• Peter Zijlstra's avatar
    x86/uaccess, kasan: Fix KASAN vs SMAP · 57b78a62
    Peter Zijlstra authored
    
    
    KASAN inserts extra code for every LOAD/STORE emitted by te compiler.
    Much of this code is simple and safe to run with AC=1, however the
    kasan_report() function, called on error, is most certainly not safe
    to call with AC=1.
    
    Therefore wrap kasan_report() in user_access_{save,restore}; which for
    x86 SMAP, saves/restores EFLAGS and clears AC before calling the real
    function.
    
    Also ensure all the functions are without __fentry__ hook. The
    function tracer is also not safe.
    Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
    Cc: Borislav Petkov <bp@alien8.de>
    Cc: Dmitry Vyukov <dvyukov@google.com>
    Cc: Josh Poimboeuf <jpoimboe@redhat.com>
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
    57b78a62