Merge tag 'perf-urgent-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/urgent

Cherry picked fixes from perf/core, together with the kernel fix (1018faa6),
the sampling tools (top, record) are back working on AMD systems.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Just fall back to resetting those fields, if set, warning the user that
that feature is not available.

If guest samples appear they will just be discarded because no struct
machine will be found and thus the event will be accounted as not
handled and dropped, see 0c095715.
Reported-by: Namhyung Kim <namhyung@gmail.com>
Tested-by: Joerg Roedel <joerg.roedel@amd.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Joerg Roedel <joerg.roedel@amd.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-vuwxig36mzprl5n7nzvnxxsh@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Setting perf_guest to true by default makes no sense because the perf
subcommands can not setup guest symbol information and thus not process
and guest samples. The only exception is perf-kvm which changes the
perf_guest value on its own.  So change the default for perf_guest back
to false.

Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1328893505-4115-3-git-send-email-joerg.roedel@amd.comSigned-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

A recent refactoring of perf-record introduced the following:

perf record -a -B
Couldn't generating buildids. Use --no-buildid to profile anyway.
sleep: Terminated

I believe the triple negative was meant to be only a double negative.
:-) While I'm there, fixed the grammar on the error message.

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1328567272-13190-1-git-send-email-dsahern@gmail.comSigned-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

It turned out that a performance counter on AMD does not
count at all when the GO or HO bit is set in the control
register and SVM is disabled in EFER.

This patch works around this issue by masking out the HO bit
in the performance counter control register when SVM is not
enabled.

The GO bit is not touched because it is only set when the
user wants to count in guest-mode only. So when SVM is
disabled the counter should not run at all and the
not-counting is the intended behaviour.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Avi Kivity <avi@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Gleb Natapov <gleb@redhat.com>
Cc: Robert Richter <robert.richter@amd.com>
Cc: stable@vger.kernel.org # v3.2
Link: http://lkml.kernel.org/r/1330523852-19566-1-git-send-email-joerg.roedel@amd.comSigned-off-by: Ingo Molnar <mingo@elte.hu>

Merge tag 'perf-urgent-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/urgent

Various smaller perf/urgent fixes.
Signed-off-by: Ingo Molnar <mingo@elte.hu>

The 'perf probe' command allows kprobe to be inserted at any offset from
a function start, which results in adding kprobes to unintended
location.  (example: perf probe do_fork+10000 is allowed even though
size of do_fork is ~904).

My previous patch https://lkml.org/lkml/2012/2/24/42 addressed the case
where DWARF info was available for the kernel. This patch fixes the
case where perf probe is used on a kernel without debuginfo available.
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/4F4C544D.1010909@linux.vnet.ibm.comSigned-off-by: Prashanth Nageshappa <prashanth@linux.vnet.ibm.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

If threads in a multi-threaded process have names shorter than the main
thread the comm for the named threads is not properly terminated.

E.g., for the process 'namedthreads' where each thread is named noploop%d
where %d is the thread number:

Before:
    perf script -f comm,tid,ip,sym,dso
    noploop:4ads 21616  400a49 noploop (/tmp/namedthreads)
The 'ads' in the thread comm bleeds over from the process name.

After:
    perf script -f comm,tid,ip,sym,dso
       noploop:4 21616  400a49 noploop (/tmp/namedthreads)

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1330111898-68071-1-git-send-email-dsahern@gmail.comSigned-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

The perf probe command allows kprobe to be inserted at any offset from a
function start, which results in adding kprobes to unintended location.

Example: perf probe do_fork+10000 is allowed even though size of do_fork
is ~904.

This patch will ensure probe addition fails when the offset specified is
greater than size of the function.
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Link: http://lkml.kernel.org/r/4F473F33.4060409@linux.vnet.ibm.comSigned-off-by: Prashanth Nageshappa <prashanth@linux.vnet.ibm.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

On old kernels that don't support sample_id_all feature,
perf_evlist__id2evsel() returns NULL for non-sampling events.

This breaks perf top when multiple events are given on command line. Fix
it by using first evsel in the evlist. This will also prevent getting
the same (potential) problem in such new tool/ old kernel combo.
Suggested-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1329702447-25045-1-git-send-email-namhyung.kim@lge.comSigned-off-by: Namhyung Kim <namhyung.kim@lge.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

If kzalloc() for TYPE_DATA failed on a given cpu, previous chunk
of TYPE_INST will be leaked. Fix it.

Thanks to Peter Zijlstra for suggesting this better solution. It
should work as long as the initial value of the region is all
0's and that's the case of static (per-cpu) memory allocation.
Signed-off-by: Namhyung Kim <namhyung.kim@lge.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Link: http://lkml.kernel.org/r/1330391978-28070-1-git-send-email-namhyung.kim@lge.comSigned-off-by: Ingo Molnar <mingo@elte.hu>

Here are some trivial NTFS changes (a spelling fix and two use before
NULL check cases found by Coverity as well as an update in MAINTAINERS
for the path to the ntfs git repo) together with a simple LDM fix for
parsing fragmented VBLKs.

* git://git.kernel.org/pub/scm/linux/kernel/git/aia21/ntfs:
  NTFS: Update git repo path in MAINTAINERS file.
  LDM: Fix reassembly of extended VBLKs.
  NTFS: Correct two spelling errors "dealocate" to "deallocate" in mft.c.
  NTFS: Do not dereference pointer before checking for NULL.
  NTFS: Remove unused variable.

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mce/AMD: Fix UP build error
  x86: Specify a size for the cmp in the NMI handler
  x86/nmi: Test saved %cs in NMI to determine nested NMI case
  x86/amd: Fix L1i and L2 cache sharing information for AMD family 15h processors
  x86/microcode: Remove noisy AMD microcode warning

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/events: Revert trace_sched_stat_sleeptime()

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  genirq: Handle pending irqs in irq_startup()
  genirq: Unmask oneshot irqs when thread was not woken

The new is_compat_task() define for the !COMPAT case in
include/linux/compat.h conflicts with a similar define in
arch/s390/include/asm/compat.h.

This is the minimal patch which fixes the build issues.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: Anton Altaparmakov <anton@tuxera.com>

Merge tag 'stable/for-linus-fixes-3.3-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen

Two fixes to fix a memory corruption bug when WC pages never get
converted back to WB but end up being recycled in the general memory
pool as WC.

There is a better way of fixing this, but there is not enough time to do
the full benchmarking to pick one of the right options - so picking the
one that favors stability for right now.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

* tag 'stable/for-linus-fixes-3.3-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
  xen/pat: Disable PAT support for now.
  xen/setup: Remove redundant filtering of PTE masks.

* tag 'for-linus' of git://github.com/rustyrussell/linux:
  mod/file2alias: make modpost compile on darwin again

The autofs mailing list has moved to vger.kernel.org.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

commit e49ce141 breaks cross compiling
the linux kernel on darwin hosts.
This fix introduce some minimal glue to adopt linker section handling
for darwin hosts.
Signed-off-by: Andreas Bießmann <andreas@biessmann.de>
CC: Rusty Russell <rusty@rustcorp.com.au>
CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CC: Jochen Friedrich <jochen@scram.de>
CC: Samuel Ortiz <sameo@linux.intel.com>
CC: "K. Y. Srinivasan" <kys@microsoft.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Tested-by: Bernhard Walle <bernhard@bwalle.de>

1) ICMP sockets leave err uninitialized but we try to return it for the
   unsupported MSG_OOB case, reported by Dave Jones.

2) Add new Zaurus device ID entries, from Dave Jones.

3) Pointer calculation in hso driver memset is wrong, from Dan
   Carpenter.

4) ks8851_probe() checks unsigned value as negative, fix also from Dan
   Carpenter.

5) Fix crashes in atl1c driver due to TX queue handling, from Eric
   Dumazet.  I anticipate some TX side locking fixes coming in the near
   future for this driver as well.

6) The inline directive fix in Bluetooth which was breaking the build
   only with very new versions of GCC, from Johan Hedberg.

7) Fix crashes in the ATP CLIP code due to ARP cleanups this merge
   window, reported by Meelis Roos and fixed by Eric Dumazet.

8) JME driver doesn't flush RX FIFO correctly, from Guo-Fu Tseng.

9) Some ip6_route_output() callers test the return value for NULL, but
   this never happens as the convention is to return a dst entry with
   dst->error set.  Fixes from RonQing Li.

10) Logitech Harmony 900 should be handled by zaurus driver not
   cdc_ether, update white lists and black lists accordingly.  From
   Scott Talbert.

11) Receiving from certain kinds of devices there won't be a MAC header,
   so there is no MAC header to fixup in the IPSEC code, and if we try
   to do it we'll crash.  Fix from Eric Dumazet.

12) Port type array indexing off-by-one in mlx4 driver, fix from Yevgeny
   Petrilin.

13) Fix regression in link-down handling in davinci_emac which causes
   all RX descriptors to be freed up and therefore RX to wedge
   completely, from Christian Riesch.

14) It took two attempts, but ctnetlink soft lockups seem to be
   cured now, from Pablo Neira Ayuso.

15) Endianness bug fix in ENIC driver, from Santosh Nayak.

16) The long ago conversion of the PPP fragmentation code over to
   abstracted SKB list handling wasn't perfect, once we get an
   out of sequence SKB we don't flush the rest of them like we
   should.  From Ben McKeegan.

17) Fix regression of ->ip_summed initialization in sfc driver.
   From Ben Hutchings.

18) Bluetooth timeout mistakenly using msecs instead of jiffies,
   from Andrzej Kaczmarek.

19) Using _sync variant of work cancellation results in deadlocks,
   use the non _sync variants instead.  From Andre Guedes.

20) Bluetooth rfcomm code had reference counting problems leading
   to crashes, fix from Octavian Purdila.

21) The conversion of netem over to classful qdisc handling added
   two bugs to netem_dequeue(), fixes from Eric Dumazet.

22) Missing pci_iounmap() in ATM Solos driver.  Fix from Julia Lawall.

23) b44_pci_exit() should not have __exit tag since it's invoked from
   non-__exit code.  From Nikola Pajkovsky.

24) The conversion of the neighbour hash tables over to RCU added a
   race, fixed here by adding the necessary reread of tbl->nht, fix
   from Michel Machado.

25) When we added VF (virtual function) attributes for network device
   dumps, this potentially bloats up the size of the dump of one
   network device such that the dump size is too large for the buffer
   allocated by properly written netlink applications.

   In particular, if you add 255 VFs to a network device, parts of
   GLIBC stop working.

   To fix this, we add an attribute that is used to turn on these
   extended portions of the network device dump.  Sophisticaed
   applications like 'ip' that want to see this stuff  will be changed
   to set the attribute, whereas things like GLIBC that don't care
   about VFs simply will not, and therefore won't be busted by the
   mere presence of VFs on a network device.

   Thanks to the tireless work of Greg Rose on this fix.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (53 commits)
  sfc: Fix assignment of ip_summed for pre-allocated skbs
  ppp: fix 'ppp_mp_reconstruct bad seq' errors
  enic: Fix endianness bug.
  gre: fix spelling in comments
  netfilter: ctnetlink: fix soft lockup when netlink adds new entries (v2)
  Revert "netfilter: ctnetlink: fix soft lockup when netlink adds new entries"
  davinci_emac: Do not free all rx dma descriptors during init
  mlx4_core: Fixing array indexes when setting port types
  phy: IC+101G and PHY_HAS_INTERRUPT flag
  netdev/phy/icplus: Correct broken phy_init code
  ipsec: be careful of non existing mac headers
  Move Logitech Harmony 900 from cdc_ether to zaurus
  hso: memsetting wrong data in hso_get_count()
  netfilter: ip6_route_output() never returns NULL.
  ethernet/broadcom: ip6_route_output() never returns NULL.
  ipv6: ip6_route_output() never returns NULL.
  jme: Fix FIFO flush issue
  atm: clip: remove clip_tbl
  ipv4: ping: Fix recvmsg MSG_OOB error handling.
  rtnetlink: Fix problem with buffer allocation
  ...

The autofs compat handling fix caused a compile failure when
CONFIG_COMPAT isn't defined.

Instead of adding random #ifdef'fery in autofs, let's just make the
compat helpers earlier to use: without CONFIG_COMPAT, is_compat_task()
just hardcodes to zero.

We could probably do something similar for a number of other cases where
we have #ifdef's in code, but this is the low-hanging fruit.
Reported-and-tested-by: Andreas Schwab <schwab@linux-m68k.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Couple of minor driver fixes.

* tag 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging:
  hwmon: (max34440) Fix resetting temperature history
  hwmon: (f75375s) Fix register write order when setting fans to full speed
  hwmon: (ads1015) Fix file leak in probe function
  hwmon: (max6639) Fix PPR register initialization to set both channels
  hwmon: (max6639) Fix FAN_FROM_REG calculation

three kbuild fixes for 3.3:
 - make deb-pkg symlink race fix.
 - make coccicheck fix.
 - Dropping the check for modutils.  This is not a regression, but
   allows the module-init-tools replacement kmod work with the 3.3
   kernel.

* 'rc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild:
  coccicheck: change handling of C={1,2} when M= is set
  builddeb: Don't create files in /tmp with predictable names
  kbuild: do not check for ancient modutils tools

When the autofs protocol version 5 packet type was added in commit
5c0a32fc ("autofs4: add new packet type for v5 communications"), it
obvously tried quite hard to be word-size agnostic, and uses explicitly
sized fields that are all correctly aligned.

However, with the final "char name[NAME_MAX+1]" array at the end, the
actual size of the structure ends up being not very well defined:
because the struct isn't marked 'packed', doing a "sizeof()" on it will
align the size of the struct up to the biggest alignment of the members
it has.

And despite all the members being the same, the alignment of them is
different: a "__u64" has 4-byte alignment on x86-32, but native 8-byte
alignment on x86-64.  And while 'NAME_MAX+1' ends up being a nice round
number (256), the name[] array starts out a 4-byte aligned.

End result: the "packed" size of the structure is 300 bytes: 4-byte, but
not 8-byte aligned.

As a result, despite all the fields being in the same place on all
architectures, sizeof() will round up that size to 304 bytes on
architectures that have 8-byte alignment for u64.

Note that this is *not* a problem for 32-bit compat mode on POWER, since
there __u64 is 8-byte aligned even in 32-bit mode.  But on x86, 32-bit
and 64-bit alignment is different for 64-bit entities, and as a result
the structure that has exactly the same layout has different sizes.

So on x86-64, but no other architecture, we will just subtract 4 from
the size of the structure when running in a compat task.  That way we
will write the properly sized packet that user mode expects.

Not pretty.  Sadly, this very subtle, and unnecessary, size difference
has been encoded in user space that wants to read packets of *exactly*
the right size, and will refuse to touch anything else.
Reported-and-tested-by: Thomas Meyer <thomas@m3y3r.de>
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

One InfiniBand/RDMA regression fix for 3.3:

 - mlx4 SR-IOV changes added static exported functions, which doesn't
   build on powerpc at least.  Fix from Doug Ledford for this.

* tag 'rdma-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/roland/infiniband:
  mlx4_core: Exported functions can't be static

When pre-allocating skbs for received packets, we set ip_summed =
CHECKSUM_UNNCESSARY.  We used to change it back to CHECKSUM_NONE when
the received packet had an incorrect checksum or unhandled protocol.

Commit bc8acf2c ('drivers/net: avoid
some skb->ip_summed initializations') mistakenly replaced the latter
assignment with a DEBUG-only assertion that ip_summed ==
CHECKSUM_NONE.  This assertion is always false, but it seems no-one
has exercised this code path in a DEBUG build.

Fix this by moving our assignment of CHECKSUM_UNNECESSARY into
efx_rx_packet_gro().
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>

SCSI fixes on 20120224:
 "This is a set of assorted bug fixes for power management, mpt2sas,
  ipr, the rdac device handler and quite a big chunk for qla2xxx (plus a
  use after free of scsi_host in scsi_scan.c). "

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-rc-fixes-2.6:
  [SCSI] scsi_dh_rdac: Fix for unbalanced reference count
  [SCSI] scsi_pm: Fix bug in the SCSI power management handler
  [SCSI] scsi_scan: Fix 'Poison overwritten' warning caused by using freed 'shost'
  [SCSI] qla2xxx: Update version number to 8.03.07.13-k.
  [SCSI] qla2xxx: Proper detection of firmware abort error code for ISP82xx.
  [SCSI] qla2xxx: Remove resetting memory during device initialization for ISP82xx.
  [SCSI] qla2xxx: Complete mailbox command timedout to avoid initialization failures during next reset cycle.
  [SCSI] qla2xxx: Remove check for null fcport from host reset handler.
  [SCSI] qla2xxx: Correct out of bounds read of ISP2200 mailbox registers.
  [SCSI] qla2xxx: Remove errant clearing of MBX_INTERRUPT flag during CT-IOCB processing.
  [SCSI] qla2xxx: Clear options-flags while issuing stop-firmware mbx command.
  [SCSI] qla2xxx: Add an "is reset active" helper.
  [SCSI] qla2xxx: Add check for null fcport references in qla2xxx_queuecommand.
  [SCSI] qla2xxx: Propagate up abort failures.
  [SCSI] isci: Fix NULL ptr dereference when no firmware is being loaded
  [SCSI] ipr: fix eeh recovery for 64-bit adapters
  [SCSI] mpt2sas: Fix mismatch in mpt2sas_base_hard_reset_handler() mutex lock-unlock

This patch fixes a (mostly cosmetic) bug introduced by the patch
'ppp: Use SKB queue abstraction interfaces in fragment processing'
found here: http://www.spinics.net/lists/netdev/msg153312.html

The above patch rewrote and moved the code responsible for cleaning
up discarded fragments but the new code does not catch every case
where this is necessary.  This results in some discarded fragments
remaining in the queue, and triggering a 'bad seq' error on the
subsequent call to ppp_mp_reconstruct.  Fragments are discarded
whenever other fragments of the same frame have been lost.
This can generate a lot of unwanted and misleading log messages.

This patch also adds additional detail to the debug logging to
make it clearer which fragments were lost and which other fragments
were discarded as a result of losses. (Run pppd with 'kdebug 1'
option to enable debug logging.)
Signed-off-by: Ben McKeegan <ben@netservers.co.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

Sparse complaints the endian bug.
Signed-off-by: Santosh Nayak <santoshprasadnayak@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This patch reverts a portion of d0bc1fb4 so that coccicheck will
work properly when C=1 or C=2.
Reported-and-tested-by: Brice Goglin <Brice.Goglin@inria.fr>
Signed-off-by: Greg Dietsche <Gregory.Dietsche@cuw.edu>
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Michal Marek <mmarek@suse.cz>

The original spelling and bad word choice makes these comments hard to read.
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

* 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media:
  [media] hdpvr: update picture controls to support firmware versions > 0.15
  [media] wl128x: fix build errors when GPIOLIB is not enabled
  [media] hdpvr: fix race conditon during start of streaming
  [media] omap3isp: Fix crash caused by subdevs now having a pointer to devnodes
  [media] imon: don't wedge hardware after early callbacks

signalfd_cleanup() ensures that ->signalfd_wqh is not used, but
this is not enough. eppoll_entry->whead still points to the memory
we are going to free, ep_unregister_pollwait()->remove_wait_queue()
is obviously unsafe.

Change ep_poll_callback(POLLFREE) to set eppoll_entry->whead = NULL,
change ep_unregister_pollwait() to check pwq->whead != NULL under
rcu_read_lock() before remove_wait_queue(). We add the new helper,
ep_remove_wait_queue(), for this.

This works because sighand_cachep is SLAB_DESTROY_BY_RCU and because
->signalfd_wqh is initialized in sighand_ctor(), not in copy_sighand.
ep_unregister_pollwait()->remove_wait_queue() can play with already
freed and potentially reused ->sighand, but this is fine. This memory
must have the valid ->signalfd_wqh until rcu_read_unlock().
Reported-by: Maxime Bizon <mbizon@freebox.fr>
Cc: <stable@kernel.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

This patch is intentionally incomplete to simplify the review.
It ignores ep_unregister_pollwait() which plays with the same wqh.
See the next change.

epoll assumes that the EPOLL_CTL_ADD'ed file controls everything
f_op->poll() needs. In particular it assumes that the wait queue
can't go away until eventpoll_release(). This is not true in case
of signalfd, the task which does EPOLL_CTL_ADD uses its ->sighand
which is not connected to the file.

This patch adds the special event, POLLFREE, currently only for
epoll. It expects that init_poll_funcptr()'ed hook should do the
necessary cleanup. Perhaps it should be defined as EPOLLFREE in
eventpoll.

__cleanup_sighand() is changed to do wake_up_poll(POLLFREE) if
->signalfd_wqh is not empty, we add the new signalfd_cleanup()
helper.

ep_poll_callback(POLLFREE) simply does list_del_init(task_list).
This make this poll entry inconsistent, but we don't care. If you
share epoll fd which contains our sigfd with another process you
should blame yourself. signalfd is "really special". I simply do
not know how we can define the "right" semantics if it used with
epoll.

The main problem is, epoll calls signalfd_poll() once to establish
the connection with the wait queue, after that signalfd_poll(NULL)
returns the different/inconsistent results depending on who does
EPOLL_CTL_MOD/signalfd_read/etc. IOW: apart from sigmask, signalfd
has nothing to do with the file, it works with the current thread.

In short: this patch is the hack which tries to fix the symptoms.
It also assumes that nobody can take tasklist_lock under epoll
locks, this seems to be true.

Note:

	- we do not have wake_up_all_poll() but wake_up_poll()
	  is fine, poll/epoll doesn't use WQ_FLAG_EXCLUSIVE.

	- signalfd_cleanup() uses POLLHUP along with POLLFREE,
	  we need a couple of simple changes in eventpoll.c to
	  make sure it can't be "lost".
Reported-by: Maxime Bizon <mbizon@freebox.fr>
Cc: <stable@kernel.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>