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path: root/kernel/trace/ftrace.c
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2008-12-18ftrace: add not to regex on filtering functionsSteven Rostedt
Impact: enhancement Ingo Molnar has asked about a way to remove items from the filter lists. Currently, you can only add or replace items. The way items are added to the list is through opening one of the list files (set_ftrace_filter or set_ftrace_notrace) via append. If the file is opened for truncate, the list is cleared. echo spin_lock > /debug/tracing/set_ftrace_filter The above will replace the list with only spin_lock echo spin_lock >> /debug/tracing/set_ftrace_filter The above will add spin_lock to the list. Now this patch adds: echo '!spin_lock' >> /debug/tracing/set_ftrace_filter This will remove spin_lock from the list. The limited glob features of these lists also can be notted. echo '!spin_*' >> /debug/tracing/set_ftrace_filter This will remove all functions that start with 'spin_' Note: echo '!spin_*' > /debug/tracing/set_ftrace_filter will simply clear out the list (notice the '>' instead of '>>') Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-08tracing/function-graph-tracer: append the tracing_graph_flagFrederic Weisbecker
Impact: Provide a way to pause the function graph tracer As suggested by Steven Rostedt, the previous patch that prevented from spinlock function tracing shouldn't use the raw_spinlock to fix it. It's much better to follow lockdep with normal spinlock, so this patch adds a new flag for each task to make the function graph tracer able to be paused. We also can send an ftrace_printk whithout worrying of the irrelevant traced spinlock during insertion. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-05ftrace: use init_struct_pid as swapper pidSteven Rostedt
Impact: clean up Using (struct pid *)-1 as the pointer for ftrace_swapper_pid is a little confusing for others. This patch uses the address of the actual init pid structure instead. This change is only for clarity. It does not affect the code itself. Hopefully soon the swapper tasks will all have their own pid structure and then we can clean up the code a bit more. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-04ftrace: avoid duplicated function when writing set_graph_functionLiming Wang
Impact: fix a bug in function filter setting when writing function to set_graph_function, we should check whether it has existed in set_graph_function to avoid duplicating. Signed-off-by: Liming Wang <liming.wang@windriver.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-04ftrace: add ability to only trace swapper tasksSteven Rostedt
Impact: new feature This patch lets the swapper tasks of all CPUS be filtered by the set_ftrace_pid file. If '0' is echoed into this file, then all the idle tasks (aka swapper) is flagged to be traced. This affects all CPU idle tasks. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-04ftrace: use struct pidSteven Rostedt
Impact: clean up, extend PID filtering to PID namespaces Eric Biederman suggested using the struct pid for filtering on pids in the kernel. This patch is based off of a demonstration of an implementation that Eric sent me in an email. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-04ftrace: trace single pid for function graph tracerSteven Rostedt
Impact: New feature This patch makes the changes to set_ftrace_pid apply to the function graph tracer. # echo $$ > /debugfs/tracing/set_ftrace_pid # echo function_graph > /debugfs/tracing/current_tracer Will cause only the current task to be traced. Note, the trace flags are also inherited by child processes, so the children of the shell will also be traced. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-04ftrace: use task struct trace flag to filter on pidSteven Rostedt
Impact: clean up Use the new task struct trace flags to determine if a process should be traced or not. Note: this moves the searching of the pid to the slow path of setting the pid field. This needs to be converted to the pid name space. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-04ftrace: graph of a single functionSteven Rostedt
This patch adds the file: /debugfs/tracing/set_graph_function which can be used along with the function graph tracer. When this file is empty, the function graph tracer will act as usual. When the file has a function in it, the function graph tracer will only trace that function. For example: # echo blk_unplug > /debugfs/tracing/set_graph_function # cat /debugfs/tracing/trace [...] ------------------------------------------ | 2) make-19003 => kjournald-2219 ------------------------------------------ 2) | blk_unplug() { 2) | dm_unplug_all() { 2) | dm_get_table() { 2) 1.381 us | _read_lock(); 2) 0.911 us | dm_table_get(); 2) 1. 76 us | _read_unlock(); 2) + 12.912 us | } 2) | dm_table_unplug_all() { 2) | blk_unplug() { 2) 0.778 us | generic_unplug_device(); 2) 2.409 us | } 2) 5.992 us | } 2) 0.813 us | dm_table_put(); 2) + 29. 90 us | } 2) + 34.532 us | } You can add up to 32 functions into this file. Currently we limit it to 32, but this may change with later improvements. To add another function, use the append '>>': # echo sys_read >> /debugfs/tracing/set_graph_function # cat /debugfs/tracing/set_graph_function blk_unplug sys_read Using the '>' will clear out the function and write anew: # echo sys_write > /debug/tracing/set_graph_function # cat /debug/tracing/set_graph_function sys_write Note, if you have function graph running while doing this, the small time between clearing it and updating it will cause the graph to record all functions. This should not be an issue because after it sets the filter, only those functions will be recorded from then on. If you need to only record a particular function then set this file first before starting the function graph tracer. In the future this side effect may be corrected. The set_graph_function file is similar to the set_ftrace_filter but it does not take wild cards nor does it allow for more than one function to be set with a single write. There is no technical reason why this is the case, I just do not have the time yet to implement that. Note, dynamic ftrace must be enabled for this to appear because it uses the dynamic ftrace records to match the name to the mcount call sites. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-03ftrace: function graph return for function entrySteven Rostedt
Impact: feature, let entry function decide to trace or not This patch lets the graph tracer entry function decide if the tracing should be done at the end as well. This requires all function graph entry functions return 1 if it should trace, or 0 if the return should not be traced. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-03ftrace: add ftrace_graph_stop()Steven Rostedt
Impact: new ftrace_graph_stop function While developing more features of function graph, I hit a bug that caused the WARN_ON to trigger in the prepare_ftrace_return function. Well, it was hard for me to find out that was happening because the bug would not print, it would just cause a hard lockup or reboot. The reason is that it is not safe to call printk from this function. Looking further, I also found that it calls unregister_ftrace_graph, which grabs a mutex and calls kstop machine. This would definitely lock the box up if it were to trigger. This patch adds a fast and safe ftrace_graph_stop() which will stop the function tracer. Then it is safe to call the WARN ON. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-03Merge branches 'tracing/ftrace' and 'tracing/function-graph-tracer' into ↵Ingo Molnar
tracing/core
2008-12-02tracing/function-graph-tracer: support for x86-64Frederic Weisbecker
Impact: extend and enable the function graph tracer to 64-bit x86 This patch implements the support for function graph tracer under x86-64. Both static and dynamic tracing are supported. This causes some small CPP conditional asm on arch/x86/kernel/ftrace.c I wanted to use probe_kernel_read/write to make the return address saving/patching code more generic but it causes tracing recursion. That would be perhaps useful to implement a notrace version of these function for other archs ports. Note that arch/x86/process_64.c is not traced, as in X86-32. I first thought __switch_to() was responsible of crashes during tracing because I believed current task were changed inside but that's actually not the case (actually yes, but not the "current" pointer). So I will have to investigate to find the functions that harm here, to enable tracing of the other functions inside (but there is no issue at this time, while process_64.c stays out of -pg flags). A little possible race condition is fixed inside this patch too. When the tracer allocate a return stack dynamically, the current depth is not initialized before but after. An interrupt could occur at this time and, after seeing that the return stack is allocated, the tracer could try to trace it with a random uninitialized depth. It's a prevention, even if I hadn't problems with it. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tim Bird <tim.bird@am.sony.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-02function trace: fix a bug of single thread function traceLiming Wang
Impact: fix "no output from tracer" bug caused by ftrace_update_pid_func() When disabling single thread function trace using "echo -1 > set_ftrace_pid", the normal function trace has to restore to original function, otherwise the normal function trace will not work well. Without this commit, something like below: $ ps |grep 850 850 root 2556 S -/bin/sh $ echo 850 > /debug/tracing/set_ftrace_pid $ echo function > /debug/tracing/current_tracer $ echo 1 > /debug/tracing/tracing_enabled $ sleep 1 $ echo 0 > /debug/tracing/tracing_enabled $ cat /debug/tracing/trace_pipe |wc -l 59704 $ echo -1 > /debug/tracing/set_ftrace_pid $ echo 1 > /debug/tracing/tracing_enabled $ sleep 1 $ echo 0 > /debug/tracing/tracing_enabled $ more /debug/tracing/trace_pipe <====== nothing output now! it should output trace record. Signed-off-by: Liming Wang <liming.wang@windriver.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-28ftrace: improve seq_operation of ftraceLiming Wang
Impact: make ftrace position computing more sane First remove useless ->pos field. Then we needn't check seq_printf in .show like other place. Signed-off-by: Liming Wang <liming.wang@windriver.com> Reviewed-by: Bruce Ashfield <bruce.ashfield@windriver.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-26ftrace: let function tracing and function return run togetherSteven Rostedt
Impact: feature This patch enables function tracing and function return to run together. I've tested this by enabling the stack tracer and return tracer, where both the function entry and function return are used together with dynamic ftrace. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-26ftrace: use code patching for ftrace graph tracerSteven Rostedt
Impact: more efficient code for ftrace graph tracer This patch uses the dynamic patching, when available, to patch the function graph code into the kernel. This patch will ease the way for letting both function tracing and function graph tracing run together. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-26ftrace: add function tracing to single threadSteven Rostedt
Impact: feature to function trace a single thread This patch adds the ability to function trace a single thread. The file: /debugfs/tracing/set_ftrace_pid contains the pid to trace. Valid pids are any positive integer. Writing any negative number to this file will disable the pid tracing and the function tracer will go back to tracing all of threads. This feature works with both static and dynamic function tracing. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-26tracing/function-return-tracer: set a more human readable outputFrederic Weisbecker
Impact: feature This patch sets a C-like output for the function graph tracing. For this aim, we now call two handler for each function: one on the entry and one other on return. This way we can draw a well-ordered call stack. The pid of the previous trace is loosely stored to be compared against the one of the current trace to see if there were a context switch. Without this little feature, the call tree would seem broken at some locations. We could use the sched_tracer to capture these sched_events but this way of processing is much more simpler. 2 spaces have been chosen for indentation to fit the screen while deep calls. The time of execution in nanosecs is printed just after closed braces, it seems more easy this way to find the corresponding function. If the time was printed as a first column, it would be not so easy to find the corresponding function if it is called on a deep depth. I plan to output the return value but on 32 bits CPU, the return value can be 32 or 64, and its difficult to guess on which case we are. I don't know what would be the better solution on X86-32: only print eax (low-part) or even edx (high-part). Actually it's thee same problem when a function return a 8 bits value, the high part of eax could contain junk values... Here is an example of trace: sys_read() { fget_light() { } 526 vfs_read() { rw_verify_area() { security_file_permission() { cap_file_permission() { } 519 } 1564 } 2640 do_sync_read() { pipe_read() { __might_sleep() { } 511 pipe_wait() { prepare_to_wait() { } 760 deactivate_task() { dequeue_task() { dequeue_task_fair() { dequeue_entity() { update_curr() { update_min_vruntime() { } 504 } 1587 clear_buddies() { } 512 add_cfs_task_weight() { } 519 update_min_vruntime() { } 511 } 5602 dequeue_entity() { update_curr() { update_min_vruntime() { } 496 } 1631 clear_buddies() { } 496 update_min_vruntime() { } 527 } 4580 hrtick_update() { hrtick_start_fair() { } 488 } 1489 } 13700 } 14949 } 16016 msecs_to_jiffies() { } 496 put_prev_task_fair() { } 504 pick_next_task_fair() { } 489 pick_next_task_rt() { } 496 pick_next_task_fair() { } 489 pick_next_task_idle() { } 489 ------------8<---------- thread 4 ------------8<---------- finish_task_switch() { } 1203 do_softirq() { __do_softirq() { __local_bh_disable() { } 669 rcu_process_callbacks() { __rcu_process_callbacks() { cpu_quiet() { rcu_start_batch() { } 503 } 1647 } 3128 __rcu_process_callbacks() { } 542 } 5362 _local_bh_enable() { } 587 } 8880 } 9986 kthread_should_stop() { } 669 deactivate_task() { dequeue_task() { dequeue_task_fair() { dequeue_entity() { update_curr() { calc_delta_mine() { } 511 update_min_vruntime() { } 511 } 2813 Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-26tracing/function-return-tracer: change the name into function-graph-tracerFrederic Weisbecker
Impact: cleanup This patch changes the name of the "return function tracer" into function-graph-tracer which is a more suitable name for a tracing which makes one able to retrieve the ordered call stack during the code flow. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-23tracing/function-return-tracer: don't trace kfree while it frees the return ↵Frederic Weisbecker
stack Impact: fix a crash While I killed the cat process, I got sometimes the following (but rare) crash: [ 65.689027] Pid: 2969, comm: cat Not tainted (2.6.28-rc6-tip #83) AMILO Li 2727 [ 65.689027] EIP: 0060:[<00000000>] EFLAGS: 00010082 CPU: 1 [ 65.689027] EIP is at 0x0 [ 65.689027] EAX: 00000000 EBX: f66cd780 ECX: c019a64a EDX: f66cd780 [ 65.689027] ESI: 00000286 EDI: f66cd780 EBP: f630be2c ESP: f630be24 [ 65.689027] DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068 [ 65.689027] Process cat (pid: 2969, ti=f630a000 task=f66cd780 task.ti=f630a000) [ 65.689027] Stack: [ 65.689027] 00000012 f630bd54 f630be7c c012c853 00000000 c0133cc9 f66cda54 f630be5c [ 65.689027] f630be68 f66cda54 f66cd88c f66cd878 f7070000 00000001 f630be90 c0135dbc [ 65.689027] f614a614 f630be68 f630be68 f65ba200 00000002 f630bf10 f630be90 c012cad6 [ 65.689027] Call Trace: [ 65.689027] [<c012c853>] ? do_exit+0x603/0x850 [ 65.689027] [<c0133cc9>] ? next_signal+0x9/0x40 [ 65.689027] [<c0135dbc>] ? dequeue_signal+0x8c/0x180 [ 65.689027] [<c012cad6>] ? do_group_exit+0x36/0x90 [ 65.689027] [<c013709c>] ? get_signal_to_deliver+0x20c/0x390 [ 65.689027] [<c0102b69>] ? do_notify_resume+0x99/0x8b0 [ 65.689027] [<c02e6d1a>] ? tty_ldisc_deref+0x5a/0x80 [ 65.689027] [<c014db9b>] ? trace_hardirqs_on+0xb/0x10 [ 65.689027] [<c02e6d1a>] ? tty_ldisc_deref+0x5a/0x80 [ 65.689027] [<c02e39b0>] ? n_tty_write+0x0/0x340 [ 65.689027] [<c02e1812>] ? redirected_tty_write+0x82/0x90 [ 65.689027] [<c019ee99>] ? vfs_write+0x99/0xd0 [ 65.689027] [<c02e1790>] ? redirected_tty_write+0x0/0x90 [ 65.689027] [<c019f342>] ? sys_write+0x42/0x70 [ 65.689027] [<c01035ca>] ? work_notifysig+0x13/0x19 [ 65.689027] Code: Bad EIP value. [ 65.689027] EIP: [<00000000>] 0x0 SS:ESP 0068:f630be24 This is because on do_exit(), kfree is called to free the return addresses stack but kfree is traced and stored its return address in this stack. This patch fixes it. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-23tracing/function-return-tracer: store return stack into task_struct and ↵Frederic Weisbecker
allocate it dynamically Impact: use deeper function tracing depth safely Some tests showed that function return tracing needed a more deeper depth of function calls. But it could be unsafe to store these return addresses to the stack. So these arrays will now be allocated dynamically into task_struct of current only when the tracer is activated. Typical scheme when tracer is activated: - allocate a return stack for each task in global list. - fork: allocate the return stack for the newly created task - exit: free return stack of current - idle init: same as fork I chose a default depth of 50. I don't have overruns anymore. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-17Merge branches 'tracing/branch-tracer', 'tracing/ftrace', ↵Ingo Molnar
'tracing/function-return-tracer', 'tracing/tracepoints' and 'tracing/urgent' into tracing/core
2008-11-16function tracing: fix wrong pos computing when read buffer has been fulfilledwalimis
Impact: make output of available_filter_functions complete phenomenon: The first value of dyn_ftrace_total_info is not equal with `cat available_filter_functions | wc -l`, but they should be equal. root cause: When printing functions with seq_printf in t_show, if the read buffer is just overflowed by current function record, then this function won't be printed to user space through read buffer, it will just be dropped. So we can't see this function printing. So, every time the last function to fill the read buffer, if overflowed, will be dropped. This also applies to set_ftrace_filter if set_ftrace_filter has more bytes than read buffer. fix: Through checking return value of seq_printf, if less than 0, we know this function doesn't be printed. Then we decrease position to force this function to be printed next time, in next read buffer. Another little fix is to show correct allocating pages count. Signed-off-by: walimis <walimisdev@gmail.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-16tracing/function-return-tracer: support for dynamic ftrace on function ↵Frederic Weisbecker
return tracer This patch adds the support for dynamic tracing on the function return tracer. The whole difference with normal dynamic function tracing is that we don't need to hook on a particular callback. The only pro that we want is to nop or set dynamically the calls to ftrace_caller (which is ftrace_return_caller here). Some security checks ensure that we are not trying to launch dynamic tracing for return tracing while normal function tracing is already running. An example of trace with getnstimeofday set as a filter: ktime_get_ts+0x22/0x50 -> getnstimeofday (2283 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1396 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1382 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1825 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1426 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1464 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1524 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1382 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1382 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1434 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1464 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1502 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1404 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1397 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1051 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1314 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1344 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1163 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1390 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1374 ns) Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-16ftrace: make filtered functions effective on settingSteven Rostedt
Impact: set filtered functions at time the filter is set It can be confusing when the set_filter_functions is set (or cleared) and the functions being recorded by the dynamic tracer does not match. This patch causes the code to be updated if the function tracer is enabled and the filter is changed. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-16ftrace: fix dyn ftrace filterSteven Rostedt
Impact: correct implementation of dyn ftrace filter The old decisions made by the filter algorithm was complex and incorrect. This lead to inconsistent enabling or disabling of functions when the filter was used. This patch simplifies that code and in doing so, corrects the usage of the filters. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-16ftrace: allow NULL pointers in mcount_locSteven Rostedt
Impact: make ftrace_convert_nops() more permissive Due to the way different architecture linkers combine the data sections of the mcount_loc (the section that lists all the locations that call mcount), there may be zeros added in that section. This is usually due to strange alignments that the linker performs, that pads in zeros. This patch makes the conversion code to nops skip any pointer in the mcount_loc section that is NULL. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-16ftrace: pass module struct to arch dynamic ftrace functionsSteven Rostedt
Impact: allow archs more flexibility on dynamic ftrace implementations Dynamic ftrace has largly been developed on x86. Since x86 does not have the same limitations as other architectures, the ftrace interaction between the generic code and the architecture specific code was not flexible enough to handle some of the issues that other architectures have. Most notably, module trampolines. Due to the limited branch distance that archs make in calling kernel core code from modules, the module load code must create a trampoline to jump to what will make the larger jump into core kernel code. The problem arises when this happens to a call to mcount. Ftrace checks all code before modifying it and makes sure the current code is what it expects. Right now, there is not enough information to handle modifying module trampolines. This patch changes the API between generic dynamic ftrace code and the arch dependent code. There is now two functions for modifying code: ftrace_make_nop(mod, rec, addr) - convert the code at rec->ip into a nop, where the original text is calling addr. (mod is the module struct if called by module init) ftrace_make_caller(rec, addr) - convert the code rec->ip that should be a nop into a caller to addr. The record "rec" now has a new field called "arch" where the architecture can add any special attributes to each call site record. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-16ftrace: do not process freed recordsSteven Rostedt
Impact: keep from converting freed records When the tracer is started or stopped, it converts all code pointed to by the saved records into callers to ftrace or nops. When modules are unloaded, their records are freed, but they still exist within the record pages. This patch changes the code to skip over freed records. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-16ftrace: disable ftrace on anomalies in trace start and stopSteven Rostedt
Impact: robust feature to disable ftrace on start or stop tracing on error Currently only the initial conversion to nops will disable ftrace on an anomaly. But if an anomaly happens on start or stopping of the tracer, it will silently fail. This patch adds a check there too, to disable ftrace and warn if the conversion fails. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-16ftrace: remove condition from ftrace_record_ipSteven Rostedt
Impact: let module functions be recorded when dyn ftrace not enabled When dynamic ftrace had a daemon and a hash to record the locations of mcount callers at run time, the recording needed to stop when ftrace was disabled. But now that the recording is done at compile time and the ftrace_record_ip is only called at boot up and when a module is loaded, we no longer need to check if ftrace_enabled is set. In fact, this breaks module load if it is not set because we skip over module functions. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-13ftrace: remove unnecessary if condition of __unregister_ftrace_functionwalimis
Because it has goto out before ftrace_list == &ftrace_list_end, that's to say, we never meet this condition. Signed-off-by: walimis <walimisdev@gmail.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-12Merge branch 'tracing/function-return-tracer' into tracing/fastbootIngo Molnar
2008-11-12Merge branches 'tracing/ftrace' and 'tracing/urgent' into tracing/coreIngo Molnar
Conflicts: kernel/trace/ring_buffer.c
2008-11-11ring-buffer: buffer record on/off switchSteven Rostedt
Impact: enable/disable ring buffer recording API added Several kernel developers have requested that there be a way to stop recording into the ring buffers with a simple switch that can also be enabled from userspace. This patch addes a new kernel API to the ring buffers called: tracing_on() tracing_off() When tracing_off() is called, all ring buffers will not be able to record into their buffers. tracing_on() will enable the ring buffers again. These two act like an on/off switch. That is, there is no counting of the number of times tracing_off or tracing_on has been called. A new file is added to the debugfs/tracing directory called tracing_on This allows for userspace applications to also flip the switch. echo 0 > debugfs/tracing/tracing_on disables the tracing. echo 1 > /debugfs/tracing/tracing_on enables it. Note, this does not disable or enable any tracers. It only sets or clears a flag that needs to be set in order for the ring buffers to write to their buffers. It is a global flag, and affects all ring buffers. The buffers start out with tracing_on enabled. There are now three flags that control recording into the buffers: tracing_on: which affects all ring buffer tracers. buffer->record_disabled: which affects an allocated buffer, which may be set if an anomaly is detected, and tracing is disabled. cpu_buffer->record_disabled: which is set by tracing_stop() or if an anomaly is detected. tracing_start can not reenable this if an anomaly occurred. The userspace debugfs/tracing/tracing_enabled is implemented with tracing_stop() but the user space code can not enable it if the kernel called tracing_stop(). Userspace can enable the tracing_on even if the kernel disabled it. It is just a switch used to stop tracing if a condition was hit. tracing_on is not for protecting critical areas in the kernel nor is it for stopping tracing if an anomaly occurred. This is because userspace can reenable it at any time. Side effect: With this patch, I discovered a dead variable in ftrace.c called tracing_on. This patch removes it. Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2008-11-11tracing: add a tracer to catch execution time of kernel functionsFrederic Weisbecker
Impact: add new tracing plugin which can trace full (entry+exit) function calls This tracer uses the low level function return ftrace plugin to measure the execution time of the kernel functions. The first field is the caller of the function, the second is the measured function, and the last one is the execution time in nanoseconds. - v3: - HAVE_FUNCTION_RET_TRACER have been added. Each arch that support ftrace return should enable it. - ftrace_return_stub becomes ftrace_stub. - CONFIG_FUNCTION_RET_TRACER depends now on CONFIG_FUNCTION_TRACER - Return traces printing can be used for other tracers on trace.c - Adapt to the new tracing API (no more ctrl_update callback) - Correct the check of "disabled" during insertion. - Minor changes... Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-08ftrace: fix set_ftrace_filterSteven Rostedt
Impact: fix of output of set_ftrace_filter Commit ftrace: do not show freed records in available_filter_functions Removed a bit too much from the set_ftrace_filter code, where we now see all functions in the set_ftrace_filter file even when we set a filter. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-06ftrace: add quick function trace stopSteven Rostedt
Impact: quick start and stop of function tracer This patch adds a way to disable the function tracer quickly without the need to run kstop_machine. It adds a new variable called function_trace_stop which will stop the calls to functions from mcount when set. This is just an on/off switch and does not handle recursion like preempt_disable(). It's main purpose is to help other tracers/debuggers start and stop tracing fuctions without the need to call kstop_machine. The config option HAVE_FUNCTION_TRACE_MCOUNT_TEST is added for archs that implement the testing of the function_trace_stop in the mcount arch dependent code. Otherwise, the test is done in the C code. x86 is the only arch at the moment that supports this. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-28ftrace: perform an initialization for ftrace to enable itFrederic Weisbecker
Impact: corrects a bug which made the non-dyn function tracer not functional With latest git, the non-dynamic function tracer didn't get any trace. The problem was the fact that ftrace_enabled wasn't initialized to 1 because ftrace hasn't any init function when DYNAMIC_FTRACE is disabled. So when a tracer tries to register an ftrace_ops struct, __register_ftrace_function failed to set the hook. This patch corrects it by setting an init function to initialize ftrace during the boot. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-24ftrace: warning in kernel/trace/ftrace.cIngo Molnar
this warning: kernel/trace/ftrace.c:189: warning: ‘frozen_record_count’ defined but not used triggers because frozen_record_count is only used in the KCONFIG_MARKERS case. Move the variable it there. Alas, this frozen-record facility seems to have little use. The frozen_record_count variable is not used by anything, nor the flags. So this section might need a bit of dead-code-removal care as well. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-23ftrace: fix build failureIngo Molnar
fix: kernel/trace/ftrace.c: In function 'ftrace_release': kernel/trace/ftrace.c:271: error: implicit declaration of function 'ftrace_release_hash' release_hash is not needed without dftraced. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-23ftrace: remove ftrace hashSteven Rostedt
The ftrace hash was used by the ftrace_daemon code. The record ip function would place the calling address (ip) into the hash. The daemon would later read the hash and modify that code. The hash complicates the code. This patch removes it. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-23ftrace: remove mcount setSteven Rostedt
The arch dependent function ftrace_mcount_set was only used by the daemon start up code. This patch removes it. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-23ftrace: remove daemonSteven Rostedt
The ftrace daemon is complex and error prone. This patch strips it out of the code. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-23ftrace: add ftrace warn on to disable ftraceSteven Rostedt
Add ftrace warn on to disable ftrace as well as report a warning. [ Thanks to Andrew Morton for suggesting using the WARN_ON return value ] Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-23ftrace: only have ftrace_kill atomicSteven Rostedt
When an anomaly is detected, we need a way to completely disable ftrace. Right now we have two functions: ftrace_kill and ftrace_kill_atomic. The ftrace_kill tries to do it in a "nice" way by converting everything back to a nop. The "nice" way is dangerous itself, so this patch removes it and only has the "atomic" version, which is all that is needed. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-23ftrace: return error on failed modified text.Steven Rostedt
Have the ftrace_modify_code return error values: -EFAULT on error of reading the address -EINVAL if what is read does not match what it expected -EPERM if the write fails to update after a successful match. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-20ftrace: release functions from hashSteven Rostedt
The x86 architecture uses a static recording of mcount caller locations and is not affected by this patch. For architectures still using the dynamic ftrace daemon, this patch is critical. It removes the race between the recording of a function that calls mcount, the unloading of a module, and the ftrace daemon updating the call sites. This patch adds the releasing of the hash functions that the daemon uses to update the mcount call sites. When a module is unloaded, not only are the replaced call site table update, but now so is the hash recorded functions that the ftrace daemon will use. Again, architectures that implement MCOUNT_RECORD are not affected by this (which currently only x86 has). Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14ftrace: warn on failure to disable mcount callersSteven Rostedt
With the recent updates to ftrace, there should not be any failures when modifying the code. If there is, then we need to warn about it. This patch has a cleaned up version of the code that I used to discover that the weak symbols were causing failures. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>