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  1. 16 Jul, 2012 1 commit
    • Eric Dumazet's avatar
      drop_monitor: dont sleep in atomic context · f375a27c
      Eric Dumazet authored
      [ Upstream commit bec4596b ]
      
      drop_monitor calls several sleeping functions while in atomic context.
      
       BUG: sleeping function called from invalid context at mm/slub.c:943
       in_atomic(): 1, irqs_disabled(): 0, pid: 2103, name: kworker/0:2
       Pid: 2103, comm: kworker/0:2 Not tainted 3.5.0-rc1+ #55
       Call Trace:
        [<ffffffff810697ca>] __might_sleep+0xca/0xf0
        [<ffffffff811345a3>] kmem_cache_alloc_node+0x1b3/0x1c0
        [<ffffffff8105578c>] ? queue_delayed_work_on+0x11c/0x130
        [<ffffffff815343fb>] __alloc_skb+0x4b/0x230
        [<ffffffffa00b0360>] ? reset_per_cpu_data+0x160/0x160 [drop_monitor]
        [<ffffffffa00b022f>] reset_per_cpu_data+0x2f/0x160 [drop_monitor]
        [<ffffffffa00b03ab>] send_dm_alert+0x4b/0xb0 [drop_monitor]
        [<ffffffff810568e0>] process_one_work+0x130/0x4c0
        [<ffffffff81058249>] worker_thread+0x159/0x360
        [<ffffffff810580f0>] ? manage_workers.isra.27+0x240/0x240
        [<ffffffff8105d403>] kthread+0x93/0xa0
        [<ffffffff816be6d4>] kernel_thread_helper+0x4/0x10
        [<ffffffff8105d370>] ? kthread_freezable_should_stop+0x80/0x80
        [<ffffffff816be6d0>] ? gs_change+0xb/0xb
      
      Rework the logic to call the sleeping functions in right context.
      
      Use standard timer/workqueue api to let system chose any cpu to perform
      the allocation and netlink send.
      
      Also avoid a loop if reset_per_cpu_data() cannot allocate memory :
      use mod_timer() to wait 1/10 second before next try.
      Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
      Cc: Neil Horman <nhorman@tuxdriver.com>
      Reviewed-by: default avatarNeil Horman <nhorman@tuxdriver.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      f375a27c
  2. 03 May, 2012 1 commit
    • Neil Horman's avatar
      drop_monitor: prevent init path from scheduling on the wrong cpu · 4fdcfa12
      Neil Horman authored
      I just noticed after some recent updates, that the init path for the drop
      monitor protocol has a minor error.  drop monitor maintains a per cpu structure,
      that gets initalized from a single cpu.  Normally this is fine, as the protocol
      isn't in use yet, but I recently made a change that causes a failed skb
      allocation to reschedule itself .  Given the current code, the implication is
      that this workqueue reschedule will take place on the wrong cpu.  If drop
      monitor is used early during the boot process, its possible that two cpus will
      access a single per-cpu structure in parallel, possibly leading to data
      corruption.
      
      This patch fixes the situation, by storing the cpu number that a given instance
      of this per-cpu data should be accessed from.  In the case of a need for a
      reschedule, the cpu stored in the struct is assigned the rescheule, rather than
      the currently executing cpu
      
      Tested successfully by myself.
      Signed-off-by: default avatarNeil Horman <nhorman@tuxdriver.com>
      CC: David Miller <davem@davemloft.net>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      4fdcfa12
  3. 28 Apr, 2012 2 commits
    • Neil Horman's avatar
      drop_monitor: Make updating data->skb smp safe · 3885ca78
      Neil Horman authored
      Eric Dumazet pointed out to me that the drop_monitor protocol has some holes in
      its smp protections.  Specifically, its possible to replace data->skb while its
      being written.  This patch corrects that by making data->skb an rcu protected
      variable.  That will prevent it from being overwritten while a tracepoint is
      modifying it.
      Signed-off-by: default avatarNeil Horman <nhorman@tuxdriver.com>
      Reported-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
      CC: David Miller <davem@davemloft.net>
      Acked-by: default avatarEric Dumazet <edumazet@google.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      3885ca78
    • Neil Horman's avatar
      drop_monitor: fix sleeping in invalid context warning · cde2e9a6
      Neil Horman authored
      Eric Dumazet pointed out this warning in the drop_monitor protocol to me:
      
      [   38.352571] BUG: sleeping function called from invalid context at kernel/mutex.c:85
      [   38.352576] in_atomic(): 1, irqs_disabled(): 0, pid: 4415, name: dropwatch
      [   38.352580] Pid: 4415, comm: dropwatch Not tainted 3.4.0-rc2+ #71
      [   38.352582] Call Trace:
      [   38.352592]  [<ffffffff8153aaf0>] ? trace_napi_poll_hit+0xd0/0xd0
      [   38.352599]  [<ffffffff81063f2a>] __might_sleep+0xca/0xf0
      [   38.352606]  [<ffffffff81655b16>] mutex_lock+0x26/0x50
      [   38.352610]  [<ffffffff8153aaf0>] ? trace_napi_poll_hit+0xd0/0xd0
      [   38.352616]  [<ffffffff810b72d9>] tracepoint_probe_register+0x29/0x90
      [   38.352621]  [<ffffffff8153a585>] set_all_monitor_traces+0x105/0x170
      [   38.352625]  [<ffffffff8153a8ca>] net_dm_cmd_trace+0x2a/0x40
      [   38.352630]  [<ffffffff8154a81a>] genl_rcv_msg+0x21a/0x2b0
      [   38.352636]  [<ffffffff810f8029>] ? zone_statistics+0x99/0xc0
      [   38.352640]  [<ffffffff8154a600>] ? genl_rcv+0x30/0x30
      [   38.352645]  [<ffffffff8154a059>] netlink_rcv_skb+0xa9/0xd0
      [   38.352649]  [<ffffffff8154a5f0>] genl_rcv+0x20/0x30
      [   38.352653]  [<ffffffff81549a7e>] netlink_unicast+0x1ae/0x1f0
      [   38.352658]  [<ffffffff81549d76>] netlink_sendmsg+0x2b6/0x310
      [   38.352663]  [<ffffffff8150824f>] sock_sendmsg+0x10f/0x130
      [   38.352668]  [<ffffffff8150abe0>] ? move_addr_to_kernel+0x60/0xb0
      [   38.352673]  [<ffffffff81515f04>] ? verify_iovec+0x64/0xe0
      [   38.352677]  [<ffffffff81509c46>] __sys_sendmsg+0x386/0x390
      [   38.352682]  [<ffffffff810ffaf9>] ? handle_mm_fault+0x139/0x210
      [   38.352687]  [<ffffffff8165b5bc>] ? do_page_fault+0x1ec/0x4f0
      [   38.352693]  [<ffffffff8106ba4d>] ? set_next_entity+0x9d/0xb0
      [   38.352699]  [<ffffffff81310b49>] ? tty_ldisc_deref+0x9/0x10
      [   38.352703]  [<ffffffff8106d363>] ? pick_next_task_fair+0x63/0x140
      [   38.352708]  [<ffffffff8150b8d4>] sys_sendmsg+0x44/0x80
      [   38.352713]  [<ffffffff8165f8e2>] system_call_fastpath+0x16/0x1b
      
      It stems from holding a spinlock (trace_state_lock) while attempting to register
      or unregister tracepoint hooks, making in_atomic() true in this context, leading
      to the warning when the tracepoint calls might_sleep() while its taking a mutex.
      Since we only use the trace_state_lock to prevent trace protocol state races, as
      well as hardware stat list updates on an rcu write side, we can just convert the
      spinlock to a mutex to avoid this problem.
      Signed-off-by: default avatarNeil Horman <nhorman@tuxdriver.com>
      Reported-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
      CC: David Miller <davem@davemloft.net>
      Acked-by: default avatarEric Dumazet <edumazet@google.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      cde2e9a6
  4. 21 Apr, 2012 1 commit
  5. 08 May, 2011 1 commit
  6. 22 Mar, 2011 1 commit
  7. 27 Jul, 2010 1 commit
  8. 20 Jul, 2010 1 commit
  9. 14 May, 2010 1 commit
    • Steven Rostedt's avatar
      tracing: Let tracepoints have data passed to tracepoint callbacks · 38516ab5
      Steven Rostedt authored
      This patch adds data to be passed to tracepoint callbacks.
      
      The created functions from DECLARE_TRACE() now need a mandatory data
      parameter. For example:
      
      DECLARE_TRACE(mytracepoint, int value, value)
      
      Will create the register function:
      
      int register_trace_mytracepoint((void(*)(void *data, int value))probe,
                                      void *data);
      
      As the first argument, all callbacks (probes) must take a (void *data)
      parameter. So a callback for the above tracepoint will look like:
      
      void myprobe(void *data, int value)
      {
      }
      
      The callback may choose to ignore the data parameter.
      
      This change allows callbacks to register a private data pointer along
      with the function probe.
      
      	void mycallback(void *data, int value);
      
      	register_trace_mytracepoint(mycallback, mydata);
      
      Then the mycallback() will receive the "mydata" as the first parameter
      before the args.
      
      A more detailed example:
      
        DECLARE_TRACE(mytracepoint, TP_PROTO(int status), TP_ARGS(status));
      
        /* In the C file */
      
        DEFINE_TRACE(mytracepoint, TP_PROTO(int status), TP_ARGS(status));
      
        [...]
      
             trace_mytracepoint(status);
      
        /* In a file registering this tracepoint */
      
        int my_callback(void *data, int status)
        {
      	struct my_struct my_data = data;
      	[...]
        }
      
        [...]
      	my_data = kmalloc(sizeof(*my_data), GFP_KERNEL);
      	init_my_data(my_data);
      	register_trace_mytracepoint(my_callback, my_data);
      
      The same callback can also be registered to the same tracepoint as long
      as the data registered is different. Note, the data must also be used
      to unregister the callback:
      
      	unregister_trace_mytracepoint(my_callback, my_data);
      
      Because of the data parameter, tracepoints declared this way can not have
      no args. That is:
      
        DECLARE_TRACE(mytracepoint, TP_PROTO(void), TP_ARGS());
      
      will cause an error.
      
      If no arguments are needed, a new macro can be used instead:
      
        DECLARE_TRACE_NOARGS(mytracepoint);
      
      Since there are no arguments, the proto and args fields are left out.
      
      This is part of a series to make the tracepoint footprint smaller:
      
         text	   data	    bss	    dec	    hex	filename
      4913961	1088356	 861512	6863829	 68bbd5	vmlinux.orig
      4914025	1088868	 861512	6864405	 68be15	vmlinux.class
      4918492	1084612	 861512	6864616	 68bee8	vmlinux.tracepoint
      
      Again, this patch also increases the size of the kernel, but
      lays the ground work for decreasing it.
      
       v5: Fixed net/core/drop_monitor.c to handle these updates.
      
       v4: Moved the DECLARE_TRACE() DECLARE_TRACE_NOARGS out of the
           #ifdef CONFIG_TRACE_POINTS, since the two are the same in both
           cases. The __DECLARE_TRACE() is what changes.
           Thanks to Frederic Weisbecker for pointing this out.
      
       v3: Made all register_* functions require data to be passed and
           all callbacks to take a void * parameter as its first argument.
           This makes the calling functions comply with C standards.
      
           Also added more comments to the modifications of DECLARE_TRACE().
      
       v2: Made the DECLARE_TRACE() have the ability to pass arguments
           and added a new DECLARE_TRACE_NOARGS() for tracepoints that
           do not need any arguments.
      Acked-by: default avatarMathieu Desnoyers <mathieu.desnoyers@efficios.com>
      Acked-by: default avatarMasami Hiramatsu <mhiramat@redhat.com>
      Acked-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      Cc: Neil Horman <nhorman@tuxdriver.com>
      Cc: David S. Miller <davem@davemloft.net>
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      38516ab5
  10. 30 Mar, 2010 1 commit
    • Tejun Heo's avatar
      include cleanup: Update gfp.h and slab.h includes to prepare for breaking... · 5a0e3ad6
      Tejun Heo authored
      include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
      
      percpu.h is included by sched.h and module.h and thus ends up being
      included when building most .c files.  percpu.h includes slab.h which
      in turn includes gfp.h making everything defined by the two files
      universally available and complicating inclusion dependencies.
      
      percpu.h -> slab.h dependency is about to be removed.  Prepare for
      this change by updating users of gfp and slab facilities include those
      headers directly instead of assuming availability.  As this conversion
      needs to touch large number of source files, the following script is
      used as the basis of conversion.
      
        http://userweb.kernel.org/~tj/misc/slabh-sweep.py
      
      The script does the followings.
      
      * Scan files for gfp and slab usages and update includes such that
        only the necessary includes are there.  ie. if only gfp is used,
        gfp.h, if slab is used, slab.h.
      
      * When the script inserts a new include, it looks at the include
        blocks and try to put the new include such that its order conforms
        to its surrounding.  It's put in the include block which contains
        core kernel includes, in the same order that the rest are ordered -
        alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
        doesn't seem to be any matching order.
      
      * If the script can't find a place to put a new include (mostly
        because the file doesn't have fitting include block), it prints out
        an error message indicating which .h file needs to be added to the
        file.
      
      The conversion was done in the following steps.
      
      1. The initial automatic conversion of all .c files updated slightly
         over 4000 files, deleting around 700 includes and adding ~480 gfp.h
         and ~3000 slab.h inclusions.  The script emitted errors for ~400
         files.
      
      2. Each error was manually checked.  Some didn't need the inclusion,
         some needed manual addition while adding it to implementation .h or
         embedding .c file was more appropriate for others.  This step added
         inclusions to around 150 files.
      
      3. The script was run again and the output was compared to the edits
         from #2 to make sure no file was left behind.
      
      4. Several build tests were done and a couple of problems were fixed.
         e.g. lib/decompress_*.c used malloc/free() wrappers around slab
         APIs requiring slab.h to be added manually.
      
      5. The script was run on all .h files but without automatically
         editing them as sprinkling gfp.h and slab.h inclusions around .h
         files could easily lead to inclusion dependency hell.  Most gfp.h
         inclusion directives were ignored as stuff from gfp.h was usually
         wildly available and often used in preprocessor macros.  Each
         slab.h inclusion directive was examined and added manually as
         necessary.
      
      6. percpu.h was updated not to include slab.h.
      
      7. Build test were done on the following configurations and failures
         were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
         distributed build env didn't work with gcov compiles) and a few
         more options had to be turned off depending on archs to make things
         build (like ipr on powerpc/64 which failed due to missing writeq).
      
         * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
         * powerpc and powerpc64 SMP allmodconfig
         * sparc and sparc64 SMP allmodconfig
         * ia64 SMP allmodconfig
         * s390 SMP allmodconfig
         * alpha SMP allmodconfig
         * um on x86_64 SMP allmodconfig
      
      8. percpu.h modifications were reverted so that it could be applied as
         a separate patch and serve as bisection point.
      
      Given the fact that I had only a couple of failures from tests on step
      6, I'm fairly confident about the coverage of this conversion patch.
      If there is a breakage, it's likely to be something in one of the arch
      headers which should be easily discoverable easily on most builds of
      the specific arch.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Guess-its-ok-by: default avatarChristoph Lameter <cl@linux-foundation.org>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
      5a0e3ad6
  11. 17 Feb, 2010 1 commit
  12. 07 Nov, 2009 1 commit
  13. 02 Sep, 2009 2 commits
  14. 21 May, 2009 1 commit
    • Neil Horman's avatar
      dropmon: add ability to detect when hardware dropsrxpackets · 4ea7e386
      Neil Horman authored
      Patch to add the ability to detect drops in hardware interfaces via dropwatch.
      Adds a tracepoint to net_rx_action to signal everytime a napi instance is
      polled.  The dropmon code then periodically checks to see if the rx_frames
      counter has changed, and if so, adds a drop notification to the netlink
      protocol, using the reserved all-0's vector to indicate the drop location was in
      hardware, rather than somewhere in the code.
      Signed-off-by: default avatarNeil Horman <nhorman@tuxdriver.com>
      
       include/linux/net_dropmon.h |    8 ++
       include/trace/napi.h        |   11 +++
       net/core/dev.c              |    5 +
       net/core/drop_monitor.c     |  124 ++++++++++++++++++++++++++++++++++++++++++--
       net/core/net-traces.c       |    4 +
       net/core/netpoll.c          |    2
       6 files changed, 149 insertions(+), 5 deletions(-)
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      4ea7e386
  15. 27 Apr, 2009 1 commit
    • Neil Horman's avatar
      drop_monitor: Update netlink protocol to include netlink attribute header in alert message · 683703a2
      Neil Horman authored
      When I initially implemented this protocol, I disregarded the use of netlink
      attribute headers, thinking for my purposes they weren't needed.  I've come to
      find out that, as I'm starting to work with sending down messages with
      associated data (like config messages), the kernel code spits out warnings about
      trailing data in a netlink skb that doesn't have an associated header on it.  As
      such, I'm going to start including attribute headers in my netlink transaction,
      and so for completeness, I should likely include them on messages bound from the
      kernel to user space.  This patch adds that header to the kernel, and bumps the
      protocol version accordingly
      Signed-off-by: default avatarNeil Horman <nhorman@tuxdriver.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      683703a2
  16. 15 Apr, 2009 1 commit
    • Steven Rostedt's avatar
      tracing/events: move trace point headers into include/trace/events · ad8d75ff
      Steven Rostedt authored
      Impact: clean up
      
      Create a sub directory in include/trace called events to keep the
      trace point headers in their own separate directory. Only headers that
      declare trace points should be defined in this directory.
      
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Neil Horman <nhorman@tuxdriver.com>
      Cc: Zhao Lei <zhaolei@cn.fujitsu.com>
      Cc: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
      Cc: Pekka Enberg <penberg@cs.helsinki.fi>
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      ad8d75ff
  17. 13 Mar, 2009 1 commit