18414a4a2e
syzbot reports that recv is using an uninitialized value: ===================================================== BUG: KMSAN: uninit-value in io_req_cqe_overflow io_uring/io_uring.c:810 [inline] BUG: KMSAN: uninit-value in io_req_complete_post io_uring/io_uring.c:937 [inline] BUG: KMSAN: uninit-value in io_issue_sqe+0x1f1b/0x22c0 io_uring/io_uring.c:1763 io_req_cqe_overflow io_uring/io_uring.c:810 [inline] io_req_complete_post io_uring/io_uring.c:937 [inline] io_issue_sqe+0x1f1b/0x22c0 io_uring/io_uring.c:1763 io_wq_submit_work+0xa17/0xeb0 io_uring/io_uring.c:1860 io_worker_handle_work+0xc04/0x2000 io_uring/io-wq.c:597 io_wq_worker+0x447/0x1410 io_uring/io-wq.c:651 ret_from_fork+0x6d/0x90 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Uninit was stored to memory at: io_req_set_res io_uring/io_uring.h:215 [inline] io_recv_finish+0xf10/0x1560 io_uring/net.c:861 io_recv+0x12ec/0x1ea0 io_uring/net.c:1175 io_issue_sqe+0x429/0x22c0 io_uring/io_uring.c:1751 io_wq_submit_work+0xa17/0xeb0 io_uring/io_uring.c:1860 io_worker_handle_work+0xc04/0x2000 io_uring/io-wq.c:597 io_wq_worker+0x447/0x1410 io_uring/io-wq.c:651 ret_from_fork+0x6d/0x90 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Uninit was created at: slab_post_alloc_hook mm/slub.c:3877 [inline] slab_alloc_node mm/slub.c:3918 [inline] __do_kmalloc_node mm/slub.c:4038 [inline] __kmalloc+0x6e4/0x1060 mm/slub.c:4052 kmalloc include/linux/slab.h:632 [inline] io_alloc_async_data+0xc0/0x220 io_uring/io_uring.c:1662 io_msg_alloc_async io_uring/net.c:166 [inline] io_recvmsg_prep_setup io_uring/net.c:725 [inline] io_recvmsg_prep+0xbe8/0x1a20 io_uring/net.c:806 io_init_req io_uring/io_uring.c:2135 [inline] io_submit_sqe io_uring/io_uring.c:2182 [inline] io_submit_sqes+0x1135/0x2f10 io_uring/io_uring.c:2335 __do_sys_io_uring_enter io_uring/io_uring.c:3246 [inline] __se_sys_io_uring_enter+0x40f/0x3c80 io_uring/io_uring.c:3183 __x64_sys_io_uring_enter+0x11f/0x1a0 io_uring/io_uring.c:3183 x64_sys_call+0x2c0/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:427 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f which appears to be io_recv_finish() reading kmsg->msg.msg_inq to decide if it needs to set IORING_CQE_F_SOCK_NONEMPTY or not. If the recv is entered with buffer selection, but no buffer is available, then we jump error path which calls io_recv_finish() without having assigned kmsg->msg_inq. This might cause an errant setting of the NONEMPTY flag for a request get gets errored with -ENOBUFS. Reported-by: syzbot+b1647099e82b3b349fbf@syzkaller.appspotmail.com Fixes: 4a3223f7bfda ("io_uring/net: switch io_recv() to using io_async_msghdr") Signed-off-by: Jens Axboe <axboe@kernel.dk>
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 reStructuredText 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.