kernel/linux.git/io_uring/tctx.c, branch v6.12.80

io_uring/tctx: work around xa_store() allocation error issue

2024-12-14T19:04:10+00:00

[ Upstream commit 7eb75ce7527129d7f1fee6951566af409a37a1c4 ] syzbot triggered the following WARN_ON: WARNING: CPU: 0 PID: 16 at io_uring/tctx.c:51 __io_uring_free+0xfa/0x140 io_uring/tctx.c:51 which is the WARN_ON_ONCE(!xa_empty(&tctx->xa)); sanity check in __io_uring_free() when a io_uring_task is going through its final put. The syzbot test case includes injecting memory allocation failures, and it very much looks like xa_store() can fail one of its memory allocations and end up with ->head being non-NULL even though no entries exist in the xarray. Until this issue gets sorted out, work around it by attempting to iterate entries in our xarray, and WARN_ON_ONCE() if one is found. Reported-by: syzbot+cc36d44ec9f368e443d3@syzkaller.appspotmail.com Link: https://lore.kernel.org/io-uring/673c1643.050a0220.87769.0066.GAE@google.com/ Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

io_uring: Add io_uring_setup flag to pre-register ring fd and never install it

2023-05-16T14:06:00+00:00

With IORING_REGISTER_USE_REGISTERED_RING, an application can register the ring fd and use it via registered index rather than installed fd. This allows using a registered ring for everything *except* the initial mmap. With IORING_SETUP_NO_MMAP, io_uring_setup uses buffers allocated by the user, rather than requiring a subsequent mmap. The combination of the two allows a user to operate *entirely* via a registered ring fd, making it unnecessary to ever install the fd in the first place. So, add a flag IORING_SETUP_REGISTERED_FD_ONLY to make io_uring_setup register the fd and return a registered index, without installing the fd. This allows an application to avoid touching the fd table at all, and allows a library to never even momentarily install a file descriptor. This splits out an io_ring_add_registered_file helper from io_ring_add_registered_fd, for use by io_uring_setup. Signed-off-by: Josh Triplett Link: https://lore.kernel.org/r/bc8f431bada371c183b95a83399628b605e978a3.1682699803.git.josh@joshtriplett.org Signed-off-by: Jens Axboe

io_uring: rename 'in_idle' to 'in_cancel'

2023-02-22T16:57:23+00:00

This better describes what it does - it's incremented when the task is currently undergoing a cancelation operation, due to exiting or exec'ing. Signed-off-by: Jens Axboe

io_uring: remove io_register_submitter

2022-10-07T18:25:30+00:00

this is no longer needed, as submitter_task is set at creation time. Signed-off-by: Dylan Yudaken Fixes: 97bbdc06a444 ("io_uring: add IORING_SETUP_SINGLE_ISSUER") Signed-off-by: Jens Axboe

io_uring: simplify __io_uring_add_tctx_node

2022-10-07T18:25:30+00:00

Remove submitter parameter from __io_uring_add_tctx_node. It was only called from one place, and we can do that logic in that one place. Signed-off-by: Dylan Yudaken Fixes: 97bbdc06a444 ("io_uring: add IORING_SETUP_SINGLE_ISSUER") Signed-off-by: Jens Axboe

io_uring: lockless task list

2022-07-25T00:39:15+00:00

With networking use cases we see contention on the spinlock used to protect the task_list when multiple threads try and add completions at once. Instead we can use a lockless list, and assume that the first caller to add to the list is responsible for kicking off task work. Signed-off-by: Dylan Yudaken Link: https://lore.kernel.org/r/20220622134028.2013417-4-dylany@fb.com Signed-off-by: Jens Axboe

io_uring: remove priority tw list optimisation

2022-07-25T00:39:15+00:00

This optimisation has some built in assumptions that make it easy to introduce bugs. It also does not have clear wins that make it worth keeping. Signed-off-by: Dylan Yudaken Link: https://lore.kernel.org/r/20220622134028.2013417-2-dylany@fb.com Signed-off-by: Jens Axboe

io_uring: kill extra io_uring_types.h includes

2022-07-25T00:39:14+00:00

io_uring/io_uring.h already includes io_uring_types.h, no need to include it every time. Kill it in a bunch of places, it prepares us for following patches. Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/94d8c943fbe0ef949981c508ddcee7fc1c18850f.1655384063.git.asml.silence@gmail.com Signed-off-by: Jens Axboe

io_uring: add IORING_SETUP_SINGLE_ISSUER

2022-07-25T00:39:13+00:00

Add a new IORING_SETUP_SINGLE_ISSUER flag and the userspace visible part of it, i.e. put limitations of submitters. Also, don't allow it together with IOPOLL as we're not going to put it to good use. Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/4bcc41ee467fdf04c8aab8baf6ce3ba21858c3d4.1655371007.git.asml.silence@gmail.com Reviewed-by: Hao Xu Signed-off-by: Jens Axboe

io_uring: inline ->registered_rings

2022-07-25T00:39:13+00:00

There can be only 16 registered rings, no need to allocate an array for them separately but store it in tctx. Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/495f0b953c87994dd9e13de2134019054fa5830d.1655310733.git.asml.silence@gmail.com Signed-off-by: Jens Axboe