[tip:perf/urgent] kprobes: Make hash_64() as always inlined

From: tip-bot for Masami Hiramatsu
Date: Mon Mar 18 2013 - 07:13:42 EST

Commit-ID: 65c10553552b487a71bf5e4676743435046fae6f
Gitweb: http://git.kernel.org/tip/65c10553552b487a71bf5e4676743435046fae6f
Author: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
AuthorDate: Thu, 14 Mar 2013 20:52:30 +0900
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Mon, 18 Mar 2013 10:21:23 +0100

kprobes: Make hash_64() as always inlined

Because 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 uses __always_inline instead of inline to
prevent gcc from doing such things.

Reported-by: Timo Juhani Lindfors <timo.lindfors@xxxxxx>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
Acked-by: Ananth N Mavinakayanahalli <ananth@xxxxxxxxxx>
Cc: Pavel Emelyanov <xemul@xxxxxxxxxxxxx>
Cc: Jiri Kosina <jkosina@xxxxxxx>
Cc: Nadia Yvette Chambers <nyc@xxxxxxxxxxxxxx>
Cc: yrl.pp-manager.tt@xxxxxxxxxxx
Cc: David S. Miller <davem@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20130314115230.19690.39387.stgit@mhiramat-M0-7522
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
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..f09a0ae 100644
--- a/include/linux/hash.h
+++ b/include/linux/hash.h
@@ -15,6 +15,7 @@

#include <asm/types.h>
+#include <linux/compiler.h>

/* 2^31 + 2^29 - 2^25 + 2^22 - 2^19 - 2^16 + 1 */
#define GOLDEN_RATIO_PRIME_32 0x9e370001UL
@@ -31,7 +32,7 @@
#error Wordsize not 32 or 64

-static inline u64 hash_64(u64 val, unsigned int bits)
+static __always_inline u64 hash_64(u64 val, unsigned int bits)
u64 hash = val;

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