io_uring: fix removing the wrong file in __io_sqe_files_update()

Index here is already the position of the file in fixed_file_table, we
should not use io_file_from_index() again to get it. Otherwise, the
wrong file which still in use may be released unexpectedly.

Cc: stable@vger.kernel.org # v5.6
Fixes: 05f3fb3c5397 ("io_uring: avoid ring quiesce for fixed file set unregister and update")
Signed-off-by: Jiufei Xue <jiufei.xue@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 852c2eaf1a9ac77514b21fc430952bda53c39705..a06b562890394463183527aceb5e9b460567088b 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -7324,7 +7324,7 @@ static int __io_sqe_files_update(struct io_ring_ctx *ctx,
                table = &ctx->file_data->table[i >> IORING_FILE_TABLE_SHIFT];
                index = i & IORING_FILE_TABLE_MASK;
                if (table->files[index]) {
-                       file = io_file_from_index(ctx, index);
+                       file = table->files[index];
                        err = io_queue_file_removal(data, file);
                        if (err)
                                break;