Pull io_uring fixes from Jens Axboe:

 - dmabug offset fix for zcrx

 - Fix for the POLLERR connect work around handling

* tag 'io_uring-6.16-20250718' of git://git.kernel.dk/linux:
  io_uring/poll: fix POLLERR handling
  io_uring/zcrx: disallow user selected dmabuf offset and size

8c8492ca64e7 ("io_uring/net: don't retry connect operation on EPOLLERR")
is a little dirty hack that
1) wrongfully assumes that POLLERR equals to a failed request, which
breaks all POLLERR users, e.g. all error queue recv interfaces.
2) deviates the connection request behaviour from connect(2), and
3) racy and solved at a wrong level.

Nothing can be done with 2) now, and 3) is beyond the scope of the
patch. At least solve 1) by moving the hack out of generic poll handling
into io_connect().

Cc: stable@vger.kernel.org
Fixes: 8c8492ca64e79 ("io_uring/net: don't retry connect operation on EPOLLERR")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/3dc89036388d602ebd84c28e5042e457bdfc952b.1752682444.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

zcrx shouldn't be so frivolous about cutting a dmabuf sgtable and taking
a subrange into it, the dmabuf layer might be not expecting that. It
shouldn't be a problem for now, but since the zcrx dmabuf support is new
and there shouldn't be any real users, let's play safe and reject user
provided ranges into dmabufs. Also, it shouldn't be needed as userspace
should size them appropriately.

Fixes: a5c98e9424573 ("io_uring/zcrx: dmabuf backed zerocopy receive")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/be899f1afed32053eb2e2079d0da241514674aca.1752443579.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Pull io_uring fixes from Jens Axboe:

 - Remove a pointless warning in the zcrx code

 - Fix for MSG_RING commands, where the allocated io_kiocb
   needs to be freed under RCU as well

 - Revert the work-around we had in place for the anon inodes
   pretending to be regular files. Since that got reworked
   upstream, the work-around is no longer needed

* tag 'io_uring-6.16-20250710' of git://git.kernel.dk/linux:
  Revert "io_uring: gate REQ_F_ISREG on !S_ANON_INODE as well"
  io_uring/msg_ring: ensure io_kiocb freeing is deferred for RCU
  io_uring/zcrx: fix pp destruction warnings

This reverts commit 6f11adcc6f36ffd8f33dbdf5f5ce073368975bc3.

The problematic commit was fixed in mainline, so the work-around in
io_uring can be removed at this point. Anonymous inodes no longer
pretend to be regular files after:

1e7ab6f67824 ("anon_inode: rework assertions")

Signed-off-by: Jens Axboe <axboe@kernel.dk>

syzbot reports that defer/local task_work adding via msg_ring can hit
a request that has been freed:

CPU: 1 UID: 0 PID: 19356 Comm: iou-wrk-19354 Not tainted 6.16.0-rc4-syzkaller-00108-g17bbde2e1716 #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0xd2/0x2b0 mm/kasan/report.c:521
 kasan_report+0x118/0x150 mm/kasan/report.c:634
 io_req_local_work_add io_uring/io_uring.c:1184 [inline]
 __io_req_task_work_add+0x589/0x950 io_uring/io_uring.c:1252
 io_msg_remote_post io_uring/msg_ring.c:103 [inline]
 io_msg_data_remote io_uring/msg_ring.c:133 [inline]
 __io_msg_ring_data+0x820/0xaa0 io_uring/msg_ring.c:151
 io_msg_ring_data io_uring/msg_ring.c:173 [inline]
 io_msg_ring+0x134/0xa00 io_uring/msg_ring.c:314
 __io_issue_sqe+0x17e/0x4b0 io_uring/io_uring.c:1739
 io_issue_sqe+0x165/0xfd0 io_uring/io_uring.c:1762
 io_wq_submit_work+0x6e9/0xb90 io_uring/io_uring.c:1874
 io_worker_handle_work+0x7cd/0x1180 io_uring/io-wq.c:642
 io_wq_worker+0x42f/0xeb0 io_uring/io-wq.c:696
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

which is supposed to be safe with how requests are allocated. But msg
ring requests alloc and free on their own, and hence must defer freeing
to a sane time.

Add an rcu_head and use kfree_rcu() in both spots where requests are
freed. Only the one in io_msg_tw_complete() is strictly required as it
has been visible on the other ring, but use it consistently in the other
spot as well.

This should not cause any other issues outside of KASAN rightfully
complaining about it.

Link: https://lore.kernel.org/io-uring/686cd2ea.a00a0220.338033.0007.GAE@google.com/
Reported-by: syzbot+54cbbfb4db9145d26fc2@syzkaller.appspotmail.com
Cc: stable@vger.kernel.org
Fixes: 0617bb500bfa ("io_uring/msg_ring: improve handling of target CQE posting")
Signed-off-by: Jens Axboe <axboe@kernel.dk>

With multiple page pools and in some other cases we can have allocated
niovs on page pool destruction. Remove a misplaced warning checking that
all niovs are returned to zcrx on io_pp_zc_destroy(). It was reported
before but apparently got lost.

Reported-by: Pedro Tammela <pctammela@mojatatu.com>
Fixes: 34a3e60821ab9 ("io_uring/zcrx: implement zerocopy receive pp memory provider")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/b9e6d919d2964bc48ddbf8eb52fc9f5d118e9bc1.1751878185.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Pull io_uring fix from Jens Axboe:
 "Now that anonymous inodes set S_IFREG, this breaks the io_uring
  read/write retries for short reads/writes. As things like timerfd and
  eventfd are anon inodes, applications that previously did:

    unsigned long event_data[2];

    io_uring_prep_read(sqe, evfd, event_data, sizeof(event_data), 0);

  and just got a short read when 1 event was posted, will now wait for
  the full amount before posting a completion.

  This caused issues for the ghostty application, making it basically
  unusable due to excessive buffering"

* tag 'io_uring-6.16-20250630' of git://git.kernel.dk/linux:
  io_uring: gate REQ_F_ISREG on !S_ANON_INODE as well

io_uring marks a request as dealing with a regular file on S_ISREG. This
drives things like retries on short reads or writes, which is generally
not expected on a regular file (or bdev). Applications tend to not
expect that, so io_uring tries hard to ensure it doesn't deliver short
IO on regular files.

However, a recent commit added S_IFREG to anonymous inodes. When
io_uring is used to read from various things that are backed by anon
inodes, like eventfd, timerfd, etc, then it'll now all of a sudden wait
for more data when rather than deliver what was read or written in a
single operation. This breaks applications that issue reads on anon
inodes, if they ask for more data than a single read delivers.

Add a check for !S_ANON_INODE as well before setting REQ_F_ISREG to
prevent that.

Cc: Christian Brauner <brauner@kernel.org>
Cc: stable@vger.kernel.org
Link: https://github.com/ghostty-org/ghostty/discussions/7720
Fixes: cfd86ef7e8e7 ("anon_inode: use a proper mode internally")
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Pull io_uring fixes from Jens Axboe:

 - Two tweaks for a recent fix: fixing a memory leak if multiple iovecs
   were initially mapped but only the first was used and hence turned
   into a UBUF rathan than an IOVEC iterator, and catching a case where
   a retry would be done even if the previous segment wasn't full

 - Small series fixing an issue making the vm unhappy if debugging is
   turned on, hitting a VM_BUG_ON_PAGE()

 - Fix a resource leak in io_import_dmabuf() in the error handling case,
   which is a regression in this merge window

 - Mark fallocate as needing to be write serialized, as is already done
   for truncate and buffered writes

* tag 'io_uring-6.16-20250626' of git://git.kernel.dk/linux:
  io_uring/kbuf: flag partial buffer mappings
  io_uring/net: mark iov as dynamically allocated even for single segments
  io_uring: fix resource leak in io_import_dmabuf()
  io_uring: don't assume uaddr alignment in io_vec_fill_bvec
  io_uring/rsrc: don't rely on user vaddr alignment
  io_uring/rsrc: fix folio unpinning
  io_uring: make fallocate be hashed work