On Wed, Sep 22, 2021 at 05:06:53PM +0800, Li Wang wrote: > Hi, Li, > > I confirmed this patch (applied on 5.14) gets rid of the below userfaultfd > test failure. > > # ./userfaultfd anon 16 2 > nr_pages: 4096, nr_pages_per_cpu: 256 > bounces: 1, mode: rnd read, userfaults: 313 missing > (51+34+37+26+41+28+15+20+16+12+13+7+10+2+0+1) 995 wp > (121+79+96+53+90+104+48+61+56+82+56+41+49+26+11+22) > bounces: 0, mode: read, userfaults: 64 missing > (15+8+10+6+5+2+4+3+3+1+4+0+0+2+0+1) 2157 wp > (223+274+189+141+116+132+203+153+143+126+110+114+101+66+42+24) > testing uffd-wp with pagemap (pgsize=4096): done > testing uffd-wp with pagemap (pgsize=2097152): done > testing UFFDIO_ZEROPAGE: done. > testing signal delivery: done. > testing events (fork, remap, remove): ERROR: nr 3933 memory corruption 0 1 > (errno=0, line=963) > ERROR: faulting process failed (errno=0, line=1117) Just to keep a record within this thread - my understanding is above issue is a separate issue from what Nadav has fixed. The other fix could be: https://lore.kernel.org/lkml/20210923232512.210092-1-peterx@xxxxxxxxxx/ When verify with Nadav's patch, please check whether you have thp enabled globally: # echo always > /sys/kernel/mm/transparent_hugepage/enabled Thanks, -- Peter Xu
