Messages in this thread | | | Date | Fri, 28 May 2021 17:33:50 -0700 | From | Andres Freund <> | Subject | Memory uninitialized after "io_uring: keep table of pointers to ubufs" |
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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...
It only doesn't fail as root because the rlimit doesn't apply.
This is caused by
commit 41edf1a5ec967bf4bddedb83c48e02dfea8315b4 Author: Pavel Begunkov <asml.silence@gmail.com> Date: 2021-04-25 14:32:23 +0100
io_uring: keep table of pointers to ubufs
Greetings,
Andres Freund
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