• Peter Zijlstra's avatar
    perf: Fix race in swevent hash · 12ca6ad2
    Peter Zijlstra authored
    There's a race on CPU unplug where we free the swevent hash array
    while it can still have events on. This will result in a
    use-after-free which is BAD.
    
    Simply do not free the hash array on unplug. This leaves the thing
    around and no use-after-free takes place.
    
    When the last swevent dies, we do a for_each_possible_cpu() iteration
    anyway to clean these up, at which time we'll free it, so no leakage
    will occur.
    Reported-by: default avatarSasha Levin <sasha.levin@oracle.com>
    Tested-by: default avatarSasha Levin <sasha.levin@oracle.com>
    Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
    Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
    Cc: Frederic Weisbecker <fweisbec@gmail.com>
    Cc: Jiri Olsa <jolsa@redhat.com>
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Stephane Eranian <eranian@google.com>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: Vince Weaver <vincent.weaver@maine.edu>
    Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
    12ca6ad2
core.c 220 KB