diff options
| -rw-r--r-- | samples/fprobe/fprobe_example.c | 29 |
1 files changed, 25 insertions, 4 deletions
diff --git a/samples/fprobe/fprobe_example.c b/samples/fprobe/fprobe_example.c index 24d3cf109140..01ee6c8c8382 100644 --- a/samples/fprobe/fprobe_example.c +++ b/samples/fprobe/fprobe_example.c @@ -21,6 +21,7 @@ #define BACKTRACE_DEPTH 16 #define MAX_SYMBOL_LEN 4096 struct fprobe sample_probe; +static unsigned long nhit; static char symbol[MAX_SYMBOL_LEN] = "kernel_clone"; module_param_string(symbol, symbol, sizeof(symbol), 0644); @@ -28,6 +29,8 @@ static char nosymbol[MAX_SYMBOL_LEN] = ""; module_param_string(nosymbol, nosymbol, sizeof(nosymbol), 0644); static bool stackdump = true; module_param(stackdump, bool, 0644); +static bool use_trace = false; +module_param(use_trace, bool, 0644); static void show_backtrace(void) { @@ -40,7 +43,15 @@ static void show_backtrace(void) static void sample_entry_handler(struct fprobe *fp, unsigned long ip, struct pt_regs *regs) { - pr_info("Enter <%pS> ip = 0x%p\n", (void *)ip, (void *)ip); + if (use_trace) + /* + * This is just an example, no kernel code should call + * trace_printk() except when actively debugging. + */ + trace_printk("Enter <%pS> ip = 0x%p\n", (void *)ip, (void *)ip); + else + pr_info("Enter <%pS> ip = 0x%p\n", (void *)ip, (void *)ip); + nhit++; if (stackdump) show_backtrace(); } @@ -49,8 +60,17 @@ static void sample_exit_handler(struct fprobe *fp, unsigned long ip, struct pt_r { unsigned long rip = instruction_pointer(regs); - pr_info("Return from <%pS> ip = 0x%p to rip = 0x%p (%pS)\n", - (void *)ip, (void *)ip, (void *)rip, (void *)rip); + if (use_trace) + /* + * This is just an example, no kernel code should call + * trace_printk() except when actively debugging. + */ + trace_printk("Return from <%pS> ip = 0x%p to rip = 0x%p (%pS)\n", + (void *)ip, (void *)ip, (void *)rip, (void *)rip); + else + pr_info("Return from <%pS> ip = 0x%p to rip = 0x%p (%pS)\n", + (void *)ip, (void *)ip, (void *)rip, (void *)rip); + nhit++; if (stackdump) show_backtrace(); } @@ -112,7 +132,8 @@ static void __exit fprobe_exit(void) { unregister_fprobe(&sample_probe); - pr_info("fprobe at %s unregistered\n", symbol); + pr_info("fprobe at %s unregistered. %ld times hit, %ld times missed\n", + symbol, nhit, sample_probe.nmissed); } module_init(fprobe_init) |