[PATCHv2 0/5] perf/hw_breakpoint: Fix breakpoint modify

[Jiri Olsa <jolsa@kernel.org>]

hi,
Milind reported that modify_user_hw_breakpoint wouldn't
allow the breakpoint changing if the new attr had 'disabled'
set to true.

I found a case where it actualy prevents ptrace user interface
to change the breakpoint. It's described in patch 1 as perf test,
patch 2 is the breakpoint code fix.

I ran strace tests, nothing (new) broken there..

v2 changes:
  - added Oleg's ack for patch 2
  - added new changes based on Oleg's questions
    plus new test code

thanks,
jirka

---
Jiri Olsa (5):
      perf tests: Add breakpoint modify tests
      perf/hw_breakpoint: Modify breakpoint even if the new attr has disabled set
      perf/hw_breakpoint: Remove superfluous bp->attr.disabled = 0
      perf/hw_breakpoint: Set breakpoint as disabled in modify_user_hw_breakpoint error path
      perf/hw_breakpoint: Add fallback code for ptrace_set_breakpoint_addr

 arch/x86/kernel/ptrace.c                 |   5 +++
 kernel/events/hw_breakpoint.c            |  15 +++++----
 tools/perf/arch/x86/include/arch-tests.h |   1 +
 tools/perf/arch/x86/tests/Build          |   1 +
 tools/perf/arch/x86/tests/arch-tests.c   |   6 ++++
 tools/perf/arch/x86/tests/bp-modify.c    | 213 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 6 files changed, 235 insertions(+), 6 deletions(-)
 create mode 100644 tools/perf/arch/x86/tests/bp-modify.c