From: Pavel Begunkov asml.silence@gmail.com
commit 9faadcc8abe4b83d0263216dc3a6321d5bbd616b upstream.
Once we created a file for current context during setup, we should not call io_ring_ctx_wait_and_kill() directly as it'll be done by fput(file)
Cc: stable@vger.kernel.org # 5.10 Reported-by: syzbot+c9937dfb2303a5f18640@syzkaller.appspotmail.com Signed-off-by: Pavel Begunkov asml.silence@gmail.com [axboe: fix unused 'ret' for !CONFIG_UNIX] Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/io_uring.c | 71 +++++++++++++++++++++++++++++++--------------------------- 1 file changed, 39 insertions(+), 32 deletions(-)
--- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -9195,55 +9195,52 @@ static int io_allocate_scq_urings(struct return 0; }
+static int io_uring_install_fd(struct io_ring_ctx *ctx, struct file *file) +{ + int ret, fd; + + fd = get_unused_fd_flags(O_RDWR | O_CLOEXEC); + if (fd < 0) + return fd; + + ret = io_uring_add_task_file(ctx, file); + if (ret) { + put_unused_fd(fd); + return ret; + } + fd_install(fd, file); + return fd; +} + /* * Allocate an anonymous fd, this is what constitutes the application * visible backing of an io_uring instance. The application mmaps this * fd to gain access to the SQ/CQ ring details. If UNIX sockets are enabled, * we have to tie this fd to a socket for file garbage collection purposes. */ -static int io_uring_get_fd(struct io_ring_ctx *ctx) +static struct file *io_uring_get_file(struct io_ring_ctx *ctx) { struct file *file; +#if defined(CONFIG_UNIX) int ret; - int fd;
-#if defined(CONFIG_UNIX) ret = sock_create_kern(&init_net, PF_UNIX, SOCK_RAW, IPPROTO_IP, &ctx->ring_sock); if (ret) - return ret; + return ERR_PTR(ret); #endif
- ret = get_unused_fd_flags(O_RDWR | O_CLOEXEC); - if (ret < 0) - goto err; - fd = ret; - file = anon_inode_getfile("[io_uring]", &io_uring_fops, ctx, O_RDWR | O_CLOEXEC); - if (IS_ERR(file)) { - put_unused_fd(fd); - ret = PTR_ERR(file); - goto err; - } - #if defined(CONFIG_UNIX) - ctx->ring_sock->file = file; -#endif - ret = io_uring_add_task_file(ctx, file); - if (ret) { - fput(file); - put_unused_fd(fd); - goto err; + if (IS_ERR(file)) { + sock_release(ctx->ring_sock); + ctx->ring_sock = NULL; + } else { + ctx->ring_sock->file = file; } - fd_install(fd, file); - return fd; -err: -#if defined(CONFIG_UNIX) - sock_release(ctx->ring_sock); - ctx->ring_sock = NULL; #endif - return ret; + return file; }
static int io_uring_create(unsigned entries, struct io_uring_params *p, @@ -9251,6 +9248,7 @@ static int io_uring_create(unsigned entr { struct user_struct *user = NULL; struct io_ring_ctx *ctx; + struct file *file; bool limit_mem; int ret;
@@ -9397,13 +9395,22 @@ static int io_uring_create(unsigned entr goto err; }
+ file = io_uring_get_file(ctx); + if (IS_ERR(file)) { + ret = PTR_ERR(file); + goto err; + } + /* * Install ring fd as the very last thing, so we don't risk someone * having closed it before we finish setup */ - ret = io_uring_get_fd(ctx); - if (ret < 0) - goto err; + ret = io_uring_install_fd(ctx, file); + if (ret < 0) { + /* fput will clean it up */ + fput(file); + return ret; + }
trace_io_uring_create(ret, ctx, p->sq_entries, p->cq_entries, p->flags); return ret;