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    Merge branch 'core-stacktrace-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip · 2c6a392c
    Linus Torvalds authored
    Pull stack trace updates from Ingo Molnar:
     "So Thomas looked at the stacktrace code recently and noticed a few
      weirdnesses, and we all know how such stories of crummy kernel code
      meeting German engineering perfection end: a 45-patch series to clean
      it all up! :-)
    
      Here's the changes in Thomas's words:
    
       'Struct stack_trace is a sinkhole for input and output parameters
        which is largely pointless for most usage sites. In fact if embedded
        into other data structures it creates indirections and extra storage
        overhead for no benefit.
    
        Looking at all usage sites makes it clear that they just require an
        interface which is based on a storage array. That array is either on
        stack, global or embedded into some other data structure.
    
        Some of the stack depot usage sites are outright wrong, but
        fortunately the wrongness just causes more stack being used for
        nothing and does not have functional impact.
    
        Another oddity is the inconsistent termination of the stack trace
        with ULONG_MAX. It's pointless as the number of entries is what
        determines the length of the stored trace. In fact quite some call
        sites remove the ULONG_MAX marker afterwards with or without nasty
        comments about it. Not all architectures do that and those which do,
        do it inconsistenly either conditional on nr_entries == 0 or
        unconditionally.
    
        The following series cleans that up by:
    
          1) Removing the ULONG_MAX termination in the architecture code
    
          2) Removing the ULONG_MAX fixups at the call sites
    
          3) Providing plain storage array based interfaces for stacktrace
             and stackdepot.
    
          4) Cleaning up the mess at the callsites including some related
             cleanups.
    
          5) Removing the struct stack_trace based interfaces
    
        This is not changing the struct stack_trace interfaces at the
        architecture level, but it removes the exposure to the generic
        code'"
    
    * 'core-stacktrace-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (45 commits)
      x86/stacktrace: Use common infrastructure
      stacktrace: Provide common infrastructure
      lib/stackdepot: Remove obsolete functions
      stacktrace: Remove obsolete functions
      livepatch: Simplify stack trace retrieval
      tracing: Remove the last struct stack_trace usage
      tracing: Simplify stack trace retrieval
      tracing: Make ftrace_trace_userstack() static and conditional
      tracing: Use percpu stack trace buffer more intelligently
      tracing: Simplify stacktrace retrieval in histograms
      lockdep: Simplify stack trace handling
      lockdep: Remove save argument from check_prev_add()
      lockdep: Remove unused trace argument from print_circular_bug()
      drm: Simplify stacktrace handling
      dm persistent data: Simplify stack trace handling
      dm bufio: Simplify stack trace retrieval
      btrfs: ref-verify: Simplify stack trace retrieval
      dma/debug: Simplify stracktrace retrieval
      fault-inject: Simplify stacktrace retrieval
      mm/page_owner: Simplify stack trace handling
      ...
    2c6a392c