infrastructure for saner ret_from_kernel_thread semantics
* allow kernel_execve() leave the actual return to userland to
caller (selected by CONFIG_GENERIC_KERNEL_EXECVE). Callers
updated accordingly.
* architecture that does select GENERIC_KERNEL_EXECVE in its
Kconfig should have its ret_from_kernel_thread() do this:
call schedule_tail
call the callback left for it by copy_thread(); if it ever
returns, that's because it has just done successful kernel_execve()
jump to return from syscall
IOW, its only difference from ret_from_fork() is that it does call the
callback.
* such an architecture should also get rid of ret_from_kernel_execve()
and __ARCH_WANT_KERNEL_EXECVE
This is the last part of infrastructure patches in that area - from
that point on work on different architectures can live independently.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/init/main.c b/init/main.c
index a490ffe..02df2dd 100644
--- a/init/main.c
+++ b/init/main.c
@@ -69,6 +69,7 @@
#include <linux/slab.h>
#include <linux/perf_event.h>
#include <linux/file.h>
+#include <linux/ptrace.h>
#include <asm/io.h>
#include <asm/bugs.h>
@@ -788,10 +789,10 @@
do_one_initcall(*fn);
}
-static void run_init_process(const char *init_filename)
+static int run_init_process(const char *init_filename)
{
argv_init[0] = init_filename;
- kernel_execve(init_filename, argv_init, envp_init);
+ return kernel_execve(init_filename, argv_init, envp_init);
}
static void __init kernel_init_freeable(void);
@@ -810,7 +811,8 @@
flush_delayed_fput();
if (ramdisk_execute_command) {
- run_init_process(ramdisk_execute_command);
+ if (!run_init_process(ramdisk_execute_command))
+ return 0;
printk(KERN_WARNING "Failed to execute %s\n",
ramdisk_execute_command);
}
@@ -822,14 +824,16 @@
* trying to recover a really broken machine.
*/
if (execute_command) {
- run_init_process(execute_command);
+ if (!run_init_process(execute_command))
+ return 0;
printk(KERN_WARNING "Failed to execute %s. Attempting "
"defaults...\n", execute_command);
}
- run_init_process("/sbin/init");
- run_init_process("/etc/init");
- run_init_process("/bin/init");
- run_init_process("/bin/sh");
+ if (!run_init_process("/sbin/init") ||
+ !run_init_process("/etc/init") ||
+ !run_init_process("/bin/init") ||
+ !run_init_process("/bin/sh"))
+ return 0;
panic("No init found. Try passing init= option to kernel. "
"See Linux Documentation/init.txt for guidance.");