* Masami Hiramatsu <[email protected]> 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 <[email protected]>
> Reported-by: Timo Juhani Lindfors <[email protected]>
> Cc: "David S. Miller" <[email protected]>
> Cc: Nadia Yvette Chambers <[email protected]>
> Cc: Pavel Emelyanov <[email protected]>
> Cc: Jiri Kosina <[email protected]>
> Cc: Ananth N Mavinakayanahalli <[email protected]>
> ---
> 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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