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  1. 11 3月, 2015 1 次提交
  3. 10 3月, 2015 3 次提交
  5. 06 3月, 2015 2 次提交
  7. 05 3月, 2015 1 次提交
  9. 04 3月, 2015 1 次提交
  11. 03 3月, 2015 1 次提交
    • R
      KVM: SVM: fix interrupt injection (apic->isr_count always 0) · f563db4b
      由 Radim Krčmář 提交于 
      In commit b4eef9b3, we started to use hwapic_isr_update() != NULL
instead of kvm_apic_vid_enabled(vcpu->kvm).  This didn't work because
SVM had it defined and "apicv" path in apic_{set,clear}_isr() does not
change apic->isr_count, because it should always be 1.  The initial
value of apic->isr_count was based on kvm_apic_vid_enabled(vcpu->kvm),
which is always 0 for SVM, so KVM could have injected interrupts when it
shouldn't.

Fix it by implicitly setting SVM's hwapic_isr_update to NULL and make the
initial isr_count depend on hwapic_isr_update() for good measure.

Fixes: b4eef9b3 ("kvm: x86: vmx: NULL out hwapic_isr_update() in case of !enable_apicv")
Reported-and-tested-by: NBorislav Petkov <bp@suse.de>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>
      f563db4b
  13. 28 2月, 2015 1 次提交
  15. 24 2月, 2015 6 次提交
  17. 22 2月, 2015 1 次提交
  19. 21 2月, 2015 2 次提交
    • P
      kprobes/x86: Check for invalid ftrace location in __recover_probed_insn() · 2a6730c8
      由 Petr Mladek 提交于 
      __recover_probed_insn() should always be called from an address
where an instructions starts. The check for ftrace_location()
might help to discover a potential inconsistency.

This patch adds WARN_ON() when the inconsistency is detected.
Also it adds handling of the situation when the original code
can not get recovered.
Suggested-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: NPetr Mladek <pmladek@suse.cz>
Cc: Ananth NMavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/1424441250-27146-3-git-send-email-pmladek@suse.czSigned-off-by: NIngo Molnar <mingo@kernel.org>
      2a6730c8
    • P
      kprobes/x86: Use 5-byte NOP when the code might be modified by ftrace · 650b7b23
      由 Petr Mladek 提交于 
      can_probe() checks if the given address points to the beginning
of an instruction. It analyzes all the instructions from the
beginning of the function until the given address. The code
might be modified by another Kprobe. In this case, the current
code is read into a buffer, int3 breakpoint is replaced by the
saved opcode in the buffer, and can_probe() analyzes the buffer
instead.

There is a bug that __recover_probed_insn() tries to restore
the original code even for Kprobes using the ftrace framework.
But in this case, the opcode is not stored. See the difference
between arch_prepare_kprobe() and arch_prepare_kprobe_ftrace().
The opcode is stored by arch_copy_kprobe() only from
arch_prepare_kprobe().

This patch makes Kprobe to use the ideal 5-byte NOP when the
code can be modified by ftrace. It is the original instruction,
see ftrace_make_nop() and ftrace_nop_replace().

Note that we always need to use the NOP for ftrace locations.
Kprobes do not block ftrace and the instruction might get
modified at anytime. It might even be in an inconsistent state
because it is modified step by step using the int3 breakpoint.

The patch also fixes indentation of the touched comment.

Note that I found this problem when playing with Kprobes. I did
it on x86_64 with gcc-4.8.3 that supported -mfentry. I modified
samples/kprobes/kprobe_example.c and added offset 5 to put
the probe right after the fentry area:

 static struct kprobe kp = {
 	.symbol_name	= "do_fork",
+	.offset = 5,
 };

Then I was able to load kprobe_example before jprobe_example
but not the other way around:

  $> modprobe jprobe_example
  $> modprobe kprobe_example
  modprobe: ERROR: could not insert 'kprobe_example': Invalid or incomplete multibyte or wide character

It did not make much sense and debugging pointed to the bug
described above.
Signed-off-by: NPetr Mladek <pmladek@suse.cz>
Acked-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Ananth NMavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/1424441250-27146-2-git-send-email-pmladek@suse.czSigned-off-by: NIngo Molnar <mingo@kernel.org>
      650b7b23
  21. 20 2月, 2015 2 次提交
  23. 19 2月, 2015 16 次提交
  25. 18 2月, 2015 3 次提交
    • J
      x86/irq: Check for valid irq descriptor in check_irq_vectors_for_cpu_disable() · d97eb896
      由 Joerg Roedel 提交于 
      When an interrupt is migrated away from a cpu it will stay
in its vector_irq array until smp_irq_move_cleanup_interrupt
succeeded. The cfg->move_in_progress flag is cleared already
when the IPI was sent.

When the interrupt is destroyed after migration its 'struct
irq_desc' is freed and the vector_irq arrays are cleaned up.
But since cfg->move_in_progress is already 0 the references
at cpus before the last migration will not be cleared. So
this would leave a reference to an already destroyed irq
alive.

When the cpu is taken down at this point, the
check_irq_vectors_for_cpu_disable() function finds a valid irq
number in the vector_irq array, but gets NULL for its
descriptor and dereferences it, causing a kernel panic.

This has been observed on real systems at shutdown. Add a
check to check_irq_vectors_for_cpu_disable() for a valid
'struct irq_desc' to prevent this issue.
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: NJiang Liu <jiang.liu@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jan Beulich <JBeulich@suse.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: alnovak@suse.com
Cc: joro@8bytes.org
Link: http://lkml.kernel.org/r/20150204132754.GA10078@suse.deSigned-off-by: NIngo Molnar <mingo@kernel.org>
      d97eb896
    • J
      x86/irq: Fix regression caused by commit b568b860 · 1ea76fba
      由 Jiang Liu 提交于 
      Commit b568b860 ("Treat SCI interrupt as normal GSI interrupt")
accidently removes support of legacy PIC interrupt when fixing a
regression for Xen, which causes a nasty regression on HP/Compaq
nc6000 where we fail to register the ACPI interrupt, and thus
lose eg. thermal notifications leading a potentially overheated
machine.

So reintroduce support of legacy PIC based ACPI SCI interrupt.
Reported-by: NVille Syrjälä <syrjala@sci.fi>
Tested-by: NVille Syrjälä <syrjala@sci.fi>
Signed-off-by: NJiang Liu <jiang.liu@linux.intel.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: NPavel Machek <pavel@ucw.cz>
Cc: <stable@vger.kernel.org> # 3.19+
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Sander Eikelenboom <linux@eikelenboom.it>
Cc: linux-pm@vger.kernel.org
Link: http://lkml.kernel.org/r/1424052673-22974-1-git-send-email-jiang.liu@linux.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      1ea76fba
    • R
      x86/spinlocks/paravirt: Fix memory corruption on unlock · d6abfdb2
      由 Raghavendra K T 提交于 
      Paravirt spinlock clears slowpath flag after doing unlock.
As explained by Linus currently it does:

                prev = *lock;
                add_smp(&lock->tickets.head, TICKET_LOCK_INC);

                /* add_smp() is a full mb() */

                if (unlikely(lock->tickets.tail & TICKET_SLOWPATH_FLAG))
                        __ticket_unlock_slowpath(lock, prev);

which is *exactly* the kind of things you cannot do with spinlocks,
because after you've done the "add_smp()" and released the spinlock
for the fast-path, you can't access the spinlock any more.  Exactly
because a fast-path lock might come in, and release the whole data
structure.

Linus suggested that we should not do any writes to lock after unlock(),
and we can move slowpath clearing to fastpath lock.

So this patch implements the fix with:

 1. Moving slowpath flag to head (Oleg):
    Unlocked locks don't care about the slowpath flag; therefore we can keep
    it set after the last unlock, and clear it again on the first (try)lock.
    -- this removes the write after unlock. note that keeping slowpath flag would
    result in unnecessary kicks.
    By moving the slowpath flag from the tail to the head ticket we also avoid
    the need to access both the head and tail tickets on unlock.

 2. use xadd to avoid read/write after unlock that checks the need for
    unlock_kick (Linus):
    We further avoid the need for a read-after-release by using xadd;
    the prev head value will include the slowpath flag and indicate if we
    need to do PV kicking of suspended spinners -- on modern chips xadd
    isn't (much) more expensive than an add + load.

Result:
 setup: 16core (32 cpu +ht sandy bridge 8GB 16vcpu guest)
 benchmark overcommit %improve
 kernbench  1x           -0.13
 kernbench  2x            0.02
 dbench     1x           -1.77
 dbench     2x           -0.63

[Jeremy: Hinted missing TICKET_LOCK_INC for kick]
[Oleg: Moved slowpath flag to head, ticket_equals idea]
[PeterZ: Added detailed changelog]
Suggested-by: NLinus Torvalds <torvalds@linux-foundation.org>
Reported-by: NSasha Levin <sasha.levin@oracle.com>
Tested-by: NSasha Levin <sasha.levin@oracle.com>
Signed-off-by: NRaghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: NOleg Nesterov <oleg@redhat.com>
Cc: Andrew Jones <drjones@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Jones <davej@redhat.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Fernando Luis Vázquez Cao <fernando_b1@lab.ntt.co.jp>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Cc: Waiman Long <Waiman.Long@hp.com>
Cc: a.ryabinin@samsung.com
Cc: dave@stgolabs.net
Cc: hpa@zytor.com
Cc: jasowang@redhat.com
Cc: jeremy@goop.org
Cc: paul.gortmaker@windriver.com
Cc: riel@redhat.com
Cc: tglx@linutronix.de
Cc: waiman.long@hp.com
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/20150215173043.GA7471@linux.vnet.ibm.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      d6abfdb2