<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/arch/x86/kernel, branch v3.10.60</title>
<subtitle>Linux kernel for Apalis and Colibri modules</subtitle>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/'/>
<entry>
<title>x86, apic: Handle a bad TSC more gracefully</title>
<updated>2014-11-14T16:48:00+00:00</updated>
<author>
<name>Andy Lutomirski</name>
<email>luto@amacapital.net</email>
</author>
<published>2014-10-15T17:12:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=2d1fef447d8e19ac23b8226e4655b78f072569bd'/>
<id>2d1fef447d8e19ac23b8226e4655b78f072569bd</id>
<content type='text'>
commit b47dcbdc5161d3d5756f430191e2840d9b855492 upstream.

If the TSC is unusable or disabled, then this patch fixes:

 - Confusion while trying to clear old APIC interrupts.
 - Division by zero and incorrect programming of the TSC deadline
   timer.

This fixes boot if the CPU has a TSC deadline timer but a missing or
broken TSC.  The failure to boot can be observed with qemu using
-cpu qemu64,-tsc,+tsc-deadline

This also happens to me in nested KVM for unknown reasons.
With this patch, I can boot cleanly (although without a TSC).

Signed-off-by: Andy Lutomirski &lt;luto@amacapital.net&gt;
Cc: Bandan Das &lt;bsd@redhat.com&gt;
Link: http://lkml.kernel.org/r/e2fa274e498c33988efac0ba8b7e3120f7f92d78.1413393027.git.luto@amacapital.net
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit b47dcbdc5161d3d5756f430191e2840d9b855492 upstream.

If the TSC is unusable or disabled, then this patch fixes:

 - Confusion while trying to clear old APIC interrupts.
 - Division by zero and incorrect programming of the TSC deadline
   timer.

This fixes boot if the CPU has a TSC deadline timer but a missing or
broken TSC.  The failure to boot can be observed with qemu using
-cpu qemu64,-tsc,+tsc-deadline

This also happens to me in nested KVM for unknown reasons.
With this patch, I can boot cleanly (although without a TSC).

Signed-off-by: Andy Lutomirski &lt;luto@amacapital.net&gt;
Cc: Bandan Das &lt;bsd@redhat.com&gt;
Link: http://lkml.kernel.org/r/e2fa274e498c33988efac0ba8b7e3120f7f92d78.1413393027.git.luto@amacapital.net
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>x86_64, entry: Filter RFLAGS.NT on entry from userspace</title>
<updated>2014-11-14T16:47:54+00:00</updated>
<author>
<name>Andy Lutomirski</name>
<email>luto@amacapital.net</email>
</author>
<published>2014-10-01T18:49:04+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=b1a9c1e7969403e9d31ac335f4ebb43c9461ab59'/>
<id>b1a9c1e7969403e9d31ac335f4ebb43c9461ab59</id>
<content type='text'>
commit 8c7aa698baca5e8f1ba9edb68081f1e7a1abf455 upstream.

The NT flag doesn't do anything in long mode other than causing IRET
to #GP.  Oddly, CPL3 code can still set NT using popf.

Entry via hardware or software interrupt clears NT automatically, so
the only relevant entries are fast syscalls.

If user code causes kernel code to run with NT set, then there's at
least some (small) chance that it could cause trouble.  For example,
user code could cause a call to EFI code with NT set, and who knows
what would happen?  Apparently some games on Wine sometimes do
this (!), and, if an IRET return happens, they will segfault.  That
segfault cannot be handled, because signal delivery fails, too.

This patch programs the CPU to clear NT on entry via SYSCALL (both
32-bit and 64-bit, by my reading of the AMD APM), and it clears NT
in software on entry via SYSENTER.

To save a few cycles, this borrows a trick from Jan Beulich in Xen:
it checks whether NT is set before trying to clear it.  As a result,
it seems to have very little effect on SYSENTER performance on my
machine.

There's another minor bug fix in here: it looks like the CFI
annotations were wrong if CONFIG_AUDITSYSCALL=n.

Testers beware: on Xen, SYSENTER with NT set turns into a GPF.

I haven't touched anything on 32-bit kernels.

The syscall mask change comes from a variant of this patch by Anish
Bhatt.

Note to stable maintainers: there is no known security issue here.
A misguided program can set NT and cause the kernel to try and fail
to deliver SIGSEGV, crashing the program.  This patch fixes Far Cry
on Wine: https://bugs.winehq.org/show_bug.cgi?id=33275

Reported-by: Anish Bhatt &lt;anish@chelsio.com&gt;
Signed-off-by: Andy Lutomirski &lt;luto@amacapital.net&gt;
Link: http://lkml.kernel.org/r/395749a5d39a29bd3e4b35899cf3a3c1340e5595.1412189265.git.luto@amacapital.net
Signed-off-by: H. Peter Anvin &lt;hpa@zytor.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 8c7aa698baca5e8f1ba9edb68081f1e7a1abf455 upstream.

The NT flag doesn't do anything in long mode other than causing IRET
to #GP.  Oddly, CPL3 code can still set NT using popf.

Entry via hardware or software interrupt clears NT automatically, so
the only relevant entries are fast syscalls.

If user code causes kernel code to run with NT set, then there's at
least some (small) chance that it could cause trouble.  For example,
user code could cause a call to EFI code with NT set, and who knows
what would happen?  Apparently some games on Wine sometimes do
this (!), and, if an IRET return happens, they will segfault.  That
segfault cannot be handled, because signal delivery fails, too.

This patch programs the CPU to clear NT on entry via SYSCALL (both
32-bit and 64-bit, by my reading of the AMD APM), and it clears NT
in software on entry via SYSENTER.

To save a few cycles, this borrows a trick from Jan Beulich in Xen:
it checks whether NT is set before trying to clear it.  As a result,
it seems to have very little effect on SYSENTER performance on my
machine.

There's another minor bug fix in here: it looks like the CFI
annotations were wrong if CONFIG_AUDITSYSCALL=n.

Testers beware: on Xen, SYSENTER with NT set turns into a GPF.

I haven't touched anything on 32-bit kernels.

The syscall mask change comes from a variant of this patch by Anish
Bhatt.

Note to stable maintainers: there is no known security issue here.
A misguided program can set NT and cause the kernel to try and fail
to deliver SIGSEGV, crashing the program.  This patch fixes Far Cry
on Wine: https://bugs.winehq.org/show_bug.cgi?id=33275

Reported-by: Anish Bhatt &lt;anish@chelsio.com&gt;
Signed-off-by: Andy Lutomirski &lt;luto@amacapital.net&gt;
Link: http://lkml.kernel.org/r/395749a5d39a29bd3e4b35899cf3a3c1340e5595.1412189265.git.luto@amacapital.net
Signed-off-by: H. Peter Anvin &lt;hpa@zytor.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>x86, flags: Rename X86_EFLAGS_BIT1 to X86_EFLAGS_FIXED</title>
<updated>2014-11-14T16:47:54+00:00</updated>
<author>
<name>H. Peter Anvin</name>
<email>hpa@linux.intel.com</email>
</author>
<published>2013-04-27T23:10:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=9f03d6fef32533a2d62d65656afba90ccd3a57d6'/>
<id>9f03d6fef32533a2d62d65656afba90ccd3a57d6</id>
<content type='text'>
commit 1adfa76a95fe4444124a502f7cc858a39d5b8e01 upstream.

Bit 1 in the x86 EFLAGS is always set.  Name the macro something that
actually tries to explain what it is all about, rather than being a
tautology.

Signed-off-by: H. Peter Anvin &lt;hpa@linux.intel.com&gt;
Cc: Rusty Russell &lt;rusty@rustcorp.com.au&gt;
Cc: Gleb Natapov &lt;gleb@redhat.com&gt;
Cc: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
Link: http://lkml.kernel.org/n/tip-f10rx5vjjm6tfnt8o1wseb3v@git.kernel.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 1adfa76a95fe4444124a502f7cc858a39d5b8e01 upstream.

Bit 1 in the x86 EFLAGS is always set.  Name the macro something that
actually tries to explain what it is all about, rather than being a
tautology.

Signed-off-by: H. Peter Anvin &lt;hpa@linux.intel.com&gt;
Cc: Rusty Russell &lt;rusty@rustcorp.com.au&gt;
Cc: Gleb Natapov &lt;gleb@redhat.com&gt;
Cc: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
Link: http://lkml.kernel.org/n/tip-f10rx5vjjm6tfnt8o1wseb3v@git.kernel.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>x86, fpu: shift drop_init_fpu() from save_xstate_sig() to handle_signal()</title>
<updated>2014-11-14T16:47:54+00:00</updated>
<author>
<name>Oleg Nesterov</name>
<email>oleg@redhat.com</email>
</author>
<published>2014-09-02T17:57:13+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=fb5b6e7ecfefa65efd7280f4824741ac76e10c4b'/>
<id>fb5b6e7ecfefa65efd7280f4824741ac76e10c4b</id>
<content type='text'>
commit 66463db4fc5605d51c7bb81d009d5bf30a783a2c upstream.

save_xstate_sig()-&gt;drop_init_fpu() doesn't look right. setup_rt_frame()
can fail after that, in this case the next setup_rt_frame() triggered
by SIGSEGV won't save fpu simply because the old state was lost. This
obviously mean that fpu won't be restored after sys_rt_sigreturn() from
SIGSEGV handler.

Shift drop_init_fpu() into !failed branch in handle_signal().

Test-case (needs -O2):

	#include &lt;stdio.h&gt;
	#include &lt;signal.h&gt;
	#include &lt;unistd.h&gt;
	#include &lt;sys/syscall.h&gt;
	#include &lt;sys/mman.h&gt;
	#include &lt;pthread.h&gt;
	#include &lt;assert.h&gt;

	volatile double D;

	void test(double d)
	{
		int pid = getpid();

		for (D = d; D == d; ) {
			/* sys_tkill(pid, SIGHUP); asm to avoid save/reload
			 * fp regs around "C" call */
			asm ("" : : "a"(200), "D"(pid), "S"(1));
			asm ("syscall" : : : "ax");
		}

		printf("ERR!!\n");
	}

	void sigh(int sig)
	{
	}

	char altstack[4096 * 10] __attribute__((aligned(4096)));

	void *tfunc(void *arg)
	{
		for (;;) {
			mprotect(altstack, sizeof(altstack), PROT_READ);
			mprotect(altstack, sizeof(altstack), PROT_READ|PROT_WRITE);
		}
	}

	int main(void)
	{
		stack_t st = {
			.ss_sp = altstack,
			.ss_size = sizeof(altstack),
			.ss_flags = SS_ONSTACK,
		};

		struct sigaction sa = {
			.sa_handler = sigh,
		};

		pthread_t pt;

		sigaction(SIGSEGV, &amp;sa, NULL);
		sigaltstack(&amp;st, NULL);
		sa.sa_flags = SA_ONSTACK;
		sigaction(SIGHUP, &amp;sa, NULL);

		pthread_create(&amp;pt, NULL, tfunc, NULL);

		test(123.456);
		return 0;
	}

Reported-by: Bean Anderson &lt;bean@azulsystems.com&gt;
Signed-off-by: Oleg Nesterov &lt;oleg@redhat.com&gt;
Link: http://lkml.kernel.org/r/20140902175713.GA21646@redhat.com
Signed-off-by: H. Peter Anvin &lt;hpa@linux.intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 66463db4fc5605d51c7bb81d009d5bf30a783a2c upstream.

save_xstate_sig()-&gt;drop_init_fpu() doesn't look right. setup_rt_frame()
can fail after that, in this case the next setup_rt_frame() triggered
by SIGSEGV won't save fpu simply because the old state was lost. This
obviously mean that fpu won't be restored after sys_rt_sigreturn() from
SIGSEGV handler.

Shift drop_init_fpu() into !failed branch in handle_signal().

Test-case (needs -O2):

	#include &lt;stdio.h&gt;
	#include &lt;signal.h&gt;
	#include &lt;unistd.h&gt;
	#include &lt;sys/syscall.h&gt;
	#include &lt;sys/mman.h&gt;
	#include &lt;pthread.h&gt;
	#include &lt;assert.h&gt;

	volatile double D;

	void test(double d)
	{
		int pid = getpid();

		for (D = d; D == d; ) {
			/* sys_tkill(pid, SIGHUP); asm to avoid save/reload
			 * fp regs around "C" call */
			asm ("" : : "a"(200), "D"(pid), "S"(1));
			asm ("syscall" : : : "ax");
		}

		printf("ERR!!\n");
	}

	void sigh(int sig)
	{
	}

	char altstack[4096 * 10] __attribute__((aligned(4096)));

	void *tfunc(void *arg)
	{
		for (;;) {
			mprotect(altstack, sizeof(altstack), PROT_READ);
			mprotect(altstack, sizeof(altstack), PROT_READ|PROT_WRITE);
		}
	}

	int main(void)
	{
		stack_t st = {
			.ss_sp = altstack,
			.ss_size = sizeof(altstack),
			.ss_flags = SS_ONSTACK,
		};

		struct sigaction sa = {
			.sa_handler = sigh,
		};

		pthread_t pt;

		sigaction(SIGSEGV, &amp;sa, NULL);
		sigaltstack(&amp;st, NULL);
		sa.sa_flags = SA_ONSTACK;
		sigaction(SIGHUP, &amp;sa, NULL);

		pthread_create(&amp;pt, NULL, tfunc, NULL);

		test(123.456);
		return 0;
	}

Reported-by: Bean Anderson &lt;bean@azulsystems.com&gt;
Signed-off-by: Oleg Nesterov &lt;oleg@redhat.com&gt;
Link: http://lkml.kernel.org/r/20140902175713.GA21646@redhat.com
Signed-off-by: H. Peter Anvin &lt;hpa@linux.intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>x86, fpu: __restore_xstate_sig()-&gt;math_state_restore() needs preempt_disable()</title>
<updated>2014-11-14T16:47:54+00:00</updated>
<author>
<name>Oleg Nesterov</name>
<email>oleg@redhat.com</email>
</author>
<published>2014-09-02T17:57:17+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=b888e3d442069e3107d9b4a43c1321e4d555b6cd'/>
<id>b888e3d442069e3107d9b4a43c1321e4d555b6cd</id>
<content type='text'>
commit df24fb859a4e200d9324e2974229fbb7adf00aef upstream.

Add preempt_disable() + preempt_enable() around math_state_restore() in
__restore_xstate_sig(). Otherwise __switch_to() after __thread_fpu_begin()
can overwrite fpu-&gt;state we are going to restore.

Signed-off-by: Oleg Nesterov &lt;oleg@redhat.com&gt;
Link: http://lkml.kernel.org/r/20140902175717.GA21649@redhat.com
Reviewed-by: Suresh Siddha &lt;sbsiddha@gmail.com&gt;
Signed-off-by: H. Peter Anvin &lt;hpa@linux.intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit df24fb859a4e200d9324e2974229fbb7adf00aef upstream.

Add preempt_disable() + preempt_enable() around math_state_restore() in
__restore_xstate_sig(). Otherwise __switch_to() after __thread_fpu_begin()
can overwrite fpu-&gt;state we are going to restore.

Signed-off-by: Oleg Nesterov &lt;oleg@redhat.com&gt;
Link: http://lkml.kernel.org/r/20140902175717.GA21649@redhat.com
Reviewed-by: Suresh Siddha &lt;sbsiddha@gmail.com&gt;
Signed-off-by: H. Peter Anvin &lt;hpa@linux.intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>x86/intel/quark: Switch off CR4.PGE so TLB flush uses CR3 instead</title>
<updated>2014-10-30T16:35:10+00:00</updated>
<author>
<name>Bryan O'Donoghue</name>
<email>pure.logic@nexus-software.ie</email>
</author>
<published>2014-09-23T23:26:24+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=75b6cf03dd5cae671b84f60e018a6c08e5f6d4b7'/>
<id>75b6cf03dd5cae671b84f60e018a6c08e5f6d4b7</id>
<content type='text'>
commit ee1b5b165c0a2f04d2107e634e51f05d0eb107de upstream.

Quark x1000 advertises PGE via the standard CPUID method
PGE bits exist in Quark X1000's PTEs. In order to flush
an individual PTE it is necessary to reload CR3 irrespective
of the PTE.PGE bit.

See Quark Core_DevMan_001.pdf section 6.4.11

This bug was fixed in Galileo kernels, unfixed vanilla kernels are expected to
crash and burn on this platform.

Signed-off-by: Bryan O'Donoghue &lt;pure.logic@nexus-software.ie&gt;
Cc: Borislav Petkov &lt;bp@alien8.de&gt;
Link: http://lkml.kernel.org/r/1411514784-14885-1-git-send-email-pure.logic@nexus-software.ie
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit ee1b5b165c0a2f04d2107e634e51f05d0eb107de upstream.

Quark x1000 advertises PGE via the standard CPUID method
PGE bits exist in Quark X1000's PTEs. In order to flush
an individual PTE it is necessary to reload CR3 irrespective
of the PTE.PGE bit.

See Quark Core_DevMan_001.pdf section 6.4.11

This bug was fixed in Galileo kernels, unfixed vanilla kernels are expected to
crash and burn on this platform.

Signed-off-by: Bryan O'Donoghue &lt;pure.logic@nexus-software.ie&gt;
Cc: Borislav Petkov &lt;bp@alien8.de&gt;
Link: http://lkml.kernel.org/r/1411514784-14885-1-git-send-email-pure.logic@nexus-software.ie
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>sched: Fix unreleased llc_shared_mask bit during CPU hotplug</title>
<updated>2014-10-05T21:54:14+00:00</updated>
<author>
<name>Wanpeng Li</name>
<email>wanpeng.li@linux.intel.com</email>
</author>
<published>2014-09-24T08:38:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=90d52e914efdb0f22779888f181f232ce453592e'/>
<id>90d52e914efdb0f22779888f181f232ce453592e</id>
<content type='text'>
commit 03bd4e1f7265548832a76e7919a81f3137c44fd1 upstream.

The following bug can be triggered by hot adding and removing a large number of
xen domain0's vcpus repeatedly:

	BUG: unable to handle kernel NULL pointer dereference at 0000000000000004 IP: [..] find_busiest_group
	PGD 5a9d5067 PUD 13067 PMD 0
	Oops: 0000 [#3] SMP
	[...]
	Call Trace:
	load_balance
	? _raw_spin_unlock_irqrestore
	idle_balance
	__schedule
	schedule
	schedule_timeout
	? lock_timer_base
	schedule_timeout_uninterruptible
	msleep
	lock_device_hotplug_sysfs
	online_store
	dev_attr_store
	sysfs_write_file
	vfs_write
	SyS_write
	system_call_fastpath

Last level cache shared mask is built during CPU up and the
build_sched_domain() routine takes advantage of it to setup
the sched domain CPU topology.

However, llc_shared_mask is not released during CPU disable,
which leads to an invalid sched domainCPU topology.

This patch fix it by releasing the llc_shared_mask correctly
during CPU disable.

Yasuaki also reported that this can happen on real hardware:

  https://lkml.org/lkml/2014/7/22/1018

His case is here:

	==
	Here is an example on my system.
	My system has 4 sockets and each socket has 15 cores and HT is
	enabled. In this case, each core of sockes is numbered as
	follows:

		 | CPU#
	Socket#0 | 0-14 , 60-74
	Socket#1 | 15-29, 75-89
	Socket#2 | 30-44, 90-104
	Socket#3 | 45-59, 105-119

	Then llc_shared_mask of CPU#30 has 0x3fff80000001fffc0000000.

	It means that last level cache of Socket#2 is shared with
	CPU#30-44 and 90-104.

	When hot-removing socket#2 and #3, each core of sockets is
	numbered as follows:

		 | CPU#
	Socket#0 | 0-14 , 60-74
	Socket#1 | 15-29, 75-89

	But llc_shared_mask is not cleared. So llc_shared_mask of CPU#30
	remains having 0x3fff80000001fffc0000000.

	After that, when hot-adding socket#2 and #3, each core of
	sockets is numbered as follows:

		 | CPU#
	Socket#0 | 0-14 , 60-74
	Socket#1 | 15-29, 75-89
	Socket#2 | 30-59
	Socket#3 | 90-119

	Then llc_shared_mask of CPU#30 becomes
	0x3fff8000fffffffc0000000. It means that last level cache of
	Socket#2 is shared with CPU#30-59 and 90-104. So the mask has
	the wrong value.

Signed-off-by: Wanpeng Li &lt;wanpeng.li@linux.intel.com&gt;
Tested-by: Linn Crosetto &lt;linn@hp.com&gt;
Reviewed-by: Borislav Petkov &lt;bp@suse.de&gt;
Reviewed-by: Toshi Kani &lt;toshi.kani@hp.com&gt;
Reviewed-by: Yasuaki Ishimatsu &lt;isimatu.yasuaki@jp.fujitsu.com&gt;
Cc: David Rientjes &lt;rientjes@google.com&gt;
Cc: Prarit Bhargava &lt;prarit@redhat.com&gt;
Cc: Steven Rostedt &lt;srostedt@redhat.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: http://lkml.kernel.org/r/1411547885-48165-1-git-send-email-wanpeng.li@linux.intel.com
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 03bd4e1f7265548832a76e7919a81f3137c44fd1 upstream.

The following bug can be triggered by hot adding and removing a large number of
xen domain0's vcpus repeatedly:

	BUG: unable to handle kernel NULL pointer dereference at 0000000000000004 IP: [..] find_busiest_group
	PGD 5a9d5067 PUD 13067 PMD 0
	Oops: 0000 [#3] SMP
	[...]
	Call Trace:
	load_balance
	? _raw_spin_unlock_irqrestore
	idle_balance
	__schedule
	schedule
	schedule_timeout
	? lock_timer_base
	schedule_timeout_uninterruptible
	msleep
	lock_device_hotplug_sysfs
	online_store
	dev_attr_store
	sysfs_write_file
	vfs_write
	SyS_write
	system_call_fastpath

Last level cache shared mask is built during CPU up and the
build_sched_domain() routine takes advantage of it to setup
the sched domain CPU topology.

However, llc_shared_mask is not released during CPU disable,
which leads to an invalid sched domainCPU topology.

This patch fix it by releasing the llc_shared_mask correctly
during CPU disable.

Yasuaki also reported that this can happen on real hardware:

  https://lkml.org/lkml/2014/7/22/1018

His case is here:

	==
	Here is an example on my system.
	My system has 4 sockets and each socket has 15 cores and HT is
	enabled. In this case, each core of sockes is numbered as
	follows:

		 | CPU#
	Socket#0 | 0-14 , 60-74
	Socket#1 | 15-29, 75-89
	Socket#2 | 30-44, 90-104
	Socket#3 | 45-59, 105-119

	Then llc_shared_mask of CPU#30 has 0x3fff80000001fffc0000000.

	It means that last level cache of Socket#2 is shared with
	CPU#30-44 and 90-104.

	When hot-removing socket#2 and #3, each core of sockets is
	numbered as follows:

		 | CPU#
	Socket#0 | 0-14 , 60-74
	Socket#1 | 15-29, 75-89

	But llc_shared_mask is not cleared. So llc_shared_mask of CPU#30
	remains having 0x3fff80000001fffc0000000.

	After that, when hot-adding socket#2 and #3, each core of
	sockets is numbered as follows:

		 | CPU#
	Socket#0 | 0-14 , 60-74
	Socket#1 | 15-29, 75-89
	Socket#2 | 30-59
	Socket#3 | 90-119

	Then llc_shared_mask of CPU#30 becomes
	0x3fff8000fffffffc0000000. It means that last level cache of
	Socket#2 is shared with CPU#30-59 and 90-104. So the mask has
	the wrong value.

Signed-off-by: Wanpeng Li &lt;wanpeng.li@linux.intel.com&gt;
Tested-by: Linn Crosetto &lt;linn@hp.com&gt;
Reviewed-by: Borislav Petkov &lt;bp@suse.de&gt;
Reviewed-by: Toshi Kani &lt;toshi.kani@hp.com&gt;
Reviewed-by: Yasuaki Ishimatsu &lt;isimatu.yasuaki@jp.fujitsu.com&gt;
Cc: David Rientjes &lt;rientjes@google.com&gt;
Cc: Prarit Bhargava &lt;prarit@redhat.com&gt;
Cc: Steven Rostedt &lt;srostedt@redhat.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: http://lkml.kernel.org/r/1411547885-48165-1-git-send-email-wanpeng.li@linux.intel.com
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>x86_64/vsyscall: Fix warn_bad_vsyscall log output</title>
<updated>2014-09-05T23:28:36+00:00</updated>
<author>
<name>Andy Lutomirski</name>
<email>luto@amacapital.net</email>
</author>
<published>2014-07-25T23:30:27+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=27cca923cd5ddcbb57262216b96ffb89ef7372e4'/>
<id>27cca923cd5ddcbb57262216b96ffb89ef7372e4</id>
<content type='text'>
commit 53b884ac3745353de220d92ef792515c3ae692f0 upstream.

This commit in Linux 3.6:

    commit c767a54ba0657e52e6edaa97cbe0b0a8bf1c1655
    Author: Joe Perches &lt;joe@perches.com&gt;
    Date:   Mon May 21 19:50:07 2012 -0700

        x86/debug: Add KERN_&lt;LEVEL&gt; to bare printks, convert printks to pr_&lt;level&gt;

caused warn_bad_vsyscall to output garbage in the middle of the
line.  Revert the bad part of it.

The printk in question isn't actually bare; the level is "%s".

The bug this fixes is purely cosmetic; backports are optional.

Signed-off-by: Andy Lutomirski &lt;luto@amacapital.net&gt;
Link: http://lkml.kernel.org/r/03eac1f24110bbe496ecc12a4df467e0d88466d4.1406330947.git.luto@amacapital.net
Signed-off-by: H. Peter Anvin &lt;hpa@linux.intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 53b884ac3745353de220d92ef792515c3ae692f0 upstream.

This commit in Linux 3.6:

    commit c767a54ba0657e52e6edaa97cbe0b0a8bf1c1655
    Author: Joe Perches &lt;joe@perches.com&gt;
    Date:   Mon May 21 19:50:07 2012 -0700

        x86/debug: Add KERN_&lt;LEVEL&gt; to bare printks, convert printks to pr_&lt;level&gt;

caused warn_bad_vsyscall to output garbage in the middle of the
line.  Revert the bad part of it.

The printk in question isn't actually bare; the level is "%s".

The bug this fixes is purely cosmetic; backports are optional.

Signed-off-by: Andy Lutomirski &lt;luto@amacapital.net&gt;
Link: http://lkml.kernel.org/r/03eac1f24110bbe496ecc12a4df467e0d88466d4.1406330947.git.luto@amacapital.net
Signed-off-by: H. Peter Anvin &lt;hpa@linux.intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>x86: don't exclude low BIOS area when allocating address space for non-PCI cards</title>
<updated>2014-09-05T23:28:36+00:00</updated>
<author>
<name>Christoph Schulz</name>
<email>develop@kristov.de</email>
</author>
<published>2014-07-16T08:00:57+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=6dc6da0cc9a64f26304f2589fbd262e5198e207d'/>
<id>6dc6da0cc9a64f26304f2589fbd262e5198e207d</id>
<content type='text'>
commit cbace46a9710a480cae51e4611697df5de41713e upstream.

Commit 30919b0bf356 ("x86: avoid low BIOS area when allocating address
space") moved the test for resource allocations that fall within the first
1MB of address space from the PCI-specific path to a generic path, such
that all resource allocations will avoid this area.  However, this breaks
ISA cards which need to allocate a memory region within the first 1MB.  An
example is the i82365 PCMCIA controller and derivatives like the Ricoh
RF5C296/396 which map part of the PCMCIA socket memory address space into
the first 1MB of system memory address space.  They do not work anymore as
no usable memory region exists due to this change:

  Intel ISA PCIC probe: Ricoh RF5C296/396 ISA-to-PCMCIA at port 0x3e0 ofs 0x00, 2 sockets
  host opts [0]: none
  host opts [1]: none
  ISA irqs (scanned) = 3,4,5,9,10 status change on irq 10
  pcmcia_socket pcmcia_socket1: pccard: PCMCIA card inserted into slot 1
  pcmcia_socket pcmcia_socket0: cs: IO port probe 0xc00-0xcff: excluding 0xcf8-0xcff
  pcmcia_socket pcmcia_socket0: cs: IO port probe 0xa00-0xaff: clean.
  pcmcia_socket pcmcia_socket0: cs: IO port probe 0x100-0x3ff: excluding 0x170-0x177 0x1f0-0x1f7 0x2f8-0x2ff 0x370-0x37f 0x3c0-0x3e7 0x3f0-0x3ff
  pcmcia_socket pcmcia_socket0: cs: memory probe 0x0a0000-0x0affff: excluding 0xa0000-0xaffff
  pcmcia_socket pcmcia_socket0: cs: memory probe 0x0b0000-0x0bffff: excluding 0xb0000-0xbffff
  pcmcia_socket pcmcia_socket0: cs: memory probe 0x0c0000-0x0cffff: excluding 0xc0000-0xcbfff
  pcmcia_socket pcmcia_socket0: cs: memory probe 0x0d0000-0x0dffff: clean.
  pcmcia_socket pcmcia_socket0: cs: memory probe 0x0e0000-0x0effff: clean.
  pcmcia_socket pcmcia_socket0: cs: memory probe 0x60000000-0x60ffffff: clean.
  pcmcia_socket pcmcia_socket0: cs: memory probe 0xa0000000-0xa0ffffff: clean.
  pcmcia_socket pcmcia_socket1: cs: IO port probe 0xc00-0xcff: excluding 0xcf8-0xcff
  pcmcia_socket pcmcia_socket1: cs: IO port probe 0xa00-0xaff: clean.
  pcmcia_socket pcmcia_socket1: cs: IO port probe 0x100-0x3ff: excluding 0x170-0x177 0x1f0-0x1f7 0x2f8-0x2ff 0x370-0x37f 0x3c0-0x3e7 0x3f0-0x3ff
  pcmcia_socket pcmcia_socket1: cs: memory probe 0x0a0000-0x0affff: excluding 0xa0000-0xaffff
  pcmcia_socket pcmcia_socket1: cs: memory probe 0x0b0000-0x0bffff: excluding 0xb0000-0xbffff
  pcmcia_socket pcmcia_socket1: cs: memory probe 0x0c0000-0x0cffff: excluding 0xc0000-0xcbfff
  pcmcia_socket pcmcia_socket1: cs: memory probe 0x0d0000-0x0dffff: clean.
  pcmcia_socket pcmcia_socket1: cs: memory probe 0x0e0000-0x0effff: clean.
  pcmcia_socket pcmcia_socket1: cs: memory probe 0x60000000-0x60ffffff: clean.
  pcmcia_socket pcmcia_socket1: cs: memory probe 0xa0000000-0xa0ffffff: clean.
  pcmcia_socket pcmcia_socket1: cs: memory probe 0x0cc000-0x0effff: excluding 0xe0000-0xeffff
  pcmcia_socket pcmcia_socket1: cs: unable to map card memory!

If filtering out the first 1MB is reverted, everything works as expected.

Tested-by: Robert Resch &lt;fli4l@robert.reschpara.de&gt;
Signed-off-by: Christoph Schulz &lt;develop@kristov.de&gt;
Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit cbace46a9710a480cae51e4611697df5de41713e upstream.

Commit 30919b0bf356 ("x86: avoid low BIOS area when allocating address
space") moved the test for resource allocations that fall within the first
1MB of address space from the PCI-specific path to a generic path, such
that all resource allocations will avoid this area.  However, this breaks
ISA cards which need to allocate a memory region within the first 1MB.  An
example is the i82365 PCMCIA controller and derivatives like the Ricoh
RF5C296/396 which map part of the PCMCIA socket memory address space into
the first 1MB of system memory address space.  They do not work anymore as
no usable memory region exists due to this change:

  Intel ISA PCIC probe: Ricoh RF5C296/396 ISA-to-PCMCIA at port 0x3e0 ofs 0x00, 2 sockets
  host opts [0]: none
  host opts [1]: none
  ISA irqs (scanned) = 3,4,5,9,10 status change on irq 10
  pcmcia_socket pcmcia_socket1: pccard: PCMCIA card inserted into slot 1
  pcmcia_socket pcmcia_socket0: cs: IO port probe 0xc00-0xcff: excluding 0xcf8-0xcff
  pcmcia_socket pcmcia_socket0: cs: IO port probe 0xa00-0xaff: clean.
  pcmcia_socket pcmcia_socket0: cs: IO port probe 0x100-0x3ff: excluding 0x170-0x177 0x1f0-0x1f7 0x2f8-0x2ff 0x370-0x37f 0x3c0-0x3e7 0x3f0-0x3ff
  pcmcia_socket pcmcia_socket0: cs: memory probe 0x0a0000-0x0affff: excluding 0xa0000-0xaffff
  pcmcia_socket pcmcia_socket0: cs: memory probe 0x0b0000-0x0bffff: excluding 0xb0000-0xbffff
  pcmcia_socket pcmcia_socket0: cs: memory probe 0x0c0000-0x0cffff: excluding 0xc0000-0xcbfff
  pcmcia_socket pcmcia_socket0: cs: memory probe 0x0d0000-0x0dffff: clean.
  pcmcia_socket pcmcia_socket0: cs: memory probe 0x0e0000-0x0effff: clean.
  pcmcia_socket pcmcia_socket0: cs: memory probe 0x60000000-0x60ffffff: clean.
  pcmcia_socket pcmcia_socket0: cs: memory probe 0xa0000000-0xa0ffffff: clean.
  pcmcia_socket pcmcia_socket1: cs: IO port probe 0xc00-0xcff: excluding 0xcf8-0xcff
  pcmcia_socket pcmcia_socket1: cs: IO port probe 0xa00-0xaff: clean.
  pcmcia_socket pcmcia_socket1: cs: IO port probe 0x100-0x3ff: excluding 0x170-0x177 0x1f0-0x1f7 0x2f8-0x2ff 0x370-0x37f 0x3c0-0x3e7 0x3f0-0x3ff
  pcmcia_socket pcmcia_socket1: cs: memory probe 0x0a0000-0x0affff: excluding 0xa0000-0xaffff
  pcmcia_socket pcmcia_socket1: cs: memory probe 0x0b0000-0x0bffff: excluding 0xb0000-0xbffff
  pcmcia_socket pcmcia_socket1: cs: memory probe 0x0c0000-0x0cffff: excluding 0xc0000-0xcbfff
  pcmcia_socket pcmcia_socket1: cs: memory probe 0x0d0000-0x0dffff: clean.
  pcmcia_socket pcmcia_socket1: cs: memory probe 0x0e0000-0x0effff: clean.
  pcmcia_socket pcmcia_socket1: cs: memory probe 0x60000000-0x60ffffff: clean.
  pcmcia_socket pcmcia_socket1: cs: memory probe 0xa0000000-0xa0ffffff: clean.
  pcmcia_socket pcmcia_socket1: cs: memory probe 0x0cc000-0x0effff: excluding 0xe0000-0xeffff
  pcmcia_socket pcmcia_socket1: cs: unable to map card memory!

If filtering out the first 1MB is reverted, everything works as expected.

Tested-by: Robert Resch &lt;fli4l@robert.reschpara.de&gt;
Signed-off-by: Christoph Schulz &lt;develop@kristov.de&gt;
Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>x86/espfix/xen: Fix allocation of pages for paravirt page tables</title>
<updated>2014-08-07T21:30:27+00:00</updated>
<author>
<name>Boris Ostrovsky</name>
<email>boris.ostrovsky@oracle.com</email>
</author>
<published>2014-07-09T17:18:18+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=d12cb4b5cd29230b0def8c8fec29f59c33592a46'/>
<id>d12cb4b5cd29230b0def8c8fec29f59c33592a46</id>
<content type='text'>
commit 8762e5092828c4dc0f49da5a47a644c670df77f3 upstream.

init_espfix_ap() is currently off by one level when informing hypervisor
that allocated pages will be used for ministacks' page tables.

The most immediate effect of this on a PV guest is that if
'stack_page = __get_free_page()' returns a non-zeroed-out page the hypervisor
will refuse to use it for a page table (which it shouldn't be anyway). This will
result in warnings by both Xen and Linux.

More importantly, a subsequent write to that page (again, by a PV guest) is
likely to result in fatal page fault.

Signed-off-by: Boris Ostrovsky &lt;boris.ostrovsky@oracle.com&gt;
Link: http://lkml.kernel.org/r/1404926298-5565-1-git-send-email-boris.ostrovsky@oracle.com
Reviewed-by: Konrad Rzeszutek Wilk &lt;konrad.wilk@oracle.com&gt;
Signed-off-by: H. Peter Anvin &lt;hpa@linux.intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 8762e5092828c4dc0f49da5a47a644c670df77f3 upstream.

init_espfix_ap() is currently off by one level when informing hypervisor
that allocated pages will be used for ministacks' page tables.

The most immediate effect of this on a PV guest is that if
'stack_page = __get_free_page()' returns a non-zeroed-out page the hypervisor
will refuse to use it for a page table (which it shouldn't be anyway). This will
result in warnings by both Xen and Linux.

More importantly, a subsequent write to that page (again, by a PV guest) is
likely to result in fatal page fault.

Signed-off-by: Boris Ostrovsky &lt;boris.ostrovsky@oracle.com&gt;
Link: http://lkml.kernel.org/r/1404926298-5565-1-git-send-email-boris.ostrovsky@oracle.com
Reviewed-by: Konrad Rzeszutek Wilk &lt;konrad.wilk@oracle.com&gt;
Signed-off-by: H. Peter Anvin &lt;hpa@linux.intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
</feed>
