[PATCH 0/1] MR7640: server: Fall back to epoll_wait if epoll_pwait2 doesn't work

[Alfred Agrell (＠Alcaro)]

Fixes hangs if Wine is built with newer headers than kernel

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/7640

[PATCH 1/1] server: Fall back to epoll_wait if epoll_pwait2 doesn't work

[Alfred Agrell]

From: Alfred Agrell <floating(a)muncher.se>

Fixes: 87ca5db40e2c1b37423bdc25101a5c5e39e67e6f
---
 server/fd.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/server/fd.c b/server/fd.c
index e1b969a0439..7324283b818 100644
--- a/server/fd.c
+++ b/server/fd.c
@@ -566,6 +566,9 @@ static inline void main_loop_epoll(void)
     int i, ret, timeout;
     struct timespec ts;
     struct epoll_event events[128];
+#ifdef HAVE_EPOLL_PWAIT2
+    static int failed_epoll_pwait2 = 0;
+#endif
 
     assert( POLLIN == EPOLLIN );
     assert( POLLOUT == EPOLLOUT );
@@ -582,10 +585,15 @@ static inline void main_loop_epoll(void)
         if (epoll_fd == -1) break;  /* an error occurred with epoll */
 
 #ifdef HAVE_EPOLL_PWAIT2
-        ret = epoll_pwait2( epoll_fd, events, ARRAY_SIZE( events ), timeout == -1 ? NULL : &ts, NULL );
-#else
-        ret = epoll_wait( epoll_fd, events, ARRAY_SIZE( events ), timeout );
+        if (!failed_epoll_pwait2)
+        {
+            ret = epoll_pwait2( epoll_fd, events, ARRAY_SIZE( events ), timeout == -1 ? NULL : &ts, NULL );
+            if (ret == -1 && errno == -ENOSYS)
+                failed_epoll_pwait2 = 1;
+        }
+        if (failed_epoll_pwait2)
 #endif
+            ret = epoll_wait( epoll_fd, events, ARRAY_SIZE( events ), timeout );
 
         set_current_time();
 
-- 
GitLab

https://gitlab.winehq.org/wine/wine/-/merge_requests/7640

[Alfred Agrell (＠Alcaro)]

cc @whrvt, you introduced this syscall (!7392)

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/7640#note_98716