_max_depth; i++) { 161 __trace_special(tr, data, 2, regs->ip, 0);
160 frame.next_fp = 0;
161 frame.return_address = 0;
162 if (!copy_stack_frame(fp, &frame))
163 break;
164 if ((unsigned long)fp < regs->sp)
165 break;
166 162
167 __trace_special(tr, data, 2, frame.return_address, 163 while (i < sample_max_depth) {
168 (unsigned long)fp); 164 frame.next_fp = 0;
169 fp = frame.next_fp; 165 frame.return_address = 0;
170 } 166 if (!copy_stack_frame(fp, &frame))
167 break;
168 if ((unsigned long)fp < regs->sp)
169 break;
171 170
172 __trace_special(tr, data, 3, current->pid, i); 171 __trace_special(tr, data, 2, frame.return_address,
172 (unsigned long)fp);
173 fp = frame.next_fp;
174
175 i++;
176 }
177
178 }
173 179
174 /* 180 /*
175 * Special trace entry if we overflow the max depth: 181 * Special trace entry if we overflow the max depth:
176 */ 182 */
177 if (i == sample_max_depth) 183 if (i == sample_max_depth)
178 __trace_special(tr, data, -1, -1, -1); 184 __trace_special(tr, data, -1, -1, -1);
185
186 __trace_special(tr, data, 3, current->pid, i);
179} 187}
180 188
181static enum hrtimer_restart stack_trace_timer_fn(struct hrtimer *hrtimer) 189static enum hrtimer_restart stack_trace_timer_fn(struct hrtimer *hrtimer)