[parisc-linux] missing barrier in _raw_spin_lock?

[Joel Soete]

Arnd Bergmann wrote:
> We stumbled over a problem on s390 that can cause random memory corruption
> under high load on SMP. It turned out to be a missing on :"memory" clobber
> on the _raw_spin_lock primitive.
> 
> As far as I can see, the same problem is in the parisc spinlock definition
> in linux-2.6.1, but none of the other architectures.
> 
> The code below demonstrates the problem. With the broken spinlock, the
> compiler does not emit code for the second "if" or for the assignment.
> Similar code can be found in mempool_free().
> 
> 	Arnd <><
> 
> ----
> #include <linux/spinlock.h>
> 
hmm yet another stupid question of mine: what would we have to use _linux_/spinlock.h or _asm_/spinlock.h

Thanks in advance,
	Joel


> static int x;
> static spinlock_t lock;
> 
> void test(void)
> {
>         if (x) {
>                 spin_lock(&lock);
>                 if (!x)
>                         x = 0x1234;
>                 spin_unlock(&lock);
>         }
> }
> 
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