On Mon, 14 Apr 2014 19:23:34 +0200 (CEST) Sebastian Ott <sebott@xxxxxxxxxxxxxxxxxx> wrote: > Memory obtained via mempool_alloc is not always zeroed even when > called with __GFP_ZERO. Add a note and VM_BUG_ON statement to make > that clear. > > .. > > @@ -200,6 +201,7 @@ void * mempool_alloc(mempool_t *pool, gf > wait_queue_t wait; > gfp_t gfp_temp; > > + VM_BUG_ON(gfp_mask & __GFP_ZERO); > might_sleep_if(gfp_mask & __GFP_WAIT); > > gfp_mask |= __GFP_NOMEMALLOC; /* don't allocate emergency reserves */ hm, BUG is a bit harsh. How about --- a/mm/mempool.c~mm-mempool-warn-about-__gfp_zero-usage-fix +++ a/mm/mempool.c @@ -201,7 +201,9 @@ void * mempool_alloc(mempool_t *pool, gf wait_queue_t wait; gfp_t gfp_temp; - VM_BUG_ON(gfp_mask & __GFP_ZERO); +#ifdef CONFIG_DEBUG_VM + WARN_ON_ONCE(gfp_mask & __GFP_ZERO); /* Where's VM_WARN_ON_ONCE()? */ +#endif might_sleep_if(gfp_mask & __GFP_WAIT); gfp_mask |= __GFP_NOMEMALLOC; /* don't allocate emergency reserves */ ? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>