user/sven/linux.git/include/trace/ftrace.h, branch v3.12.6

tracing: Allow events to have NULL strings

2013-12-04T19:05:56Z

commit 4e58e54754dc1fec21c3a9e824bc108b05fdf46e upstream. If an TRACE_EVENT() uses __assign_str() or __get_str on a NULL pointer then the following oops will happen: BUG: unable to handle kernel NULL pointer dereference at (null) IP: [] strlen+0x10/0x1a *pde = 00000000 ^M Oops: 0000 [#1] PREEMPT SMP Modules linked in: CPU: 1 PID: 0 Comm: swapper/1 Not tainted 3.13.0-rc1-test+ #2 Hardware name: /DG965MQ, BIOS MQ96510J.86A.0372.2006.0605.1717 06/05/2006^M task: f5cde9f0 ti: f5e5e000 task.ti: f5e5e000 EIP: 0060:[] EFLAGS: 00210046 CPU: 1 EIP is at strlen+0x10/0x1a EAX: 00000000 EBX: c2472da8 ECX: ffffffff EDX: c2472da8 ESI: c1c5e5fc EDI: 00000000 EBP: f5e5fe84 ESP: f5e5fe80 DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 CR0: 8005003b CR2: 00000000 CR3: 01f32000 CR4: 000007d0 Stack: f5f18b90 f5e5feb8 c10687a8 0759004f 00000005 00000005 00000005 00200046 00000002 00000000 c1082a93 f56c7e28 c2472da8 c1082a93 f5e5fee4 c106bc61^M 00000000 c1082a93 00000000 00000000 00000001 00200046 00200082 00000000 Call Trace: [] ftrace_raw_event_lock+0x39/0xc0 [] ? ktime_get+0x29/0x69 [] ? ktime_get+0x29/0x69 [] lock_release+0x57/0x1a5 [] ? ktime_get+0x29/0x69 [] read_seqcount_begin.constprop.7+0x4d/0x75 [] ? ktime_get+0x29/0x69^M [] ktime_get+0x29/0x69 [] __tick_nohz_idle_enter+0x1e/0x426 [] ? lock_release_holdtime.part.19+0x48/0x4d [] ? time_hardirqs_off+0xe/0x28 [] ? trace_hardirqs_off_caller+0x3f/0xaf [] tick_nohz_idle_enter+0x59/0x62 [] cpu_startup_entry+0x64/0x192 [] start_secondary+0x277/0x27c Code: 90 89 c6 89 d0 88 c4 ac 38 e0 74 09 84 c0 75 f7 be 01 00 00 00 89 f0 48 5e 5d c3 55 89 e5 57 66 66 66 66 90 83 c9 ff 89 c7 31 c0 ae f7 d1 8d 41 ff 5f 5d c3 55 89 e5 57 66 66 66 66 90 31 ff EIP: [] strlen+0x10/0x1a SS:ESP 0068:f5e5fe80 CR2: 0000000000000000 ---[ end trace 01bc47bf519ec1b2 ]--- New tracepoints have been added that have allowed for NULL pointers being assigned to strings. To fix this, change the TRACE_EVENT() code to check for NULL and if it is, it will assign "(null)" to it instead (similar to what glibc printf does). Reported-by: Shuah Khan Reported-by: Jovi Zhangwei Link: http://lkml.kernel.org/r/CAGdX0WFeEuy+DtpsJzyzn0343qEEjLX97+o1VREFkUEhndC+5Q@mail.gmail.com Link: http://lkml.kernel.org/r/528D6972.9010702@samsung.com Fixes: 9cbf117662e2 ("tracing/events: provide string with undefined size support") Signed-off-by: Steven Rostedt Signed-off-by: Greg Kroah-Hartman

tracing/perf: Avoid perf_trace_buf_*() in perf_trace_##call() when possible

2013-08-14T01:06:30Z

perf_trace_buf_prepare() + perf_trace_buf_submit(task => NULL) make no sense if hlist_empty(head). Change perf_trace_##call() to check ->perf_events beforehand and do nothing if it is empty. This removes the overhead for tasks without events associated with them. For example, "perf record -e sched:sched_switch -p1" attaches the counter(s) to the single task, but every task in system will do perf_trace_buf_prepare/submit() just to realize that it was not attached to this event. However, we can only do this if __task == NULL, so we also add the __builtin_constant_p(__task) check. With this patch "perf bench sched pipe" shows approximately 4% improvement when "perf record -p1" runs in parallel, many thanks to Steven for the testing. Link: http://lkml.kernel.org/r/20130806160847.GA2746@redhat.com Tested-by: David Ahern Acked-by: Peter Zijlstra Signed-off-by: Oleg Nesterov Signed-off-by: Steven Rostedt

tracing/perf: Reimplement TP_perf_assign() logic

2013-08-14T01:05:57Z

The next patch tries to avoid the costly perf_trace_buf_* calls when possible but there is a problem. We can only do this if __task == NULL, perf_tp_event(task != NULL) has the additional code for this case. Unfortunately, TP_perf_assign/__perf_xxx which changes the default values of __count/__task variables for perf_trace_buf_submit() is called "too late", after we already did perf_trace_buf_prepare(), and the optimization above can't work. So this patch simply embeds __perf_xxx() into TP_ARGS(), this way DECLARE_EVENT_CLASS() can use the result of assignments hidden in "args" right after ftrace_get_offsets_##call() which is mostly trivial. This allows us to have the fast-path "__task != NULL" check at the start, see the next patch. Link: http://lkml.kernel.org/r/20130806160844.GA2739@redhat.com Tested-by: David Ahern Acked-by: Peter Zijlstra Signed-off-by: Oleg Nesterov Signed-off-by: Steven Rostedt

tracing/perf: Expand TRACE_EVENT(sched_stat_runtime)

2013-08-14T01:05:12Z

To simplify the review of the next patches: 1. We are going to reimplent __perf_task/counter and embedd them into TP_ARGS(). expand TRACE_EVENT(sched_stat_runtime) into DECLARE_EVENT_CLASS() + DEFINE_EVENT(), this way they can use different TP_ARGS's. 2. Change perf_trace_##call() macro to do perf_fetch_caller_regs() right before perf_trace_buf_prepare(). This way it evaluates TP_ARGS() asap, the next patch explores this fact. Note: after 87f44bbc perf_trace_buf_prepare() doesn't need "struct pt_regs *regs", perhaps it makes sense to remove this argument. And perhaps we can teach perf_trace_buf_submit() to accept regs == NULL and do fetch_caller_regs(CALLER_ADDR1) in this case. 3. Cosmetic, but the typecast from "void*" buys nothing. It just adds the noise, remove it. Link: http://lkml.kernel.org/r/20130806160841.GA2736@redhat.com Acked-by: Peter Zijlstra Tested-by: David Ahern Signed-off-by: Oleg Nesterov Signed-off-by: Steven Rostedt

tracing/perf: Move the PERF_MAX_TRACE_SIZE check into perf_trace_buf_prepare()

2013-07-19T01:31:28Z

Every perf_trace_buf_prepare() caller does WARN_ONCE(size > PERF_MAX_TRACE_SIZE, message) and "message" is almost the same. Shift this WARN_ONCE() into perf_trace_buf_prepare(). This changes the meaning of _ONCE, but I think this is fine. - 4947014 2932448 10104832 17984294 1126b26 vmlinux + 4948422 2932448 10104832 17985702 11270a6 vmlinux on my build. Link: http://lkml.kernel.org/r/20130617170211.GA19813@redhat.com Acked-by: Peter Zijlstra Signed-off-by: Oleg Nesterov Signed-off-by: Steven Rostedt

tracing: Add DEFINE_EVENT_FN() macro

2013-06-21T05:24:32Z

Each TRACE_EVENT() adds several helper functions. If two or more trace events share the same structure and print format, they can also share most of these helper functions and save a lot of space from duplicate code. This is why the DECLARE_EVENT_CLASS() and DEFINE_EVENT() were created. Some events require a trigger to be called at registering and unregistering of the event and to do so they use TRACE_EVENT_FN(). If multiple events require a trigger, they currently have no choice but to use TRACE_EVENT_FN() as there's no DEFINE_EVENT_FN() available. This unfortunately causes a lot of wasted duplicate code created. By adding a DEFINE_EVENT_FN(), these events can still use a DECLARE_EVENT_CLASS() and then define their own triggers. Signed-off-by: Steven Rostedt Link: http://lkml.kernel.org/r/51C3236C.8030508@hds.com Signed-off-by: Seiji Aguchi Signed-off-by: H. Peter Anvin

tracing: Remove obsolete macro guard _TRACE_PROFILE_INIT

2013-04-13T03:02:33Z

The macro _TRACE_PROFILE_INIT was removed a long time ago, but an "#undef" guard was left behind. Remove it. Link: http://lkml.kernel.org/r/514684EE.6000805@huawei.com Signed-off-by: zhangwei(Jovi) Signed-off-by: Steven Rostedt

tracing: Add a way to soft disable trace events

2013-03-15T04:36:03Z

In order to let triggers enable or disable events, we need a 'soft' method for doing so. For example, if a function probe is added that lets a user enable or disable events when a function is called, that change must be done without taking locks or a mutex, and definitely it can't sleep. But the full enabling of a tracepoint is expensive. By adding a 'SOFT_DISABLE' flag, and converting the flags to be updated without the protection of a mutex (using set/clear_bit()), this soft disable flag can be used to allow critical sections to enable or disable events from being traced (after the event has been placed into "SOFT_MODE"). Some caveats though: The comm recorder (to map pids with a comm) can not be soft disabled (yet). If you disable an event with with a "soft" disable and wait a while before reading the trace, the comm cache may be replaced and you'll get a bunch of <...> for comms in the trace. Reading the "enable" file for an event that is disabled will now give you "0*" where the '*' denotes that the tracepoint is still active but the event itself is "disabled". [ fixed _BIT used in & operation : thanks to Dan Carpenter and smatch ] Cc: Dan Carpenter Cc: Tom Zanussi Signed-off-by: Steven Rostedt

tracing: Fix some section mismatch warnings

2013-03-15T04:34:54Z

As we've added __init annotation to field-defining functions, we should add __refdata annotation to event_call variables, which reference those functions. Link: http://lkml.kernel.org/r/51343C1F.2050502@huawei.com Reported-by: Fengguang Wu Signed-off-by: Li Zefan Signed-off-by: Steven Rostedt

tracing: Annotate event field-defining functions with __init

2013-03-15T04:34:51Z

Those functions are called either during kernel boot or module init. Before: $ dmesg | grep 'Freeing unused kernel memory' Freeing unused kernel memory: 1208k freed Freeing unused kernel memory: 1360k freed Freeing unused kernel memory: 1960k freed After: $ dmesg | grep 'Freeing unused kernel memory' Freeing unused kernel memory: 1236k freed Freeing unused kernel memory: 1388k freed Freeing unused kernel memory: 1960k freed Link: http://lkml.kernel.org/r/5125877D.5000201@huawei.com Signed-off-by: Li Zefan Signed-off-by: Steven Rostedt