Revision 7695fb04aca62e2d8a7ca6ede50f6211e1d71e53 authored by Darren Salt on 07 February 2009, 06:02:07 UTC, committed by Len Brown on 07 February 2009, 06:02:07 UTC
I got the following oops while changing the backlight brightness during startup. When it happens, it prevents use of the hotkeys, Fn-Fx, and the lid button. It's a clear use-before-init, as I verified by testing with an appropriately-placed "else printk". BUG: unable to handle kernel NULL pointer dereference at 00000000 *pde = 00000000 Oops: 0002 [#1] PREEMPT SMP Pid: 160, comm: kacpi_notify Not tainted (2.6.28.1-eee901 #4) 901 EIP: 0060:[<c0264e68>] [<c0264e68>] eeepc_hotk_notify+26/da EFLAGS: 00010246 CPU: 1 Using defaults from ksymoops -t elf32-i386 -a i386 EAX: 00000009 EBX: 00000000 ECX: 00000009 EDX: f70dbf64 ESI: 00000029 EDI: f7335188 EBP: c02112c9 ESP: f70dbf80 DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068 f70731e0 f73acd50 c02164ac f7335180 f70aa040 c02112e6 f733518c c012b62f f70aa044 f70aa040 c012bdba f70aa04c 00000000 c012be6e 00000000 f70bdf80 c012e198 f70dbfc4 f70dbfc4 f70aa040 c012bdba 00000000 c012e0c9 c012e091 Call Trace: [<c02164ac>] ? acpi_ev_notify_dispatch+4c/55 [<c02112e6>] ? acpi_os_execute_deferred+1d/25 [<c012b62f>] ? run_workqueue+71/f1 [<c012bdba>] ? worker_thread+0/bf [<c012be6e>] ? worker_thread+b4/bf [<c012e198>] ? autoremove_wake_function+0/2b [<c012bdba>] ? worker_thread+0/bf [<c012e0c9>] ? kthread+38/5f [<c012e091>] ? kthread+0/5f [<c0103abf>] ? kernel_thread_helper+7/10 Code: 00 00 00 00 c3 83 3d 60 5c 50 c0 00 56 89 d6 53 0f 84 c4 00 00 00 8d 42 e0 83 f8 0f 77 0f 8b 1d 68 5c 50 c0 89 d8 e8 a9 fa ff ff <89> 03 8b 1d 60 5c 50 c0 89 f2 83 e2 7f 0f b7 4c 53 10 8d 41 01 Signed-off-by: Darren Salt <linux@youmustbejoking.demon.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com>
1 parent 386e4a8
pid_namespace.c
/*
* Pid namespaces
*
* Authors:
* (C) 2007 Pavel Emelyanov <xemul@openvz.org>, OpenVZ, SWsoft Inc.
* (C) 2007 Sukadev Bhattiprolu <sukadev@us.ibm.com>, IBM
* Many thanks to Oleg Nesterov for comments and help
*
*/
#include <linux/pid.h>
#include <linux/pid_namespace.h>
#include <linux/syscalls.h>
#include <linux/err.h>
#include <linux/acct.h>
#define BITS_PER_PAGE (PAGE_SIZE*8)
struct pid_cache {
int nr_ids;
char name[16];
struct kmem_cache *cachep;
struct list_head list;
};
static LIST_HEAD(pid_caches_lh);
static DEFINE_MUTEX(pid_caches_mutex);
static struct kmem_cache *pid_ns_cachep;
/*
* creates the kmem cache to allocate pids from.
* @nr_ids: the number of numerical ids this pid will have to carry
*/
static struct kmem_cache *create_pid_cachep(int nr_ids)
{
struct pid_cache *pcache;
struct kmem_cache *cachep;
mutex_lock(&pid_caches_mutex);
list_for_each_entry(pcache, &pid_caches_lh, list)
if (pcache->nr_ids == nr_ids)
goto out;
pcache = kmalloc(sizeof(struct pid_cache), GFP_KERNEL);
if (pcache == NULL)
goto err_alloc;
snprintf(pcache->name, sizeof(pcache->name), "pid_%d", nr_ids);
cachep = kmem_cache_create(pcache->name,
sizeof(struct pid) + (nr_ids - 1) * sizeof(struct upid),
0, SLAB_HWCACHE_ALIGN, NULL);
if (cachep == NULL)
goto err_cachep;
pcache->nr_ids = nr_ids;
pcache->cachep = cachep;
list_add(&pcache->list, &pid_caches_lh);
out:
mutex_unlock(&pid_caches_mutex);
return pcache->cachep;
err_cachep:
kfree(pcache);
err_alloc:
mutex_unlock(&pid_caches_mutex);
return NULL;
}
static struct pid_namespace *create_pid_namespace(unsigned int level)
{
struct pid_namespace *ns;
int i;
ns = kmem_cache_zalloc(pid_ns_cachep, GFP_KERNEL);
if (ns == NULL)
goto out;
ns->pidmap[0].page = kzalloc(PAGE_SIZE, GFP_KERNEL);
if (!ns->pidmap[0].page)
goto out_free;
ns->pid_cachep = create_pid_cachep(level + 1);
if (ns->pid_cachep == NULL)
goto out_free_map;
kref_init(&ns->kref);
ns->level = level;
set_bit(0, ns->pidmap[0].page);
atomic_set(&ns->pidmap[0].nr_free, BITS_PER_PAGE - 1);
for (i = 1; i < PIDMAP_ENTRIES; i++)
atomic_set(&ns->pidmap[i].nr_free, BITS_PER_PAGE);
return ns;
out_free_map:
kfree(ns->pidmap[0].page);
out_free:
kmem_cache_free(pid_ns_cachep, ns);
out:
return ERR_PTR(-ENOMEM);
}
static void destroy_pid_namespace(struct pid_namespace *ns)
{
int i;
for (i = 0; i < PIDMAP_ENTRIES; i++)
kfree(ns->pidmap[i].page);
kmem_cache_free(pid_ns_cachep, ns);
}
struct pid_namespace *copy_pid_ns(unsigned long flags, struct pid_namespace *old_ns)
{
struct pid_namespace *new_ns;
BUG_ON(!old_ns);
new_ns = get_pid_ns(old_ns);
if (!(flags & CLONE_NEWPID))
goto out;
new_ns = ERR_PTR(-EINVAL);
if (flags & CLONE_THREAD)
goto out_put;
new_ns = create_pid_namespace(old_ns->level + 1);
if (!IS_ERR(new_ns))
new_ns->parent = get_pid_ns(old_ns);
out_put:
put_pid_ns(old_ns);
out:
return new_ns;
}
void free_pid_ns(struct kref *kref)
{
struct pid_namespace *ns, *parent;
ns = container_of(kref, struct pid_namespace, kref);
parent = ns->parent;
destroy_pid_namespace(ns);
if (parent != NULL)
put_pid_ns(parent);
}
void zap_pid_ns_processes(struct pid_namespace *pid_ns)
{
int nr;
int rc;
/*
* The last thread in the cgroup-init thread group is terminating.
* Find remaining pid_ts in the namespace, signal and wait for them
* to exit.
*
* Note: This signals each threads in the namespace - even those that
* belong to the same thread group, To avoid this, we would have
* to walk the entire tasklist looking a processes in this
* namespace, but that could be unnecessarily expensive if the
* pid namespace has just a few processes. Or we need to
* maintain a tasklist for each pid namespace.
*
*/
read_lock(&tasklist_lock);
nr = next_pidmap(pid_ns, 1);
while (nr > 0) {
kill_proc_info(SIGKILL, SEND_SIG_PRIV, nr);
nr = next_pidmap(pid_ns, nr);
}
read_unlock(&tasklist_lock);
do {
clear_thread_flag(TIF_SIGPENDING);
rc = sys_wait4(-1, NULL, __WALL, NULL);
} while (rc != -ECHILD);
acct_exit_ns(pid_ns);
return;
}
static __init int pid_namespaces_init(void)
{
pid_ns_cachep = KMEM_CACHE(pid_namespace, SLAB_PANIC);
return 0;
}
__initcall(pid_namespaces_init);
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