io_uring: fix big-endian compat signal mask handling

On big-endian architectures, the signal masks are differnet
between 32-bit and 64-bit tasks, so we have to use a different
function for reading them from user space.

io_cqring_wait() initially got this wrong, and always interprets
this as a native structure. This is ok on x86 and most arm64,
but not on s390, ppc64be, mips64be, sparc64 and parisc.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 6aaa305..8f48d29 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1968,7 +1968,15 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
                return 0;
 
        if (sig) {
-               ret = set_user_sigmask(sig, &ksigmask, &sigsaved, sigsz);
+#ifdef CONFIG_COMPAT
+               if (in_compat_syscall())
+                       ret = set_compat_user_sigmask((const compat_sigset_t __user *)sig,
+                                                     &ksigmask, &sigsaved, sigsz);
+               else
+#endif
+                       ret = set_user_sigmask(sig, &ksigmask,
+                                              &sigsaved, sigsz);
+
                if (ret)
                        return ret;
        }