• Thomas Gleixner's avatar
    cpu/hotplug: Keep enough storage space if SMP=n to avoid array out of bounds scribble · a7c73414
    Thomas Gleixner authored
    Xiaolong Ye reported lock debug warnings triggered by the following commit:
    
      8de4a0066106 ("perf/x86: Convert the core to the hotplug state machine")
    
    The bug is the following: the cpuhp_bp_states[] array is cut short when
    CONFIG_SMP=n, but the dynamically registered callbacks are stored nevertheless
    and happily scribble outside of the array bounds...
    
    We need to store them in case that the state is unregistered so we can invoke
    the teardown function. That's independent of CONFIG_SMP. Make sure the array
    is large enough.
    Reported-by: default avatarkernel test robot <xiaolong.ye@intel.com>
    Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
    Cc: Adam Borowski <kilobyte@angband.pl>
    Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
    Cc: Anna-Maria Gleixner <anna-maria@linutronix.de>
    Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
    Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
    Cc: Borislav Petkov <bp@suse.de>
    Cc: Jiri Olsa <jolsa@redhat.com>
    Cc: Kan Liang <kan.liang@intel.com>
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
    Cc: Stephane Eranian <eranian@google.com>
    Cc: Vince Weaver <vincent.weaver@maine.edu>
    Cc: lkp@01.org
    Cc: stable@vger.kernel.org
    Cc: tipbuild@zytor.com
    Fixes: cff7d378 "cpu/hotplug: Convert to a state machine for the control processor"
    Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1607122144560.4083@nanosSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
    a7c73414
cpu.c 41.4 KB