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Message-ID: <20071210180009.GA9338@c2.user-mode-linux.org>
Date: Mon, 10 Dec 2007 13:00:09 -0500
From: Jeff Dike <jdike@...toit.com>
To: Andrew Morton <akpm@...l.org>
Cc: LKML <linux-kernel@...r.kernel.org>,
uml-devel <user-mode-linux-devel@...ts.sourceforge.net>,
caker@...ode.com
Subject: [PATCH 4/5] UML - Install panic notifier earlier
It turns out that if there's a panic early enough, UML will just sit
there in the LED-blinking loop because the panic notifier hadn't been
installed yet.
This patch installs it earlier.
It also fixes the problem which exposed the hang, namely that if you
give UML a zero-sized initrd, it will ask alloc_bootmem for zero
bytes, and that will cause the panic.
While I was in initrd.c, I gave it a style makeover.
Prompted by checkpatch, I moved a couple extern declarations of
uml_exitcode to kern_util.h.
Signed-off-by: Jeff Dike <jdike@...ux.intel.com>
---
arch/um/include/kern_util.h | 2 ++
arch/um/kernel/initrd.c | 29 ++++++++++++++++++++---------
arch/um/kernel/um_arch.c | 41 ++++++++++++++++++++---------------------
arch/um/os-Linux/main.c | 2 --
4 files changed, 42 insertions(+), 32 deletions(-)
Index: linux-2.6-git/arch/um/kernel/um_arch.c
===================================================================
--- linux-2.6-git.orig/arch/um/kernel/um_arch.c 2007-12-07 17:19:58.000000000 -0500
+++ linux-2.6-git/arch/um/kernel/um_arch.c 2007-12-07 17:31:32.000000000 -0500
@@ -223,6 +223,23 @@ static void __init uml_postsetup(void)
return;
}
+static int panic_exit(struct notifier_block *self, unsigned long unused1,
+ void *unused2)
+{
+ bust_spinlocks(1);
+ show_regs(&(current->thread.regs));
+ bust_spinlocks(0);
+ uml_exitcode = 1;
+ os_dump_core();
+ return 0;
+}
+
+static struct notifier_block panic_exit_notifier = {
+ .notifier_call = panic_exit,
+ .next = NULL,
+ .priority = 0
+};
+
/* Set during early boot */
unsigned long task_size;
EXPORT_SYMBOL(task_size);
@@ -336,6 +353,9 @@ int __init linux_main(int argc, char **a
printf("Kernel virtual memory size shrunk to %lu bytes\n",
virtmem_size);
+ atomic_notifier_chain_register(&panic_notifier_list,
+ &panic_exit_notifier);
+
uml_postsetup();
stack_protections((unsigned long) &init_thread_info);
@@ -344,29 +364,8 @@ int __init linux_main(int argc, char **a
return start_uml();
}
-extern int uml_exitcode;
-
-static int panic_exit(struct notifier_block *self, unsigned long unused1,
- void *unused2)
-{
- bust_spinlocks(1);
- show_regs(&(current->thread.regs));
- bust_spinlocks(0);
- uml_exitcode = 1;
- os_dump_core();
- return 0;
-}
-
-static struct notifier_block panic_exit_notifier = {
- .notifier_call = panic_exit,
- .next = NULL,
- .priority = 0
-};
-
void __init setup_arch(char **cmdline_p)
{
- atomic_notifier_chain_register(&panic_notifier_list,
- &panic_exit_notifier);
paging_init();
strlcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
*cmdline_p = command_line;
Index: linux-2.6-git/arch/um/kernel/initrd.c
===================================================================
--- linux-2.6-git.orig/arch/um/kernel/initrd.c 2007-12-07 14:35:55.000000000 -0500
+++ linux-2.6-git/arch/um/kernel/initrd.c 2007-12-07 17:26:58.000000000 -0500
@@ -1,5 +1,5 @@
/*
- * Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@...aya.com)
+ * Copyright (C) 2000 - 2007 Jeff Dike (jdike@...dtoit,linux.intel}.com)
* Licensed under the GPL
*/
@@ -20,18 +20,27 @@ static int __init read_initrd(void)
long long size;
int err;
- if(initrd == NULL)
+ if (initrd == NULL)
return 0;
err = os_file_size(initrd, &size);
- if(err)
+ if (err)
return 0;
+ /*
+ * This is necessary because alloc_bootmem craps out if you
+ * ask for no memory.
+ */
+ if (size == 0) {
+ printk(KERN_ERR "\"%\" is a zero-size initrd\n");
+ return 0;
+ }
+
area = alloc_bootmem(size);
- if(area == NULL)
+ if (area == NULL)
return 0;
- if(load_initrd(initrd, area, size) == -1)
+ if (load_initrd(initrd, area, size) == -1)
return 0;
initrd_start = (unsigned long) area;
@@ -58,13 +67,15 @@ int load_initrd(char *filename, void *bu
int fd, n;
fd = os_open_file(filename, of_read(OPENFLAGS()), 0);
- if(fd < 0){
- printk("Opening '%s' failed - err = %d\n", filename, -fd);
+ if (fd < 0) {
+ printk(KERN_ERR "Opening '%s' failed - err = %d\n", filename,
+ -fd);
return -1;
}
n = os_read_file(fd, buf, size);
- if(n != size){
- printk("Read of %d bytes from '%s' failed, err = %d\n", size,
+ if (n != size) {
+ printk(KERN_ERR "Read of %d bytes from '%s' failed, "
+ "err = %d\n", size,
filename, -n);
return -1;
}
Index: linux-2.6-git/arch/um/include/kern_util.h
===================================================================
--- linux-2.6-git.orig/arch/um/include/kern_util.h 2007-12-07 14:35:55.000000000 -0500
+++ linux-2.6-git/arch/um/include/kern_util.h 2007-12-07 17:31:42.000000000 -0500
@@ -9,6 +9,8 @@
#include "sysdep/ptrace.h"
#include "sysdep/faultinfo.h"
+extern int uml_exitcode;
+
extern int ncpus;
extern int kmalloc_ok;
extern int nsyscalls;
Index: linux-2.6-git/arch/um/os-Linux/main.c
===================================================================
--- linux-2.6-git.orig/arch/um/os-Linux/main.c 2007-12-07 14:35:54.000000000 -0500
+++ linux-2.6-git/arch/um/os-Linux/main.c 2007-12-07 17:32:25.000000000 -0500
@@ -111,8 +111,6 @@ static void setup_env_path(void)
}
}
-extern int uml_exitcode;
-
extern void scan_elf_aux( char **envp);
int __init main(int argc, char **argv, char **envp)
--
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