io_uring: fix memleak in io_sqe_files_register()

I got a memleak report when doing some fuzz test:

BUG: memory leak
unreferenced object 0x607eeac06e78 (size 8):
  comm "test", pid 295, jiffies 4294735835 (age 31.745s)
  hex dump (first 8 bytes):
    00 00 00 00 00 00 00 00                          ........
  backtrace:
    [<00000000932632e6>] percpu_ref_init+0x2a/0x1b0
    [<0000000092ddb796>] __io_uring_register+0x111d/0x22a0
    [<00000000eadd6c77>] __x64_sys_io_uring_register+0x17b/0x480
    [<00000000591b89a6>] do_syscall_64+0x56/0xa0
    [<00000000864a281d>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

Call percpu_ref_exit() on error path to avoid
refcount memleak.

Fixes: 320ac128219a ("io_uring: avoid ring quiesce for fixed file set unregister and update")
Cc: stable@vger.kernel.org
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index a9ce2e6f03ddc8a9ff810889ade924f28c232dd9..fc07baf4392a8dfdd8aeb6572eb2b314dbac5b9a 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -6699,6 +6699,7 @@ static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
                for (i = 0; i < nr_tables; i++)
                        kfree(ctx->file_data->table[i].files);
 
+               percpu_ref_exit(&ctx->file_data->refs);
                kfree(ctx->file_data->table);
                kfree(ctx->file_data);
                ctx->file_data = NULL;