[PATCH ftrace/core v6 0/5] ftrace, kprobes: Introduce IPMODIFY flag for ftrace_ops to detect conflicts

[Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>]

Hi,

Here is the 6th version of the series of patches which introduces
IPMODIFY flag for ftrace_ops to detect conflicts of ftrace users
who can modify regs->ip in their handler.

This version is basically an update of previous version to the
latest ftrace/core tree.

Currently, only kprobes can change the regs->ip in the handler,
but recent Kernel Live Patching also changes it.

Here we talked on github.
 https://github.com/dynup/kpatch/issues/47

To protect modified regs-ip from each other, this series
introduces FTRACE_OPS_FL_IPMODIFY flag and ftrace now ensures
the flag can be set on each function entry location. If there
is someone who already reserve regs->ip on target function
entry, ftrace_set_filter_ip or register_ftrace_function will
return -EBUSY. Users must handle that.
The ftrace_ops with IPMODIFY flag requires at least one
entry for filter hash, and its notrace_hash must be empty,
because the IPMODIFY action is very address sensitve and
user must consider the ip address.

Thank you,

---

Masami Hiramatsu (5):
      kprobes/ftrace: Recover original IP if pre_handler doesn't change it
      ftrace, kprobes: Support IPMODIFY flag to find IP modify conflict
      kprobes: Add IPMODIFY flag to kprobe_ftrace_ops
      kprobes: Set IPMODIFY flag only if the probe can change regs->ip
      kselftest,ftrace: Add ftrace IPMODIFY flag test


 Documentation/kprobes.txt                          |   12 +
 Documentation/trace/ftrace.txt                     |    5 +
 arch/x86/kernel/kprobes/ftrace.c                   |    9 +
 include/linux/ftrace.h                             |   16 ++
 kernel/kprobes.c                                   |  123 +++++++++++++-
 kernel/trace/ftrace.c                              |  142 ++++++++++++++++-
 tools/testing/selftests/ftrace/Makefile            |   11 +
 tools/testing/selftests/ftrace/ipmodify/Makefile   |   15 ++
 tools/testing/selftests/ftrace/ipmodify/ipmodify.c |  170 ++++++++++++++++++++
 .../selftests/ftrace/ipmodify/run_ipmodify.sh      |    6 +
 10 files changed, 480 insertions(+), 29 deletions(-)
 create mode 100644 tools/testing/selftests/ftrace/ipmodify/Makefile
 create mode 100644 tools/testing/selftests/ftrace/ipmodify/ipmodify.c
 create mode 100644 tools/testing/selftests/ftrace/ipmodify/run_ipmodify.sh

--