Messages in this thread | | | Date | Tue, 12 Mar 2013 09:16:28 +0100 | From | Ingo Molnar <> | Subject | Re: [PATCH -tip ] [BUGFIX] kprobes: Move hash_64() into .text.kprobe section |
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* Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> wrote:
> Beacuse hash_64() is called from the get_kprobe() inside > int3 handler, kernel causes int3 recursion and crashes if > kprobes user puts a probe on it. > > Usually hash_64() is inlined into caller function, but in > some cases, it has instances by gcc's interprocedural > constant propagation. > > This patch adds __kprobes tag on the hash_64() and moves > all those instances into .text.kprobe section so that > kprobes can refuse probing on the instances. > > I've ensured that all hash_64 instances moves to the > address between __kprobes_text_start and __kprobes_text_end > with this patch as below. > > ffffffff8138bea0 T __kprobes_text_start > ffffffff8138bec0 t hash_64.constprop.8 > ffffffff8138ef98 t hash_64.constprop.26 > ffffffff8138efae t hash_64 > ffffffff8138f066 t hash_64.constprop.43 > ffffffff8138f649 t hash_64.constprop.25 > ffffffff8139103a t hash_64.constprop.77 > ffffffff81391050 t hash_64.constprop.24 > ffffffff81391066 t hash_64.constprop.40 > ffffffff8139107c t hash_64.constprop.15 > ffffffff81391092 T __kprobes_text_end > > 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: Nadia Yvette Chambers <nyc@holomorphy.com> > Cc: Pavel Emelyanov <xemul@parallels.com> > Cc: Jiri Kosina <jkosina@suse.cz> > Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> > --- > include/linux/hash.h | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/include/linux/hash.h b/include/linux/hash.h > index 61c97ae..d83f62f 100644 > --- a/include/linux/hash.h > +++ b/include/linux/hash.h > @@ -15,6 +15,7 @@ > */ > > #include <asm/types.h> > +#include <linux/kprobes.h>
I have no objections to the fix itself, but this inclusion of kprobes.h in hash.h is somewhat sad: kprobes.h is a 'fat' header that includes a lot of header files - while hash.h is a really basic type header included in close to a hundred .c files.
I think one solution would be for the __kprobes definition to move to a more basic header file - such as types.h or compiler.h (where the 'notrace' attribute is placed too), to stop this header dependency creep.
Thanks,
Ingo
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