- 28 5月, 2009 1 次提交
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由 Heiko Carstens 提交于
s390 code uses smp_processor_id() in __raw_spin_lock() code which reveals that a (raw) spinlock is taken without preemption disabled. This can potentially deadlock. To fix this explicitly disable and enable preemption. BUG: using smp_processor_id() in preemptible [00000000] code: cat/2278 caller is trace_find_cmdline+0x40/0xfc CPU: 0 Not tainted 2.6.30-rc7-dirty #39 Process cat (pid: 2278, task: 000000003faedb68, ksp: 000000003b33b988) 000000003b33b988 000000003b33bae0 0000000000000002 0000000000000000 000000003b33bb80 000000003b33baf8 000000003b33baf8 00000000000175d6 0000000000000001 000000003b33b988 000000003f9b0000 000000000000000b 000000000000000c 000000003b33bb40 000000003b33bae0 0000000000000000 0000000000000000 00000000000175d6 000000003b33bae0 000000003b33bb28 Call Trace: ([<00000000000174b2>] show_trace+0x112/0x170) [<0000000000017582>] show_stack+0x72/0x100 [<0000000000441538>] dump_stack+0xc8/0xd8 [<000000000025c350>] debug_smp_processor_id+0x114/0x130 [<00000000000bf0e4>] trace_find_cmdline+0x40/0xfc [<00000000000c35d4>] trace_print_context+0x58/0xac [<00000000000bb676>] print_trace_line+0x416/0x470 [<00000000000bc8fe>] s_show+0x4e/0x428 [<000000000013834e>] seq_read+0x36a/0x5d4 [<0000000000112a78>] vfs_read+0xc8/0x174 [<0000000000112c58>] SyS_read+0x74/0xc4 [<000000000002c7ae>] sysc_noemu+0x10/0x16 [<000002000012436c>] 0x2000012436c 1 lock held by cat/2278: #0: (&p->lock){+.+.+.}, at: [<0000000000138056>] seq_read+0x72/0x5d4 [ Impact: fix preempt-unsafe raw spinlock ] Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Acked-by: NSteven Rostedt <rostedt@goodmis.org> Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
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- 27 5月, 2009 2 次提交
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由 Steven Rostedt 提交于
This patch adds __print_symbolic which is similar to __print_flags but works for an enumeration type instead. That is, there is only a one to one mapping between the values and the symbols. When a match is made, then it is printed, otherwise the hex value is outputed. [ Impact: add interface for showing symbol names in events ] Signed-off-by: NSteven Rostedt <rostedt@goodmis.org> Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
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由 Steven Rostedt 提交于
Developers have been asking for the ability in the ftrace event tracer to display names of bits in a flags variable. Instead of printing out c2, it would be easier to read FOO|BAR|GOO, assuming that FOO is bit 1, BAR is bit 6 and GOO is bit 7. Some examples where this would be useful are the state flags in a context switch, kmalloc flags, and even permision flags in accessing files. [ v2 changes include: Frederic Weisbecker's idea of using a mask instead of bits, thus we can output GFP_KERNEL instead of GPF_WAIT|GFP_IO|GFP_FS. Li Zefan's idea of allowing the caller of __print_flags to add their own delimiter (or no delimiter) where we can get for file permissions rwx instead of r|w|x. ] [ v3 changes: Christoph Hellwig's idea of using an array instead of va_args. ] [ Impact: better displaying of flags in trace output ] Signed-off-by: NSteven Rostedt <rostedt@goodmis.org> Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
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- 26 5月, 2009 3 次提交
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由 Zhaolei 提交于
Always use ftrace_event_enable_disable() to enable/disable an event so that we can factorize out the event toggling code. [ Impact: factorize and cleanup event tracing code ] Signed-off-by: NZhao Lei <zhaolei@cn.fujitsu.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tom Zanussi <tzanussi@gmail.com> LKML-Reference: <4A14FDFE.2080402@cn.fujitsu.com> Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
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由 Zhaolei 提交于
If we enable a trace event alone without any tracer running (such as function tracer, sched switch tracer, etc...) it can't output enough task command information. We need to use the tracing_{start/stop}_cmdline_record() helpers which are designed to keep track of cmdlines for any tasks that were scheduled during the tracing. Before this patch: # echo 1 > debugfs/tracing/events/sched/sched_switch/enable # cat debugfs/tracing/trace # tracer: nop # # TASK-PID CPU# TIMESTAMP FUNCTION # | | | | | <...>-2289 [000] 526276.724790: sched_switch: task bash:2289 [120] ==> sshd:2287 [120] <...>-2287 [000] 526276.725231: sched_switch: task sshd:2287 [120] ==> bash:2289 [120] <...>-2289 [000] 526276.725452: sched_switch: task bash:2289 [120] ==> sshd:2287 [120] <...>-2287 [000] 526276.727181: sched_switch: task sshd:2287 [120] ==> swapper:0 [140] <idle>-0 [000] 526277.032734: sched_switch: task swapper:0 [140] ==> events/0:5 [115] <...>-5 [000] 526277.032782: sched_switch: task events/0:5 [115] ==> swapper:0 [140] ... After this patch: # tracer: nop # # TASK-PID CPU# TIMESTAMP FUNCTION # | | | | | bash-2269 [000] 527347.989229: sched_switch: task bash:2269 [120] ==> sshd:2267 [120] sshd-2267 [000] 527347.990960: sched_switch: task sshd:2267 [120] ==> bash:2269 [120] bash-2269 [000] 527347.991143: sched_switch: task bash:2269 [120] ==> sshd:2267 [120] sshd-2267 [000] 527347.992959: sched_switch: task sshd:2267 [120] ==> swapper:0 [140] <idle>-0 [000] 527348.531989: sched_switch: task swapper:0 [140] ==> events/0:5 [115] events/0-5 [000] 527348.532115: sched_switch: task events/0:5 [115] ==> swapper:0 [140] ... Changelog: v1->v2: Update Kconfig to select CONTEXT_SWITCH_TRACER in ENABLE_EVENT_TRACING v2->v3: v2 can solve problem that was caused by config EVENT_TRACING alone, but when CONFIG_FTRACE is off and CONFIG_TRACING is selected by other config, compile fail happened again. This version solves it. [ Impact: fix incomplete output of event tracing ] Signed-off-by: NZhao Lei <zhaolei@cn.fujitsu.com> Cc: Tom Zanussi <tzanussi@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <4A14FDFE.2080402@cn.fujitsu.com> Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
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由 Lai Jiangshan 提交于
I found that there is nothing to protect event_hash in ftrace_find_event(). Rcu protects the event hashlist but not the event itself while we use it after its extraction through ftrace_find_event(). This lack of a proper locking in this spot opens a race window between any event dereferencing and module removal. Eg: --Task A-- print_trace_line(trace) { event = find_ftrace_event(trace) --Task B-- trace_module_remove_events(mod) { list_trace_events_module(ev, mod) { unregister_ftrace_event(ev->event) { hlist_del(ev->event->node) list_del(....) } } } |--> module removed, the event has been dropped --Task A-- event->print(trace); // Dereferencing freed memory If the event retrieved belongs to a module and this module is concurrently removed, we may end up dereferencing a data from a freed module. RCU could solve this, but it would add latency to the kernel and forbid tracers output callbacks to call any sleepable code. So this fix converts 'trace_event_mutex' to a read/write semaphore, and adds trace_event_read_lock() to protect ftrace_find_event(). [ Impact: fix possible freed memory dereference in ftrace ] Signed-off-by: NLai Jiangshan <laijs@cn.fujitsu.com> Acked-by: NSteven Rostedt <rostedt@goodmis.org> LKML-Reference: <4A114806.7090302@cn.fujitsu.com> Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
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- 21 5月, 2009 1 次提交
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由 Ming Lei 提交于
register_module_notifier() returns zero in the success case. So fix the inverted fail case check in trace events modules handler. [ Impact: fix spurious warning on ftrace initialization] Reported-by: NLi Zefan <lizf@cn.fujitsu.com> Signed-off-by: NMing Lei <tom.leiming@gmail.com> Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
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- 19 5月, 2009 1 次提交
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由 Stefan Raspl 提交于
debugfs directory entries for devices are not removed on some of the failure pathes in do_blk_trace_setup(). One way to reproduce is to start blktrace on multiple devices with insufficient Vmalloc space: Devices will fail with a message like this: BLKTRACESETUP(2) /dev/sdu failed: 5/Input/output error If so, the respective entries in debugfs (e.g. /sys/kernel/debug/block/sdu) will remain and subsequent attempts to start blktrace on the respective devices will not succeed due to existing directories. [ Impact: fix /debug/tracing file cleanup corner case ] Signed-off-by: NStefan Raspl <stefan.raspl@linux.vnet.ibm.com> Acked-by: NLi Zefan <lizf@cn.fujitsu.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: schwidefsky@de.ibm.com Cc: heiko.carstens@de.ibm.com LKML-Reference: <4A1266CC.5040801@linux.vnet.ibm.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 18 5月, 2009 1 次提交
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由 Ming Lei 提交于
return zero should be correct, so fix it. [ Impact: eliminate incorrect syslog message ] Signed-off-by: NMing Lei <tom.leiming@gmail.com> Acked-by: NFrederic Weisbecker <fweisbec@gmail.com> Acked-by: NLi Zefan <lizf@cn.fujitsu.com> Cc: rostedt@goodmis.org LKML-Reference: <1242545498-7285-1-git-send-email-tom.leiming@gmail.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 15 5月, 2009 5 次提交
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由 Jason Wessel 提交于
Commit 79e53945 introduced a regression where you cannot use sysrq 'g' to enter kgdb. The solution is to move the intel fb sysrq over to V for video instead of G for graphics. The SMP VOYAGER code to register for the sysrq-v is not anywhere to be found in the mainline kernel, so the comments in the code were cleaned up as well. This patch also cleans up the sysrq definitions for kgdb to make it generic for the kernel debugger, such that the sysrq 'g' can be used in the future to enter a gdbstub or another kernel debugger. Signed-off-by: NJason Wessel <jason.wessel@windriver.com> Acked-by: NJesse Barnes <jbarnes@virtuousgeek.org> Acked-by: NRandy Dunlap <randy.dunlap@oracle.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
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由 Jens Axboe 提交于
This reverts commit fafd688e. Work is progressing to switch away from pdflush as the process backing for flushing out dirty data. So it seems pointless to add more knobs to control pdflush threads. The original author of the patch did not have any specific use cases for adding the knobs, so we can easily revert this before 2.6.30 to avoid having to maintain this API forever. Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Li Zefan 提交于
We should leave the last slot for the ending '\0'. [ Impact: fix possible crash when the length of an operand is 128 ] Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com> LKML-Reference: <4A0CDC8C.30602@cn.fujitsu.com> Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
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由 Li Zefan 提交于
[ Impact: fix deadlock in a rare case we fail to allocate memory ] Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com> LKML-Reference: <4A0CDC6F.7070200@cn.fujitsu.com> Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
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由 Steven Rostedt 提交于
The stack tracer stores eight entries in the ring buffer when an event traces the stack. The output outputs all eight entries regardless of how many entries were recorded. This patch breaks out of the loop when a null entry is discovered. [ Impact: only print the stack that is recorded ] Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
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- 12 5月, 2009 7 次提交
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由 Steven Rostedt 提交于
This is a bit of micro-optimizations. But since the ring buffer is used in tracing every function call, it is an extreme hot path. Every nanosecond counts. This change shows over 5% improvement in the ring-buffer-benchmark. [ Impact: more efficient code ] Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
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由 Steven Rostedt 提交于
The ring_buffer_time_stamp that is exported adds a little more overhead than is needed for using it internally. This patch adds an internal timestamp function that can be inlined (a single line function) and used internally for the ring buffer. [ Impact: a little less overhead to the ring buffer ] Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
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由 Steven Rostedt 提交于
Doing some small changes in the fast path of the ring buffer recording saves over 3% in the ring-buffer-benchmark test. [ Impact: a little faster ring buffer recording ] Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
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由 Steven Rostedt 提交于
The event length is calculated and passed in to rb_reserve_next_event in two different locations. Having rb_reserve_next_event do the calculations directly makes only one location to do the change and causes the calculation to be inlined by gcc. Before: text data bss dec hex filename 16538 24 12 16574 40be kernel/trace/ring_buffer.o After: text data bss dec hex filename 16490 24 12 16526 408e kernel/trace/ring_buffer.o [ Impact: smaller more efficient code ] Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
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由 Steven Rostedt 提交于
The rb_reserve_next_event is only called for the data type (type = 0). There is no reason to pass in the type to the function. Before: text data bss dec hex filename 16554 24 12 16590 40ce kernel/trace/ring_buffer.o After: text data bss dec hex filename 16538 24 12 16574 40be kernel/trace/ring_buffer.o [ Impact: cleaner, smaller and slightly more efficient code ] Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
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由 Steven Rostedt 提交于
Although we check if "missed" is not zero, we divide by hit + missed, and the addition can possible overflow and become a divide by zero. This patch checks for this case, and will report it when it happens then modify "hit" to make the calculation be non zero. [ Impact: prevent possible divide by zero in ring-buffer-benchmark ] Reported-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
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由 Steven Rostedt 提交于
The use of numeric constants is discouraged. It is cleaner and more descriptive to use macros for constant time conversions. This patch also removes an extra new line. [ Impact: more descriptive time conversions ] Reported-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
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- 11 5月, 2009 1 次提交
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由 Li Zefan 提交于
I got this: 8,0 1 305.417782332 2037 I R 32 (ffffff9e 10 00 ...) [bash] It should be: 8,0 1 305.417782332 2037 I R 32 (9e 10 00 ...) [bash] [ Impact: fix output of pc events ] Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <4A07C6B3.9080802@cn.fujitsu.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 09 5月, 2009 4 次提交
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由 Al Viro 提交于
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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由 Masami Hiramatsu 提交于
Fix kprobes to lock text_mutex around some arch_arm/disarm_kprobe() which are newly added by commit de5bd88d. Signed-off-by: NMasami Hiramatsu <mhiramat@redhat.com> Acked-by: NAnanth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: Jim Keniston <jkenisto@us.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Steven Rostedt 提交于
Other parts of the kernel may need to be able to enable or disable specific events. Especially parts that create trace events. [ Impact: allow enabling of trace events by those that create the event ] Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
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由 Steven Rostedt 提交于
Commit 8f31bfe5 tracing/events: clean up for ftrace_set_clr_event() Moved out the code for ftrace_set_clr_event into a helper funciton but did not initialize the return value. As a result, we do not warn about a typo in the echoing of events in set_event. This patch restores the old warning: # echo foobar > set_event -bash: echo: write error: Invalid argument [ Impact: restore warning of invalid entries to set_event ] Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
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- 08 5月, 2009 6 次提交
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由 Li Zefan 提交于
A smarter way to figure out the output of an enable file. [ Impact: clean up ] Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com> Acked-by: NSteven Rostedt <rostedt@goodmis.org> Acked-by: NFrederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <4A0399A5.2080603@cn.fujitsu.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Li Zefan 提交于
Add a helper function __ftrace_set_clr_event(), and replace some ftrace_set_clr_event() calls with this helper, thus we don't need any kstrdup() or kmalloc(). As a side effect, this patch fixes an issue in self tests code, which is similar to the one fixed in commit d6bf81ef ("tracing: append ":*" to internal setting of system events") It's a small issue and won't cause any bug in fact, but we should do things right anyway. [ Impact: prevent spurious event-enabling in tracing self-tests ] Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com> Acked-by: NSteven Rostedt <rostedt@goodmis.org> Acked-by: NFrederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <4A03998E.3020503@cn.fujitsu.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Steven Rostedt 提交于
There's a WARN_ON in the ring buffer code that makes sure preemption is disabled. It checks "!preempt_count()". But when CONFIG_PREEMPT is not enabled, preempt_count() is always zero, and this will trigger the warning. [ Impact: prevent false warning on non preemptible kernels ] Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
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由 Steven Rostedt 提交于
It is nice to see the overhead of the benchmark test when tracing is disabled. That is, we turn off the ring buffer just to see what the cost of running the loop that calls into the ring buffer is. Currently, if no entries wer made, we get 0. This is not informative. This patch changes it to check if we had any "missed" (non recorded) events. If so, a total count is also reported. [ Impact: evaluate the over head of the ring buffer benchmark test ] Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
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由 Steven Rostedt 提交于
Calling cond_resched at every iteration of the loop adds a bit of overhead to the benchmark. This patch does two things. 1) only calls cond-resched when CONFIG_PREEMPT is not enabled 2) only calls cond-resched after so many traces has been performed. [ Impact: less overhead to the ring-buffer-benchmark ] Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
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由 Steven Rostedt 提交于
Tracing can be very helpful to debug the kernel. When DEBUG_KERNEL is enabled it is nice to enable the trace menu as well. This patch only make the tracing menu enabled by default, it does not make any of the tracers enabled. And the menu is only enabled by default if DEBUG_KERNEL is enabled. [ Impact: show tracing options to those debugging the kernel ] Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
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- 07 5月, 2009 8 次提交
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由 Steven Rostedt 提交于
The system enabling of events uses the same code as the set_event file. It passes in the name of the system to the parser and that will enable all the events that has that system as a name. The problem is that it will also enable events with the same name as the system. If you have system name foo, and system name bar, but within the system bar, there exists an event called foo. By setting the system name foo, you will also be enabling the event foo in the system bar. This is not an expected result. The solution is to pass in "foo:*", which will only enable the system foo and not events called foo. [ Impact: prevent accidental enabling of events with same name as a system ] Reported-by: NLi Zefan <lizf@cn.fujitsu.com> Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
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由 Steven Rostedt 提交于
Ingo Molnar thought that the code to calculate the time in cond_resched is a bit too ugly and is not needed. This patch removes it and replaces it with a simple call to cond_resched. I kept the comment that explains the reason for the cond_resched. [ Impact: remove ugly code ] Reported-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
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由 Li Zefan 提交于
In filter_add_subsystem_pred() we should release event_mutex before calling filter_free_subsystem_preds(), since both functions hold event_mutex. [ Impact: fix deadlock when writing invalid pred into subsystem filter ] Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com> Cc: tzanussi@gmail.com Cc: a.p.zijlstra@chello.nl Cc: fweisbec@gmail.com Cc: rostedt@goodmis.org LKML-Reference: <4A028993.7020509@cn.fujitsu.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Frederic Weisbecker 提交于
When we set a filter for an event, such as: echo "name == my_lock_name" > \ /debug/tracing/events/lockdep/lock_acquired/filter then the following order of token type is parsed: - space - operator - parentheses - operand Because the operators and parentheses have a higher precedence than the operand characters, which is normal, then we can't use any string containing such special characters: ()=<>!&| To get this support and also avoid ambiguous intepretation from the parser or the human, we can do it using double quotes so that we keep the usual languages habits. Then after this patch you can still declare string condition like before: echo name == myname But if you want to compare against a string containing an operator character, you can use double quotes: echo 'name == "&myname"' Don't forget to include the whole expression into single quotes or the double ones will be eaten by echo. [ Impact: support strings with special characters for tracing filters ] Cc: Tom Zanussi <tzanussi@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Zhaolei <zhaolei@cn.fujitsu.com> Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
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由 Frederic Weisbecker 提交于
Currently the filtering infrastructure supports well the numeric types and fixed sized array types. But the recently added __string() field uses a specific indirect offset mechanism which requires a specific predicate. Until now it wasn't supported. This patch adds this support and implies very few changes, only a new predicate is needed, the management of this specific field can be done through the usual string helpers in the filtering infrastructure. [ Impact: support all kinds of strings in the tracing filters ] Cc: Tom Zanussi <tzanussi@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Zhaolei <zhaolei@cn.fujitsu.com> Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
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由 Steven Rostedt 提交于
With the current event directory, you can only enable individual events. The file debugfs/tracing/set_event is used to be able to enable or disable several events at once. But that can still be awkward. This patch adds hierarchical enabling of events. That is, each directory in debugfs/tracing/events has an "enable" file. This file can enable or disable all events within the directory and below. # echo 1 > /debugfs/tracing/events/enable will enable all events. # echo 1 > /debugfs/tracing/events/sched/enable will enable all events in the sched subsystem. # echo 1 > /debugfs/tracing/events/enable # echo 0 > /debugfs/tracing/events/irq/enable will enable all events, but then disable just the irq subsystem events. When reading one of these enable files, there are four results: 0 - all events this file affects are disabled 1 - all events this file affects are enabled X - there is a mixture of events enabled and disabled ? - this file does not affect any event Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
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由 Steven Rostedt 提交于
Li Zefan found that there's a race using the event ids of events and modules. When a module is loaded, an event id is incremented. We only have 16 bits for event ids (65536) and there is a possible (but highly unlikely) race that we could load and unload a module that registers events so many times that the event id counter overflows. When it overflows, it then restarts and goes looking for available ids. An id is available if it was added by a module and released. The race is if you have one module add an id, and then is removed. Another module loaded can use that same event id. But if the old module still had events in the ring buffer, the new module's call back would get bogus data. At best (and most likely) the output would just be garbage. But if the module for some reason used pointers (not recommended) then this could potentially crash. The safest thing to do is just reset the ring buffer if a module that registered events is removed. [ Impact: prevent unpredictable results of event id overflows ] Reported-by: NLi Zefan <lizf@cn.fujitsu.com> LKML-Reference: <49FEAFD0.30106@cn.fujitsu.com> Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
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由 Andi Kleen 提交于
When building with gcc 3.2 I get thousands of warnings such as include/linux/gfp.h: In function `allocflags_to_migratetype': include/linux/gfp.h:105: warning: null format string due to passing a NULL format string to warn_slowpath() in #define __WARN() warn_slowpath(__FILE__, __LINE__, NULL) Split this case out into a separate call. This also shrinks the kernel slightly: text data bss dec hex filename 4802274 707668 712704 6222646 5ef336 vmlinux text data bss dec hex filename 4799027 703572 712704 6215303 5ed687 vmlinux due to removeing one argument from the commonly-called __WARN(). [akpm@linux-foundation.org: reduce scope of `empty'] Acked-by: NJesper Nilsson <jesper.nilsson@axis.com> Acked-by: NJohannes Weiner <hannes@cmpxchg.org> Acked-by: NArjan van de Ven <arjan@linux.intel.com> Signed-off-by: NAndi Kleen <ak@linux.intel.com> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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