tracing: Still trace filtered irq functions when irq trace is disabled
If a function is set to be traced by the set_graph_function, but the option funcgraph-irqs is zero, and the traced function happens to be called from a interrupt, it will not be traced. The point of funcgraph-irqs is to not trace interrupts when we are preempted by an irq, not to not trace functions we want to trace that happen to be *in* a irq. Luckily the current->trace_recursion element is perfect to add a flag to help us be able to trace functions within an interrupt even when we are not tracing interrupts that preempt the trace. Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com> Tested-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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@ -278,6 +278,29 @@ struct tracer {
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};
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};
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/* Only current can touch trace_recursion */
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#define trace_recursion_inc() do { (current)->trace_recursion++; } while (0)
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#define trace_recursion_dec() do { (current)->trace_recursion--; } while (0)
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/* Ring buffer has the 10 LSB bits to count */
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#define trace_recursion_buffer() ((current)->trace_recursion & 0x3ff)
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/* for function tracing recursion */
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#define TRACE_INTERNAL_BIT (1<<11)
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#define TRACE_GLOBAL_BIT (1<<12)
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/*
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* Abuse of the trace_recursion.
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* As we need a way to maintain state if we are tracing the function
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* graph in irq because we want to trace a particular function that
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* was called in irq context but we have irq tracing off. Since this
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* can only be modified by current, we can reuse trace_recursion.
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*/
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#define TRACE_IRQ_BIT (1<<13)
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#define trace_recursion_set(bit) do { (current)->trace_recursion |= (bit); } while (0)
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#define trace_recursion_clear(bit) do { (current)->trace_recursion &= ~(bit); } while (0)
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#define trace_recursion_test(bit) ((current)->trace_recursion & (bit))
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#define TRACE_PIPE_ALL_CPU -1
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#define TRACE_PIPE_ALL_CPU -1
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int tracer_init(struct tracer *t, struct trace_array *tr);
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int tracer_init(struct tracer *t, struct trace_array *tr);
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@ -516,8 +539,18 @@ static inline int ftrace_graph_addr(unsigned long addr)
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return 1;
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return 1;
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for (i = 0; i < ftrace_graph_count; i++) {
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for (i = 0; i < ftrace_graph_count; i++) {
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if (addr == ftrace_graph_funcs[i])
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if (addr == ftrace_graph_funcs[i]) {
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/*
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* If no irqs are to be traced, but a set_graph_function
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* is set, and called by an interrupt handler, we still
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* want to trace it.
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*/
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if (in_irq())
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trace_recursion_set(TRACE_IRQ_BIT);
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else
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trace_recursion_clear(TRACE_IRQ_BIT);
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return 1;
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return 1;
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}
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}
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}
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return 0;
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return 0;
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@ -794,19 +827,4 @@ extern const char *__stop___trace_bprintk_fmt[];
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FTRACE_ENTRY(call, struct_name, id, PARAMS(tstruct), PARAMS(print))
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FTRACE_ENTRY(call, struct_name, id, PARAMS(tstruct), PARAMS(print))
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#include "trace_entries.h"
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#include "trace_entries.h"
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/* Only current can touch trace_recursion */
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#define trace_recursion_inc() do { (current)->trace_recursion++; } while (0)
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#define trace_recursion_dec() do { (current)->trace_recursion--; } while (0)
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/* Ring buffer has the 10 LSB bits to count */
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#define trace_recursion_buffer() ((current)->trace_recursion & 0x3ff)
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/* for function tracing recursion */
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#define TRACE_INTERNAL_BIT (1<<11)
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#define TRACE_GLOBAL_BIT (1<<12)
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#define trace_recursion_set(bit) do { (current)->trace_recursion |= (bit); } while (0)
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#define trace_recursion_clear(bit) do { (current)->trace_recursion &= ~(bit); } while (0)
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#define trace_recursion_test(bit) ((current)->trace_recursion & (bit))
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#endif /* _LINUX_KERNEL_TRACE_H */
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#endif /* _LINUX_KERNEL_TRACE_H */
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@ -227,7 +227,7 @@ int __trace_graph_entry(struct trace_array *tr,
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static inline int ftrace_graph_ignore_irqs(void)
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static inline int ftrace_graph_ignore_irqs(void)
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{
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{
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if (!ftrace_graph_skip_irqs)
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if (!ftrace_graph_skip_irqs || trace_recursion_test(TRACE_IRQ_BIT))
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return 0;
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return 0;
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return in_irq();
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return in_irq();
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