io_uring: make sure openat/openat2 honor rlimit nofile
Dmitry reports that a test case shows that io_uring isn't honoring a
modified rlimit nofile setting. get_unused_fd_flags() checks the task
signal->rlimi[] for the limits. As this isn't easily inheritable,
provide a __get_unused_fd_flags() that takes the value instead. Then we
can grab it when the request is prepared (from the original task), and
pass that in when we do the async part part of the open.
Reported-by: Dmitry Kadashev <dkadashev@gmail.com>
Tested-by: Dmitry Kadashev <dkadashev@gmail.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/fs/file.c b/fs/file.c
index a364e1a..c8a4e4c 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -540,9 +540,14 @@ static int alloc_fd(unsigned start, unsigned flags)
return __alloc_fd(current->files, start, rlimit(RLIMIT_NOFILE), flags);
}
+int __get_unused_fd_flags(unsigned flags, unsigned long nofile)
+{
+ return __alloc_fd(current->files, 0, nofile, flags);
+}
+
int get_unused_fd_flags(unsigned flags)
{
- return __alloc_fd(current->files, 0, rlimit(RLIMIT_NOFILE), flags);
+ return __get_unused_fd_flags(flags, rlimit(RLIMIT_NOFILE));
}
EXPORT_SYMBOL(get_unused_fd_flags);
diff --git a/fs/io_uring.c b/fs/io_uring.c
index b1fbc44..fe5ded7 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -397,6 +397,7 @@ struct io_open {
struct filename *filename;
struct statx __user *buffer;
struct open_how how;
+ unsigned long nofile;
};
struct io_files_update {
@@ -2577,6 +2578,7 @@ static int io_openat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
return ret;
}
+ req->open.nofile = rlimit(RLIMIT_NOFILE);
req->flags |= REQ_F_NEED_CLEANUP;
return 0;
}
@@ -2618,6 +2620,7 @@ static int io_openat2_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
return ret;
}
+ req->open.nofile = rlimit(RLIMIT_NOFILE);
req->flags |= REQ_F_NEED_CLEANUP;
return 0;
}
@@ -2636,7 +2639,7 @@ static int io_openat2(struct io_kiocb *req, struct io_kiocb **nxt,
if (ret)
goto err;
- ret = get_unused_fd_flags(req->open.how.flags);
+ ret = __get_unused_fd_flags(req->open.how.flags, req->open.nofile);
if (ret < 0)
goto err;