linux-stable.git/arch, branch v3.12.57 Linux kernel stable tree KVM: x86: move steal time initialization to vcpu entry time 2016-03-14T22:10:31+00:00 Marcelo Tosatti mtosatti@redhat.com 2015-10-14T22:33:09+00:00 b7dc78251de7c991a3858ab5a7a56ba604cbb908 commit 7cae2bedcbd4680b155999655e49c27b9cf020fa upstream. As reported at https://bugs.launchpad.net/qemu/+bug/1494350, it is possible to have vcpu->arch.st.last_steal initialized from a thread other than vcpu thread, say the iothread, via KVM_SET_MSRS. Which can cause an overflow later (when subtracting from vcpu threads sched_info.run_delay). To avoid that, move steal time accumulation to vcpu entry time, before copying steal time data to guest. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Reviewed-by: David Matlack <dmatlack@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz> 
commit 7cae2bedcbd4680b155999655e49c27b9cf020fa upstream.

As reported at https://bugs.launchpad.net/qemu/+bug/1494350,
it is possible to have vcpu->arch.st.last_steal initialized
from a thread other than vcpu thread, say the iothread, via
KVM_SET_MSRS.

Which can cause an overflow later (when subtracting from vcpu threads
sched_info.run_delay).

To avoid that, move steal time accumulation to vcpu entry time,
before copying steal time data to guest.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Reviewed-by: David Matlack <dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
powerpc: Fix dedotify for binutils >= 2.26 2016-03-14T22:10:31+00:00 Andreas Schwab schwab@linux-m68k.org 2016-02-05T18:50:03+00:00 63ec4087e92fb510ab047f1115ccd9bdff37e1ef commit f15838e9cac8f78f0cc506529bb9d3b9fa589c1f upstream. Since binutils 2.26 BFD is doing suffix merging on STRTAB sections. But dedotify modifies the symbol names in place, which can also modify unrelated symbols with a name that matches a suffix of a dotted name. To remove the leading dot of a symbol name we can just increment the pointer into the STRTAB section instead. Backport to all stables to avoid breakage when people update their binutils - mpe. Signed-off-by: Andreas Schwab <schwab@linux-m68k.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Jiri Slaby <jslaby@suse.cz> 
commit f15838e9cac8f78f0cc506529bb9d3b9fa589c1f upstream.

Since binutils 2.26 BFD is doing suffix merging on STRTAB sections.  But
dedotify modifies the symbol names in place, which can also modify
unrelated symbols with a name that matches a suffix of a dotted name.  To
remove the leading dot of a symbol name we can just increment the pointer
into the STRTAB section instead.

Backport to all stables to avoid breakage when people update their
binutils - mpe.

Signed-off-by: Andreas Schwab <schwab@linux-m68k.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
KVM: VMX: disable PEBS before a guest entry 2016-03-14T12:38:06+00:00 Radim Krčmář rkrcmar@redhat.com 2016-03-04T14:08:42+00:00 b6199e8f4a8b9ab205d5c61726915e6f187d5435 commit 7099e2e1f4d9051f31bbfa5803adf954bb5d76ef upstream. Linux guests on Haswell (and also SandyBridge and Broadwell, at least) would crash if you decided to run a host command that uses PEBS, like perf record -e 'cpu/mem-stores/pp' -a This happens because KVM is using VMX MSR switching to disable PEBS, but SDM [2015-12] 18.4.4.4 Re-configuring PEBS Facilities explains why it isn't safe: When software needs to reconfigure PEBS facilities, it should allow a quiescent period between stopping the prior event counting and setting up a new PEBS event. The quiescent period is to allow any latent residual PEBS records to complete its capture at their previously specified buffer address (provided by IA32_DS_AREA). There might not be a quiescent period after the MSR switch, so a CPU ends up using host's MSR_IA32_DS_AREA to access an area in guest's memory. (Or MSR switching is just buggy on some models.) The guest can learn something about the host this way: If the guest doesn't map address pointed by MSR_IA32_DS_AREA, it results in #PF where we leak host's MSR_IA32_DS_AREA through CR2. After that, a malicious guest can map and configure memory where MSR_IA32_DS_AREA is pointing and can therefore get an output from host's tracing. This is not a critical leak as the host must initiate with PEBS tracing and I have not been able to get a record from more than one instruction before vmentry in vmx_vcpu_run() (that place has most registers already overwritten with guest's). We could disable PEBS just few instructions before vmentry, but disabling it earlier shouldn't affect host tracing too much. We also don't need to switch MSR_IA32_PEBS_ENABLE on VMENTRY, but that optimization isn't worth its code, IMO. (If you are implementing PEBS for guests, be sure to handle the case where both host and guest enable PEBS, because this patch doesn't.) Fixes: 26a4f3c08de4 ("perf/x86: disable PEBS on a guest entry.") Reported-by: Jiří Olša <jolsa@redhat.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz> 
commit 7099e2e1f4d9051f31bbfa5803adf954bb5d76ef upstream.

Linux guests on Haswell (and also SandyBridge and Broadwell, at least)
would crash if you decided to run a host command that uses PEBS, like
  perf record -e 'cpu/mem-stores/pp' -a

This happens because KVM is using VMX MSR switching to disable PEBS, but
SDM [2015-12] 18.4.4.4 Re-configuring PEBS Facilities explains why it
isn't safe:
  When software needs to reconfigure PEBS facilities, it should allow a
  quiescent period between stopping the prior event counting and setting
  up a new PEBS event. The quiescent period is to allow any latent
  residual PEBS records to complete its capture at their previously
  specified buffer address (provided by IA32_DS_AREA).

There might not be a quiescent period after the MSR switch, so a CPU
ends up using host's MSR_IA32_DS_AREA to access an area in guest's
memory.  (Or MSR switching is just buggy on some models.)

The guest can learn something about the host this way:
If the guest doesn't map address pointed by MSR_IA32_DS_AREA, it results
in #PF where we leak host's MSR_IA32_DS_AREA through CR2.

After that, a malicious guest can map and configure memory where
MSR_IA32_DS_AREA is pointing and can therefore get an output from
host's tracing.

This is not a critical leak as the host must initiate with PEBS tracing
and I have not been able to get a record from more than one instruction
before vmentry in vmx_vcpu_run() (that place has most registers already
overwritten with guest's).

We could disable PEBS just few instructions before vmentry, but
disabling it earlier shouldn't affect host tracing too much.
We also don't need to switch MSR_IA32_PEBS_ENABLE on VMENTRY, but that
optimization isn't worth its code, IMO.

(If you are implementing PEBS for guests, be sure to handle the case
 where both host and guest enable PEBS, because this patch doesn't.)

Fixes: 26a4f3c08de4 ("perf/x86: disable PEBS on a guest entry.")
Reported-by: Jiří Olša <jolsa@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
MIPS: traps: Fix SIGFPE information leak from `do_ov' and `do_trap_or_bp' 2016-03-14T12:10:03+00:00 Maciej W. Rozycki macro@imgtec.com 2016-03-04T01:42:49+00:00 e7d14f3420e856cc38fa64915e08e8ca98297692 commit e723e3f7f9591b79e8c56b3d7c5a204a9c571b55 upstream. Avoid sending a partially initialised `siginfo_t' structure along SIGFPE signals issued from `do_ov' and `do_trap_or_bp', leading to information leaking from the kernel stack. Signed-off-by: Maciej W. Rozycki <macro@imgtec.com> Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Jiri Slaby <jslaby@suse.cz> 
commit e723e3f7f9591b79e8c56b3d7c5a204a9c571b55 upstream.

Avoid sending a partially initialised `siginfo_t' structure along SIGFPE
signals issued from `do_ov' and `do_trap_or_bp', leading to information
leaking from the kernel stack.

Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
PM / sleep / x86: Fix crash on graph trace through x86 suspend 2016-03-07T15:05:24+00:00 Todd E Brandt todd.e.brandt@linux.intel.com 2016-03-03T00:05:29+00:00 7dabf7e04ad03585ddfa7bc9d5e982ab79521a02 commit 92f9e179a702a6adbc11e2fedc76ecd6ffc9e3f7 upstream. Pause/unpause graph tracing around do_suspend_lowlevel as it has inconsistent call/return info after it jumps to the wakeup vector. The graph trace buffer will otherwise become misaligned and may eventually crash and hang on suspend. To reproduce the issue and test the fix: Run a function_graph trace over suspend/resume and set the graph function to suspend_devices_and_enter. This consistently hangs the system without this fix. Signed-off-by: Todd Brandt <todd.e.brandt@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz> 
commit 92f9e179a702a6adbc11e2fedc76ecd6ffc9e3f7 upstream.

Pause/unpause graph tracing around do_suspend_lowlevel as it has
inconsistent call/return info after it jumps to the wakeup vector.
The graph trace buffer will otherwise become misaligned and
may eventually crash and hang on suspend.

To reproduce the issue and test the fix:
Run a function_graph trace over suspend/resume and set the graph
function to suspend_devices_and_enter. This consistently hangs the
system without this fix.

Signed-off-by: Todd Brandt <todd.e.brandt@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
x86/entry/compat: Add missing CLAC to entry_INT80_32 2016-03-07T15:05:23+00:00 Andy Lutomirski luto@kernel.org 2016-02-24T20:18:49+00:00 acdb842ee6a5c997c3ea1c4e393bd71aa093b139 commit 3d44d51bd339766f0178f0cf2e8d048b4a4872aa upstream. This doesn't seem to fix a regression -- I don't think the CLAC was ever there. I double-checked in a debugger: entries through the int80 gate do not automatically clear AC. Stable maintainers: I can provide a backport to 4.3 and earlier if needed. This needs to be backported all the way to 3.10. Reported-by: Brian Gerst <brgerst@gmail.com> Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: 63bcff2a307b ("x86, smap: Add STAC and CLAC instructions to control user space access") Link: http://lkml.kernel.org/r/b02b7e71ae54074be01fc171cbd4b72517055c0e.1456345086.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> [ kamal: backport to 3.10 through 3.19-stable: file rename; context ] Signed-off-by: Kamal Mostafa <kamal@canonical.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz> 
commit 3d44d51bd339766f0178f0cf2e8d048b4a4872aa upstream.

This doesn't seem to fix a regression -- I don't think the CLAC was
ever there.

I double-checked in a debugger: entries through the int80 gate do
not automatically clear AC.

Stable maintainers: I can provide a backport to 4.3 and earlier if
needed.  This needs to be backported all the way to 3.10.

Reported-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 63bcff2a307b ("x86, smap: Add STAC and CLAC instructions to control user space access")
Link: http://lkml.kernel.org/r/b02b7e71ae54074be01fc171cbd4b72517055c0e.1456345086.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
[ kamal: backport to 3.10 through 3.19-stable: file rename; context ]
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
sparc64: fix incorrect sign extension in sys_sparc64_personality 2016-03-03T11:46:03+00:00 Dmitry V. Levin ldv@altlinux.org 2015-12-26T23:13:27+00:00 a6827009cb013e8cffb430e960f656d6c6b9d60e commit 525fd5a94e1be0776fa652df5c687697db508c91 upstream. The value returned by sys_personality has type "long int". It is saved to a variable of type "int", which is not a problem yet because the type of task_struct->pesonality is "unsigned int". The problem is the sign extension from "int" to "long int" that happens on return from sys_sparc64_personality. For example, a userspace call personality((unsigned) -EINVAL) will result to any subsequent personality call, including absolutely harmless read-only personality(0xffffffff) call, failing with errno set to EINVAL. Signed-off-by: Dmitry V. Levin <ldv@altlinux.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Jiri Slaby <jslaby@suse.cz> 
commit 525fd5a94e1be0776fa652df5c687697db508c91 upstream.

The value returned by sys_personality has type "long int".
It is saved to a variable of type "int", which is not a problem
yet because the type of task_struct->pesonality is "unsigned int".
The problem is the sign extension from "int" to "long int"
that happens on return from sys_sparc64_personality.

For example, a userspace call personality((unsigned) -EINVAL) will
result to any subsequent personality call, including absolutely
harmless read-only personality(0xffffffff) call, failing with
errno set to EINVAL.

Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
uml: flush stdout before forking 2016-03-03T11:46:01+00:00 Vegard Nossum vegard.nossum@oracle.com 2015-12-18T20:28:53+00:00 c8ed7e3ffb97fe30b10dad8d2279af599fd32cc5 commit 0754fb298f2f2719f0393491d010d46cfb25d043 upstream. I was seeing some really weird behaviour where piping UML's output somewhere would cause output to get duplicated: $ ./vmlinux | head -n 40 Checking that ptrace can change system call numbers...Core dump limits : soft - 0 hard - NONE OK Checking syscall emulation patch for ptrace...Core dump limits : soft - 0 hard - NONE OK Checking advanced syscall emulation patch for ptrace...Core dump limits : soft - 0 hard - NONE OK Core dump limits : soft - 0 hard - NONE This is because these tests do a fork() which duplicates the non-empty stdout buffer, then glibc flushes the duplicated buffer as each child exits. A simple workaround is to flush before forking. Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com> Signed-off-by: Richard Weinberger <richard@nod.at> Signed-off-by: Jiri Slaby <jslaby@suse.cz> 
commit 0754fb298f2f2719f0393491d010d46cfb25d043 upstream.

I was seeing some really weird behaviour where piping UML's output
somewhere would cause output to get duplicated:

  $ ./vmlinux | head -n 40
  Checking that ptrace can change system call numbers...Core dump limits :
          soft - 0
          hard - NONE
  OK
  Checking syscall emulation patch for ptrace...Core dump limits :
          soft - 0
          hard - NONE
  OK
  Checking advanced syscall emulation patch for ptrace...Core dump limits :
          soft - 0
          hard - NONE
  OK
  Core dump limits :
          soft - 0
          hard - NONE

This is because these tests do a fork() which duplicates the non-empty
stdout buffer, then glibc flushes the duplicated buffer as each child
exits.

A simple workaround is to flush before forking.

Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
dts: vt8500: Add SDHC node to DTS file for WM8650 2016-03-03T11:45:55+00:00 Roman Volkov rvolkov@v1ros.org 2016-01-01T13:38:11+00:00 77e16d341c043b6da844895b4d4e0834061fdf50 commit 0f090bf14e51e7eefb71d9d1c545807f8b627986 upstream. Since WM8650 has the same 'WMT' SDHC controller as WM8505, and the driver is already in the kernel, this node enables the controller support for WM8650 Signed-off-by: Roman Volkov <rvolkov@v1ros.org> Reviewed-by: Alexey Charkov <alchark@gmail.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Jiri Slaby <jslaby@suse.cz> 
commit 0f090bf14e51e7eefb71d9d1c545807f8b627986 upstream.

Since WM8650 has the same 'WMT' SDHC controller as WM8505, and the driver
is already in the kernel, this node enables the controller support for
WM8650

Signed-off-by: Roman Volkov <rvolkov@v1ros.org>
Reviewed-by: Alexey Charkov <alchark@gmail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
m32r: fix m32104ut_defconfig build fail 2016-02-25T09:49:13+00:00 Sudip Mukherjee sudipm.mukherjee@gmail.com 2016-01-14T23:16:47+00:00 2194c6e713de1508c203148638faa91cbd992aac commit 601f1db653217f205ffa5fb33514b4e1711e56d1 upstream. The build of m32104ut_defconfig for m32r arch was failing for long long time with the error: ERROR: "memory_start" [fs/udf/udf.ko] undefined! ERROR: "memory_end" [fs/udf/udf.ko] undefined! ERROR: "memory_end" [drivers/scsi/sg.ko] undefined! ERROR: "memory_start" [drivers/scsi/sg.ko] undefined! ERROR: "memory_end" [drivers/i2c/i2c-dev.ko] undefined! ERROR: "memory_start" [drivers/i2c/i2c-dev.ko] undefined! As done in other architectures export the symbols to fix the error. Reported-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Jiri Slaby <jslaby@suse.cz> 
commit 601f1db653217f205ffa5fb33514b4e1711e56d1 upstream.

The build of m32104ut_defconfig for m32r arch was failing for long long
time with the error:

  ERROR: "memory_start" [fs/udf/udf.ko] undefined!
  ERROR: "memory_end" [fs/udf/udf.ko] undefined!
  ERROR: "memory_end" [drivers/scsi/sg.ko] undefined!
  ERROR: "memory_start" [drivers/scsi/sg.ko] undefined!
  ERROR: "memory_end" [drivers/i2c/i2c-dev.ko] undefined!
  ERROR: "memory_start" [drivers/i2c/i2c-dev.ko] undefined!

As done in other architectures export the symbols to fix the error.

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>