Linus Torvalds <[EMAIL PROTECTED]> writes: > Hmm.. We seem to not have any tests for the counts becoming negative, and > this would seem to be an easy mistake to make considering that both I and > Dave did it.
I stole this from -mm. -- OGAWA Hirofumi <[EMAIL PROTECTED]> From: Ingo Molnar <[EMAIL PROTECTED]> The patch below will detect atomic counter underflows. This has been test-driven in the -RT patchset for some time. qdisc_destroy() triggered it sometimes (in a seemingly nonfatal way, during device shutdown) - with DaveM suggesting that it is most likely a bug in the networking code. So it would be nice to have this in -mm for some time to validate all atomic counters on a broader base. Signed-off-by: Ingo Molnar <[EMAIL PROTECTED]> Signed-off-by: Andrew Morton <[EMAIL PROTECTED]> --- 25-akpm/include/asm-i386/atomic.h | 4 ++++ 1 files changed, 4 insertions(+) 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) _ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/