On Thu, Mar 14, 2013 at 08:52:43PM +0900, Masami Hiramatsu wrote: > Currently kprobes check whether the copied instruction modifies > IF (interrupt flag) on each probe hit. This means not only > introducing overhead but also involving inat_get_opcode_attribute > into kprobes hot path, and it can cause an infinit recursive > call (and kernel panic in the end). > > Actually, since the copied instruction itself never be modified > on the buffer, it is needless to analyze the instruction every > probe hit. > > To fix this issue, we checks it only once when registering probe > and store the result on ainsn->if_modifier. > > Signed-off-by: Masami Hiramatsu <masami.hiramatsu...@hitachi.com> > Reported-by: Timo Juhani Lindfors <timo.lindf...@iki.fi> > Cc: "David S. Miller" <da...@davemloft.net> > Cc: Ananth N Mavinakayanahalli <ana...@in.ibm.com> > Cc: Thomas Gleixner <t...@linutronix.de> > Cc: Ingo Molnar <mi...@redhat.com> > Cc: "H. Peter Anvin" <h...@zytor.com> > Cc: Steven Rostedt <rost...@goodmis.org> > Cc: Linus Torvalds <torva...@linux-foundation.org>
Acked-by: Ananth N Mavinakayanahalli <ana...@in.ibm.com> -- 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/
