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  1. 10 Feb, 2015 6 commits
    • Lai Jiangshan's avatar
      smpboot: Add missing get_online_cpus() in smpboot_register_percpu_thread() · f5010861
      Lai Jiangshan authored 
      commit 4bee9686 upstream.

The following race exists in the smpboot percpu threads management:

CPU0	      	   	     CPU1
cpu_up(2)
  get_online_cpus();
  smpboot_create_threads(2);
			     smpboot_register_percpu_thread();
			     for_each_online_cpu();
			       __smpboot_create_thread();
  __cpu_up(2);

This results in a missing per cpu thread for the newly onlined cpu2 and
in a NULL pointer dereference on a consecutive offline of that cpu.

Proctect smpboot_register_percpu_thread() with get_online_cpus() to
prevent that.

[ tglx: Massaged changelog and removed the change in
        smpboot_unregister_percpu_thread() because that's an
        optimization and therefor not stable material. ]
Signed-off-by: default avatarLai Jiangshan <laijs@cn.fujitsu.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: David Rientjes <rientjes@google.com>
Link: http://lkml.kernel.org/r/1406777421-12830-1-git-send-email-laijs@cn.fujitsu.comSigned-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      f5010861
    • Sachin Prabhu's avatar
      Complete oplock break jobs before closing file handle · 058f35e3
      Sachin Prabhu authored 
      commit ca7df8e0 upstream.

Commit
c11f1df5
requires writers to wait for any pending oplock break handler to
complete before proceeding to write. This is done by waiting on bit
CIFS_INODE_PENDING_OPLOCK_BREAK in cifsFileInfo->flags. This bit is
cleared by the oplock break handler job queued on the workqueue once it
has completed handling the oplock break allowing writers to proceed with
writing to the file.

While testing, it was noticed that the filehandle could be closed while
there is a pending oplock break which results in the oplock break
handler on the cifsiod workqueue being cancelled before it has had a
chance to execute and clear the CIFS_INODE_PENDING_OPLOCK_BREAK bit.
Any subsequent attempt to write to this file hangs waiting for the
CIFS_INODE_PENDING_OPLOCK_BREAK bit to be cleared.

We fix this by ensuring that we also clear the bit
CIFS_INODE_PENDING_OPLOCK_BREAK when we remove the oplock break handler
from the workqueue.

The bug was found by Red Hat QA while testing using ltp's fsstress
command.
Signed-off-by: default avatarSachin Prabhu <sprabhu@redhat.com>
Acked-by: default avatarShirish Pargaonkar <shirishpargaonkar@gmail.com>
Signed-off-by: default avatarJeff Layton <jlayton@samba.org>
Signed-off-by: default avatarSteve French <steve.french@primarydata.com>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      058f35e3
    • Felix Fietkau's avatar
      MIPS: IRQ: Fix disable_irq on CPU IRQs · 9d1d715c
      Felix Fietkau authored 
      commit a3e6c1ef upstream.

If the irq_chip does not define .irq_disable, any call to disable_irq
will defer disabling the IRQ until it fires while marked as disabled.
This assumes that the handler function checks for this condition, which
handle_percpu_irq does not. In this case, calling disable_irq leads to
an IRQ storm, if the interrupt fires while disabled.

This optimization is only useful when disabling the IRQ is slow, which
is not true for the MIPS CPU IRQ.

Disable this optimization by implementing .irq_disable and .irq_enable
Signed-off-by: default avatarFelix Fietkau <nbd@openwrt.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/8949/Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      9d1d715c
    • Mark Rutland's avatar
      arm64: Fix up /proc/cpuinfo · 33285ead
      Mark Rutland authored 
      commit 44b82b77 upstream.

[backport to 3.16.x: fold in missing MIDR_EL1 recording]

Commit d7a49086 (arm64: cpuinfo: print info for all CPUs)
attempted to clean up /proc/cpuinfo, but due to concerns regarding
further changes was reverted in commit 5e39977e (Revert "arm64:
cpuinfo: print info for all CPUs").

There are two major issues with the arm64 /proc/cpuinfo format
currently:

* The "Features" line describes (only) the 64-bit hwcaps, which is
  problematic for some 32-bit applications which attempt to parse it. As
  the same names are used for analogous ISA features (e.g. aes) despite
  these generally being architecturally unrelated, it is not possible to
  simply append the 64-bit and 32-bit hwcaps in a manner that might not
  be misleading to some applications.

  Various potential solutions have appeared in vendor kernels. Typically
  the format of the Features line varies depending on whether the task
  is 32-bit.

* Information is only printed regarding a single CPU. This does not
  match the ARM format, and does not provide sufficient information in
  big.LITTLE systems where CPUs are heterogeneous. The CPU information
  printed is queried from the current CPU's registers, which is racy
  w.r.t. cross-cpu migration.

This patch attempts to solve these issues. The following changes are
made:

* When a task with a LINUX32 personality attempts to read /proc/cpuinfo,
  the "Features" line contains the decoded 32-bit hwcaps, as with the
  arm port. Otherwise, the decoded 64-bit hwcaps are shown. This aligns
  with the behaviour of COMPAT_UTS_MACHINE and COMPAT_ELF_PLATFORM. In
  the absense of compat support, the Features line is empty.

  The set of hwcaps injected into a task's auxval are unaffected.

* Properties are printed per-cpu, as with the ARM port. The per-cpu
  information is queried from pre-recorded cpu information (as used by
  the sanity checks).

* As with the previous attempt at fixing up /proc/cpuinfo, the hardware
  field is removed. The only users so far are 32-bit applications tied
  to particular boards, so no portable applications should be affected,
  and this should prevent future tying to particular boards.

The following differences remain:

* No model_name is printed, as this cannot be queried from the hardware
  and cannot be provided in a stable fashion. Use of the CPU
  {implementor,variant,part,revision} fields is sufficient to identify a
  CPU and is portable across arm and arm64.

* The following system-wide properties are not provided, as they are not
  possible to provide generally. Programs relying on these are already
  tied to particular (32-bit only) boards:
  - Hardware
  - Revision
  - Serial

No software has yet been identified for which these remaining
differences are problematic.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Ian Campbell <ijc@hellion.org.uk>
Signed-off-by: default avatarMark Rutland <mark.rutland@arm.com>
[Mark: backport to v3.16.x]
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      33285ead
    • Richard Guy Briggs's avatar
      powerpc: add little endian flag to syscall_get_arch() · b5746f2f
      Richard Guy Briggs authored 
      commit 63f13448 upstream.

Since both ppc and ppc64 have LE variants which are now reported by uname, add
that flag (__AUDIT_ARCH_LE) to syscall_get_arch() and add AUDIT_ARCH_PPC64LE
variant.

Without this,  perf trace and auditctl fail.

Mainline kernel reports ppc64le (per a0588015) but there is no matching
AUDIT_ARCH_PPC64LE.

Since 32-bit PPC LE is not supported by audit, don't advertise it in
AUDIT_ARCH_PPC* variants.

See:
	https://www.redhat.com/archives/linux-audit/2014-August/msg00082.html
	https://www.redhat.com/archives/linux-audit/2014-December/msg00004.htmlSigned-off-by: default avatarRichard Guy Briggs <rgb@redhat.com>
Acked-by: default avatarPaul Moore <paul@paul-moore.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
[bwh: Backported to 3.16: arch is passed in by do_syscall_trace_enter()
 rather than queried by calling syscall_get_arch()]
Signed-off-by: default avatarBen Hutchings <ben@decadent.org.uk>
Tested-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      b5746f2f
    • Luis Henriques's avatar
      Linux 3.16.7-ckt6 · 4ba6745b
      Luis Henriques authored 
      Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      4ba6745b
  3. 04 Feb, 2015 34 commits
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