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authorLinus Torvalds <torvalds@linux-foundation.org>2020-12-24 12:35:00 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2020-12-24 12:35:00 -0800
commit60e8edd2513abffdb6d4a9b5affca7f9dd5ec73d (patch)
treeedfd57fa53a3242c297e2820a5c75ee406c098ad
parent771e7e4161053e606592b9cd056ef7e2ea2316d5 (diff)
parentc07e6719511e77c4b289f62bfe96423eb6ea061d (diff)
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Merge tag 'io_uring-5.11-2020-12-23' of git://git.kernel.dk/linux-block
Pull io_uring fixes from Jens Axboe: "All straight fixes, or a prep patch for a fix, either bound for stable or fixing issues from this merge window. In particular: - Fix new shutdown op not breaking links on failure - Hold mm->mmap_sem for mm->locked_vm manipulation - Various cancelation fixes (me, Pavel) - Fix error path potential double ctx free (Pavel) - IOPOLL fixes (Xiaoguang)" * tag 'io_uring-5.11-2020-12-23' of git://git.kernel.dk/linux-block: io_uring: hold uring_lock while completing failed polled io in io_wq_submit_work() io_uring: fix double io_uring free io_uring: fix ignoring xa_store errors io_uring: end waiting before task cancel attempts io_uring: always progress task_work on task cancel io-wq: kill now unused io_wq_cancel_all() io_uring: make ctx cancel on exit targeted to actual ctx io_uring: fix 0-iov read buffer select io_uring: close a small race gap for files cancel io_uring: fix io_wqe->work_list corruption io_uring: limit {io|sq}poll submit locking scope io_uring: inline io_cqring_mark_overflow() io_uring: consolidate CQ nr events calculation io_uring: remove racy overflow list fast checks io_uring: cancel reqs shouldn't kill overflow list io_uring: hold mmap_sem for mm->locked_vm manipulation io_uring: break links on shutdown failure
-rw-r--r--fs/io-wq.c30
-rw-r--r--fs/io-wq.h3
-rw-r--r--fs/io_uring.c210
3 files changed, 120 insertions, 123 deletions
diff --git a/fs/io-wq.c b/fs/io-wq.c
index f72d53848dcb..a564f36e260c 100644
--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -36,8 +36,7 @@ enum {
enum {
IO_WQ_BIT_EXIT = 0, /* wq exiting */
- IO_WQ_BIT_CANCEL = 1, /* cancel work on list */
- IO_WQ_BIT_ERROR = 2, /* error on setup */
+ IO_WQ_BIT_ERROR = 1, /* error on setup */
};
enum {
@@ -561,12 +560,6 @@ get_next:
next_hashed = wq_next_work(work);
io_impersonate_work(worker, work);
- /*
- * OK to set IO_WQ_WORK_CANCEL even for uncancellable
- * work, the worker function will do the right thing.
- */
- if (test_bit(IO_WQ_BIT_CANCEL, &wq->state))
- work->flags |= IO_WQ_WORK_CANCEL;
old_work = work;
linked = wq->do_work(work);
@@ -732,12 +725,6 @@ static inline bool io_wqe_need_worker(struct io_wqe *wqe, int index)
return acct->nr_workers < acct->max_workers;
}
-static bool io_wqe_worker_send_sig(struct io_worker *worker, void *data)
-{
- send_sig(SIGINT, worker->task, 1);
- return false;
-}
-
/*
* Iterate the passed in list and call the specific function for each
* worker that isn't exiting
@@ -938,21 +925,6 @@ void io_wq_hash_work(struct io_wq_work *work, void *val)
work->flags |= (IO_WQ_WORK_HASHED | (bit << IO_WQ_HASH_SHIFT));
}
-void io_wq_cancel_all(struct io_wq *wq)
-{
- int node;
-
- set_bit(IO_WQ_BIT_CANCEL, &wq->state);
-
- rcu_read_lock();
- for_each_node(node) {
- struct io_wqe *wqe = wq->wqes[node];
-
- io_wq_for_each_worker(wqe, io_wqe_worker_send_sig, NULL);
- }
- rcu_read_unlock();
-}
-
struct io_cb_cancel_data {
work_cancel_fn *fn;
void *data;
diff --git a/fs/io-wq.h b/fs/io-wq.h
index 069496c6d4f9..b158f8addcf3 100644
--- a/fs/io-wq.h
+++ b/fs/io-wq.h
@@ -59,6 +59,7 @@ static inline void wq_list_add_tail(struct io_wq_work_node *node,
list->last->next = node;
list->last = node;
}
+ node->next = NULL;
}
static inline void wq_list_cut(struct io_wq_work_list *list,
@@ -128,8 +129,6 @@ static inline bool io_wq_is_hashed(struct io_wq_work *work)
return work->flags & IO_WQ_WORK_HASHED;
}
-void io_wq_cancel_all(struct io_wq *wq);
-
typedef bool (work_cancel_fn)(struct io_wq_work *, void *);
enum io_wq_cancel io_wq_cancel_cb(struct io_wq *wq, work_cancel_fn *cancel,
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 6f9392c35eef..7e35283fc0b1 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1693,6 +1693,11 @@ static inline bool io_should_trigger_evfd(struct io_ring_ctx *ctx)
return io_wq_current_is_worker();
}
+static inline unsigned __io_cqring_events(struct io_ring_ctx *ctx)
+{
+ return ctx->cached_cq_tail - READ_ONCE(ctx->rings->cq.head);
+}
+
static void io_cqring_ev_posted(struct io_ring_ctx *ctx)
{
if (waitqueue_active(&ctx->wait))
@@ -1703,15 +1708,6 @@ static void io_cqring_ev_posted(struct io_ring_ctx *ctx)
eventfd_signal(ctx->cq_ev_fd, 1);
}
-static void io_cqring_mark_overflow(struct io_ring_ctx *ctx)
-{
- if (list_empty(&ctx->cq_overflow_list)) {
- clear_bit(0, &ctx->sq_check_overflow);
- clear_bit(0, &ctx->cq_check_overflow);
- ctx->rings->sq_flags &= ~IORING_SQ_CQ_OVERFLOW;
- }
-}
-
/* Returns true if there are no backlogged entries after the flush */
static bool io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool force,
struct task_struct *tsk,
@@ -1721,23 +1717,13 @@ static bool io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool force,
struct io_kiocb *req, *tmp;
struct io_uring_cqe *cqe;
unsigned long flags;
+ bool all_flushed;
LIST_HEAD(list);
- if (!force) {
- if (list_empty_careful(&ctx->cq_overflow_list))
- return true;
- if ((ctx->cached_cq_tail - READ_ONCE(rings->cq.head) ==
- rings->cq_ring_entries))
- return false;
- }
+ if (!force && __io_cqring_events(ctx) == rings->cq_ring_entries)
+ return false;
spin_lock_irqsave(&ctx->completion_lock, flags);
-
- /* if force is set, the ring is going away. always drop after that */
- if (force)
- ctx->cq_overflow_flushed = 1;
-
- cqe = NULL;
list_for_each_entry_safe(req, tmp, &ctx->cq_overflow_list, compl.list) {
if (!io_match_task(req, tsk, files))
continue;
@@ -1758,9 +1744,14 @@ static bool io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool force,
}
}
- io_commit_cqring(ctx);
- io_cqring_mark_overflow(ctx);
+ all_flushed = list_empty(&ctx->cq_overflow_list);
+ if (all_flushed) {
+ clear_bit(0, &ctx->sq_check_overflow);
+ clear_bit(0, &ctx->cq_check_overflow);
+ ctx->rings->sq_flags &= ~IORING_SQ_CQ_OVERFLOW;
+ }
+ io_commit_cqring(ctx);
spin_unlock_irqrestore(&ctx->completion_lock, flags);
io_cqring_ev_posted(ctx);
@@ -1770,7 +1761,7 @@ static bool io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool force,
io_put_req(req);
}
- return cqe != NULL;
+ return all_flushed;
}
static void __io_cqring_fill_event(struct io_kiocb *req, long res, long cflags)
@@ -2320,8 +2311,6 @@ static void io_double_put_req(struct io_kiocb *req)
static unsigned io_cqring_events(struct io_ring_ctx *ctx, bool noflush)
{
- struct io_rings *rings = ctx->rings;
-
if (test_bit(0, &ctx->cq_check_overflow)) {
/*
* noflush == true is from the waitqueue handler, just ensure
@@ -2336,7 +2325,7 @@ static unsigned io_cqring_events(struct io_ring_ctx *ctx, bool noflush)
/* See comment at the top of this file */
smp_rmb();
- return ctx->cached_cq_tail - READ_ONCE(rings->cq.head);
+ return __io_cqring_events(ctx);
}
static inline unsigned int io_sqring_entries(struct io_ring_ctx *ctx)
@@ -3136,9 +3125,7 @@ static ssize_t io_iov_buffer_select(struct io_kiocb *req, struct iovec *iov,
iov[0].iov_len = kbuf->len;
return 0;
}
- if (!req->rw.len)
- return 0;
- else if (req->rw.len > 1)
+ if (req->rw.len != 1)
return -EINVAL;
#ifdef CONFIG_COMPAT
@@ -3784,6 +3771,8 @@ static int io_shutdown(struct io_kiocb *req, bool force_nonblock)
return -ENOTSOCK;
ret = __sys_shutdown_sock(sock, req->shutdown.how);
+ if (ret < 0)
+ req_set_fail_links(req);
io_req_complete(req, ret);
return 0;
#else
@@ -6107,15 +6096,15 @@ static void io_req_drop_files(struct io_kiocb *req)
struct io_uring_task *tctx = req->task->io_uring;
unsigned long flags;
+ put_files_struct(req->work.identity->files);
+ put_nsproxy(req->work.identity->nsproxy);
spin_lock_irqsave(&ctx->inflight_lock, flags);
list_del(&req->inflight_entry);
- if (atomic_read(&tctx->in_idle))
- wake_up(&tctx->wait);
spin_unlock_irqrestore(&ctx->inflight_lock, flags);
req->flags &= ~REQ_F_INFLIGHT;
- put_files_struct(req->work.identity->files);
- put_nsproxy(req->work.identity->nsproxy);
req->work.flags &= ~IO_WQ_WORK_FILES;
+ if (atomic_read(&tctx->in_idle))
+ wake_up(&tctx->wait);
}
static void __io_clean_op(struct io_kiocb *req)
@@ -6343,19 +6332,28 @@ static struct io_wq_work *io_wq_submit_work(struct io_wq_work *work)
}
if (ret) {
+ struct io_ring_ctx *lock_ctx = NULL;
+
+ if (req->ctx->flags & IORING_SETUP_IOPOLL)
+ lock_ctx = req->ctx;
+
/*
- * io_iopoll_complete() does not hold completion_lock to complete
- * polled io, so here for polled io, just mark it done and still let
- * io_iopoll_complete() complete it.
+ * io_iopoll_complete() does not hold completion_lock to
+ * complete polled io, so here for polled io, we can not call
+ * io_req_complete() directly, otherwise there maybe concurrent
+ * access to cqring, defer_list, etc, which is not safe. Given
+ * that io_iopoll_complete() is always called under uring_lock,
+ * so here for polled io, we also get uring_lock to complete
+ * it.
*/
- if (req->ctx->flags & IORING_SETUP_IOPOLL) {
- struct kiocb *kiocb = &req->rw.kiocb;
+ if (lock_ctx)
+ mutex_lock(&lock_ctx->uring_lock);
- kiocb_done(kiocb, ret, NULL);
- } else {
- req_set_fail_links(req);
- io_req_complete(req, ret);
- }
+ req_set_fail_links(req);
+ io_req_complete(req, ret);
+
+ if (lock_ctx)
+ mutex_unlock(&lock_ctx->uring_lock);
}
return io_steal_work(req);
@@ -6824,8 +6822,7 @@ static int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr)
/* if we have a backlog and couldn't flush it all, return BUSY */
if (test_bit(0, &ctx->sq_check_overflow)) {
- if (!list_empty(&ctx->cq_overflow_list) &&
- !io_cqring_overflow_flush(ctx, false, NULL, NULL))
+ if (!io_cqring_overflow_flush(ctx, false, NULL, NULL))
return -EBUSY;
}
@@ -8155,10 +8152,13 @@ static void io_unaccount_mem(struct io_ring_ctx *ctx, unsigned long nr_pages,
__io_unaccount_mem(ctx->user, nr_pages);
if (ctx->mm_account) {
- if (acct == ACCT_LOCKED)
+ if (acct == ACCT_LOCKED) {
+ mmap_write_lock(ctx->mm_account);
ctx->mm_account->locked_vm -= nr_pages;
- else if (acct == ACCT_PINNED)
+ mmap_write_unlock(ctx->mm_account);
+ }else if (acct == ACCT_PINNED) {
atomic64_sub(nr_pages, &ctx->mm_account->pinned_vm);
+ }
}
}
@@ -8174,10 +8174,13 @@ static int io_account_mem(struct io_ring_ctx *ctx, unsigned long nr_pages,
}
if (ctx->mm_account) {
- if (acct == ACCT_LOCKED)
+ if (acct == ACCT_LOCKED) {
+ mmap_write_lock(ctx->mm_account);
ctx->mm_account->locked_vm += nr_pages;
- else if (acct == ACCT_PINNED)
+ mmap_write_unlock(ctx->mm_account);
+ } else if (acct == ACCT_PINNED) {
atomic64_add(nr_pages, &ctx->mm_account->pinned_vm);
+ }
}
return 0;
@@ -8643,10 +8646,19 @@ static void io_ring_exit_work(struct work_struct *work)
io_ring_ctx_free(ctx);
}
+static bool io_cancel_ctx_cb(struct io_wq_work *work, void *data)
+{
+ struct io_kiocb *req = container_of(work, struct io_kiocb, work);
+
+ return req->ctx == data;
+}
+
static void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx)
{
mutex_lock(&ctx->uring_lock);
percpu_ref_kill(&ctx->refs);
+ /* if force is set, the ring is going away. always drop after that */
+ ctx->cq_overflow_flushed = 1;
if (ctx->rings)
io_cqring_overflow_flush(ctx, true, NULL, NULL);
mutex_unlock(&ctx->uring_lock);
@@ -8655,7 +8667,7 @@ static void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx)
io_poll_remove_all(ctx, NULL, NULL);
if (ctx->io_wq)
- io_wq_cancel_all(ctx->io_wq);
+ io_wq_cancel_cb(ctx->io_wq, io_cancel_ctx_cb, ctx, true);
/* if we failed setting up the ctx, we might not have any rings */
io_iopoll_try_reap_events(ctx);
@@ -8798,9 +8810,9 @@ static void __io_uring_cancel_task_requests(struct io_ring_ctx *ctx,
ret |= io_poll_remove_all(ctx, task, NULL);
ret |= io_kill_timeouts(ctx, task, NULL);
+ ret |= io_run_task_work();
if (!ret)
break;
- io_run_task_work();
cond_resched();
}
}
@@ -8849,10 +8861,9 @@ static void io_uring_cancel_task_requests(struct io_ring_ctx *ctx,
static int io_uring_add_task_file(struct io_ring_ctx *ctx, struct file *file)
{
struct io_uring_task *tctx = current->io_uring;
+ int ret;
if (unlikely(!tctx)) {
- int ret;
-
ret = io_uring_alloc_task_context(current);
if (unlikely(ret))
return ret;
@@ -8863,7 +8874,12 @@ static int io_uring_add_task_file(struct io_ring_ctx *ctx, struct file *file)
if (!old) {
get_file(file);
- xa_store(&tctx->xa, (unsigned long)file, file, GFP_KERNEL);
+ ret = xa_err(xa_store(&tctx->xa, (unsigned long)file,
+ file, GFP_KERNEL));
+ if (ret) {
+ fput(file);
+ return ret;
+ }
}
tctx->last = file;
}
@@ -8986,9 +9002,9 @@ void __io_uring_task_cancel(void)
if (inflight != tctx_inflight(tctx))
continue;
schedule();
+ finish_wait(&tctx->wait, &wait);
} while (1);
- finish_wait(&tctx->wait, &wait);
atomic_dec(&tctx->in_idle);
}
@@ -9156,10 +9172,13 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit,
*/
ret = 0;
if (ctx->flags & IORING_SETUP_SQPOLL) {
- io_ring_submit_lock(ctx, (ctx->flags & IORING_SETUP_IOPOLL));
- if (!list_empty_careful(&ctx->cq_overflow_list))
+ if (!list_empty_careful(&ctx->cq_overflow_list)) {
+ bool needs_lock = ctx->flags & IORING_SETUP_IOPOLL;
+
+ io_ring_submit_lock(ctx, needs_lock);
io_cqring_overflow_flush(ctx, false, NULL, NULL);
- io_ring_submit_unlock(ctx, (ctx->flags & IORING_SETUP_IOPOLL));
+ io_ring_submit_unlock(ctx, needs_lock);
+ }
if (flags & IORING_ENTER_SQ_WAKEUP)
wake_up(&ctx->sq_data->wait);
if (flags & IORING_ENTER_SQ_WAIT)
@@ -9369,55 +9388,52 @@ static int io_allocate_scq_urings(struct io_ring_ctx *ctx,
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,
@@ -9425,6 +9441,7 @@ static int io_uring_create(unsigned entries, struct io_uring_params *p,
{
struct user_struct *user = NULL;
struct io_ring_ctx *ctx;
+ struct file *file;
bool limit_mem;
int ret;
@@ -9572,13 +9589,22 @@ static int io_uring_create(unsigned entries, struct io_uring_params *p,
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;