Messages in this thread Patch in this message | | | From | Kamal Mostafa <> | Subject | [PATCH 060/105] x86: kvmclock: zero initialize pvclock shared memory area | Date | Fri, 28 Jun 2013 11:51:22 -0700 |
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3.8.13.4 -stable review patch. If anyone has any objections, please let me know.
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From: Igor Mammedov <imammedo@redhat.com>
commit 07868fc6aaf57847b0f3a3d53086b7556eb83f4a upstream.
kernel might hung in pvclock_clocksource_read() due to uninitialized memory might contain odd version value in following cycle:
do { version = __pvclock_read_cycles(src, &ret, &flags); } while ((src->version & 1) || version != src->version);
if secondary kvmclock is accessed before it's registered with kvm.
Clear garbage in pvclock shared memory area right after it's allocated to avoid this issue.
Ref: https://bugzilla.kernel.org/show_bug.cgi?id=59521 Signed-off-by: Igor Mammedov <imammedo@redhat.com> [See BZ for analysis. We may want a different fix for 3.11, but this is the safest for now - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- arch/x86/kernel/kvmclock.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c index 5bedbdd..a855a2e 100644 --- a/arch/x86/kernel/kvmclock.c +++ b/arch/x86/kernel/kvmclock.c @@ -238,6 +238,7 @@ void __init kvmclock_init(void) if (!mem) return; hv_clock = __va(mem); + memset(hv_clock, 0, size); if (kvm_register_clock("boot clock")) { hv_clock = NULL; -- 1.8.1.2
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