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authorEric Andersen <andersen@codepoet.org>2003-04-24 11:41:28 +0000
committerEric Andersen <andersen@codepoet.org>2003-04-24 11:41:28 +0000
commit2c1de61023d384fd0a365405925940c3528cb75a (patch)
tree5839e97767864319de033cec3448767e0e43d016
parentafc01cd48544d4e0e7575a8518e575dd499e297c (diff)
downloadbusybox-2c1de61023d384fd0a365405925940c3528cb75a.tar.gz
There have been many reports of init failing to reboot and/or failing to halt
over the years. Well I finally took the time to track this down. It turns out that inside linux/kernel/sys.c the kernel will call machine_halt(); do_exit(0); when halting, or will call machine_power_off(); do_exit(0); during a reboot. Unlike sysv init, we call reboot from within the init process, so if the call to machine_halt() or machine_power_off() returns, the call to do_exit(0) will cause the kernel to panic. Which is a very bad thing to happen. So I just added this little patch to fork and call the reboot syscall from within the forked child process, thereby neatly avoiding the problem. But IMHO, both calls to do_exit(0) within linux/kernel/sys.c are bugs and should be fixed. -Erik
-rw-r--r--init/init.c28
1 files changed, 21 insertions, 7 deletions
diff --git a/init/init.c b/init/init.c
index be91d6a8f..8adff1cd2 100644
--- a/init/init.c
+++ b/init/init.c
@@ -46,6 +46,10 @@
#ifdef CONFIG_SYSLOGD
# include <sys/syslog.h>
#endif
+#if (__GNU_LIBRARY__ > 5) || defined(__dietlibc__)
+#include <sys/reboot.h>
+#endif
+
#if defined(__UCLIBC__) && !defined(__UCLIBC_HAS_MMU__)
#define fork vfork
@@ -80,13 +84,6 @@ struct serial_struct {
};
-#if (__GNU_LIBRARY__ > 5) || defined(__dietlibc__)
-#include <sys/reboot.h>
-#define init_reboot(magic) reboot(magic)
-#else
-#define init_reboot(magic) reboot(0xfee1dead, 672274793, magic)
-#endif
-
#ifndef _PATH_STDPATH
#define _PATH_STDPATH "/usr/bin:/bin:/usr/sbin:/sbin"
#endif
@@ -663,6 +660,23 @@ static void run_actions(int action)
}
#ifndef DEBUG_INIT
+static void init_reboot(unsigned long magic)
+{
+ pid_t pid;
+ /* We have to fork here, since the kernel calls do_exit(0) in
+ * linux/kernel/sys.c, which can cause the machint to panic when
+ * the init process is killed.... */
+ if ((pid = fork()) == 0) {
+#if (__GNU_LIBRARY__ > 5) || defined(__dietlibc__)
+ reboot(magic);
+#else
+ reboot(0xfee1dead, 672274793, magic);
+#endif
+ _exit(0);
+ }
+ waitpid (pid, NULL, 0);
+}
+
static void shutdown_system(void)
{
sigset_t block_signals;