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| author | Michael Kelley <mikelley@microsoft.com> | 2017-05-18 10:46:07 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-05-25 15:42:42 +0200 |
| commit | 13b9abfc92be7c4454bff912021b9f835dea6e15 (patch) | |
| tree | 134b32b899c3684a7ebcef5c3a6d23784afe28b7 /drivers/hv | |
| parent | 3110010896f17f381bd74d72b9d4a46a087c46b8 (diff) | |
| download | linux-stable-13b9abfc92be7c4454bff912021b9f835dea6e15.tar.gz linux-stable-13b9abfc92be7c4454bff912021b9f835dea6e15.tar.bz2 linux-stable-13b9abfc92be7c4454bff912021b9f835dea6e15.zip | |
Drivers: hv: vmbus: Close timing hole that can corrupt per-cpu page
Extend the disabling of preemption to include the hypercall so that
another thread can't get the CPU and corrupt the per-cpu page used
for hypercall arguments.
Cc: <Stable@vger.kernel.org> #4.11
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/hv')
| -rw-r--r-- | drivers/hv/hv.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c index 61fc8ce169a5..2ea12207caa0 100644 --- a/drivers/hv/hv.c +++ b/drivers/hv/hv.c @@ -82,10 +82,15 @@ int hv_post_message(union hv_connection_id connection_id, aligned_msg->message_type = message_type; aligned_msg->payload_size = payload_size; memcpy((void *)aligned_msg->payload, payload, payload_size); - put_cpu_ptr(hv_cpu); status = hv_do_hypercall(HVCALL_POST_MESSAGE, aligned_msg, NULL); + /* Preemption must remain disabled until after the hypercall + * so some other thread can't get scheduled onto this cpu and + * corrupt the per-cpu post_msg_page + */ + put_cpu_ptr(hv_cpu); + return status & 0xFFFF; } |