[PATCH 0/4] perf: Support multiple stacks (v3)

[Arun Sharma <asharma@fb.com>]

If userspace has two or more stacks and we happen to take a sample when
the stack pointer is pointing to a higher stack, we get truncated
callchains. This patch series tries to address that.

Changelog:

v3: add explicit checks to copy_from_user_nmi
v3: add explicit checks in perf_callchain_user*

v2: do this for compat32 as well
v2: improve safety checks and reduce max callchain size


Arun Sharma (4):
  perf, x86: Allow multiple stacks
  perf: Limit callchains to 127
  perf, x86: Check if user fp is valid
  x86: Check user address explicitly in copy_from_user_nmi()

 arch/x86/include/asm/uaccess.h   |   13 +++++++------
 arch/x86/kernel/cpu/perf_event.c |   11 +++++++++--
 arch/x86/lib/usercopy.c          |    3 +++
 include/linux/perf_event.h       |    2 +-
 4 files changed, 20 insertions(+), 9 deletions(-)

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1.7.8.4