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, --- 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(-) -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
