Messages in this thread | | | Subject | [PATCH ftrace/core 0/2] ftrace, kprobes: Introduce IPMODIFY flag for ftrace_ops to detect conflicts | From | Masami Hiramatsu <> | Date | Tue, 10 Jun 2014 10:50:01 +0000 |
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Hi,
Here is a pair of patches which introduces IPMODIFY flag for ftrace_ops to detect conflicts of ftrace users who can modify regs->ip in their handler. 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.
At this point, all kprobes will reserve regs->ip, since jprobe requires it.
Thank you,
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Masami Hiramatsu (2): ftrace: Simplify ftrace_hash_disable/enable path in ftrace_hash_move ftrace, kprobes: Support IPMODIFY flag to find IP modify conflict
Documentation/trace/ftrace.txt | 5 + include/linux/ftrace.h | 10 ++- kernel/kprobes.c | 2 - kernel/trace/ftrace.c | 152 ++++++++++++++++++++++++++++++++++------ 4 files changed, 143 insertions(+), 26 deletions(-)
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