io_uring/rsrc: fix rogue rsrc node grabbing

We should not be looking at ctx->rsrc_node and anyhow modifying the node
without holding uring_lock, grabbing references in such a way is not
safe either.

Cc: stable@vger.kernel.org
Fixes: 5106dd6e74ab6 ("io_uring: propagate issue_flags state down to file assignment")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/1202ede2d7bb90136e3482b2b84aad9ed483e5d6.1680098433.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/io_uring/rsrc.h b/io_uring/rsrc.h
index 2b87436..f27f497 100644 (file)
--- a/io_uring/rsrc.h
+++ b/io_uring/rsrc.h
@@ -144,15 +144,13 @@ static inline void io_req_set_rsrc_node(struct io_kiocb *req,
                                        unsigned int issue_flags)
 {
        if (!req->rsrc_node) {
-               req->rsrc_node = ctx->rsrc_node;
+               io_ring_submit_lock(ctx, issue_flags);
 
-               if (!(issue_flags & IO_URING_F_UNLOCKED)) {
-                       lockdep_assert_held(&ctx->uring_lock);
+               lockdep_assert_held(&ctx->uring_lock);
 
-                       io_charge_rsrc_node(ctx);
-               } else {
-                       percpu_ref_get(&req->rsrc_node->refs);
-               }
+               req->rsrc_node = ctx->rsrc_node;
+               io_charge_rsrc_node(ctx);
+               io_ring_submit_unlock(ctx, issue_flags);
        }
 }