1. 24 Mar, 2009 7 commits
    • Lai Jiangshan's avatar
      tracing: use union for multi-usages field · ee000b7f
      Lai Jiangshan authored
      
      
      Impact: cleanup
      
      struct dyn_ftrace::ip has different usages in his lifecycle,
      we use union for it. And also for struct dyn_ftrace::flags.
      Signed-off-by: default avatarLai Jiangshan <laijs@cn.fujitsu.com>
      Cc: Steven Rostedt <srostedt@redhat.com>
      Cc: Frederic Weisbecker <fweisbec@gmail.com>
      LKML-Reference: <49C871BE.3080405@cn.fujitsu.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      ee000b7f
    • Lai Jiangshan's avatar
      ftrace: show virtual PID · cc59c9e8
      Lai Jiangshan authored
      
      
      Impact: fix PID output under namespaces
      
      When current namespace is not the global namespace,
      pid read from set_ftrace_pid is no correct.
      
       # ~/newpid_namespace_run bash
       # echo $$
       1
       # echo 1 > set_ftrace_pid
       # cat set_ftrace_pid
       3756
      
      Since we write virtual PID to set_ftrace_pid, we need get
      virtual PID when we read it.
      Signed-off-by: default avatarLai Jiangshan <laijs@cn.fujitsu.com>
      Cc: Steven Rostedt <srostedt@redhat.com>
      Cc: Frederic Weisbecker <fweisbec@gmail.com>
      LKML-Reference: <49C84D65.9050606@cn.fujitsu.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      cc59c9e8
    • Steven Rostedt's avatar
      function-graph: add option for include sleep times · be6f164a
      Steven Rostedt authored
      
      
      Impact: give user a choice to show times spent while sleeping
      
      The user may want to see the time a function spent sleeping.
      This patch adds the trace option "sleep-time" to allow that.
      The "sleep-time" option is default on.
      
       echo sleep-time > /debug/tracing/trace_options
      
      produces:
      
       ------------------------------------------
       2)  avahi-d-3428  =>    <idle>-0
       ------------------------------------------
      
       2)               |      finish_task_switch() {
       2)   0.621 us    |        _spin_unlock_irq();
       2)   2.202 us    |      }
       2) ! 1002.197 us |    }
       2) ! 1003.521 us |  }
      
      where as,
      
       echo nosleep-time > /debug/tracing/trace_options
      
      produces:
      
       0)    <idle>-0    =>  yum-upd-3416
       ------------------------------------------
      
       0)               |              finish_task_switch() {
       0)   0.643 us    |                _spin_unlock_irq();
       0)   2.342 us    |              }
       0) + 41.302 us   |            }
       0) + 42.453 us   |          }
      Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      be6f164a
    • Steven Rostedt's avatar
      function-graph: ignore times across schedule · 8aef2d28
      Steven Rostedt authored
      
      
      Impact: more accurate timings
      
      The current method of function graph tracing does not take into
      account the time spent when a task is not running. This shows functions
      that call schedule have increased costs:
      
       3) + 18.664 us   |      }
       ------------------------------------------
       3)    <idle>-0    =>  kblockd-123
       ------------------------------------------
      
       3)               |      finish_task_switch() {
       3)   1.441 us    |        _spin_unlock_irq();
       3)   3.966 us    |      }
       3) ! 2959.433 us |    }
       3) ! 2961.465 us |  }
      
      This patch uses the tracepoint in the scheduling context switch to
      account for time that has elapsed while a task is scheduled out.
      Now we see:
      
       ------------------------------------------
       3)    <idle>-0    =>  edac-po-1067
       ------------------------------------------
      
       3)               |      finish_task_switch() {
       3)   0.685 us    |        _spin_unlock_irq();
       3)   2.331 us    |      }
       3) + 41.439 us   |    }
       3) + 42.663 us   |  }
      Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      8aef2d28
    • Steven Rostedt's avatar
      function-graph: prevent more than one tracer registering · 05ce5818
      Steven Rostedt authored
      
      
      Impact: prevent crash due to multiple function graph tracers
      
      The function graph tracer can currently only handle a single tracer
      being registered. If another tracer registers with the function
      graph tracer it can crash the system.
      Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      05ce5818
    • Steven Rostedt's avatar
      function-graph: moved the timestamp from arch to generic code · 5d1a03dc
      Steven Rostedt authored
      
      
      This patch move the timestamp from happening in the arch specific
      code into the general code. This allows for better control by the tracer
      to time manipulation.
      Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      5d1a03dc
    • Steven Rostedt's avatar
      tracing: fix memory leak in trace_stat · 09833521
      Steven Rostedt authored
      
      
      If the function profiler does not have any items recorded and one were
      to cat the function stat file, the kernel would take a BUG with a NULL
      pointer dereference.
      
      Looking further into this, I found that returning NULL from stat_start
      did not stop the stat logic, and would later call stat_next. This breaks
      from the way seq_file works, so I looked into fixing the stat code.
      
      This is where I noticed that the last next_entry is never freed.
      It is allocated, and if the stat_next returns NULL, the code breaks out
      of the loop, unlocks the mutex and exits. We never link the next_entry
      nor do we free it. Thus it is a real memory leak.
      
      This patch rearranges the code a bit to not only fix the memory leak,
      but also to act more like seq_file where nothing is printed if there
      is nothing to print. That is, stat_start returns NULL.
      Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      09833521
  2. 23 Mar, 2009 3 commits
    • Anton Vorontsov's avatar
      tracing: Fix TRACING_SUPPORT dependency for PPC32 · 45b95608
      Anton Vorontsov authored
      commit 40ada30f
      
       ("tracing: clean up menu"),
      despite the "clean up" in its purpose, introduced a behavioural
      change for Kconfig symbols: we no longer able to select tracing
      support on PPC32 (because IRQFLAGS_SUPPORT isn't yet implemented).
      
      The IRQFLAGS_SUPPORT is not mandatory for most tracers, tracing core
      has a special case for platforms w/o irqflags (which, by the way, has
      become useless as of the commit above).
      
      Though according to Ingo Molnar, there was periodic build failures on
      weird, unmaintained architectures that had no irqflags-tracing support
      and hence didn't know the raw_irqs_save/restore primitives. Thus we'd
      better not enable irqflags-less tracing for all architectures.
      
      This patch restores the old behaviour for PPC32, and thus brings the
      tracing back. Other architectures can either add themselves to the
      exception list or (better) implement TRACE_IRQFLAGS_SUPPORT.
      Signed-off-by: default avatarAnton Vorontsov <avorontsov@ru.mvista.com>
      Acked-b: Steven Rostedt <rostedt@goodmis.org>
      Cc: linuxppc-dev@ozlabs.org
      LKML-Reference: <20090323220724.GA9851@oksana.dev.rtsoft.ru>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      45b95608
    • Frederic Weisbecker's avatar
      tracing/ftrace: check if debugfs is registered before creating files · 3e1f60b8
      Frederic Weisbecker authored
      
      
      Impact: fix a crash with ftrace={nop,boot} parameter
      
      If the nop or initcall tracers are launched as boot tracers,
      they will attempt to create their option directory and files.
      But these tracers are registered very early and then assigned
      as "boot tracers" very early if asked to.
      
      Since they do this before debugfs has been registered (core initcall),
      a crash is triggered.
      
      Another early tracers could also come later. So we fix it by
      checking if debugfs is initialized before creating the root
      tracing directory.
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      Cc: Greg Kroah-Hartman <gregkh@suse.de>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      LKML-Reference: <1237759847-21025-3-git-send-email-fweisbec@gmail.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      3e1f60b8
    • Frederic Weisbecker's avatar
      debugfs: function to know if debugfs is initialized · c0f92ba9
      Frederic Weisbecker authored
      
      
      Impact: add new debugfs API
      
      With ftrace, some tracers are registered in early initcalls
      and attempt to create files on the debugfs filesystem.
      Depending on when they are activated, they can try to create their
      file at any time. Some checks can be done on the tracing area
      but providing a helper to know if debugfs is registered make it
      really more easy.
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      Acked-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      LKML-Reference: <1237759847-21025-2-git-send-email-fweisbec@gmail.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      c0f92ba9
  3. 22 Mar, 2009 4 commits
    • Dmitri Vorobiev's avatar
      tracing: fix four sparse warnings · b8b94265
      Dmitri Vorobiev authored
      
      
      Impact: cleanup.
      
      This patch fixes the following sparse warnings:
      
       kernel/trace/trace.c:385:9: warning: symbol 'trace_seq_to_buffer' was
       not declared. Should it be static?
      
       kernel/trace/trace_clock.c:29:13: warning: symbol 'trace_clock_local'
       was not declared. Should it be static?
      
       kernel/trace/trace_clock.c:54:13: warning: symbol 'trace_clock' was not
       declared. Should it be static?
      
       kernel/trace/trace_clock.c:74:13: warning: symbol 'trace_clock_global'
       was not declared. Should it be static?
      Signed-off-by: default avatarDmitri Vorobiev <dmitri.vorobiev@movial.com>
      LKML-Reference: <1237741871-5827-4-git-send-email-dmitri.vorobiev@movial.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      b8b94265
    • Ingo Molnar's avatar
      Merge branches 'tracing/ftrace', 'tracing/hw-breakpoints',... · a524446f
      Ingo Molnar authored
      Merge branches 'tracing/ftrace', 'tracing/hw-breakpoints', 'tracing/ring-buffer', 'tracing/textedit' and 'linus' into tracing/core
      a524446f
    • Frederic Weisbecker's avatar
      tracing: keep the tracing buffer after self-test failure · 0cf53ff6
      Frederic Weisbecker authored
      
      
      Instead of using ftrace_dump_on_oops, it's far more convenient
      to have the trace leading up to a self-test failure available
      in /debug/tracing/trace.
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      LKML-Reference: <1237694675-23509-1-git-send-email-fweisbec@gmail.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      0cf53ff6
    • Frederic Weisbecker's avatar
      tracing/function-graph-tracer: prevent hangs during self-tests · cf586b61
      Frederic Weisbecker authored
      
      
      Impact: detect tracing related hangs
      
      Sometimes, with some configs, the function graph tracer can make
      the timer interrupt too much slow, hanging the kernel in an endless
      loop of timer interrupts servicing.
      
      As suggested by Ingo, this patch brings a watchdog which stops the
      selftest after a defined number of functions traced, definitely
      disabling this tracer.
      
      For those who want to debug the cause of the function graph trace
      hang, you can pass the ftrace_dump_on_oops kernel parameter to dump
      the traces after this hang detection.
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      LKML-Reference: <1237694675-23509-1-git-send-email-fweisbec@gmail.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      cf586b61
  4. 21 Mar, 2009 1 commit
    • Frederic Weisbecker's avatar
      tracing/ring-buffer: don't annotate rb_cpu_notify with __cpuinit · 09c9e84d
      Frederic Weisbecker authored
      
      
      Impact: remove a section warning
      
      CONFIG_DEBUG_SECTION_MISMATCH raises the following warning on -tip:
      
        WARNING: kernel/trace/built-in.o(.text+0x5bc5): Section mismatch in
        reference from the function ring_buffer_alloc() to the function
        .cpuinit.text:rb_cpu_notify()
        The function ring_buffer_alloc() references
        the function __cpuinit rb_cpu_notify().
      
      This is actually harmless. The code in the ring buffer don't build
      rb_cpu_notify and other cpu hotplug stuffs when !CONFIG_HOTPLUG_CPU
      so we have no risk to reference freed memory here (it would even
      be harmless if we unconditionally build it because register_cpu_notifier
      would do nothing when !CONFIG_HOTPLUG_CPU.
      
      But since ring_buffer_alloc() can be called everytime, we don't want it
      to be annotated with __cpuinit so we drop the __cpuinit from
      rb_cpu_notify.
      
      This is not a waste of memory because it is only defined and used on
      CONFIG_HOTPLUG_CPU.
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      LKML-Reference: <1237606416-22268-1-git-send-email-fweisbec@gmail.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      09c9e84d
  5. 20 Mar, 2009 6 commits
  6. 19 Mar, 2009 15 commits
    • Jeff Moyer's avatar
      aio: lookup_ioctx can return the wrong value when looking up a bogus context · 65c24491
      Jeff Moyer authored
      The libaio test harness turned up a problem whereby lookup_ioctx on a
      bogus io context was returning the 1 valid io context from the list
      (harness/cases/3.p).
      
      Because of that, an extra put_iocontext was done, and when the process
      exited, it hit a BUG_ON in the put_iocontext macro called from exit_aio
      (since we expect a users count of 1 and instead get 0).
      
      The problem was introduced by "aio: make the lookup_ioctx() lockless"
      (commit abf137dd
      
      ).
      
      Thanks to Zach for pointing out that hlist_for_each_entry_rcu will not
      return with a NULL tpos at the end of the loop, even if the entry was
      not found.
      Signed-off-by: default avatarJeff Moyer <jmoyer@redhat.com>
      Acked-by: default avatarZach Brown <zach.brown@oracle.com>
      Acked-by: default avatarJens Axboe <jens.axboe@oracle.com>
      Cc: Benjamin LaHaise <bcrl@kvack.org>
      Cc: <stable@kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      65c24491
    • Davide Libenzi's avatar
      eventfd: remove fput() call from possible IRQ context · 87c3a86e
      Davide Libenzi authored
      
      
      Remove a source of fput() call from inside IRQ context.  Myself, like Eric,
      wasn't able to reproduce an fput() call from IRQ context, but Jeff said he was
      able to, with the attached test program.  Independently from this, the bug is
      conceptually there, so we might be better off fixing it.  This patch adds an
      optimization similar to the one we already do on ->ki_filp, on ->ki_eventfd.
      Playing with ->f_count directly is not pretty in general, but the alternative
      here would be to add a brand new delayed fput() infrastructure, that I'm not
      sure is worth it.
      Signed-off-by: default avatarDavide Libenzi <davidel@xmailserver.org>
      Cc: Benjamin LaHaise <bcrl@kvack.org>
      Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
      Cc: Eric Dumazet <dada1@cosmosbay.com>
      Signed-off-by: default avatarJeff Moyer <jmoyer@redhat.com>
      Cc: Zach Brown <zach.brown@oracle.com>
      Cc: <stable@kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      87c3a86e
    • Linus Torvalds's avatar
      Move cc-option to below arch-specific setup · d0115552
      Linus Torvalds authored
      
      
      Sam Ravnborg says:
       "We have several architectures that plays strange games with $(CC) and
        $(CROSS_COMPILE).
      
        So we need to postpone any use of $(call cc-option..) until we have
        included the arch specific Makefile so we try with the correct $(CC)
        version."
      Requested-by: default avatarSam Ravnborg <sam@ravnborg.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      d0115552
    • Linus Torvalds's avatar
      Merge branch 'for-linus' of git://git390.marist.edu/pub/scm/linux-2.6 · caa81d67
      Linus Torvalds authored
      * 'for-linus' of git://git390.marist.edu/pub/scm/linux-2.6:
        [S390] make page table upgrade work again
        [S390] make page table walking more robust
        [S390] Dont check for pfn_valid() in uaccess_pt.c
        [S390] ftrace/mcount: fix kernel stack backchain
        [S390] topology: define SD_MC_INIT to fix performance regression
        [S390] __div64_31 broken for CONFIG_MARCH_G5
      caa81d67
    • Linus Torvalds's avatar
      Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid · 2d8620cb
      Linus Torvalds authored
      * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid:
        HID: fix waitqueue usage in hiddev
        HID: fix incorrect free in hiddev
      2d8620cb
    • Linus Torvalds's avatar
      Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable · fe2fd6cc
      Linus Torvalds authored
      * git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable:
        Btrfs: Clear space_info full when adding new devices
        Btrfs: Fix locking around adding new space_info
      fe2fd6cc
    • Steven Rostedt's avatar
      function-graph: show binary events as comments · 5087f8d2
      Steven Rostedt authored
      
      
      With the added TRACE_EVENT macro, the events no longer appear in
      the function graph tracer. This was because the function graph
      did not know how to display the entries. The graph tracer was
      only aware of its own entries and the printk entries.
      
      By using the event call back feature, the graph tracer can now display
      the events.
      
       # echo irq > /debug/tracing/set_event
      
      Which can show:
      
       0)               |          handle_IRQ_event() {
       0)               |            /* irq_handler_entry: irq=48 handler=eth0 */
       0)               |            e1000_intr() {
       0)   0.926 us    |              __napi_schedule();
       0)   3.888 us    |            }
       0)               |            /* irq_handler_exit: irq=48 return=handled */
       0)   0.655 us    |            runqueue_is_locked();
       0)               |            __wake_up() {
       0)   0.831 us    |              _spin_lock_irqsave();
      
      The irq entry and exit events show up as comments.
      Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      5087f8d2
    • Steven Rostedt's avatar
      tracing: remove recording function depth from trace_printk · 40ce74f1
      Steven Rostedt authored
      
      
      The function depth in trace_printk was to facilitate the function
      graph output. Now that the function graph calculates the depth within
      the trace output, we no longer need to record the depth when the
      trace_printk is called.
      Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      40ce74f1
    • Steven Rostedt's avatar
      function-graph: calculate function depth within function graph tracer · 2fbcdb35
      Steven Rostedt authored
      
      
      Currently, the function graph tracer depends on the trace_printk
      to record the depth. All the information is already there in the trace
      to calculate function depth, with the exception of having the printk
      be the first item. But as soon as a entry or exit is reached, then
      we know the depth.
      
      This patch changes the iter->private data from recording a per cpu
      last_pid, to a structure that holds both the last_pid and the current
      depth. This data is used to determine the function depth for the
      printks.
      Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      2fbcdb35
    • Steven Rostedt's avatar
      tracing: make print_(b)printk_msg_only global · 5ef841f6
      Steven Rostedt authored
      
      
      This patch makes print_printk_msg_only and print_bprintk_msg_only
      global for other functions to use. It also renames them by adding
      a "trace_" to the beginning to avoid namespace collisions.
      Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      5ef841f6
    • Linus Torvalds's avatar
      Fix race in create_empty_buffers() vs __set_page_dirty_buffers() · a8e7d49a
      Linus Torvalds authored
      
      
      Nick Piggin noticed this (very unlikely) race between setting a page
      dirty and creating the buffers for it - we need to hold the mapping
      private_lock until we've set the page dirty bit in order to make sure
      that create_empty_buffers() might not build up a set of buffers without
      the dirty bits set when the page is dirty.
      
      I doubt anybody has ever hit this race (and it didn't solve the issue
      Nick was looking at), but as Nick says: "Still, it does appear to solve
      a real race, which we should close."
      Acked-by: default avatarNick Piggin <nickpiggin@yahoo.com.au>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      a8e7d49a
    • Linus Torvalds's avatar
      Add '-fwrapv' to gcc CFLAGS · 68df3755
      Linus Torvalds authored
      This makes sure that gcc doesn't try to optimize away wrapping
      arithmetic, which the kernel occasionally uses for overflow testing, ie
      things like
      
      	if (ptr + offset < ptr)
      
      which technically is undefined for non-unsigned types. See
      
      	http://bugzilla.kernel.org/show_bug.cgi?id=12597
      
      
      
      for details.
      
      Not all versions of gcc support it, so we need to make it conditional
      (it looks like it was introduced in gcc-3.4).
      Reminded-by: default avatarAlan Cox <alan@lxorguk.ukuu.org.uk>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      68df3755
    • Frederic Weisbecker's avatar
      tracing/ring-buffer: fix non cpu hotplug case · 3bf832ce
      Frederic Weisbecker authored
      
      
      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: default avatarIngo Molnar <mingo@elte.hu>
      Signed-off-by: default avatarFrederic 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: default avatarIngo Molnar <mingo@elte.hu>
      3bf832ce
    • Steven Rostedt's avatar
      function-graph: consolidate prologues for output · ac5f6c96
      Steven Rostedt authored
      
      
      Impact: clean up
      
      The prologue of the function graph entry, return and comments all
      start out pretty much the same. Each of these duplicate code and
      do so slightly differently.
      
      This patch consolidates the printing of the pid, absolute time,
      cpu and proc (and for entry, the interrupt).
      Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      ac5f6c96
    • Lai Jiangshan's avatar
      ftrace: protect running nmi (V3) · e9d9df44
      Lai Jiangshan authored
      
      
      When I review the sensitive code ftrace_nmi_enter(), I found
      the atomic variable nmi_running does protect NMI VS do_ftrace_mod_code(),
      but it can not protects NMI(entered nmi) VS NMI(ftrace_nmi_enter()).
      
      cpu#1                   | cpu#2                 | cpu#3
      ftrace_nmi_enter()      | do_ftrace_mod_code()  |
        not modify            |                       |
      ------------------------|-----------------------|--
      executing               | set mod_code_write = 1|
      executing             --|-----------------------|--------------------
      executing               |                       | ftrace_nmi_enter()
      executing               |                       |    do modify
      ------------------------|-----------------------|-----------------
      ftrace_nmi_exit()       |                       |
      
      cpu#3 may be being modified the code which is still being executed on cpu#1,
      it will have undefined results and possibly take a GPF, this patch
      prevents it occurred.
      Signed-off-by: default avatarLai Jiangshan <laijs@cn.fujitsu.com>
      LKML-Reference: <49C0B411.30003@cn.fujitsu.com>
      Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      e9d9df44
  7. 18 Mar, 2009 4 commits