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

From: Masami Hiramatsu
Date: Thu Nov 20 2014 - 21:29:26 EST


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.

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


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