Commit e4a3f541f0b67fdad98b326c851dfe7f4b6b6dad
Committed by
Steven Rostedt
Steven Rostedt
1 parent
e08fbb78f0
Exists in
master
and in
4 other branches
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>
Showing 2 changed files with 35 additions and 17 deletions Side-by-side Diff
kernel/trace/trace.h
| ... | ... | @@ -278,6 +278,29 @@ |
| 278 | 278 | }; |
| 279 | 279 | |
| 280 | 280 | |
| 281 | +/* Only current can touch trace_recursion */ | |
| 282 | +#define trace_recursion_inc() do { (current)->trace_recursion++; } while (0) | |
| 283 | +#define trace_recursion_dec() do { (current)->trace_recursion--; } while (0) | |
| 284 | + | |
| 285 | +/* Ring buffer has the 10 LSB bits to count */ | |
| 286 | +#define trace_recursion_buffer() ((current)->trace_recursion & 0x3ff) | |
| 287 | + | |
| 288 | +/* for function tracing recursion */ | |
| 289 | +#define TRACE_INTERNAL_BIT (1<<11) | |
| 290 | +#define TRACE_GLOBAL_BIT (1<<12) | |
| 291 | +/* | |
| 292 | + * Abuse of the trace_recursion. | |
| 293 | + * As we need a way to maintain state if we are tracing the function | |
| 294 | + * graph in irq because we want to trace a particular function that | |
| 295 | + * was called in irq context but we have irq tracing off. Since this | |
| 296 | + * can only be modified by current, we can reuse trace_recursion. | |
| 297 | + */ | |
| 298 | +#define TRACE_IRQ_BIT (1<<13) | |
| 299 | + | |
| 300 | +#define trace_recursion_set(bit) do { (current)->trace_recursion |= (bit); } while (0) | |
| 301 | +#define trace_recursion_clear(bit) do { (current)->trace_recursion &= ~(bit); } while (0) | |
| 302 | +#define trace_recursion_test(bit) ((current)->trace_recursion & (bit)) | |
| 303 | + | |
| 281 | 304 | #define TRACE_PIPE_ALL_CPU -1 |
| 282 | 305 | |
| 283 | 306 | int tracer_init(struct tracer *t, struct trace_array *tr); |
| 284 | 307 | |
| ... | ... | @@ -516,8 +539,18 @@ |
| 516 | 539 | return 1; |
| 517 | 540 | |
| 518 | 541 | for (i = 0; i < ftrace_graph_count; i++) { |
| 519 | - if (addr == ftrace_graph_funcs[i]) | |
| 542 | + if (addr == ftrace_graph_funcs[i]) { | |
| 543 | + /* | |
| 544 | + * If no irqs are to be traced, but a set_graph_function | |
| 545 | + * is set, and called by an interrupt handler, we still | |
| 546 | + * want to trace it. | |
| 547 | + */ | |
| 548 | + if (in_irq()) | |
| 549 | + trace_recursion_set(TRACE_IRQ_BIT); | |
| 550 | + else | |
| 551 | + trace_recursion_clear(TRACE_IRQ_BIT); | |
| 520 | 552 | return 1; |
| 553 | + } | |
| 521 | 554 | } |
| 522 | 555 | |
| 523 | 556 | return 0; |
| ... | ... | @@ -793,21 +826,6 @@ |
| 793 | 826 | #define FTRACE_ENTRY_DUP(call, struct_name, id, tstruct, print) \ |
| 794 | 827 | FTRACE_ENTRY(call, struct_name, id, PARAMS(tstruct), PARAMS(print)) |
| 795 | 828 | #include "trace_entries.h" |
| 796 | - | |
| 797 | -/* Only current can touch trace_recursion */ | |
| 798 | -#define trace_recursion_inc() do { (current)->trace_recursion++; } while (0) | |
| 799 | -#define trace_recursion_dec() do { (current)->trace_recursion--; } while (0) | |
| 800 | - | |
| 801 | -/* Ring buffer has the 10 LSB bits to count */ | |
| 802 | -#define trace_recursion_buffer() ((current)->trace_recursion & 0x3ff) | |
| 803 | - | |
| 804 | -/* for function tracing recursion */ | |
| 805 | -#define TRACE_INTERNAL_BIT (1<<11) | |
| 806 | -#define TRACE_GLOBAL_BIT (1<<12) | |
| 807 | - | |
| 808 | -#define trace_recursion_set(bit) do { (current)->trace_recursion |= (bit); } while (0) | |
| 809 | -#define trace_recursion_clear(bit) do { (current)->trace_recursion &= ~(bit); } while (0) | |
| 810 | -#define trace_recursion_test(bit) ((current)->trace_recursion & (bit)) | |
| 811 | 829 | |
| 812 | 830 | #endif /* _LINUX_KERNEL_TRACE_H */ |
kernel/trace/trace_functions_graph.c