linux/kernel/trace, branch v3.14

tracing: Fix traceon trigger condition to actually turn tracing on

2014-03-26T03:39:41Z

While working on my tutorial for 2014 Linux Collaboration Summit I found that the traceon trigger did not work when conditions were used. The other triggers worked fine though. Looking into it, it is because of the way the triggers use the ring buffer to store the fields it will use for the condition. But if tracing is off, nothing is stored in the buffer, and the tracepoint exits before calling the trigger to test the condition. This is fine for all the triggers that only work when tracing is on, but for traceon trigger that is to work when tracing is off, nothing happens. The fix is simple, just use a temp ring buffer to record the event if tracing is off and the event has a trace event conditional trigger enabled. The rest of the tracepoint code will work just fine, but the tracepoint wont be recorded in the other buffers. Cc: Tom Zanussi Signed-off-by: Steven Rostedt

tracing: Fix array size mismatch in format string

2014-03-20T17:21:05Z

In event format strings, the array size is reported in two locations. One in array subscript and then via the "size:" attribute. The values reported there have a mismatch. For e.g., in sched:sched_switch the prev_comm and next_comm character arrays have subscript values as [32] where as the actual field size is 16. name: sched_switch ID: 301 format: field:unsigned short common_type; offset:0; size:2; signed:0; field:unsigned char common_flags; offset:2; size:1; signed:0; field:unsigned char common_preempt_count; offset:3; size:1;signed:0; field:int common_pid; offset:4; size:4; signed:1; field:char prev_comm[32]; offset:8; size:16; signed:1; field:pid_t prev_pid; offset:24; size:4; signed:1; field:int prev_prio; offset:28; size:4; signed:1; field:long prev_state; offset:32; size:8; signed:1; field:char next_comm[32]; offset:40; size:16; signed:1; field:pid_t next_pid; offset:56; size:4; signed:1; field:int next_prio; offset:60; size:4; signed:1; After bisection, the following commit was blamed: 92edca0 tracing: Use direct field, type and system names This commit removes the duplication of strings for field->name and field->type assuming that all the strings passed in __trace_define_field() are immutable. This is not true for arrays, where the type string is created in event_storage variable and field->type for all array fields points to event_storage. Use __stringify() to create a string constant for the type string. Also, get rid of event_storage and event_storage_mutex that are not needed anymore. also, an added benefit is that this reduces the overhead of events a bit more: text data bss dec hex filename 8424787 2036472 1302528 11763787 b3804b vmlinux 8420814 2036408 1302528 11759750 b37086 vmlinux.patched Link: http://lkml.kernel.org/r/1392349908-29685-1-git-send-email-vnagarnaik@google.com Cc: Laurent Chavey Cc: stable@vger.kernel.org # 3.10+ Signed-off-by: Vaibhav Nagarnaik Signed-off-by: Steven Rostedt

tracing: Do not add event files for modules that fail tracepoints

2014-03-04T02:11:05Z

If a module fails to add its tracepoints due to module tainting, do not create the module event infrastructure in the debugfs directory. As the events will not work and worse yet, they will silently fail, making the user wonder why the events they enable do not display anything. Having a warning on module load and the events not visible to the users will make the cause of the problem much clearer. Link: http://lkml.kernel.org/r/20140227154923.265882695@goodmis.org Fixes: 6d723736e472 "tracing/events: add support for modules to TRACE_EVENT" Acked-by: Mathieu Desnoyers Cc: stable@vger.kernel.org # 2.6.31+ Cc: Rusty Russell Signed-off-by: Steven Rostedt

ring-buffer: Fix first commit on sub-buffer having non-zero delta

2014-02-11T18:38:54Z

Each sub-buffer (buffer page) has a full 64 bit timestamp. The events on that page use a 27 bit delta against that timestamp in order to save on bits written to the ring buffer. If the time between events is larger than what the 27 bits can hold, a "time extend" event is added to hold the entire 64 bit timestamp again and the events after that hold a delta from that timestamp. As a "time extend" is always paired with an event, it is logical to just allocate the event with the time extend, to make things a bit more efficient. Unfortunately, when the pairing code was written, it removed the "delta = 0" from the first commit on a page, causing the events on the page to be slightly skewed. Fixes: 69d1b839f7ee "ring-buffer: Bind time extend and data events together" Cc: stable@vger.kernel.org # 2.6.37+ Signed-off-by: Steven Rostedt

Merge branch 'for-3.14/core' of git://git.kernel.dk/linux-block

2014-01-30T19:19:05Z

Pull core block IO changes from Jens Axboe: "The major piece in here is the immutable bio_ve series from Kent, the rest is fairly minor. It was supposed to go in last round, but various issues pushed it to this release instead. The pull request contains: - Various smaller blk-mq fixes from different folks. Nothing major here, just minor fixes and cleanups. - Fix for a memory leak in the error path in the block ioctl code from Christian Engelmayer. - Header export fix from CaiZhiyong. - Finally the immutable biovec changes from Kent Overstreet. This enables some nice future work on making arbitrarily sized bios possible, and splitting more efficient. Related fixes to immutable bio_vecs: - dm-cache immutable fixup from Mike Snitzer. - btrfs immutable fixup from Muthu Kumar. - bio-integrity fix from Nic Bellinger, which is also going to stable" * 'for-3.14/core' of git://git.kernel.dk/linux-block: (44 commits) xtensa: fixup simdisk driver to work with immutable bio_vecs block/blk-mq-cpu.c: use hotcpu_notifier() blk-mq: for_each_* macro correctness block: Fix memory leak in rw_copy_check_uvector() handling bio-integrity: Fix bio_integrity_verify segment start bug block: remove unrelated header files and export symbol blk-mq: uses page->list incorrectly blk-mq: use __smp_call_function_single directly btrfs: fix missing increment of bi_remaining Revert "block: Warn and free bio if bi_end_io is not set" block: Warn and free bio if bi_end_io is not set blk-mq: fix initializing request's start time block: blk-mq: don't export blk_mq_free_queue() block: blk-mq: make blk_sync_queue support mq block: blk-mq: support draining mq queue dm cache: increment bi_remaining when bi_end_io is restored block: fixup for generic bio chaining block: Really silence spurious compiler warnings block: Silence spurious compiler warnings block: Kill bio_pair_split() ...

Merge tag 'trace-fixes-3.14' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

2014-01-27T16:22:30Z

Pull tracing fixes from Steven Rostedt: "The first two patches fix the debugfs README file to reflect better the new features added to 3.14. The third patch is a minor bugfix to the trace_puts() functions that will crash the system if a developer adds one before the tracing system is setup. It also affects trace_printk() if it has no arguments, as the code will convert it to a trace_puts() as well. Note, this bug will not affect unmodified kernels, as trace_printk() and trace_puts() should only be used by developers for testing" * tag 'trace-fixes-3.14' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: tracing: Check if tracing is enabled in trace_puts() tracing: Fix formatting of trace README file tracing/README: Add event file usage to tracing mini-HOWTO

tracing: Check if tracing is enabled in trace_puts()

2014-01-23T17:27:59Z

If trace_puts() is used very early in boot up, it can crash the machine if it is called before the ring buffer is allocated. If a trace_printk() is used with no arguments, then it will be converted into a trace_puts() and suffer the same fate. Cc: stable@vger.kernel.org # 3.10+ Fixes: 09ae72348ecc "tracing: Add trace_puts() for even faster trace_printk() tracing" Signed-off-by: Steven Rostedt

tracing: Fix formatting of trace README file

2014-01-23T05:10:04Z

Fix the formatting of the README file in the trace debugfs to fit in an 80 character window. Also add a comment about the event trigger counter with regards to traceon and traceoff. Signed-off-by: Steven Rostedt

tracing/README: Add event file usage to tracing mini-HOWTO

2014-01-23T04:06:57Z

It would be useful to have a cheat-sheet for everything under tracing/events/ alongside the existing text describing the other files in the tracing/ dir. Add short descriptions of the directories and files under events/ along with examples, similar to the existing text for the other files in tracing/. Also clean up a few minor alignment problems noticed when adding the new text. Link: http://lkml.kernel.org/r/1389993104.3040.445.camel@empanada Signed-off-by: Tom Zanussi Signed-off-by: Steven Rostedt

Merge tag 'trace-3.14' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

2014-01-23T00:35:21Z

Pull tracing updates from Steven Rostedt: "This pull request has a new feature to ftrace, namely the trace event triggers by Tom Zanussi. A trigger is a way to enable an action when an event is hit. The actions are: o trace on/off - enable or disable tracing o snapshot - save the current trace buffer in the snapshot o stacktrace - dump the current stack trace to the ringbuffer o enable/disable events - enable or disable another event Namhyung Kim added updates to the tracing uprobes code. Having the uprobes add support for fetch methods. The rest are various bug fixes with the new code, and minor ones for the old code" * tag 'trace-3.14' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (38 commits) tracing: Fix buggered tee(2) on tracing_pipe tracing: Have trace buffer point back to trace_array ftrace: Fix synchronization location disabling and freeing ftrace_ops ftrace: Have function graph only trace based on global_ops filters ftrace: Synchronize setting function_trace_op with ftrace_trace_function tracing: Show available event triggers when no trigger is set tracing: Consolidate event trigger code tracing: Fix counter for traceon/off event triggers tracing: Remove double-underscore naming in syscall trigger invocations tracing/kprobes: Add trace event trigger invocations tracing/probes: Fix build break on !CONFIG_KPROBE_EVENT tracing/uprobes: Add @+file_offset fetch method uprobes: Allocate ->utask before handler_chain() for tracing handlers tracing/uprobes: Add support for full argument access methods tracing/uprobes: Fetch args before reserving a ring buffer tracing/uprobes: Pass 'is_return' to traceprobe_parse_probe_arg() tracing/probes: Implement 'memory' fetch method for uprobes tracing/probes: Add fetch{,_size} member into deref fetch method tracing/probes: Move 'symbol' fetch method to kprobes tracing/probes: Implement 'stack' fetch method for uprobes ...