that was fast! On (06/10/16 08:34), Michal Hocko wrote: [..] > 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! after quick tests -- works for me. please see below. > 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)) so the first bio_alloc() is ok now. what about the second bio_alloc() in mpage_alloc()? it'll still see the ___GFP_HIGHMEM? may be something like this (composed in mail client) static struct bio * mpage_alloc(struct block_device *bdev, sector_t first_sector, int nr_vecs, gfp_t gfp_flags) { struct bio *bio; + gfp_flags &= GFP_KERNEL; - 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)) bio = bio_alloc(gfp_flags, nr_vecs); ^^^^^^^^^^^^^^^^^^^^ BUG? } if (bio) { bio->bi_bdev = bdev; bio->bi_iter.bi_sector = first_sector; } return bio; } ===== the second part of the original report (sleeping function called from invalid context at include/linux/sched.h:2960) is unrelated, I'll fork a new thread; seems that it's coming from a380a3c755, Christoph Lameter, 2015-11-20. -ss -- 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>