On 6/3/21 7:06 PM, Andres Freund wrote: > Hi, > > On 2021-05-29 12:03:12 +0100, Pavel Begunkov wrote: >> On 5/29/21 1:33 AM, Andres Freund wrote: >>> Hi, >>> >>> I started to see buffer registration randomly failing with ENOMEM on >>> 5.13. Registering buffer or two often succeeds, but more than that >>> rarely. Running the same program as root succeeds - but the user has a high >>> rlimit. >>> >>> The issue is that io_sqe_buffer_register() doesn't initialize >>> imu. io_buffer_account_pin() does imu->acct_pages++, before calling >>> io_account_mem(ctx, imu->acct_pages); >>> >>> Which means that a random amount of memory is being accounted for. On the first >>> few allocations this sometimes fails to fail because the memory is zero, but >>> after a bit of reuse... >> >> Makes sense, thanks for digging in. I've just sent a patch, would >> be great if you can test it or send your own. > > Sorry for the slow response, I'm off this week. I did just get around to > test and unsurprisingly: The patch does fix the issue. Yep, since you already narrowed it down. Thanks for testing -- Pavel Begunkov
