xen/x86/vpmu: Zero struct pt_regs before calling into sample handling code

BugLink: https://bugs.launchpad.net/bugs/1836287
commit 70513d58751d7c6c1a0133557b13089b9f2e3e66 upstream.

Otherwise we may leak kernel stack for events that sample user
registers.

Reported-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/arch/x86/xen/pmu.c b/arch/x86/xen/pmu.c
index 7d00d4ad44d44d62f9a6a089a2c8d4a649e6aa08..95997e6c06960073c75b713cb2be76ec74c0886c 100644 (file)
--- a/arch/x86/xen/pmu.c
+++ b/arch/x86/xen/pmu.c
@@ -478,7 +478,7 @@ static void xen_convert_regs(const struct xen_pmu_regs *xen_regs,
 irqreturn_t xen_pmu_irq_handler(int irq, void *dev_id)
 {
        int err, ret = IRQ_NONE;
-       struct pt_regs regs;
+       struct pt_regs regs = {0};
        const struct xen_pmu_data *xenpmu_data = get_xenpmu_data();
        uint8_t xenpmu_flags = get_xenpmu_flags();