[PATCH] uml: fix hang on run_helper() failure on uml_net
Fix an hang on a pipe when run_helper() fails when called by change_tramp()
(i.e. when calling uml_net) - reproduced the bug and verified this fixes it.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/um/drivers/net_user.c b/arch/um/drivers/net_user.c
index 0e2f061..0a7786e 100644
--- a/arch/um/drivers/net_user.c
+++ b/arch/um/drivers/net_user.c
@@ -182,7 +182,9 @@
pe_data.stdout = fds[1];
pid = run_helper(change_pre_exec, &pe_data, argv, NULL);
- read_output(fds[0], output, output_len);
+ if (pid > 0) /* Avoid hang as we won't get data in failure case. */
+ read_output(fds[0], output, output_len);
+
os_close_file(fds[0]);
os_close_file(fds[1]);