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authorLinus Torvalds <torvalds@linux-foundation.org>2021-11-27 11:28:37 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2021-11-27 11:28:37 -0800
commit86799cdfbcd2308cbad6c1dc983b81595b77b639 (patch)
tree821c50b6d4c16169b947e3157ba368cd9ce65083
parent650c8edf53f7ae2d3ebdd0bf64b7b7fd821bd75b (diff)
parentf6223ff799666235a80d05f8137b73e5580077b9 (diff)
Merge tag 'io_uring-5.16-2021-11-27' of git://git.kernel.dk/linux-block
Pull more io_uring fixes from Jens Axboe: "The locking fixup that was applied earlier this rc has both a deadlock and IRQ safety issue, let's get that ironed out before -rc3. This contains: - Link traversal locking fix (Pavel) - Cancelation fix (Pavel) - Relocate cond_resched() for huge buffer chain freeing, avoiding a softlockup warning (Ye) - Fix timespec validation (Ye)" * tag 'io_uring-5.16-2021-11-27' of git://git.kernel.dk/linux-block: io_uring: Fix undefined-behaviour in io_issue_sqe io_uring: fix soft lockup when call __io_remove_buffers io_uring: fix link traversal locking io_uring: fail cancellation for EXITING tasks
-rw-r--r--fs/io_uring.c73
1 files changed, 50 insertions, 23 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c
index a4c508a1e0cf..c4f217613f56 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1278,6 +1278,7 @@ static void io_refs_resurrect(struct percpu_ref *ref, struct completion *compl)
static bool io_match_task(struct io_kiocb *head, struct task_struct *task,
bool cancel_all)
+ __must_hold(&req->ctx->timeout_lock)
{
struct io_kiocb *req;
@@ -1293,6 +1294,44 @@ static bool io_match_task(struct io_kiocb *head, struct task_struct *task,
return false;
}
+static bool io_match_linked(struct io_kiocb *head)
+{
+ struct io_kiocb *req;
+
+ io_for_each_link(req, head) {
+ if (req->flags & REQ_F_INFLIGHT)
+ return true;
+ }
+ return false;
+}
+
+/*
+ * As io_match_task() but protected against racing with linked timeouts.
+ * User must not hold timeout_lock.
+ */
+static bool io_match_task_safe(struct io_kiocb *head, struct task_struct *task,
+ bool cancel_all)
+{
+ bool matched;
+
+ if (task && head->task != task)
+ return false;
+ if (cancel_all)
+ return true;
+
+ if (head->flags & REQ_F_LINK_TIMEOUT) {
+ struct io_ring_ctx *ctx = head->ctx;
+
+ /* protect against races with linked timeouts */
+ spin_lock_irq(&ctx->timeout_lock);
+ matched = io_match_linked(head);
+ spin_unlock_irq(&ctx->timeout_lock);
+ } else {
+ matched = io_match_linked(head);
+ }
+ return matched;
+}
+
static inline bool req_has_async_data(struct io_kiocb *req)
{
return req->flags & REQ_F_ASYNC_DATA;
@@ -4327,6 +4366,7 @@ static int __io_remove_buffers(struct io_ring_ctx *ctx, struct io_buffer *buf,
kfree(nxt);
if (++i == nbufs)
return i;
+ cond_resched();
}
i++;
kfree(buf);
@@ -5699,17 +5739,15 @@ static __cold bool io_poll_remove_all(struct io_ring_ctx *ctx,
int posted = 0, i;
spin_lock(&ctx->completion_lock);
- spin_lock_irq(&ctx->timeout_lock);
for (i = 0; i < (1U << ctx->cancel_hash_bits); i++) {
struct hlist_head *list;
list = &ctx->cancel_hash[i];
hlist_for_each_entry_safe(req, tmp, list, hash_node) {
- if (io_match_task(req, tsk, cancel_all))
+ if (io_match_task_safe(req, tsk, cancel_all))
posted += io_poll_remove_one(req);
}
}
- spin_unlock_irq(&ctx->timeout_lock);
spin_unlock(&ctx->completion_lock);
if (posted)
@@ -6158,6 +6196,9 @@ static int io_timeout_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe,
if (get_timespec64(&data->ts, u64_to_user_ptr(sqe->addr)))
return -EFAULT;
+ if (data->ts.tv_sec < 0 || data->ts.tv_nsec < 0)
+ return -EINVAL;
+
data->mode = io_translate_timeout_mode(flags);
hrtimer_init(&data->timer, io_timeout_get_clock(data), data->mode);
@@ -6882,10 +6923,11 @@ static inline struct file *io_file_get(struct io_ring_ctx *ctx,
static void io_req_task_link_timeout(struct io_kiocb *req, bool *locked)
{
struct io_kiocb *prev = req->timeout.prev;
- int ret;
+ int ret = -ENOENT;
if (prev) {
- ret = io_try_cancel_userdata(req, prev->user_data);
+ if (!(req->task->flags & PF_EXITING))
+ ret = io_try_cancel_userdata(req, prev->user_data);
io_req_complete_post(req, ret ?: -ETIME, 0);
io_put_req(prev);
} else {
@@ -9257,10 +9299,8 @@ static void io_destroy_buffers(struct io_ring_ctx *ctx)
struct io_buffer *buf;
unsigned long index;
- xa_for_each(&ctx->io_buffers, index, buf) {
+ xa_for_each(&ctx->io_buffers, index, buf)
__io_remove_buffers(ctx, buf, index, -1U);
- cond_resched();
- }
}
static void io_req_caches_free(struct io_ring_ctx *ctx)
@@ -9564,19 +9604,8 @@ static bool io_cancel_task_cb(struct io_wq_work *work, void *data)
{
struct io_kiocb *req = container_of(work, struct io_kiocb, work);
struct io_task_cancel *cancel = data;
- bool ret;
-
- if (!cancel->all && (req->flags & REQ_F_LINK_TIMEOUT)) {
- struct io_ring_ctx *ctx = req->ctx;
- /* protect against races with linked timeouts */
- spin_lock_irq(&ctx->timeout_lock);
- ret = io_match_task(req, cancel->task, cancel->all);
- spin_unlock_irq(&ctx->timeout_lock);
- } else {
- ret = io_match_task(req, cancel->task, cancel->all);
- }
- return ret;
+ return io_match_task_safe(req, cancel->task, cancel->all);
}
static __cold bool io_cancel_defer_files(struct io_ring_ctx *ctx,
@@ -9587,14 +9616,12 @@ static __cold bool io_cancel_defer_files(struct io_ring_ctx *ctx,
LIST_HEAD(list);
spin_lock(&ctx->completion_lock);
- spin_lock_irq(&ctx->timeout_lock);
list_for_each_entry_reverse(de, &ctx->defer_list, list) {
- if (io_match_task(de->req, task, cancel_all)) {
+ if (io_match_task_safe(de->req, task, cancel_all)) {
list_cut_position(&list, &ctx->defer_list, &de->list);
break;
}
}
- spin_unlock_irq(&ctx->timeout_lock);
spin_unlock(&ctx->completion_lock);
if (list_empty(&list))
return false;