Revision 619b0488038224391e64fa03854651ca0f5efe56 authored by Raistlin on 26 June 2008, 16:54:09 UTC, committed by Ingo Molnar on 01 July 2008, 06:23:24 UTC
Here it is another little Oops we found while configuring invalid values via cgroups: echo 0 > /dev/cgroups/0/cpu.rt_period_us or echo 4294967296 > /dev/cgroups/0/cpu.rt_period_us [ 205.509825] divide error: 0000 [#1] [ 205.510151] Modules linked in: [ 205.510151] [ 205.510151] Pid: 2339, comm: bash Not tainted (2.6.26-rc8 #33) [ 205.510151] EIP: 0060:[<c030c6ef>] EFLAGS: 00000293 CPU: 0 [ 205.510151] EIP is at div64_u64+0x5f/0x70 [ 205.510151] EAX: 0000389f EBX: 00000000 ECX: 00000000 EDX: 00000000 [ 205.510151] ESI: d9800000 EDI: 00000000 EBP: c6cede60 ESP: c6cede50 [ 205.510151] DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 0068 [ 205.510151] Process bash (pid: 2339, ti=c6cec000 task=c79be370 task.ti=c6cec000) [ 205.510151] Stack: d9800000 0000389f c05971a0 d9800000 c6cedeb4 c0214dbd 00000000 00000000 [ 205.510151] c6cede88 c0242bd8 c05377c0 c7a41b40 00000000 00000000 00000000 c05971a0 [ 205.510151] c780ed20 c7508494 c7a41b40 00000000 00000002 c6cedebc c05971a0 ffffffea [ 205.510151] Call Trace: [ 205.510151] [<c0214dbd>] ? __rt_schedulable+0x1cd/0x240 [ 205.510151] [<c0242bd8>] ? cgroup_file_open+0x18/0xe0 [ 205.510151] [<c0214fe4>] ? tg_set_bandwidth+0xa4/0xf0 [ 205.510151] [<c0215066>] ? sched_group_set_rt_period+0x36/0x50 [ 205.510151] [<c021508e>] ? cpu_rt_period_write_uint+0xe/0x10 [ 205.510151] [<c0242dc5>] ? cgroup_file_write+0x125/0x160 [ 205.510151] [<c0232c15>] ? hrtimer_interrupt+0x155/0x190 [ 205.510151] [<c02f047f>] ? security_file_permission+0xf/0x20 [ 205.510151] [<c0277ad8>] ? rw_verify_area+0x48/0xc0 [ 205.510151] [<c0283744>] ? dupfd+0x104/0x130 [ 205.510151] [<c027838c>] ? vfs_write+0x9c/0x160 [ 205.510151] [<c0242ca0>] ? cgroup_file_write+0x0/0x160 [ 205.510151] [<c027850d>] ? sys_write+0x3d/0x70 [ 205.510151] [<c0203019>] ? sysenter_past_esp+0x6a/0x91 [ 205.510151] ======================= [ 205.510151] Code: 0f 45 de 31 f6 0f ad d0 d3 ea f6 c1 20 0f 45 c2 0f 45 d6 89 45 f0 89 55 f4 8b 55 f4 31 c9 8b 45 f0 39 d3 89 c6 77 08 89 d0 31 d2 <f7> f3 89 c1 83 c4 08 89 f0 f7 f3 89 ca 5b 5e 5d c3 55 89 e5 56 [ 205.510151] EIP: [<c030c6ef>] div64_u64+0x5f/0x70 SS:ESP 0068:c6cede50 The attached patch solves the issue for me. I'm checking as soon as possible for the period not being zero since, if it is, going ahead is useless. This way we also save a mutex_lock() and a read_lock() wrt doing it inside tg_set_bandwidth() or __rt_schedulable(). Signed-off-by: Dario Faggioli <raistlin@linux.it> Signed-off-by: Michael Trimarchi <trimarchimichael@yahoo.it> Signed-off-by: Ingo Molnar <mingo@elte.hu>
1 parent 79c5379
group.c
/*
* fs/sysfs/group.c - Operations for adding/removing multiple files at once.
*
* Copyright (c) 2003 Patrick Mochel
* Copyright (c) 2003 Open Source Development Lab
*
* This file is released undert the GPL v2.
*
*/
#include <linux/kobject.h>
#include <linux/module.h>
#include <linux/dcache.h>
#include <linux/namei.h>
#include <linux/err.h>
#include "sysfs.h"
static void remove_files(struct sysfs_dirent *dir_sd, struct kobject *kobj,
const struct attribute_group *grp)
{
struct attribute *const* attr;
int i;
for (i = 0, attr = grp->attrs; *attr; i++, attr++)
sysfs_hash_and_remove(dir_sd, (*attr)->name);
}
static int create_files(struct sysfs_dirent *dir_sd, struct kobject *kobj,
const struct attribute_group *grp, int update)
{
struct attribute *const* attr;
int error = 0, i;
for (i = 0, attr = grp->attrs; *attr && !error; i++, attr++) {
mode_t mode = 0;
/* in update mode, we're changing the permissions or
* visibility. Do this by first removing then
* re-adding (if required) the file */
if (update)
sysfs_hash_and_remove(dir_sd, (*attr)->name);
if (grp->is_visible) {
mode = grp->is_visible(kobj, *attr, i);
if (!mode)
continue;
}
error = sysfs_add_file_mode(dir_sd, *attr, SYSFS_KOBJ_ATTR,
(*attr)->mode | mode);
if (unlikely(error))
break;
}
if (error)
remove_files(dir_sd, kobj, grp);
return error;
}
static int internal_create_group(struct kobject *kobj, int update,
const struct attribute_group *grp)
{
struct sysfs_dirent *sd;
int error;
BUG_ON(!kobj || (!update && !kobj->sd));
/* Updates may happen before the object has been instantiated */
if (unlikely(update && !kobj->sd))
return -EINVAL;
if (grp->name) {
error = sysfs_create_subdir(kobj, grp->name, &sd);
if (error)
return error;
} else
sd = kobj->sd;
sysfs_get(sd);
error = create_files(sd, kobj, grp, update);
if (error) {
if (grp->name)
sysfs_remove_subdir(sd);
}
sysfs_put(sd);
return error;
}
/**
* sysfs_create_group - given a directory kobject, create an attribute group
* @kobj: The kobject to create the group on
* @grp: The attribute group to create
*
* This function creates a group for the first time. It will explicitly
* warn and error if any of the attribute files being created already exist.
*
* Returns 0 on success or error.
*/
int sysfs_create_group(struct kobject *kobj,
const struct attribute_group *grp)
{
return internal_create_group(kobj, 0, grp);
}
/**
* sysfs_update_group - given a directory kobject, create an attribute group
* @kobj: The kobject to create the group on
* @grp: The attribute group to create
*
* This function updates an attribute group. Unlike
* sysfs_create_group(), it will explicitly not warn or error if any
* of the attribute files being created already exist. Furthermore,
* if the visibility of the files has changed through the is_visible()
* callback, it will update the permissions and add or remove the
* relevant files.
*
* The primary use for this function is to call it after making a change
* that affects group visibility.
*
* Returns 0 on success or error.
*/
int sysfs_update_group(struct kobject *kobj,
const struct attribute_group *grp)
{
return internal_create_group(kobj, 1, grp);
}
void sysfs_remove_group(struct kobject * kobj,
const struct attribute_group * grp)
{
struct sysfs_dirent *dir_sd = kobj->sd;
struct sysfs_dirent *sd;
if (grp->name) {
sd = sysfs_get_dirent(dir_sd, grp->name);
if (!sd) {
printk(KERN_WARNING "sysfs group %p not found for "
"kobject '%s'\n", grp, kobject_name(kobj));
WARN_ON(!sd);
return;
}
} else
sd = sysfs_get(dir_sd);
remove_files(sd, kobj, grp);
if (grp->name)
sysfs_remove_subdir(sd);
sysfs_put(sd);
}
EXPORT_SYMBOL_GPL(sysfs_create_group);
EXPORT_SYMBOL_GPL(sysfs_update_group);
EXPORT_SYMBOL_GPL(sysfs_remove_group);
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