backport "io_uring: fix race between timeout flush and removal"

[pve-kernel.git] / patches / kernel / 0014-io_uring-fix-race-between-timeout-flush-and-removal.patch

diff --git a/patches/kernel/0014-io_uring-fix-race-between-timeout-flush-and-removal.patch b/patches/kernel/0014-io_uring-fix-race-between-timeout-flush-and-removal.patch
new file mode 100644 (file)
index 0000000..d029e3f
--- /dev/null
+++ b/patches/kernel/0014-io_uring-fix-race-between-timeout-flush-and-removal.patch
@@ -0,0 +1,57 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Jens Axboe <axboe@kernel.dk>
+Date: Fri, 8 Apr 2022 11:08:58 -0600
+Subject: [PATCH] io_uring: fix race between timeout flush and removal
+
+commit e677edbcabee849bfdd43f1602bccbecf736a646 upstream.
+
+io_flush_timeouts() assumes the timeout isn't in progress of triggering
+or being removed/canceled, so it unconditionally removes it from the
+timeout list and attempts to cancel it.
+
+Leave it on the list and let the normal timeout cancelation take care
+of it.
+
+Cc: stable@vger.kernel.org # 5.5+
+Signed-off-by: Jens Axboe <axboe@kernel.dk>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
+---
+ fs/io_uring.c | 7 +++----
+ 1 file changed, 3 insertions(+), 4 deletions(-)
+
+diff --git a/fs/io_uring.c b/fs/io_uring.c
+index 156c54ebb62b..367b7ba2fcb0 100644
+--- a/fs/io_uring.c
++++ b/fs/io_uring.c
+@@ -1546,12 +1546,11 @@ static void io_flush_timeouts(struct io_ring_ctx *ctx)
+       __must_hold(&ctx->completion_lock)
+ {
+       u32 seq = ctx->cached_cq_tail - atomic_read(&ctx->cq_timeouts);
++      struct io_kiocb *req, *tmp;
+ 
+       spin_lock_irq(&ctx->timeout_lock);
+-      while (!list_empty(&ctx->timeout_list)) {
++      list_for_each_entry_safe(req, tmp, &ctx->timeout_list, timeout.list) {
+               u32 events_needed, events_got;
+-              struct io_kiocb *req = list_first_entry(&ctx->timeout_list,
+-                                              struct io_kiocb, timeout.list);
+ 
+               if (io_is_timeout_noseq(req))
+                       break;
+@@ -1568,7 +1567,6 @@ static void io_flush_timeouts(struct io_ring_ctx *ctx)
+               if (events_got < events_needed)
+                       break;
+ 
+-              list_del_init(&req->timeout.list);
+               io_kill_timeout(req, 0);
+       }
+       ctx->cq_last_tm_flush = seq;
+@@ -6209,6 +6207,7 @@ 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;
+ 
++      INIT_LIST_HEAD(&req->timeout.list);
+       data->mode = io_translate_timeout_mode(flags);
+       hrtimer_init(&data->timer, io_timeout_get_clock(data), data->mode);
+