On Sun 02-04-23 19:48:29, Tetsuo Handa wrote: > syzbot is reporting circular locking dependency which involves > zonelist_update_seq seqlock, for zonelist_update_seq is checked > while doing GFP_ATOMIC allocation. Could you explain the the deadlock scenario? > Since zonelist_update_seq is checked for avoiding unnecessary OOM kill, > there is no need to check zonelist_update_seq for memory allocations > which will fail without OOM kill. > > Therefore, let's keep locking dependency simple, by not checking > zonelist_update_seq from !__GFP_DIRECT_RECLAIM allocations. > > Reported-by: syzbot <syzbot+223c7461c58c58a4cb10@xxxxxxxxxxxxxxxxxxxxxxxxx> Is this https://lore.kernel.org/all/0000000000001d74d205f7c1821f@xxxxxxxxxx/ the underlying report ? > Link: https://syzkaller.appspot.com/bug?extid=223c7461c58c58a4cb10 > Fixes: 3d36424b3b58 ("mm/page_alloc: fix race condition between build_all_zonelists and page allocation") > Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> -- Michal Hocko SUSE Labs
