call_function_many: fix list delete vs add race

Peter pointed out there was nothing preventing the list_del_rcu in
smp_call_function_interrupt from running before the list_add_rcu in
smp_call_function_many.

Fix this by not setting refs until we have gotten the lock for the list.
Take advantage of the wmb in list_add_rcu to save an explicit additional
one.

I tried to force this race with a udelay before the lock & list_add and
by mixing all 64 online cpus with just 3 random cpus in the mask, but
was unsuccessful.  Still, inspection shows a valid race, and the fix is
a extension of the existing protection window in the current code.

Cc: stable@kernel.org (v2.6.32 and later)
Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

path: root/dissector_sll.h

/*
 * netsniff-ng - the packet sniffing beast
 * Subject to the GPL, version 2.
 */

#ifndef DISSECTOR_SLL_H
#define DISSECTOR_SLL_H

#include "hash.h"
#include "proto.h"

extern void dissector_init_sll(int fnttype);
extern void dissector_cleanup_sll(void);

extern struct protocol *dissector_get_sll_entry_point(void);
extern struct protocol *dissector_get_sll_exit_point(void);

#endif /* DISSECTOR_SLL_H */