| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.4 25/28] hv: dont reset hv_context.tsc_page on crash | Date | Tue, 25 Apr 2017 16:08:56 +0100 |
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4.4-stable review patch. If anyone has any objections, please let me know.
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From: Vitaly Kuznetsov <vkuznets@redhat.com>
commit 56ef6718a1d8d77745033c5291e025ce18504159 upstream.
It may happen that secondary CPUs are still alive and resetting hv_context.tsc_page will cause a consequent crash in read_hv_clock_tsc() as we don't check for it being not NULL there. It is safe as we're not freeing this page anyways.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/hv/hv.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
--- a/drivers/hv/hv.c +++ b/drivers/hv/hv.c @@ -305,9 +305,10 @@ void hv_cleanup(bool crash) hypercall_msr.as_uint64 = 0; wrmsrl(HV_X64_MSR_REFERENCE_TSC, hypercall_msr.as_uint64); - if (!crash) + if (!crash) { vfree(hv_context.tsc_page); - hv_context.tsc_page = NULL; + hv_context.tsc_page = NULL; + } } #endif }
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