[patch V3 00/22] bpf: Make BPF and PREEMPT_RT co-exist

[Thomas Gleixner <tglx@linutronix.de>]

Hi!

This is the third version of the BPF/RT patch set which makes both coexist
nicely. The long explanation can be found in the cover letter of the V1
submission:

  https://lore.kernel.org/r/20200214133917.304937432@linutronix.de

V2 is here:

  https://lore.kernel.org/r/20200220204517.863202864@linutronix.de

The following changes vs. V2 have been made:

  - Rebased to bpf-next, adjusted to the lock changes in the hashmap code.

  - Split the preallocation enforcement patch for instrumentation type BPF
    programs into two pieces:

    1) Emit a one-time warning on !RT kernels when any instrumentation type
       BPF program uses run-time allocation. Emit also a corresponding
       warning in the verifier log. But allow the program to run for
       backward compatibility sake. After a grace period this should be
       enforced.

    2) On RT reject such programs because on RT the memory allocator cannot
       be called from truly atomic contexts.
       
  - Fixed the fallout from V2 as reported by Alexei and 0-day

  - Removed the redundant preempt_disable() from trace_call_bpf()

  - Removed the unused export of trace_call_bpf()

The series applies on top of:

 git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master

Selftest result:
  # Summary: 1580 PASSED, 0 SKIPPED, 0 FAILED

Thanks,

	tglx
---
 include/linux/bpf.h          |   38 ++++++++-
 include/linux/filter.h       |   37 +++++++--
 kernel/bpf/hashtab.c         |  172 ++++++++++++++++++++++++++++++-------------
 kernel/bpf/lpm_trie.c        |   12 +--
 kernel/bpf/percpu_freelist.c |   20 ++---
 kernel/bpf/stackmap.c        |   18 +++-
 kernel/bpf/syscall.c         |   27 ++----
 kernel/bpf/trampoline.c      |    9 +-
 kernel/bpf/verifier.c        |   40 +++++++---
 kernel/events/core.c         |    2 
 kernel/seccomp.c             |    4 -
 kernel/trace/bpf_trace.c     |    7 -
 lib/test_bpf.c               |    4 -
 net/bpf/test_run.c           |    8 +-
 net/core/flow_dissector.c    |    4 -
 net/core/skmsg.c             |    8 --
 net/kcm/kcmsock.c            |    4 -
 17 files changed, 274 insertions(+), 140 deletions(-)