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io_uring-5.11-2020-12-23

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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
This commit is contained in:
Linus Torvalds 2020-12-24 12:35:00 -08:00
commit 60e8edd251
3 changed files with 125 additions and 128 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

30
fs/io-wq.c
View File

@ -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;

3
fs/io-wq.h
View File

@ -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,

220
fs/io_uring.c
View File

@ -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;
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);
spin_lock_irqsave(&ctx->inflight_lock, flags);
list_del(&req->inflight_entry);
spin_unlock_irqrestore(&ctx->inflight_lock, flags);
req->flags &= ~REQ_F_INFLIGHT;
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) {
/*
* 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.
*/
if (req->ctx->flags & IORING_SETUP_IOPOLL) {
struct kiocb *kiocb = &req->rw.kiocb;
struct io_ring_ctx *lock_ctx = NULL;
kiocb_done(kiocb, ret, NULL);
} else {
req_set_fail_links(req);
io_req_complete(req, ret);
}
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, 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 (lock_ctx)
mutex_lock(&lock_ctx->uring_lock);
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;
int ret;
int fd;
#if defined(CONFIG_UNIX)
int ret;
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 defined(CONFIG_UNIX)
if (IS_ERR(file)) {
put_unused_fd(fd);
ret = PTR_ERR(file);
goto err;
sock_release(ctx->ring_sock);
ctx->ring_sock = NULL;
} else {
ctx->ring_sock->file = file;
}
#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;
}
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;