Messages in this thread | | | Date | Fri, 15 Mar 2013 10:10:41 +0530 | From | Ananth N Mavinakayanahalli <> | Subject | Re: [PATCH -tip v2 2/2] [BUGFIX] kprobes/x86: Check Interrupt Flag modifier when registering probe |
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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.pt@hitachi.com> > Reported-by: Timo Juhani Lindfors <timo.lindfors@iki.fi> > Cc: "David S. Miller" <davem@davemloft.net> > Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: Ingo Molnar <mingo@redhat.com> > Cc: "H. Peter Anvin" <hpa@zytor.com> > Cc: Steven Rostedt <rostedt@goodmis.org> > Cc: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
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