Commits
Thomas Gleixner committed f508a5ba7a4
x86/tsc: Prevent NULL pointer deref in calibrate_delay_is_known() The topology_core_cpumask is used to find a neighbour cpu in calibrate_delay_is_known(). It might not be allocated at the first invocation of that function on the boot cpu, when CONFIG_CPUMASK_OFFSTACK is set. The mask is allocated later in native_smp_prepare_cpus. As a consequence the underlying find_next_bit() call dereferences a NULL pointer. Add a proper check to prevent this. Fixes: c25323c07345 "x86/tsc: Use topology functions" Reported-and-tested-by: Richard W.M. Jones <rjones@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Josh Boyer <jwboyer@fedoraproject.org> Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1603180843270.3978@nanos Signed-off-by: Thomas Gleixner <tglx@linutronix.de>