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Stefan Metzmacher 2e4c95a404 io_uring/net: fix fast_iov assignment in io_setup_async_msg()
commit 3e4cb6ebbb upstream.

I hit a very bad problem during my tests of SENDMSG_ZC.
BUG(); in first_iovec_segment() triggered very easily.
The problem was io_setup_async_msg() in the partial retry case,
which seems to happen more often with _ZC.

iov_iter_iovec_advance() may change i->iov in order to have i->iov_offset
being only relative to the first element.

Which means kmsg->msg.msg_iter.iov is no longer the
same as kmsg->fast_iov.

But this would rewind the copy to be the start of
async_msg->fast_iov, which means the internal
state of sync_msg->msg.msg_iter is inconsitent.

I tested with 5 vectors with length like this 4, 0, 64, 20, 8388608
and got a short writes with:
- ret=2675244 min_ret=8388692 => remaining 5713448 sr->done_io=2675244
- ret=-EAGAIN => io_uring_poll_arm
- ret=4911225 min_ret=5713448 => remaining 802223  sr->done_io=7586469
- ret=-EAGAIN => io_uring_poll_arm
- ret=802223  min_ret=802223  => res=8388692

While this was easily triggered with SENDMSG_ZC (queued for 6.1),
it was a potential problem starting with 7ba89d2af1
in 5.18 for IORING_OP_RECVMSG.
And also with 4c3c09439c in 5.19
for IORING_OP_SENDMSG.

However 257e84a537 introduced the critical
code into io_setup_async_msg() in 5.11.

Fixes: 7ba89d2af1 ("io_uring: ensure recv and recvmsg handle MSG_WAITALL correctly")
Fixes: 257e84a537 ("io_uring: refactor sendmsg/recvmsg iov managing")
Cc: stable@vger.kernel.org
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/b2e7be246e2fb173520862b0c7098e55767567a2.1664436949.git.metze@samba.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-24 07:22:48 +01:00
Documentation dt-bindings: phy: g12a-usb3-pcie-phy: fix compatible string documentation 2023-01-24 07:22:47 +01:00
LICENSES LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes" 2021-07-15 06:31:24 -06:00
arch x86/fpu: Use _Alignof to avoid undefined behavior in TYPE_ALIGN 2023-01-24 07:22:48 +01:00
block block: handle bio_split_to_limits() NULL return 2023-01-18 11:48:58 +01:00
certs certs/blacklist_hashes.c: fix const confusion in certs blacklist 2022-06-22 14:22:01 +02:00
crypto crypto: tcrypt - Fix multibuffer skcipher speed test mem leak 2022-12-31 13:14:24 +01:00
drivers Revert "drm/amdgpu: make display pinning more flexible (v2)" 2023-01-24 07:22:48 +01:00
fs fs/ntfs3: Fix attr_punch_hole() null pointer derenference 2023-01-24 07:22:48 +01:00
include tracing: Use alignof__(struct {type b;}) instead of offsetof() 2023-01-24 07:22:48 +01:00
init init/Kconfig: fix CC_HAS_ASM_GOTO_TIED_OUTPUT test with dash 2022-12-02 17:41:08 +01:00
io_uring io_uring/net: fix fast_iov assignment in io_setup_async_msg() 2023-01-24 07:22:48 +01:00
ipc ipc/sem: Fix dangling sem_array access in semtimedop race 2022-12-08 11:28:45 +01:00
kernel bpf: restore the ebpf program ID for BPF_AUDIT_UNLOAD and PERF_BPF_EVENT_PROG_UNLOAD 2023-01-24 07:22:46 +01:00
lib overflow: Implement size_t saturating arithmetic helpers 2022-12-31 13:14:33 +01:00
mm hugetlb: unshare some PMDs when splitting VMAs 2023-01-24 07:22:43 +01:00
net wifi: mac80211: sdata can be NULL during AMPDU start 2023-01-24 07:22:42 +01:00
samples samples: vfio-mdev: Fix missing pci_disable_device() in mdpy_fb_probe() 2022-12-31 13:14:31 +01:00
scripts scripts/faddr2line: Fix regression in name resolution on ppc64le 2022-12-08 11:28:38 +01:00
security device_cgroup: Roll back to original exceptions after copy failure 2023-01-12 11:58:59 +01:00
sound ALSA: hda/realtek: fix mute/micmute LEDs don't work for a HP platform 2023-01-24 07:22:43 +01:00
tools tools/virtio: initialize spinlocks in vring_test.c 2023-01-24 07:22:41 +01:00
usr usr/include/Makefile: add linux/nfc.h to the compile-test coverage 2022-02-01 17:27:15 +01:00
virt kvm: Add support for arch compat vm ioctls 2022-10-29 10:12:54 +02:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap mailmap: add Andrej Shadura 2021-10-18 20:22:03 -10:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Daniel Drake to credits 2021-09-21 08:34:58 +03:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS futex: Move to kernel/futex/ 2022-12-31 13:14:04 +01:00
Makefile Linux 5.15.89 2023-01-18 11:48:59 +01:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.