kernel/git/stable/linux.git/io_uring/nop.c, branch linux-7.2.y

io_uring/nop: fix file reference leak with IOSQE_FIXED_FILE

2026-06-16T12:20:01+00:00

NOP file-acquisition support choses between a fixed (registered) file and a normal fget()'d file based on its own IORING_NOP_FIXED_FILE flag in sqe->nop_flags. However, a request's REQ_F_FIXED_FILE is set independently from the generic IOSQE_FIXED_FILE sqe flag during request init, before the issue handler runs. If a NOP is submitted with IOSQE_FIXED_FILE set (so REQ_F_FIXED_FILE is set) but without IORING_NOP_FIXED_FILE, io_nop() takes the normal path and grabs a real reference via io_file_get_normal(). On completion, io_put_file() only drops the reference when REQ_F_FIXED_FILE is clear, so the fget()'d file is never released and leaks: BUG: memory leak unreferenced object 0xffff88800f42c240 (size 176): kmem_cache_alloc_noprof+0x358/0x440 alloc_empty_file+0x57/0x180 path_openat+0x44/0x1e50 do_file_open+0x121/0x200 do_sys_openat2+0xa7/0x150 __x64_sys_openat+0x82/0xf0 Decide between fixed and normal file acquisition from REQ_F_FIXED_FILE, the same way io_assign_file() does for every other opcode, and fold IORING_NOP_FIXED_FILE into REQ_F_FIXED_FILE at prep time. Cc: stable@vger.kernel.org Fixes: a85f31052bce ("io_uring/nop: add support for testing registered files and buffers") Reported-by: syzbot+2cd473471e77bda12b0e@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?id=879092631b98f73a28ea405adacfa5bb34a14a25 Signed-off-by: Vasileios Almpanis Link: https://patch.msgid.link/20260615144619.482749-1-vasilisalmpanis@gmail.com Signed-off-by: Jens Axboe

Merge tag 'for-7.2/io_uring-20260615' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux

2026-06-16T07:23:59+00:00

Pull io_uring updates from Jens Axboe: - Rework the task_work infrastructure. Both the local (DEFER_TASKRUN) and the normal (tctx) task_work lists were llist based, which is LIFO ordered, and hence each run had to do an O(n) list reversal pass first to restore queue order. Additionally, to cap the amount of task_work run, each method needed a retry list as well. Add a lockless MPCS FIFO queue (based on Dmitry Vyukov's intrusive MPSC algorithm) and switch both task_work lists to it. It performs better than llists and we can then also ditch the retry lists as well as entries are popped one-at-the-time. On top of those changes, run the tctx fallback task_work directly and remove the now-unused per-ctx fallback machinery entirely. - zcrx user notifications. Add a mechanism for zcrx to communicate conditions back to userspace via a dedicated CQE, with the initial users being notification on running out of buffers and on a frag copy fallback, plus shared-memory notification statistics. Alongside that, a series of zcrx reliability and cleanup fixes: more reliable scrubbing, poisoning pointers on unregistration, dropping an extra ifq close, adding a ctx back-pointer, reordering fd allocation in the export path, and killing a dead 'sock' member. - Allow using io_uring registered buffers for plain SEND and RECV, not just for the zero-copy send path. This enables targets like ublk's NBD backend to push/pull IO data directly to/from a registered buffer over a plain send/recv on a TCP socket. - Registered buffer improvements: account huge pages correctly, bump the io_mapped_ubuf length field to size_t, and raise the previous 1GB registered buffer size limit. - Restrict the ctx access exposed to io_uring BPF struct_ops programs by handing them an opaque type rather than the full io_ring_ctx, and add a separate MAINTAINERS entry for the bpf-ops code. - Allow opcode filtering on IORING_OP_CONNECT. - Validate ring-provided buffer addresses with access_ok(), and align the legacy buffer add limit with MAX_BIDS_PER_BGID. - Various other cleanups and minor fixes, including avoiding msghdr async data on connect/bind, dropping async_size for OP_LISTEN, making the POLL_FIRST receive side checks consistent, re-checking IO_WQ_BIT_EXIT for each linked work item, and using trace_call__##name() at guarded tracepoint call sites. * tag 'for-7.2/io_uring-20260615' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux: (31 commits) io_uring/bpf-ops: add a separate maintainer entry io_uring/net: make POLL_FIRST receive side checks consistent io_uring: remove the per-ctx fallback task_work machinery io_uring: run the tctx task_work fallback directly io_uring: switch normal task_work to a mpscq io_uring: switch local task_work to a mpscq io_uring/mpscq: add lockless multi-producer, single-consumer FIFO queue io_uring: grab RCU read lock marking task run io_uring/zcrx: kill dead 'sock' member in struct io_zcrx_args io_uring/kbuf: validate ring provided buffer addresses with access_ok() io_uring/net: support registered buffer for plain send and recv io_uring/nop: Drop a wrong comment in struct io_nop io_uring/net: Remove async_size for OP_LISTEN io_uring/net: Avoid msghdr on op_connect/op_bind async data io_uring/bpf-ops: restrict ctx access to BPF io_uring/io-wq: re-check IO_WQ_BIT_EXIT for each linked work item io_uring/kbuf: align legacy buffer add limit with MAX_BIDS_PER_BGID io_uring/zcrx: add shared-memory notification statistics io_uring/zcrx: notify user on frag copy fallback io_uring/zcrx: notify user when out of buffers ...

io_uring/nop: Drop a wrong comment in struct io_nop

2026-06-02T23:43:20+00:00

This was copy-pasted from io_rw, where the comment actually makes sense. Here, we don't have struct kiocb. Drop the comment. Signed-off-by: Gabriel Krisman Bertazi Link: https://patch.msgid.link/20260602215327.1885109-4-krisman@suse.de Signed-off-by: Jens Axboe

io_uring/nop: pass all errors to userspace

2026-05-21T17:10:56+00:00

This fixes an inconsistency where io_nop() called req_set_fail() based on ret, but passed just nop->result to userspace. Originally, ret is a even copy of nop->result, but is set to an error when such happens subsequently. Now that's also passed to userspace. Fixes: a85f31052bce ("io_uring/nop: add support for testing registered files and buffers") Signed-off-by: Alexander A. Klimov Link: https://patch.msgid.link/20260520180045.538533-1-grandmaster@al2klimov.de Signed-off-by: Jens Axboe

io_uring/nop: add support for IORING_SETUP_CQE_MIXED

2025-08-27T17:24:15+00:00

This adds support for setting IORING_NOP_CQE32 as a flag for a NOP command, in which case a 32b CQE will be posted rather than a regular one. This is the default if the ring has been setup with IORING_SETUP_CQE32. If the ring has been setup with IORING_SETUP_CQE_MIXED, then 16b CQEs will be posted without this flag set, and 32b CQEs if this flag is set. For the latter case, sqe->off is what will be posted as cqe->big_cqe[0] and sqe->addr is what will be posted as cqe->big_cqe[1]. Signed-off-by: Jens Axboe

io_uring/nop: add IORING_NOP_TW completion flag

2025-06-23T14:59:13+00:00

To test and profile the overhead of io_uring task_work and the various types of it, add IORING_NOP_TW which tells nop to signal completions through task_work rather than complete them inline. Signed-off-by: Jens Axboe

io_uring: finish IOU_OK -> IOU_COMPLETE transition

2025-05-21T14:41:16+00:00

IOU_COMPLETE is more descriptive, in that it explicitly says that the return value means "please post a completion for this request". This patch completes the transition from IOU_OK to IOU_COMPLETE, replacing existing IOU_OK users. This is a purely mechanical change. Signed-off-by: Jens Axboe

io_uring/nop: use io_find_buf_node()

2025-03-01T02:35:37+00:00

Call io_find_buf_node() to avoid duplicating it in io_nop(). Signed-off-by: Caleb Sander Mateos Link: https://lore.kernel.org/r/20250301001610.678223-2-csander@purestorage.com Signed-off-by: Jens Axboe

io_uring/nop: reuse req->buf_index

2025-02-27T14:17:39+00:00

There is already a field in io_kiocb that can store a registered buffer index, use that instead of stashing the value into struct io_nop. Signed-off-by: Keith Busch Reviewed-by: Pavel Begunkov Reviewed-by: Ming Lei Link: https://lore.kernel.org/r/20250224213116.3509093-3-kbusch@meta.com Signed-off-by: Jens Axboe

io_uring/nop: ensure nop->fd is always initialized

2024-11-21T14:15:30+00:00

A previous commit added file support for nop, but it only initializes nop->fd if IORING_NOP_FIXED_FILE is set. That check should be IORING_NOP_FILE. Fix up the condition in nop preparation, and initialize it to a sane value even if we're not going to be directly using it. While in there, do the same thing for the nop->buffer field. Reported-by: syzbot+9a8500a45c2cabdf9577@syzkaller.appspotmail.com Fixes: a85f31052bce ("io_uring/nop: add support for testing registered files and buffers") Signed-off-by: Jens Axboe