On Fri 10-06-16 15:11:39, Sergey Senozhatsky wrote: > Hello, > > [ 429.191962] gfp: 2 > [ 429.192634] ------------[ cut here ]------------ > [ 429.193281] kernel BUG at mm/slub.c:1616! [...] > [ 429.217369] [<ffffffff811ca221>] bio_alloc_bioset+0xbd/0x1b1 > [ 429.218013] [<ffffffff81148078>] mpage_alloc+0x28/0x7b > [ 429.218650] [<ffffffff8114856a>] do_mpage_readpage+0x43d/0x545 > [ 429.219282] [<ffffffff81148767>] mpage_readpages+0xf5/0x152 OK, so this is flags & GFP_SLAB_BUG_MASK BUG_ON because gfp is ___GFP_HIGHMEM. It is my [1] patch which has introduced it. I think we need the following. Andrew could you fold it into mm-memcg-use-consistent-gfp-flags-during-readahead.patch or maybe keep it as a separate patch? [1] http://lkml.kernel.org/r/1465301556-26431-1-git-send-email-mhocko@xxxxxxxxxx Thanks for the report Sergey! --- >From 89cfc9bf27b9b5af47fece7eab36deb2fb04516d Mon Sep 17 00:00:00 2001 From: Michal Hocko <mhocko@xxxxxxxx> Date: Fri, 10 Jun 2016 08:27:33 +0200 Subject: [PATCH] mm: restrict gfp mask in mpage_alloc Sergey has reported that we might hit BUG_ON in new_slab() because unrestricted gfp mask used for the readahead purposes contains incompatible flags (__GFP_HIGHMEM in his case): [ 429.191962] gfp: 2 [ 429.192634] ------------[ cut here ]------------ [ 429.193281] kernel BUG at mm/slub.c:1616! [...] [ 429.217369] [<ffffffff811ca221>] bio_alloc_bioset+0xbd/0x1b1 [ 429.218013] [<ffffffff81148078>] mpage_alloc+0x28/0x7b [ 429.218650] [<ffffffff8114856a>] do_mpage_readpage+0x43d/0x545 [ 429.219282] [<ffffffff81148767>] mpage_readpages+0xf5/0x152 Make sure that mpage_alloc always restricts the mask GFP_KERNEL subset. This is what was done before "mm, memcg: use consistent gfp flags during readahead" explicitly by mapping_gfp_constraint(mapping, GFP_KERNEL) in mpage_readpages. Reported-by: Sergey Senozhatsky <sergey.senozhatsky.work@xxxxxxxxx> Signed-off-by: Michal Hocko <mhocko@xxxxxxxx> --- fs/mpage.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/mpage.c b/fs/mpage.c index 9c11255b0797..5ce75b2e60d1 100644 --- a/fs/mpage.c +++ b/fs/mpage.c @@ -71,7 +71,7 @@ mpage_alloc(struct block_device *bdev, { struct bio *bio; - bio = bio_alloc(gfp_flags, nr_vecs); + bio = bio_alloc(gfp_flags & GFP_KERNEL, nr_vecs); if (bio == NULL && (current->flags & PF_MEMALLOC)) { while (!bio && (nr_vecs /= 2)) -- 2.8.1 -- Michal Hocko SUSE Labs -- 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>