uml: DEBUG_SHIRQ fixes
DEBUG_SHIRQ generates spurious interrupts, triggering handlers such as
mconsole_interrupt() or line_interrupt(). They expect data to be available to
be read from their sockets/pipes, but in the case of spurious interrupts, the
host didn't actually send anything, so UML hangs in read() and friends.
Setting those fd's as O_NONBLOCK makes DEBUG_SHIRQ-enabled UML kernels boot
and run correctly.
Signed-off-by: Eduard-Gabriel Munteanu <maxdamage@aladin.ro>
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/um/drivers/mconsole_user.c b/arch/um/drivers/mconsole_user.c
index 62e5ad6..f31e715 100644
--- a/arch/um/drivers/mconsole_user.c
+++ b/arch/um/drivers/mconsole_user.c
@@ -86,8 +86,9 @@
int len;
req->originlen = sizeof(req->origin);
- req->len = recvfrom(fd, &req->request, sizeof(req->request), 0,
- (struct sockaddr *) req->origin, &req->originlen);
+ req->len = recvfrom(fd, &req->request, sizeof(req->request),
+ MSG_DONTWAIT, (struct sockaddr *) req->origin,
+ &req->originlen);
if (req->len < 0)
return 0;