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4 authors
  1. Oct 09, 2013
  3. Oct 04, 2013
  5. Sep 29, 2013
    • Ingo Molnar's avatar
      Revert "perf symbols: Demangle cloned functions" · 14951f22
      Ingo Molnar authored 
      
This reverts commit de95ab53.

Markus Trippelsdorf reported that this commit broke 'perf top':

 > I just see a gray screen with no text at all. Sometimes the
 > following error messages are printed:
 >
 >  *** Error in `perf': invalid fastbin entry (free): 0x00000000029b18c0
 >  ***
 >  *** Error in `perf': malloc(): memory corruption (fast): 0x0000000000ee0b10 ***

While this code is fixable, the commit itself fails on several levels:

 - it should have been a separate helper function
 - why the heck does it do strchr() twice
 - it casts a const char * over into char *
 - sloppy style
 - it's not even a regression fix!

So lets revert it and re-try the patch in v3.13.

Reported-by: default avatarMarkus Trippelsdorf <markus@trippelsdorf.de>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
      14951f22
  7. Sep 25, 2013
  9. Sep 24, 2013
  11. Sep 20, 2013
    • Peter Zijlstra's avatar
      perf: Fix capabilities bitfield compatibility in 'struct perf_event_mmap_page' · fa731587
      Peter Zijlstra authored 
      
Solve the problems around the broken definition of perf_event_mmap_page::
cap_usr_time and cap_usr_rdpmc fields which used to overlap, partially
fixed by:

  860f085b ("perf: Fix broken union in 'struct perf_event_mmap_page'")

The problem with the fix (merged in v3.12-rc1 and not yet released
officially), noticed by Vince Weaver is that the new behavior is
not detectable by new user-space, and that due to the reuse of the
field names it's easy to mis-compile a binary if old headers are used
on a new kernel or new headers are used on an old kernel.

To solve all that make this change explicit, detectable and self-contained,
by iterating the ABI the following way:

 - Always clear bit 0, and rename it to usrpage->cap_bit0, to at least not
   confuse old user-space binaries. RDPMC will be marked as unavailable
   to old binaries but that's within the ABI, this is a capability bit.

 - Rename bit 1 to ->cap_bit0_is_deprecated and always set it to 1, so new
   libraries can reliably detect that bit 0 is deprecated and perma-zero
   without having to check the kernel version.

 - Use bits 2, 3, 4 for the newly defined, correct functionality:

	cap_user_rdpmc		: 1, /* The RDPMC instruction can be used to read counts */
	cap_user_time		: 1, /* The time_* fields are used */
	cap_user_time_zero	: 1, /* The time_zero field is used */

 - Rename all the bitfield names in perf_event.h to be different from the
   old names, to make sure it's not possible to mis-compile it
   accidentally with old assumptions.

The 'size' field can then be used in the future to add new fields and it
will act as a natural ABI version indicator as well.

Also adjust tools/perf/ userspace for the new definitions, noticed by
Adrian Hunter.

Reported-by: default avatarVince Weaver <vincent.weaver@maine.edu>
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Also-Fixed-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Link: http://lkml.kernel.org/n/tip-zr03yxjrpXesOzzupszqglbv@git.kernel.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
      fa731587
  13. Sep 19, 2013