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    x86: Put back -pg to tsc.o and add no GCOV to vread_tsc_64.o · 89e1be50
    Steven Rostedt 提交于
    The commit 44259b1a
        Author: Andy Lutomirski <luto@MIT.EDU>
        x86-64: Move vread_tsc into a new file with sensible options
    
    Removed the -pg from tsc.o which caused the function graph tracer
    to go into an infinite function call recursion as it uses the tsc
    internally outside its recursion protection, thus tracing the tsc
    breaks the function graph tracer.
    
    This commit also added the file vread_tsc_64.c that gets used
    by vdso but failed to prevent GCOV from monkeying with it,
    causing userspace to try to access kernel data when GCOV was
    enabled.
    
    Thanks to Thomas Gleixner for pointing out GCOV as the likely
    culprit that added strange kernel accesses into the vread_tsc()
    call.
    
    Cc: Author: Andy Lutomirski <luto@MIT.EDU>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
    89e1be50
Makefile 4.1 KB