2.6.10-rc2-mm1 - detect-atomic-counter-underflows.patch

[Valdis . Kletnieks]

Now, I *may* have simply shot myself in the foot, but when I tried booting
2.6.10-rc2-mm1, I got spewed *thousands* of messages triggered by this:

diff -puN include/asm-i386/atomic.h~detect-atomic-counter-underflows include/asm-i386/atomic.h
--- 25/include/asm-i386/atomic.h~detect-atomic-counter-underflows       Wed Nov  3 15:27:37 2004
+++ 25-akpm/include/asm-i386/atomic.h   Wed Nov  3 15:27:37 2004
@@ -132,6 +132,10 @@ static __inline__ int atomic_dec_and_tes
 {
        unsigned char c;
 
+       if (!atomic_read(v)) {
+               printk("BUG: atomic counter underflow at:\n");
+               dump_stack();
+       }
        __asm__ __volatile__(
                LOCK "decl %0; sete %1"
                :"=m" (v->counter), "=qm" (c)

Somehow, warning a *counter* is non-zero doesn't seem right (calling it an
underflow 4 times if the value goes 4, 3, 2, 1 and then NOT complain when it
hits zero?) , and I'm not flooded if it says:

	if (atomic_read(v) < 0) {

So is this code wrong, or did I introduce an now-detected underflow with some
self-inflicted patch that this is picking up?

Attachment: pgp00000.pgp
Description: PGP signature