linux-toradex.git/include/linux/kernel.h, branch v4.6-rc6

Merge tag 'trace-v4.6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

2016-03-24T17:52:25+00:00

Pull tracing updates from Steven Rostedt:
 "Nothing major this round.  Mostly small clean ups and fixes.

  Some visible changes:

   - A new flag was added to distinguish traces done in NMI context.

   - Preempt tracer now shows functions where preemption is disabled but
     interrupts are still enabled.

  Other notes:

   - Updates were done to function tracing to allow better performance
     with perf.

   - Infrastructure code has been added to allow for a new histogram
     feature for recording live trace event histograms that can be
     configured by simple user commands.  The feature itself was just
     finished, but needs a round in linux-next before being pulled.

     This only includes some infrastructure changes that will be needed"

* tag 'trace-v4.6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (22 commits)
  tracing: Record and show NMI state
  tracing: Fix trace_printk() to print when not using bprintk()
  tracing: Remove redundant reset per-CPU buff in irqsoff tracer
  x86: ftrace: Fix the misleading comment for arch/x86/kernel/ftrace.c
  tracing: Fix crash from reading trace_pipe with sendfile
  tracing: Have preempt(irqs)off trace preempt disabled functions
  tracing: Fix return while holding a lock in register_tracer()
  ftrace: Use kasprintf() in ftrace_profile_tracefs()
  ftrace: Update dynamic ftrace calls only if necessary
  ftrace: Make ftrace_hash_rec_enable return update bool
  tracing: Fix typoes in code comment and printk in trace_nop.c
  tracing, writeback: Replace cgroup path to cgroup ino
  tracing: Use flags instead of bool in trigger structure
  tracing: Add an unreg_all() callback to trigger commands
  tracing: Add needs_rec flag to event triggers
  tracing: Add a per-event-trigger 'paused' field
  tracing: Add get_syscall_name()
  tracing: Add event record param to trigger_ops.func()
  tracing: Make event trigger functions available
  tracing: Make ftrace_event_field checking functions available
  ...

panic: change nmi_panic from macro to function

2016-03-22T22:36:02+00:00

Commit 1717f2096b54 ("panic, x86: Fix re-entrance problem due to panic
on NMI") and commit 58c5661f2144 ("panic, x86: Allow CPUs to save
registers even if looping in NMI context") introduced nmi_panic() which
prevents concurrent/recursive execution of panic().  It also saves
registers for the crash dump on x86.

However, there are some cases where NMI handlers still use panic().
This patch set partially replaces them with nmi_panic() in those cases.

Even this patchset is applied, some NMI or similar handlers (e.g.  MCE
handler) continue to use panic().  This is because I can't test them
well and actual problems won't happen.  For example, the possibility
that normal panic and panic on MCE happen simultaneously is very low.

This patch (of 3):

Convert nmi_panic() to a proper function and export it instead of
exporting internal implementation details to modules, for obvious
reasons.

Signed-off-by: Hidehiro Kawai 
Acked-by: Borislav Petkov 
Acked-by: Michal Nazarewicz 
Cc: Michal Hocko 
Cc: Rasmus Villemoes 
Cc: Nicolas Iooss 
Cc: Javi Merino 
Cc: Gobinda Charan Maji 
Cc: "Steven Rostedt (Red Hat)" 
Cc: Thomas Gleixner 
Cc: Vitaly Kuznetsov 
Cc: HATAYAMA Daisuke 
Cc: Tejun Heo 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

tracing: Fix trace_printk() to print when not using bprintk()

2016-03-22T22:02:40+00:00

The trace_printk() code will allocate extra buffers if the compile detects
that a trace_printk() is used. To do this, the format of the trace_printk()
is saved to the __trace_printk_fmt section, and if that section is bigger
than zero, the buffers are allocated (along with a message that this has
happened).

If trace_printk() uses a format that is not a constant, and thus something
not guaranteed to be around when the print happens, the compiler optimizes
the fmt out, as it is not used, and the __trace_printk_fmt section is not
filled. This means the kernel will not allocate the special buffers needed
for the trace_printk() and the trace_printk() will not write anything to the
tracing buffer.

Adding a "__used" to the variable in the __trace_printk_fmt section will
keep it around, even though it is set to NULL. This will keep the string
from being printed in the debugfs/tracing/printk_formats section as it is
not needed.

Reported-by: Vlastimil Babka 
Fixes: 07d777fe8c398 "tracing: Add percpu buffers for trace_printk()"
Cc: stable@vger.kernel.org # v3.5+
Signed-off-by: Steven Rostedt

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next

2016-03-19T17:05:34+00:00

Pull networking updates from David Miller:
 "Highlights:

   1) Support more Realtek wireless chips, from Jes Sorenson.

   2) New BPF types for per-cpu hash and arrap maps, from Alexei
      Starovoitov.

   3) Make several TCP sysctls per-namespace, from Nikolay Borisov.

   4) Allow the use of SO_REUSEPORT in order to do per-thread processing
   of incoming TCP/UDP connections.  The muxing can be done using a
   BPF program which hashes the incoming packet.  From Craig Gallek.

   5) Add a multiplexer for TCP streams, to provide a messaged based
      interface.  BPF programs can be used to determine the message
      boundaries.  From Tom Herbert.

   6) Add 802.1AE MACSEC support, from Sabrina Dubroca.

   7) Avoid factorial complexity when taking down an inetdev interface
      with lots of configured addresses.  We were doing things like
      traversing the entire address less for each address removed, and
      flushing the entire netfilter conntrack table for every address as
      well.

   8) Add and use SKB bulk free infrastructure, from Jesper Brouer.

   9) Allow offloading u32 classifiers to hardware, and implement for
      ixgbe, from John Fastabend.

  10) Allow configuring IRQ coalescing parameters on a per-queue basis,
      from Kan Liang.

  11) Extend ethtool so that larger link mode masks can be supported.
      From David Decotigny.

  12) Introduce devlink, which can be used to configure port link types
      (ethernet vs Infiniband, etc.), port splitting, and switch device
      level attributes as a whole.  From Jiri Pirko.

  13) Hardware offload support for flower classifiers, from Amir Vadai.

  14) Add "Local Checksum Offload".  Basically, for a tunneled packet
      the checksum of the outer header is 'constant' (because with the
      checksum field filled into the inner protocol header, the payload
      of the outer frame checksums to 'zero'), and we can take advantage
      of that in various ways.  From Edward Cree"

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1548 commits)
  bonding: fix bond_get_stats()
  net: bcmgenet: fix dma api length mismatch
  net/mlx4_core: Fix backward compatibility on VFs
  phy: mdio-thunder: Fix some Kconfig typos
  lan78xx: add ndo_get_stats64
  lan78xx: handle statistics counter rollover
  RDS: TCP: Remove unused constant
  RDS: TCP: Add sysctl tunables for sndbuf/rcvbuf on rds-tcp socket
  net: smc911x: convert pxa dma to dmaengine
  team: remove duplicate set of flag IFF_MULTICAST
  bonding: remove duplicate set of flag IFF_MULTICAST
  net: fix a comment typo
  ethernet: micrel: fix some error codes
  ip_tunnels, bpf: define IP_TUNNEL_OPTS_MAX and use it
  bpf, dst: add and use dst_tclassid helper
  bpf: make skb->tc_classid also readable
  net: mvneta: bm: clarify dependencies
  cls_bpf: reset class and reuse major in da
  ldmvsw: Checkpatch sunvnet.c and sunvnet_common.c
  ldmvsw: Add ldmvsw.c driver code
  ...

lib: move strtobool() to kstrtobool()

2016-03-17T22:09:34+00:00

Create the kstrtobool_from_user() helper and move strtobool() logic into
the new kstrtobool() (matching all the other kstrto* functions).
Provides an inline wrapper for existing strtobool() callers.

Signed-off-by: Kees Cook 
Cc: Joe Perches 
Cc: Andy Shevchenko 
Cc: Rasmus Villemoes 
Cc: Daniel Borkmann 
Cc: Amitkumar Karwar 
Cc: Nishant Sarmukadam 
Cc: Kalle Valo 
Cc: Steve French 
Cc: Michael Ellerman 
Cc: Heiko Carstens 
Cc: Martin Schwidefsky 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

uapi: define DIV_ROUND_UP for userland

2016-03-04T21:10:36+00:00

DIV_ROUND_UP is defined in linux/kernel.h only for the kernel.
When ethtool.h is included by a userland app, we got the following error:

include/linux/ethtool.h:1218:8: error: variably modified 'queue_mask' at file scope
  __u32 queue_mask[DIV_ROUND_UP(MAX_NUM_QUEUE, 32)];
        ^

Let's add a common definition in uapi and use it everywhere.

Fixes: ac2c7ad0e5d6 ("net/ethtool: introduce a new ioctl for per queue setting")
CC: Kan Liang 
Suggested-by: Ben Hutchings 
Signed-off-by: Nicolas Dichtel 
Signed-off-by: David S. Miller

include/linux/kernel.h: change abs() macro so it uses consistent return type

2016-01-16T19:17:22+00:00

Rewrite abs() so that its return type does not depend on the
architecture and no unexpected type conversion happen inside of it.  The
only conversion is from unsigned to signed type.  char is left as a
return type but treated as a signed type regradless of it's actual
signedness.

With the old version, int arguments were promoted to long and depending
on architecture a long argument might result in s64 or long return type
(which may or may not be the same).

This came after some back and forth with Nicolas.  The current macro has
different return type (for the same input type) depending on
architecture which might be midly iritating.

An alternative version would promote to int like so:

	#define abs(x)	__abs_choose_expr(x, long long,			\
			__abs_choose_expr(x, long,			\
			__builtin_choose_expr(				\
				sizeof(x) <= sizeof(int),		\
				({ int __x = (x); __x<0?-__x:__x; }),	\
				((void)0))))

I have no preference but imagine Linus might.  :] Nicolas argument against
is that promoting to int causes iconsistent behaviour:

	int main(void) {
		unsigned short a = 0, b = 1, c = a - b;
		unsigned short d = abs(a - b);
		unsigned short e = abs(c);
		printf("%u %u\n", d, e);  // prints: 1 65535
	}

Then again, no sane person expects consistent behaviour from C integer
arithmetic.  ;)

Note:

  __builtin_types_compatible_p(unsigned char, char) is always false, and
  __builtin_types_compatible_p(signed char, char) is also always false.

Signed-off-by: Michal Nazarewicz 
Reviewed-by: Nicolas Pitre 
Cc: Srinivas Pandruvada 
Cc: Wey-Yi Guy 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

panic, x86: Allow CPUs to save registers even if looping in NMI context

2015-12-19T10:07:01+00:00

Currently, kdump_nmi_shootdown_cpus(), a subroutine of crash_kexec(),
sends an NMI IPI to CPUs which haven't called panic() to stop them,
save their register information and do some cleanups for crash dumping.
However, if such a CPU is infinitely looping in NMI context, we fail to
save its register information into the crash dump.

For example, this can happen when unknown NMIs are broadcast to all
CPUs as follows:

  CPU 0                             CPU 1
  ===========================       ==========================
  receive an unknown NMI
  unknown_nmi_error()
    panic()                         receive an unknown NMI
      spin_trylock(&panic_lock)     unknown_nmi_error()
      crash_kexec()                   panic()
                                        spin_trylock(&panic_lock)
                                        panic_smp_self_stop()
                                          infinite loop
        kdump_nmi_shootdown_cpus()
          issue NMI IPI -----------> blocked until IRET
                                          infinite loop...

Here, since CPU 1 is in NMI context, the second NMI from CPU 0 is
blocked until CPU 1 executes IRET. However, CPU 1 never executes IRET,
so the NMI is not handled and the callback function to save registers is
never called.

In practice, this can happen on some servers which broadcast NMIs to all
CPUs when the NMI button is pushed.

To save registers in this case, we need to:

  a) Return from NMI handler instead of looping infinitely
  or
  b) Call the callback function directly from the infinite loop

Inherently, a) is risky because NMI is also used to prevent corrupted
data from being propagated to devices.  So, we chose b).

This patch does the following:

1. Move the infinite looping of CPUs which haven't called panic() in NMI
   context (actually done by panic_smp_self_stop()) outside of panic() to
   enable us to refer pt_regs. Please note that panic_smp_self_stop() is
   still used for normal context.

2. Call a callback of kdump_nmi_shootdown_cpus() directly to save
   registers and do some cleanups after setting waiting_for_crash_ipi which
   is used for counting down the number of CPUs which handled the callback

Signed-off-by: Hidehiro Kawai 
Acked-by: Michal Hocko 
Cc: Aaron Tomlin 
Cc: Andrew Morton 
Cc: Andy Lutomirski 
Cc: Baoquan He 
Cc: Chris Metcalf 
Cc: Dave Young 
Cc: David Hildenbrand 
Cc: Don Zickus 
Cc: Eric Biederman 
Cc: Frederic Weisbecker 
Cc: Gobinda Charan Maji 
Cc: HATAYAMA Daisuke 
Cc: Hidehiro Kawai 
Cc: "H. Peter Anvin" 
Cc: Ingo Molnar 
Cc: Javi Merino 
Cc: Jiang Liu 
Cc: Jonathan Corbet 
Cc: kexec@lists.infradead.org
Cc: linux-doc@vger.kernel.org
Cc: lkml 
Cc: Masami Hiramatsu 
Cc: Michal Nazarewicz 
Cc: Nicolas Iooss 
Cc: Oleg Nesterov 
Cc: Peter Zijlstra 
Cc: Prarit Bhargava 
Cc: Rasmus Villemoes 
Cc: Seth Jennings 
Cc: Stefan Lippers-Hollmann 
Cc: Steven Rostedt 
Cc: Thomas Gleixner 
Cc: Ulrich Obergfell 
Cc: Vitaly Kuznetsov 
Cc: Vivek Goyal 
Cc: Yasuaki Ishimatsu 
Link: http://lkml.kernel.org/r/20151210014628.25437.75256.stgit@softrs
[ Cleanup comments, fixup formatting. ]
Signed-off-by: Borislav Petkov 
Signed-off-by: Thomas Gleixner

panic, x86: Fix re-entrance problem due to panic on NMI

2015-12-19T10:07:00+00:00

If panic on NMI happens just after panic() on the same CPU, panic() is
recursively called. Kernel stalls, as a result, after failing to acquire
panic_lock.

To avoid this problem, don't call panic() in NMI context if we've
already entered panic().

For that, introduce nmi_panic() macro to reduce code duplication. In
the case of panic on NMI, don't return from NMI handlers if another CPU
already panicked.

Signed-off-by: Hidehiro Kawai 
Acked-by: Michal Hocko 
Cc: Aaron Tomlin 
Cc: Andrew Morton 
Cc: Andy Lutomirski 
Cc: Baoquan He 
Cc: Chris Metcalf 
Cc: David Hildenbrand 
Cc: Don Zickus 
Cc: "Eric W. Biederman" 
Cc: Frederic Weisbecker 
Cc: Gobinda Charan Maji 
Cc: HATAYAMA Daisuke 
Cc: "H. Peter Anvin" 
Cc: Ingo Molnar 
Cc: Javi Merino 
Cc: Jonathan Corbet 
Cc: kexec@lists.infradead.org
Cc: linux-doc@vger.kernel.org
Cc: lkml 
Cc: Masami Hiramatsu 
Cc: Michal Nazarewicz 
Cc: Nicolas Iooss 
Cc: Peter Zijlstra 
Cc: Prarit Bhargava 
Cc: Rasmus Villemoes 
Cc: Rusty Russell 
Cc: Seth Jennings 
Cc: Steven Rostedt 
Cc: Thomas Gleixner 
Cc: Ulrich Obergfell 
Cc: Vitaly Kuznetsov 
Cc: Vivek Goyal 
Link: http://lkml.kernel.org/r/20151210014626.25437.13302.stgit@softrs
[ Cleanup comments, fixup formatting. ]
Signed-off-by: Borislav Petkov 
Signed-off-by: Thomas Gleixner

remove abs64()

2015-11-09T23:11:24+00:00

Switch everything to the new and more capable implementation of abs().
Mainly to give the new abs() a bit of a workout.

Cc: Michal Nazarewicz 
Cc: John Stultz 
Cc: Ingo Molnar 
Cc: Steven Rostedt 
Cc: Peter Zijlstra 
Cc: Masami Hiramatsu 
Cc: Peter Zijlstra 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds