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Subject[PATCH ftrace/core v3 0/3] ftrace, kprobes: Introduce IPMODIFY flag for ftrace_ops to detect conflicts
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Hi,

Here is the 3rd 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, however
I've descided to split the kprobe/x86 side fix to an independent
patch (which is [1/3])

Currently, only kprobes can change the regs->ip in the handler,
but recently kpatch is also want to change it. Moreover, since
the ftrace itself exported to modules, it might be considerable
senario.

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 3rd patch adds a special reservation of IPMODIFY on the
jprobed address, since it is the only user who will change
the regs->ip. Other kprobes do not change it anymore.

For testing, see the testcase in the previous version.
https://lkml.org/lkml/2014/6/17/175

Thank you,

---

Masami Hiramatsu (3):
[BUGFIX]kprobes/ftrace: Recover original IP if pre_handler doesn't change it
ftrace, kprobes: Support IPMODIFY flag to find IP modify conflict
kprobes: Set IPMODIFY flag only if the probe can change regs->ip


Documentation/kprobes.txt | 12 +--
Documentation/trace/ftrace.txt | 5 +
arch/x86/kernel/kprobes/ftrace.c | 9 ++-
include/linux/ftrace.h | 15 ++++
kernel/kprobes.c | 122 +++++++++++++++++++++++++++++++----
kernel/trace/ftrace.c | 132 +++++++++++++++++++++++++++++++++++++-
6 files changed, 266 insertions(+), 29 deletions(-)

--



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