path: root/init
diff options
authorMichael Opdenacker <michael.opdenacker@free-electrons.com>2013-11-12 15:10:21 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2013-11-13 12:09:26 +0900
commitba24762bd53faaf39cc8b991175636954b7ef4be (patch)
tree2f738251e10357223e70f2894cd8eb867e630b6e /init
parentdf3ef3af503e131f7848652af8be21747fd57419 (diff)
init: make init failures more explicit
This patch proposes to make init failures more explicit. Before this, the "No init found" message didn't help much. It could sometimes be misleading and actually mean "No *working* init found". This message could hide many different issues: - no init program candidates found at all - some init program candidates exist but can't be executed (missing execute permissions, failed to load shared libraries, executable compiled for an unknown architecture...) This patch notifies the kernel user when a candidate init program is found but can't be executed. In each failure situation, the error code is displayed, to quickly find the root cause. "No init found" is also replaced by "No working init found", which is more correct. This will help embedded Linux developers (especially the newcomers), regularly making and debugging new root filesystems. Credits to Geert Uytterhoeven and Janne Karhunen for their improvement suggestions. Signed-off-by: Michael Opdenacker <michael.opdenacker@free-electrons.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Tested-by: Janne Karhunen <Janne.Karhunen@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'init')
1 files changed, 29 insertions, 10 deletions
diff --git a/init/main.c b/init/main.c
index aa061ef17626..67ee8ef0a669 100644
--- a/init/main.c
+++ b/init/main.c
@@ -810,10 +810,26 @@ static int run_init_process(const char *init_filename)
(const char __user *const __user *)envp_init);
+static int try_to_run_init_process(const char *init_filename)
+ int ret;
+ ret = run_init_process(init_filename);
+ if (ret && ret != -ENOENT) {
+ pr_err("Starting init: %s exists but couldn't execute it (error %d)\n",
+ init_filename, ret);
+ }
+ return ret;
static noinline void __init kernel_init_freeable(void);
static int __ref kernel_init(void *unused)
+ int ret;
/* need to finish all async __init code before freeing the memory */
@@ -825,9 +841,11 @@ static int __ref kernel_init(void *unused)
if (ramdisk_execute_command) {
- if (!run_init_process(ramdisk_execute_command))
+ ret = run_init_process(ramdisk_execute_command);
+ if (!ret)
return 0;
- pr_err("Failed to execute %s\n", ramdisk_execute_command);
+ pr_err("Failed to execute %s (error %d)\n",
+ ramdisk_execute_command, ret);
@@ -837,18 +855,19 @@ static int __ref kernel_init(void *unused)
* trying to recover a really broken machine.
if (execute_command) {
- if (!run_init_process(execute_command))
+ ret = run_init_process(execute_command);
+ if (!ret)
return 0;
- pr_err("Failed to execute %s. Attempting defaults...\n",
- execute_command);
+ pr_err("Failed to execute %s (error %d). Attempting defaults...\n",
+ execute_command, ret);
- if (!run_init_process("/sbin/init") ||
- !run_init_process("/etc/init") ||
- !run_init_process("/bin/init") ||
- !run_init_process("/bin/sh"))
+ if (!try_to_run_init_process("/sbin/init") ||
+ !try_to_run_init_process("/etc/init") ||
+ !try_to_run_init_process("/bin/init") ||
+ !try_to_run_init_process("/bin/sh"))
return 0;
- panic("No init found. Try passing init= option to kernel. "
+ panic("No working init found. Try passing init= option to kernel. "
"See Linux Documentation/init.txt for guidance.");