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* blktrace: fix pdu_len when tracing packet command requestsLi Zefan2009-04-03
| | | | | | | | | | | | | | | | | | | | | | Impact: output all of packet commands - not just the first 4 / 8 bytes Since commit d7e3c3249ef23b4617393c69fe464765b4ff1645 ("block: add large command support"), struct request->cmd has been changed from unsinged char cmd[BLK_MAX_CDB] to unsigned char *cmd. v1 -> v2: by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> - make sure rq->cmd_len is always intialized, and then we can use rq->cmd_len instead of BLK_MAX_CDB. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jens Axboe <jens.axboe@oracle.com> LKML-Reference: <49D4507E.2060602@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* blktrace: small cleanup in blk_msg_write()Li Zefan2009-04-03
| | | | | | | | | Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: "Alan D. Brunelle" <alan.brunelle@hp.com> Cc: Jens Axboe <jens.axboe@oracle.com> LKML-Reference: <49D5BB56.7000807@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* blktrace: NUL-terminate user space messagesCarl Henrik Lunde2009-04-03
| | | | | | | | | | | | | | | | | | | Impact: fix corrupted blkparse output Make sure messages from user space are NUL-terminated strings, otherwise we could dump random memory to the block trace file. Additionally, I've limited the message to BLK_TN_MAX_MSG-1 characters, because the last character would be stripped by vscnprintf anyway. Signed-off-by: Carl Henrik Lunde <chlunde@ping.uio.no> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: "Alan D. Brunelle" <alan.brunelle@hp.com> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <20090403122714.GT5178@kernel.dk> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* blktrace: print out BLK_TN_MESSAGE properlyLi Zefan2009-03-31
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: improve ftrace plugin output Before this patch: # cat trace make-5383 [001] 741.240059: 8,7 P N [make] __trace_note_message: cfq1074 # echo 1 > options/blk_classic # cat trace 8,7 1 0.692221252 0 C W 130411392 + 1024 [0] Bad pc action 6361 Bad pc action 283d # echo 0 > options/blk_classic # echo bin > trace_options # cat trace_pipe | blkparse -i - (can't parse messages generated by blk_add_trace_msg()) After this patch: # cat trace <idle>-0 [001] 187.600933: 8,7 C W 145220224 + 8 [0] <idle>-0 [001] 187.600946: 8,7 m N cfq1076 complete # echo 1 > options/blk_classic # cat trace 8,7 1 0.256378996 238 I W 113190728 + 8 [pdflush] 8,7 1 0.256378998 238 m N cfq1076 insert_request # echo 0 > options/blk_classic # echo bin > trace_options # cat trace_pipe | blkparse -i - 8,7 1 0 22.973250293 0 C W 102770576 + 8 [0] 8,7 1 0 22.973259213 0 m N cfq1076 complete Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: 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> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* blktrace: extract duplidate codeLi Zefan2009-03-31
| | | | | | | | | | | | | | | | | | | | Impact: cleanup blk_trace_event_print() and blk_tracer_print_line() share most of the code. text data bss dec hex filename 8605 393 12 9010 2332 kernel/trace/blktrace.o.orig text data bss dec hex filename 8555 393 12 8960 2300 kernel/trace/blktrace.o This patch also prepares for the next patch, that prints out BLK_TN_MESSAGE. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: 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> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* blktrace: fix memory leak when freeing struct blk_io_traceLi Zefan2009-03-31
| | | | | | | | | | | | | | | | | | | Impact: fix mixed ioctl and ftrace-plugin blktrace use memory leak When mixing the use of ioctl-based blktrace and ftrace-based blktrace, we can leak memory in this way: # btrace /dev/sda > /dev/null & # echo 0 > /sys/block/sda/sda1/trace/enable now we leak bt->dropped_file, bt->msg_file, bt->rchan... Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: 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> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* blktrace: fix blk_probes_ref chaosLi Zefan2009-03-31
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: fix mixed ioctl and ftrace-plugin blktrace use refcount bugs ioctl-based blktrace allocates bt and registers tracepoints when ioctl(BLKTRACESETUP), and do all cleanups when ioctl(BLKTRACETEARDOWN). while ftrace-based blktrace allocates/frees bt when: # echo 1/0 > /sys/block/sda/sda1/trace/enable and registers/unregisters tracepoints when: # echo blk/nop > /debugfs/tracing/current_tracer or # echo 1/0 > /debugfs/tracing/tracing_enable The separatation of allocation and registeration causes 2 problems: 1. current user-space blktrace still calls ioctl(TEARDOWN) when ioctl(SETUP) failed: # echo 1 > /sys/block/sda/sda1/trace/enable # blktrace /dev/sda BLKTRACESETUP: Device or resource busy ^C and now blk_probes_ref == -1 2. Another way to make blk_probes_ref == -1: # plugin sdb && mount sdb1 # echo 1 > /sys/block/sdb/sdb1/trace/enable # remove sdb This patch does the allocation and registeration when writing sdaX/trace/enable. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: 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> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* blktrace: make classic output more classicLi Zefan2009-03-31
| | | | | | | | | | | | | | Impact: fix ftrace plugin timestamp output In the classic user-space blktrace, the output timestamp is sec.nsec not sec.usec. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: 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> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* blktrace: fix off-by-one bugLi Zefan2009-03-31
| | | | | | | | | | 'what' is used as the index of array what2act, so it can't >= the array size. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Jens Axboe <jens.axboe@oracle.com> Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* blktrace: fix the original blktraceLi Zefan2009-03-31
| | | | | | | | | | | | | | | | | | | | | | | Currently the original blktrace, which is using relay and is used via ioctl, is broken. You can use ftrace to see the output of blktrace, but user-space blktrace is unusable. It's broken by "blktrace: add ftrace plugin" (c71a896154119f4ca9e89d6078f5f63ad60ef199) - if (unlikely(bt->trace_state != Blktrace_running)) + if (unlikely(bt->trace_state != Blktrace_running || !blk_tracer_enabled)) return; With this patch, both ioctl and ftrace can be used, but of course you can't use both of them at the same time. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: 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> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* blktrace: fix a race when creating blk_tree_root in debugfsLi Zefan2009-03-31
| | | | | | | | | | | | | | | | | | | | | | t1 t2 ------ ------ do_blk_trace_setup() do_blk_trace_setup() if (!blk_tree_root) { if (!blk_tree_root) blk_tree_root = create_dir() blk_tree_root = create_dir(); (now blk_tree_root == NULL) ... dir = create_dir(name, blk_tree_root); Due to this race, t1 will create 'dir' in /debugfs but not /debugfs/block. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: 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> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* blktrace: fix timestamp in binary outputLi Zefan2009-03-31
| | | | | | | | | | | | | | | | | | | | | I found the timestamp is wrong: # echo bin > trace_option # echo blk > current_tracer # cat trace_pipe | blkparse -i - 8,0 0 0 0.000000000 504 A W ... ... 8,7 1 0 0.008534097 0 C R ... (should be 8.534097xxx) user-space blkparse expects the timestamp to be nanosecond. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: 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> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* blktrace: print human-readable act_maskLi Zefan2009-03-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: new feature, allow symbolic values in /debug/tracing/act_mask Print stringified act_mask instead of hex value: # cat act_mask read,write,barrier,sync,queue,requeue,issue,complete,fs,pc,ahead,meta, discard,drv_data # echo "meta,write" > act_mask # cat act_mask write,meta Also: - make act_mask accept "ahead", "meta", "discard" and "drv_data" - use strsep() instead of strchr() to parse user input - return -EINVAL if a token is not found in the mask map - fix a bug that 'value' is unsigned, so it can < 0 - propagate error value of blk_trace_mask2str() to userspace, but not always return -ENXIO. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Jens Axboe <jens.axboe@oracle.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> LKML-Reference: <49C8AB42.1000802@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* blktrace: fix t_error()Li Zefan2009-03-24
| | | | | | | | | | | | | | Impact: fix error flag output t_error() should return t->error but not t->sector. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Jens Axboe <jens.axboe@oracle.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> LKML-Reference: <49C8945F.5020802@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* blktrace: fix wrong calculation of RWBSLi Zefan2009-03-24
| | | | | | | | | | | | | | Impact: fix the output of IO type category characters Trace categories are the upper 16 bits, not the lower 16 bits. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Jens Axboe <jens.axboe@oracle.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> LKML-Reference: <49C89432.8010805@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* blktrace: mark ddir_act[] constLi Zefan2009-03-24
| | | | | | | | | | | | | | Impact: cleanup ddir_act and what2act always stay immutable. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Jens Axboe <jens.axboe@oracle.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> LKML-Reference: <49C89415.5080503@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* blktrace: avoid accessing NULL bdev->bd_diskLi Zefan2009-03-21
| | | | | | | | | | | | | | | | bdev->bd_disk can be NULL, if the block device is not opened. Try this against an unmounted partition, and you'll see NULL dereference: # echo 1 > /sys/block/sda/sda5/enable Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <49C30098.6080107@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* blktrace: remove sysfs_blk_trace_enable_show/store()Li Zefan2009-03-21
| | | | | | | | | | | | | sysfs_blk_trace_enable_show()/store() share most of code with sysfs_blk_trace_attr_show()/store(). Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <49C30EA3.1060004@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* blktrace: report EBUSY correctlyLi Zefan2009-03-21
| | | | | | | | | | | | | | | | | | | | | blk_trace_remove_queue() returns EINVAL if q->blk_trace == NULL, but blk_trace_setup_queue() doesn't return EBUSY if q->blk_trace != NULL. # echo 0 > sdaX/trace/enable # echo 0 > sdaX/trace/enable bash: echo: write error: Invalid argument # echo 1 > sdaX/trace/enable # echo 1 > sdaX/trace/enable (should return EBUSY) Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <49C2F614.2010101@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* blktrace: don't increase blk_probes_ref if failed to setup blk traceLi Zefan2009-03-21
| | | | | | | | | | | | | do_blk_trace_setup() may return EBUSY, but the current code doesn't decrease blk_probes_ref in this case. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <49C2F5FF.80002@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* blktrace: remove blk_probe_mutexLi Zefan2009-03-21
| | | | | | | | | | | | | blk_register_tracepoints() always returns 0, so make it return void, thus we don't need to use blk_probe_mutex to protect blk_probes_ref. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <49C2F5EA.8060606@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* blktrace: make blk_tracer_enabled a bool flagLi Zefan2009-03-21
| | | | | | | | | | | | It doesn't have to be a counter, and it can be a bool flag instead. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Steven Rostedt <rostedt@goodmis.org> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <49C2F5D3.8090104@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* blktrace: fix possible memory leakLi Zefan2009-03-21
| | | | | | | | | | | | | When we failed to create "block" debugfs dir, we should do some cleanups. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <49C2F5B2.8000800@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
*---. Merge branches 'tracing/ftrace', 'tracing/kprobes', 'tracing/tasks' and ↵Ingo Molnar2009-03-20
|\ \ \ | | | | | | | | | | | | 'linus' into tracing/core
| | | * module: fix refptr allocation and release orderMasami Hiramatsu2009-03-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: fix ref-after-free crash on failed module load Fix refptr bug: Change refptr allocation and release order not to access a module data structure pointed by 'mod' after freeing mod->module_core. This bug will cause kernel panic(e.g. failed to find undefined symbols). This bug was reported on systemtap bugzilla. http://sources.redhat.com/bugzilla/show_bug.cgi?id=9927 Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Cc: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
| | * | tracing: fix command line to pid reverse mapCarsten Emde2009-03-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: fix command line to pid mapping map_cmdline_to_pid[] is checked in trace_save_cmdline(), but never updated. This results in stale pid to command line mappings and the tracer output will associate the wrong comm string. Signed-off-by: Carsten Emde <Carsten.Emde@osadl.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Steven Rostedt <srostedt@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * | tracing: fix trace_find_cmdline()Thomas Gleixner2009-03-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: prevent stale command line output In case there is no valid command line mapping for a pid trace_find_cmdline() returns without updating the comm buffer. The trace dump keeps the previous entry which results in confusing trace output: <idle>-0 [000] 280.702056 .... <idle>-23456 [000] 280.702080 .... Update the comm buffer with "<...>" when no mapping is found. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Steven Rostedt <srostedt@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * | tracing: replace the crude (unsigned) -1 hackeryThomas Gleixner2009-03-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: cleanup The command line recorder uses (unsigned) -1 to mark non mapped entries in the pid to command line maps. The validity check is completely unintuitive: idx >= SAVED_CMDLINES There is no need for such casting games. Use a constant to mark unmapped entries and check for that constant to make the code readable and understandable. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Steven Rostedt <srostedt@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * | tracing: stop command line recording when tracing is disabledThomas Gleixner2009-03-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: prevent overwrite of command line entries When the tracer is stopped the command line recording continues to record. The check for tracing_is_on() is not sufficient here as the ringbuffer status is not affected by setting debug/tracing/tracing_enabled to 0. On a non idle system this can result in the loss of the command line information for the stopped trace, which makes the trace harder to read and analyse. Check tracer_enabled to allow further recording. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Steven Rostedt <srostedt@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | | kprobes: Fix locking imbalance in kretprobesAnanth N Mavinakayanahalli2009-03-18
| |/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fix locking imbalance in kretprobes: ===================================== [ BUG: bad unlock balance detected! ] ------------------------------------- kthreadd/2 is trying to release lock (&rp->lock) at: [<c06b3080>] pre_handler_kretprobe+0xea/0xf4 but there are no more locks to release! other info that might help us debug this: 1 lock held by kthreadd/2: #0: (rcu_read_lock){..--}, at: [<c06b2b24>] __atomic_notifier_call_chain+0x0/0x5a stack backtrace: Pid: 2, comm: kthreadd Not tainted 2.6.29-rc8 #1 Call Trace: [<c06ae498>] ? printk+0xf/0x17 [<c06b3080>] ? pre_handler_kretprobe+0xea/0xf4 [<c044ce6c>] print_unlock_inbalance_bug+0xc3/0xce [<c0444d4b>] ? clocksource_read+0x7/0xa [<c04450a4>] ? getnstimeofday+0x5f/0xf6 [<c044a9ca>] ? register_lock_class+0x17/0x293 [<c044b72c>] ? mark_lock+0x1e/0x30b [<c0448956>] ? tick_dev_program_event+0x4a/0xbc [<c0498100>] ? __slab_alloc+0xa5/0x415 [<c06b2fbe>] ? pre_handler_kretprobe+0x28/0xf4 [<c06b3080>] ? pre_handler_kretprobe+0xea/0xf4 [<c044cf1b>] lock_release_non_nested+0xa4/0x1a5 [<c06b3080>] ? pre_handler_kretprobe+0xea/0xf4 [<c044d15d>] lock_release+0x141/0x166 [<c06b07dd>] _spin_unlock_irqrestore+0x19/0x50 [<c06b3080>] pre_handler_kretprobe+0xea/0xf4 [<c06b20b5>] kprobe_exceptions_notify+0x1c9/0x43e [<c06b2b02>] notifier_call_chain+0x26/0x48 [<c06b2b5b>] __atomic_notifier_call_chain+0x37/0x5a [<c06b2b24>] ? __atomic_notifier_call_chain+0x0/0x5a [<c06b2b8a>] atomic_notifier_call_chain+0xc/0xe [<c0442d0d>] notify_die+0x2d/0x2f [<c06b0f9c>] do_int3+0x1f/0x71 [<c06b0e84>] int3+0x2c/0x34 [<c042d476>] ? do_fork+0x1/0x288 [<c040221b>] ? kernel_thread+0x71/0x79 [<c043ed1b>] ? kthread+0x0/0x60 [<c043ed1b>] ? kthread+0x0/0x60 [<c04040b8>] ? kernel_thread_helper+0x0/0x10 [<c043ec7f>] kthreadd+0xac/0x148 [<c043ebd3>] ? kthreadd+0x0/0x148 [<c04040bf>] kernel_thread_helper+0x7/0x10 Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Tested-by: Bharata B Rao <bharata@linux.vnet.ibm.com> Cc: Masami Hiramatsu <mhiramat@redhat.com> Cc: Jim Keniston <jkenisto@us.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: <stable@kernel.org> [2.6.29.x, 2.6.28.x, 2.6.27.x] LKML-Reference: <20090318113621.GB4129@in.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | tracing/ring-buffer: fix non cpu hotplug caseFrederic Weisbecker2009-03-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: fix warning with irqsoff tracer The ring buffer allocates its buffers on pre-smp time (early_initcall). It means that, at first, only the boot cpu buffer is allocated and the ring-buffer cpumask only has the boot cpu set (cpu_online_mask). Later, the secondary cpu will show up and the ring-buffer will be notified about this event: the appropriate buffer will be allocated and the cpumask will be updated. Unfortunately, if !CONFIG_CPU_HOTPLUG, the ring-buffer will not be notified about the secondary cpus, meaning that the cpumask will have only the cpu boot set, and only one cpu buffer allocated. We fix that by using cpu_possible_mask if !CONFIG_CPU_HOTPLUG. This patch fixes the following warning with irqsoff tracer running: [ 169.317794] WARNING: at kernel/trace/trace.c:466 update_max_tr_single+0xcc/0xf3() [ 169.318002] Hardware name: AMILO Li 2727 [ 169.318002] Modules linked in: [ 169.318002] Pid: 5624, comm: bash Not tainted 2.6.29-rc8-tip-02636-g6aafa6c #11 [ 169.318002] Call Trace: [ 169.318002] [<ffffffff81036182>] warn_slowpath+0xea/0x13d [ 169.318002] [<ffffffff8100b9d6>] ? ftrace_call+0x5/0x2b [ 169.318002] [<ffffffff8100b9d6>] ? ftrace_call+0x5/0x2b [ 169.318002] [<ffffffff8100b9d1>] ? ftrace_call+0x0/0x2b [ 169.318002] [<ffffffff8101ef10>] ? ftrace_modify_code+0xa9/0x108 [ 169.318002] [<ffffffff8106e27f>] ? trace_hardirqs_off+0x25/0x27 [ 169.318002] [<ffffffff8149afe7>] ? _spin_unlock_irqrestore+0x1f/0x2d [ 169.318002] [<ffffffff81064f52>] ? ring_buffer_reset_cpu+0xf6/0xfb [ 169.318002] [<ffffffff8106637c>] ? ring_buffer_reset+0x36/0x48 [ 169.318002] [<ffffffff8106aeda>] update_max_tr_single+0xcc/0xf3 [ 169.318002] [<ffffffff8100bc17>] ? sysret_check+0x22/0x5d [ 169.318002] [<ffffffff8106e3ea>] stop_critical_timing+0x142/0x204 [ 169.318002] [<ffffffff8106e4cf>] trace_hardirqs_on_caller+0x23/0x25 [ 169.318002] [<ffffffff8149ac28>] trace_hardirqs_on_thunk+0x3a/0x3c [ 169.318002] [<ffffffff8100bc17>] ? sysret_check+0x22/0x5d [ 169.318002] ---[ end trace db76cbf775a750cf ]--- Because this tracer may try to swap two cpu ring buffers for an unregistered cpu on the ring buffer. This patch might also fix a fair loss of traces due to unallocated buffers for secondary cpus. Reported-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-b: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1237470453-5427-1-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | tracepoints: dont update zero-sized tracepoint sectionsIngo Molnar2009-03-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Zero-sized tracepoint sections can occur if tracing is enabled but no tracepoint is defined. Do not emit a warning in that case. Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Jaswinder Singh Rajput <jaswinderrajput@gmail.com> LKML-Reference: <1237394936.3132.1.camel@localhost.localdomain> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | tracing: fix oops in tracepoint_update_probe_range()Jaswinder Singh Rajput2009-03-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Change this crash: BUG: unable to handle kernel NULL pointer dereference at (null) IP: [<ffffffff8107d4de>] tracepoint_update_probe_range+0x1f/0x9b PGD 13d5fb067 PUD 13d688067 PMD 0 Oops: 0000 [#1] SMP To a more debuggable WARN_ONCE(). Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1237394936.3132.1.camel@localhost.localdomain> [ moved the check outside the lock and added a WARN_ON(). ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | tracing/ftrace: stop {irqs, preempt}soff tracers when tracing is stoppedFrederic Weisbecker2009-03-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: fix a selftest warning In some cases, it's possible to see the following warning on irqsoff tracer selftest: [ 4.640003] Testing tracer irqsoff: <4>------------[ cut here ]------------ [ 4.653562] WARNING: at kernel/trace/trace.c:458 update_max_tr_single+0x9a/0xc4() [ 4.660000] Hardware name: System Product Name [ 4.660000] Modules linked in: [ 4.660000] Pid: 301, comm: kstop/1 Not tainted 2.6.29-rc8-tip #35837 [ 4.660000] Call Trace: [ 4.660000] [<4014b588>] warn_slowpath+0x79/0x8f [ 4.660000] [<402d6949>] ? put_dec+0x64/0x6b [ 4.660000] [<40162b56>] ? getnstimeofday+0x58/0xdd [ 4.660000] [<40162210>] ? clocksource_read+0x3/0xf [ 4.660000] [<4015eb44>] ? ktime_set+0x8/0x34 [ 4.660000] [<4014101a>] ? balance_runtime+0x8/0x56 [ 4.660000] [<405f6f11>] ? _spin_lock+0x3/0x10 [ 4.660000] [<4011f643>] ? ftrace_call+0x5/0x8 [ 4.660000] [<4015d0f1>] ? task_cputime_zero+0x3/0x27 [ 4.660000] [<40190ee7>] ? cpupri_set+0x90/0xcb [ 4.660000] [<405f7208>] ? _spin_lock_irqsave+0x22/0x34 [ 4.660000] [<40190f12>] ? cpupri_set+0xbb/0xcb [ 4.660000] [<405f7151>] ? _spin_unlock_irqrestore+0x23/0x35 [ 4.660000] [<4018493f>] ? ring_buffer_reset_cpu+0x27/0x51 [ 4.660000] [<405f7208>] ? _spin_lock_irqsave+0x22/0x34 [ 4.660000] [<40184962>] ? ring_buffer_reset_cpu+0x4a/0x51 [ 4.660000] [<405f7151>] ? _spin_unlock_irqrestore+0x23/0x35 [ 4.660000] [<4018cc29>] ? trace_hardirqs_off+0x1a/0x1c [ 4.660000] [<405f7151>] ? _spin_unlock_irqrestore+0x23/0x35 [ 4.660000] [<40184962>] ? ring_buffer_reset_cpu+0x4a/0x51 [ 4.660000] [<401850f3>] ? cpumask_next+0x15/0x18 [ 4.660000] [<4018a41f>] update_max_tr_single+0x9a/0xc4 [ 4.660000] [<4014e5fe>] ? exit_notify+0x16/0xf2 [ 4.660000] [<4018cd13>] check_critical_timing+0xcc/0x11e [ 4.660000] [<4014e5fe>] ? exit_notify+0x16/0xf2 [ 4.660000] [<4014e5fe>] ? exit_notify+0x16/0xf2 [ 4.660000] [<4018cdf1>] stop_critical_timing+0x8c/0x9f [ 4.660000] [<4014e5c4>] ? forget_original_parent+0xac/0xd0 [ 4.660000] [<4018ce3a>] trace_hardirqs_on+0x1a/0x1c [ 4.660000] [<4014e5c4>] forget_original_parent+0xac/0xd0 [ 4.660000] [<4014e5fe>] exit_notify+0x16/0xf2 [ 4.660000] [<4014e8a5>] do_exit+0x1cb/0x225 [ 4.660000] [<4015c72b>] ? kthread+0x0/0x69 [ 4.660000] [<4011f61d>] kernel_thread_helper+0xd/0x10 [ 4.660000] ---[ end trace a7919e7f17c0a725 ]--- [ 4.660164] .. no entries found ..FAILED! During the selftest of irqsoff tracer, we do that: /* disable interrupts for a bit */ local_irq_disable(); udelay(100); local_irq_enable(); /* stop the tracing. */ tracing_stop(); /* check both trace buffers */ ret = trace_test_buffer(tr, NULL); If a callsite performs a new max delay with irqs off just after tracing_stop, update_max_tr_single() -> ring_buffer_swap_cpu() will be called with the buffers disabled by tracing_stop(), hence the warning, then ring_buffer_swap_cpu() return -EAGAIN and update_max_tr_single() complains. Fix it by also stopping the tracer before stopping the tracing globally. A similar situation can happen with preemptoff and preemptirqsoff tracers where we apply the same fix. Reported-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1237325938-5240-1-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | Merge branch 'tip/tracing/ftrace' of ↵Ingo Molnar2009-03-18
|\ \ \ | |/ / |/| | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into tracing/ftrace
| * | tracing: make power tracer start/stop methods lighter weightSteven Rostedt2009-03-17
| | | | | | | | | | | | | | | | | | | | | The start/stop methods of a tracer should be able to be executed in all contexts. This patch converts the power tracer to do so. Signed-off-by: Steven Rostedt <srostedt@redhat.com>
| * | tracing: make sched_switch stop/start light weightSteven Rostedt2009-03-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | The stopping and starting of a tracer should be light weight and be able to be called in all contexts. The sched_switch grabbed mutexes in the start/stop functions. This patch changes it to a simple variable, on/off. Signed-off-by: Steven Rostedt <srostedt@redhat.com>
| * | tracing: add global-clock option to provide cross CPU clock to tracesSteven Rostedt2009-03-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: feature to allow better serialized clock This patch adds an option called "global-clock" that will allow the tracer to switch to a slower but more accurate (across CPUs) clock. Signed-off-by: Steven Rostedt <srostedt@redhat.com>
| * | ring-buffer: add api to allow a tracer to change clock sourceSteven Rostedt2009-03-17
| | | | | | | | | | | | | | | | | | | | | This patch adds a new function called ring_buffer_set_clock that allows a tracer to assign its own clock source to the buffer. Signed-off-by: Steven Rostedt <srostedt@redhat.com>
* | | Merge branch 'tip/tracing/ftrace' of ↵Ingo Molnar2009-03-17
|\| | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into tracing/ftrace
| * | tracing: stop comm recording on tracing offSteven Rostedt2009-03-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: fix for losing comms in trace The command lines of tasks are cached at sched switch to not need to record them at every trace point. Disabling the tracing on stops the recording of traces, but does not stop the caching of command lines. When the tracing is off the cache may overflow and cause the tracing to show incorrect tasks matching the PIDs. This patch disables prevents updates to the comm cache when the ring buffer is off. Signed-off-by: Steven Rostedt <srostedt@redhat.com>
| * | tracing: protect reader of cmdline outputSteven Rostedt2009-03-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: fix to one cause of incorrect comm outputs in trace The spinlock only protected the creation of a comm <=> pid pair. But it was possible that a reader could look up a pid, and get the wrong comm because it had no locking. This also required changing trace_find_cmdline to copy the comm cache and not just send back a pointer to it. Signed-off-by: Steven Rostedt <srostedt@redhat.com>
| * | tracing/ftrace: fix the check on nopped sitesFrederic Weisbecker2009-03-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: fix a dynamic tracing failure Recently, the function and function graph tracers failed to use dynamic tracing after the following commit: fa9d13cf135efbd454453a53b6299976bea245a9 (ftrace: don't try to __ftrace_replace_code on !FTRACE_FL_CONVERTED rec) The patch is right except a mistake on the check for the FTRACE_FL_CONVERTED flag. The code patching is aborted in case of successfully nopped sites. What we want is the opposite: ignore the callsites that haven't been nopped. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Steven Rostedt <srostedt@redhat.com>
* | | tracing: fix leak in event_format_read()Tom Zanussi2009-03-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: fix memory leak If event_format_read() exits early due to nonzero ppos, the previous kmalloc doesn't get freed - might as well do the check before the kmalloc and avoid the problem. Signed-off-by: Tom Zanussi <tzanussi@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: =?ISO-8859-1?Q?Fr=E9d=E9ric?= Weisbecker <fweisbec@gmail.com> LKML-Reference: <1237270859.8033.141.camel@charm-linux> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | tracing/core: fix early free of cpumasksFrederic Weisbecker2009-03-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: fix crashes when tracing cpumasks While ring-buffer allocation, the cpumasks are allocated too, including the tracing cpumask and the per-cpu file mask handler. But these cpumasks are freed accidentally just after. Fix it. Reported-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <1237164303-11476-1-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | tracing/ftrace: fix double calls to tracing_start()Frederic Weisbecker2009-03-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: fix a warning during preemptirqsoff selftests When the preemptirqsoff selftest fails, we see the following warning: [ 6.050000] Testing tracer preemptirqsoff: .. no entries found .. ------------[ cut here ]------------ [ 6.060000] WARNING: at kernel/trace/trace.c:688 tracing_start+0x67/0xd3() [ 6.060000] Modules linked in: [ 6.060000] Pid: 1, comm: swapper Tainted: G [ 6.060000] Call Trace: [ 6.060000] [<ffffffff802460ff>] warn_slowpath+0xb1/0x100 [ 6.060000] [<ffffffff802a8f5b>] ? trace_preempt_on+0x35/0x4b [ 6.060000] [<ffffffff802a37fb>] ? tracing_start+0x31/0xd3 [ 6.060000] [<ffffffff802a37fb>] ? tracing_start+0x31/0xd3 [ 6.060000] [<ffffffff80271e0b>] ? __lock_acquired+0xe6/0x1f2 [ 6.060000] [<ffffffff802a37fb>] ? tracing_start+0x31/0xd3 [ 6.060000] [<ffffffff802a3831>] tracing_start+0x67/0xd3 [ 6.060000] [<ffffffff802a8ace>] ? irqsoff_tracer_reset+0x2d/0x57 [ 6.060000] [<ffffffff802a4d1c>] trace_selftest_startup_preemptirqsoff+0x1c8/0x1f1 [ 6.060000] [<ffffffff802a4798>] register_tracer+0x12f/0x241 [ 6.060000] [<ffffffff810250d0>] ? init_irqsoff_tracer+0x0/0x53 [ 6.060000] [<ffffffff8102510b>] init_irqsoff_tracer+0x3b/0x53 This is because in fail case, the preemptirqsoff tracer selftest calls twice the tracing_start() function: int trace_selftest_startup_preemptirqsoff(struct tracer *trace, struct trace_array *tr) { if (!ret && !count) { printk(KERN_CONT ".. no entries found .."); ret = -1; tracing_start(); <----- goto out; } [...] out: trace->reset(tr); tracing_start(); <------ tracing_max_latency = save_max; return ret; } Since it is well handled in the out path, we don't need the conditional one. Reported-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <1237159961-7447-1-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | tracing/core: fix missing mutex unlock on tracing_set_tracer()Frederic Weisbecker2009-03-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: fix possible locking imbalance In case of ring buffer resize failure, tracing_set_tracer forgot to release trace_types_lock. Fix it. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <1237151439-6755-5-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | tracing/syscalls: select kallsysmsFrederic Weisbecker2009-03-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Syscall tracing must select kallsysms. The arch code builds a table to find the syscall metadata by syscall number. It needs the syscalls names resolution from the symbol table to know which name found on the syscalls metadatas match a function pointer from the arch sys_call_table. Reported-by: Andrew Morton <akpm@linux-foundation.org> Reported-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <1237151439-6755-4-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | tracing/syscalls: protect thread flag toggling from racesFrederic Weisbecker2009-03-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: fix syscall tracer enable/disable race The current thread flag toggling is racy as shown in the following scenario: - task A is the last user of syscall tracing, it releases the TIF_SYSCALL_FTRACE on each tasks - at the same time task B start syscall tracing. refcount == 0 so it sets up TIF_SYSCALL_FTRACE on each tasks. The effect of the mixup is unpredictable. So this fix adds a mutex on {start,stop}_syscall_tracing(). Reported-by: Andrew Morton <akpm@linux-foundation.org> Reported-by: Ingo Molnar <mingo@elte.hu> LKML-Reference: <1237151439-6755-3-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | tracing/syscalls: various cleanupsFrederic Weisbecker2009-03-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: cleanup - Drop unused cpu variable - Fix some errors on comments Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <1237151439-6755-2-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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