From: Eduard-Gabriel Munteanu <[email protected]>
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.
The patch was written and tested on Linux 2.6.22-rc2-mm1.
I have also included a couple of short/minor fixes for potential
problems.
Signed-off-by: Eduard-Gabriel Munteanu <[email protected]>
Signed-off-by: Jeff Dike <[email protected]>
--
arch/um/drivers/chan_user.c | 8 +++++++-
arch/um/drivers/mconsole_user.c | 5 +++--
arch/um/drivers/ubd_user.c | 6 ++++++
arch/um/drivers/xterm.c | 7 +++++++
4 files changed, 23 insertions(+), 3 deletions(-)
Index: linux-2.6.21-mm/arch/um/drivers/chan_user.c
===================================================================
--- linux-2.6.21-mm.orig/arch/um/drivers/chan_user.c 2007-06-06 09:28:13.000000000 -0400
+++ linux-2.6.21-mm/arch/um/drivers/chan_user.c 2007-06-11 13:51:29.000000000 -0400
@@ -170,7 +170,13 @@ static int winch_tramp(int fd, struct tt
err = -EINVAL;
goto out_close;
}
- return err ;
+
+ if (os_set_fd_block(*fd_out, 0)) {
+ printk("winch_tramp: failed to set thread_fd non-blocking.\n");
+ goto out_close;
+ }
+
+ return err;
out_close:
os_close_file(fds[1]);
Index: linux-2.6.21-mm/arch/um/drivers/mconsole_user.c
===================================================================
--- linux-2.6.21-mm.orig/arch/um/drivers/mconsole_user.c 2007-06-06 09:28:13.000000000 -0400
+++ linux-2.6.21-mm/arch/um/drivers/mconsole_user.c 2007-06-11 13:38:19.000000000 -0400
@@ -86,8 +86,9 @@ int mconsole_get_request(int fd, struct
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;
Index: linux-2.6.21-mm/arch/um/drivers/ubd_user.c
===================================================================
--- linux-2.6.21-mm.orig/arch/um/drivers/ubd_user.c 2007-06-06 09:28:13.000000000 -0400
+++ linux-2.6.21-mm/arch/um/drivers/ubd_user.c 2007-06-11 13:44:56.000000000 -0400
@@ -43,6 +43,12 @@ int start_io_thread(unsigned long sp, in
kernel_fd = fds[0];
*fd_out = fds[1];
+ err = os_set_fd_block(*fd_out, 0);
+ if (err) {
+ printk("start_io_thread - failed to set nonblocking I/O.\n");
+ goto out_close;
+ }
+
pid = clone(io_thread, (void *) sp, CLONE_FILES | CLONE_VM | SIGCHLD,
NULL);
if(pid < 0){
Index: linux-2.6.21-mm/arch/um/drivers/xterm.c
===================================================================
--- linux-2.6.21-mm.orig/arch/um/drivers/xterm.c 2007-06-06 09:28:13.000000000 -0400
+++ linux-2.6.21-mm/arch/um/drivers/xterm.c 2007-06-12 12:25:44.000000000 -0400
@@ -151,6 +151,13 @@ int xterm_open(int input, int output, in
goto out;
}
+ err = os_set_fd_block(new, 0);
+ if (err) {
+ printk("xterm_open : failed to set xterm descriptor "
+ "non-blocking, err = %d\n", -err);
+ goto out;
+ }
+
CATCH_EINTR(err = tcgetattr(new, &data->tt));
if(err){
new = err;
-
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