On Wed 11-04-12 14:12:44, Andrew Morton wrote: > On Wed, 11 Apr 2012 17:51:57 -0300 > Glauber Costa <glommer@xxxxxxxxxxxxx> wrote: > > > On 04/11/2012 05:26 PM, Andrew Morton wrote: > > >> > > >> > failed: > > >> > - BUG(); > > >> > unlock_page(page); > > >> > page_cache_release(page); > > >> > return NULL; > > > Cute. > > > > > > AFAICT what happened was that in my April 2002 rewrite of this code I > > > put a non-fatal buffer_error() warning in that case to tell us that > > > something bad happened. > > > > > > Years later we removed the temporary buffer_error() and mistakenly > > > replaced that warning with a BUG(). Only it*can* happen. > > > > > > We can remove the BUG() and fix up callers, or we can pass retry=1 into > > > alloc_page_buffers(), so grow_dev_page() "cannot fail". Immortal > > > functions are a silly fiction, so we should remove the BUG() and fix up > > > callers. > > > > > Any particular caller you are concerned with ? > > Didn't someone see a buggy caller in btrfs? No I missed that __getblk (__getblk_slow) returns NULL only if grow_buffers < 0 while it returns 0 for the allocation failure. Sorry for confusion. -- Michal Hocko SUSE Labs SUSE LINUX s.r.o. Lihovarska 1060/12 190 00 Praha 9 Czech Republic -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>