diff options
Diffstat (limited to 'kernel/trace/trace.c')
| -rw-r--r-- | kernel/trace/trace.c | 170 |
1 files changed, 123 insertions, 47 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 9d20cd9743ef..815c878f409b 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -455,6 +455,9 @@ int __trace_puts(unsigned long ip, const char *str, int size) unsigned long irq_flags; int alloc; + if (unlikely(tracing_selftest_running || tracing_disabled)) + return 0; + alloc = sizeof(*entry) + size + 2; /* possible \n added */ local_save_flags(irq_flags); @@ -495,6 +498,9 @@ int __trace_bputs(unsigned long ip, const char *str) unsigned long irq_flags; int size = sizeof(struct bputs_entry); + if (unlikely(tracing_selftest_running || tracing_disabled)) + return 0; + local_save_flags(irq_flags); buffer = global_trace.trace_buffer.buffer; event = trace_buffer_lock_reserve(buffer, TRACE_BPUTS, size, @@ -595,6 +601,28 @@ void free_snapshot(struct trace_array *tr) } /** + * tracing_alloc_snapshot - allocate snapshot buffer. + * + * This only allocates the snapshot buffer if it isn't already + * allocated - it doesn't also take a snapshot. + * + * This is meant to be used in cases where the snapshot buffer needs + * to be set up for events that can't sleep but need to be able to + * trigger a snapshot. + */ +int tracing_alloc_snapshot(void) +{ + struct trace_array *tr = &global_trace; + int ret; + + ret = alloc_snapshot(tr); + WARN_ON(ret < 0); + + return ret; +} +EXPORT_SYMBOL_GPL(tracing_alloc_snapshot); + +/** * trace_snapshot_alloc - allocate and take a snapshot of the current buffer. * * This is similar to trace_snapshot(), but it will allocate the @@ -607,11 +635,10 @@ void free_snapshot(struct trace_array *tr) */ void tracing_snapshot_alloc(void) { - struct trace_array *tr = &global_trace; int ret; - ret = alloc_snapshot(tr); - if (WARN_ON(ret < 0)) + ret = tracing_alloc_snapshot(); + if (ret < 0) return; tracing_snapshot(); @@ -623,6 +650,12 @@ void tracing_snapshot(void) WARN_ONCE(1, "Snapshot feature not enabled, but internal snapshot used"); } EXPORT_SYMBOL_GPL(tracing_snapshot); +int tracing_alloc_snapshot(void) +{ + WARN_ONCE(1, "Snapshot feature not enabled, but snapshot allocation used"); + return -ENODEV; +} +EXPORT_SYMBOL_GPL(tracing_alloc_snapshot); void tracing_snapshot_alloc(void) { /* Give warning */ @@ -3156,19 +3189,23 @@ tracing_write_stub(struct file *filp, const char __user *ubuf, return count; } -static loff_t tracing_seek(struct file *file, loff_t offset, int origin) +loff_t tracing_lseek(struct file *file, loff_t offset, int whence) { + int ret; + if (file->f_mode & FMODE_READ) - return seq_lseek(file, offset, origin); + ret = seq_lseek(file, offset, whence); else - return 0; + file->f_pos = ret = 0; + + return ret; } static const struct file_operations tracing_fops = { .open = tracing_open, .read = seq_read, .write = tracing_write_stub, - .llseek = tracing_seek, + .llseek = tracing_lseek, .release = tracing_release, }; @@ -3488,60 +3525,103 @@ static const char readme_msg[] = " instances\t\t- Make sub-buffers with: mkdir instances/foo\n" "\t\t\t Remove sub-buffer with rmdir\n" " trace_options\t\t- Set format or modify how tracing happens\n" - "\t\t\t Disable an option by adding a suffix 'no' to the option name\n" + "\t\t\t Disable an option by adding a suffix 'no' to the\n" + "\t\t\t option name\n" #ifdef CONFIG_DYNAMIC_FTRACE "\n available_filter_functions - list of functions that can be filtered on\n" - " set_ftrace_filter\t- echo function name in here to only trace these functions\n" - " accepts: func_full_name, *func_end, func_begin*, *func_middle*\n" - " modules: Can select a group via module\n" - " Format: :mod:<module-name>\n" - " example: echo :mod:ext3 > set_ftrace_filter\n" - " triggers: a command to perform when function is hit\n" - " Format: <function>:<trigger>[:count]\n" - " trigger: traceon, traceoff\n" - " enable_event:<system>:<event>\n" - " disable_event:<system>:<event>\n" + " set_ftrace_filter\t- echo function name in here to only trace these\n" + "\t\t\t functions\n" + "\t accepts: func_full_name, *func_end, func_begin*, *func_middle*\n" + "\t modules: Can select a group via module\n" + "\t Format: :mod:<module-name>\n" + "\t example: echo :mod:ext3 > set_ftrace_filter\n" + "\t triggers: a command to perform when function is hit\n" + "\t Format: <function>:<trigger>[:count]\n" + "\t trigger: traceon, traceoff\n" + "\t\t enable_event:<system>:<event>\n" + "\t\t disable_event:<system>:<event>\n" #ifdef CONFIG_STACKTRACE - " stacktrace\n" + "\t\t stacktrace\n" #endif #ifdef CONFIG_TRACER_SNAPSHOT - " snapshot\n" + "\t\t snapshot\n" #endif - " example: echo do_fault:traceoff > set_ftrace_filter\n" - " echo do_trap:traceoff:3 > set_ftrace_filter\n" - " The first one will disable tracing every time do_fault is hit\n" - " The second will disable tracing at most 3 times when do_trap is hit\n" - " The first time do trap is hit and it disables tracing, the counter\n" - " will decrement to 2. If tracing is already disabled, the counter\n" - " will not decrement. It only decrements when the trigger did work\n" - " To remove trigger without count:\n" - " echo '!<function>:<trigger> > set_ftrace_filter\n" - " To remove trigger with a count:\n" - " echo '!<function>:<trigger>:0 > set_ftrace_filter\n" + "\t example: echo do_fault:traceoff > set_ftrace_filter\n" + "\t echo do_trap:traceoff:3 > set_ftrace_filter\n" + "\t The first one will disable tracing every time do_fault is hit\n" + "\t The second will disable tracing at most 3 times when do_trap is hit\n" + "\t The first time do trap is hit and it disables tracing, the\n" + "\t counter will decrement to 2. If tracing is already disabled,\n" + "\t the counter will not decrement. It only decrements when the\n" + "\t trigger did work\n" + "\t To remove trigger without count:\n" + "\t echo '!<function>:<trigger> > set_ftrace_filter\n" + "\t To remove trigger with a count:\n" + "\t echo '!<function>:<trigger>:0 > set_ftrace_filter\n" " set_ftrace_notrace\t- echo function name in here to never trace.\n" - " accepts: func_full_name, *func_end, func_begin*, *func_middle*\n" - " modules: Can select a group via module command :mod:\n" - " Does not accept triggers\n" + "\t accepts: func_full_name, *func_end, func_begin*, *func_middle*\n" + "\t modules: Can select a group via module command :mod:\n" + "\t Does not accept triggers\n" #endif /* CONFIG_DYNAMIC_FTRACE */ #ifdef CONFIG_FUNCTION_TRACER - " set_ftrace_pid\t- Write pid(s) to only function trace those pids (function)\n" + " set_ftrace_pid\t- Write pid(s) to only function trace those pids\n" + "\t\t (function)\n" #endif #ifdef CONFIG_FUNCTION_GRAPH_TRACER " set_graph_function\t- Trace the nested calls of a function (function_graph)\n" " max_graph_depth\t- Trace a limited depth of nested calls (0 is unlimited)\n" #endif #ifdef CONFIG_TRACER_SNAPSHOT - "\n snapshot\t\t- Like 'trace' but shows the content of the static snapshot buffer\n" - "\t\t\t Read the contents for more information\n" + "\n snapshot\t\t- Like 'trace' but shows the content of the static\n" + "\t\t\t snapshot buffer. Read the contents for more\n" + "\t\t\t information\n" #endif #ifdef CONFIG_STACK_TRACER " stack_trace\t\t- Shows the max stack trace when active\n" " stack_max_size\t- Shows current max stack size that was traced\n" - "\t\t\t Write into this file to reset the max size (trigger a new trace)\n" + "\t\t\t Write into this file to reset the max size (trigger a\n" + "\t\t\t new trace)\n" #ifdef CONFIG_DYNAMIC_FTRACE - " stack_trace_filter\t- Like set_ftrace_filter but limits what stack_trace traces\n" + " stack_trace_filter\t- Like set_ftrace_filter but limits what stack_trace\n" + "\t\t\t traces\n" #endif #endif /* CONFIG_STACK_TRACER */ + " events/\t\t- Directory containing all trace event subsystems:\n" + " enable\t\t- Write 0/1 to enable/disable tracing of all events\n" + " events/<system>/\t- Directory containing all trace events for <system>:\n" + " enable\t\t- Write 0/1 to enable/disable tracing of all <system>\n" + "\t\t\t events\n" + " filter\t\t- If set, only events passing filter are traced\n" + " events/<system>/<event>/\t- Directory containing control files for\n" + "\t\t\t <event>:\n" + " enable\t\t- Write 0/1 to enable/disable tracing of <event>\n" + " filter\t\t- If set, only events passing filter are traced\n" + " trigger\t\t- If set, a command to perform when event is hit\n" + "\t Format: <trigger>[:count][if <filter>]\n" + "\t trigger: traceon, traceoff\n" + "\t enable_event:<system>:<event>\n" + "\t disable_event:<system>:<event>\n" +#ifdef CONFIG_STACKTRACE + "\t\t stacktrace\n" +#endif +#ifdef CONFIG_TRACER_SNAPSHOT + "\t\t snapshot\n" +#endif + "\t example: echo traceoff > events/block/block_unplug/trigger\n" + "\t echo traceoff:3 > events/block/block_unplug/trigger\n" + "\t echo 'enable_event:kmem:kmalloc:3 if nr_rq > 1' > \\\n" + "\t events/block/block_unplug/trigger\n" + "\t The first disables tracing every time block_unplug is hit.\n" + "\t The second disables tracing the first 3 times block_unplug is hit.\n" + "\t The third enables the kmalloc event the first 3 times block_unplug\n" + "\t is hit and has value of greater than 1 for the 'nr_rq' event field.\n" + "\t Like function triggers, the counter is only decremented if it\n" + "\t enabled or disabled tracing.\n" + "\t To remove a trigger without a count:\n" + "\t echo '!<trigger> > <system>/<event>/trigger\n" + "\t To remove a trigger with a count:\n" + "\t echo '!<trigger>:0 > <system>/<event>/trigger\n" + "\t Filters can be ignored when removing a trigger.\n" ; static ssize_t @@ -4212,12 +4292,6 @@ out: return sret; } -static void tracing_pipe_buf_release(struct pipe_inode_info *pipe, - struct pipe_buffer *buf) -{ - __free_page(buf->page); -} - static void tracing_spd_release_pipe(struct splice_pipe_desc *spd, unsigned int idx) { @@ -4229,7 +4303,7 @@ static const struct pipe_buf_operations tracing_pipe_buf_ops = { .map = generic_pipe_buf_map, .unmap = generic_pipe_buf_unmap, .confirm = generic_pipe_buf_confirm, - .release = tracing_pipe_buf_release, + .release = generic_pipe_buf_release, .steal = generic_pipe_buf_steal, .get = generic_pipe_buf_get, }; @@ -4913,7 +4987,7 @@ static const struct file_operations snapshot_fops = { .open = tracing_snapshot_open, .read = seq_read, .write = tracing_snapshot_write, - .llseek = tracing_seek, + .llseek = tracing_lseek, .release = tracing_snapshot_release, }; @@ -5883,6 +5957,8 @@ allocate_trace_buffer(struct trace_array *tr, struct trace_buffer *buf, int size rb_flags = trace_flags & TRACE_ITER_OVERWRITE ? RB_FL_OVERWRITE : 0; + buf->tr = tr; + buf->buffer = ring_buffer_alloc(size, rb_flags); if (!buf->buffer) return -ENOMEM; |