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tracing: Fix $mcount_regex for MIPS in recordmcount.pl
I found this issue in a locally patched 2.6.32.x, current kernels have moved the offending code to an __init function which is skipped by recordmcount.pl, so the bug is not currently being exercised. However, I think the patch is still a good idea, to avoid future problems if _mcount were to ever have its address taken in normal code. This is what I originally saw: Although arch/mips/kernel/ftrace.c is built without -pg, and thus contains no calls to _mcount, it does use the address of _mcount in ftrace_make_nop(). This was causing relocations to be emitted for _mcount which recordmcount.pl erronously took to be _mcount call sites. The result was that the text of ftrace_make_nop() would be patched with garbage leading to a system crash. In non-module code, all _mcount call sites will have R_MIPS_26 relocations, so we restrict $mcount_regex to only match on these. Acked-by: Ralf Baechle <[email protected]> Acked-by: Wu Zhangjin <[email protected]> Signed-off-by: David Daney <[email protected]> LKML-Reference: <[email protected]> Cc: Li Hong <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Matt Fleming <[email protected]> Signed-off-by: Steven Rostedt <[email protected]>
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