[Madwifi-devel] Problems with spin_is_locked()

[Andrew de Q. <ad...@li...>]

Hi, I'm using kernel 2.6.9, and CVS madwifi. I've been having some mysterious 
problems that I've just had a moment to look into. My using a NON SMP system, 
but with kernel preemption enabled.

If I do:
iwpriv ath0 addmac 11:22:33:44:55:66
iwpriv ath0 maccmd 3

I get an instant kernel BUG.

This comes from the ACL_LOCK_ASSERT in ieee80211_acl.c/_acl_free(). It fails.

Looking at the code in ieee80211_linux.h:
/* NB: beware, *_is_locked() are boguly defined for UP+!PREEMPT */
#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
#define ACL_LOCK_ASSERT(_as) \
        KASSERT(spin_is_locked(&(_as)->as_lock), ("ACL not locked!"))
#else
#define ACL_LOCK_ASSERT(_as)
#endif

It looks like the kernel has changed since that was written. Looking at 
linux/spinlock.h shows that spin_is_locked() now always returns 0 on a 
non-SMP system, whether you enable preemption or not, so it should really 
only test the assertion for CONFIG_SMP (for 2.6.9 at least).

Or else 2.6.10-rcX has changed this? Can someone advise?