| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <df257c05-ef8c-4e31-9ab8-0d396e1b40f7@intel.com>
Date: Fri, 23 Aug 2024 13:18:08 -0700
From: Reinette Chatre <reinette.chatre@...el.com>
To: <babu.moger@....com>, <corbet@....net>, <fenghua.yu@...el.com>,
<tglx@...utronix.de>, <mingo@...hat.com>, <bp@...en8.de>,
<dave.hansen@...ux.intel.com>
CC: <x86@...nel.org>, <hpa@...or.com>, <paulmck@...nel.org>,
<rdunlap@...radead.org>, <tj@...nel.org>, <peterz@...radead.org>,
<yanjiewtw@...il.com>, <kim.phillips@....com>, <lukas.bulwahn@...il.com>,
<seanjc@...gle.com>, <jmattson@...gle.com>, <leitao@...ian.org>,
<jpoimboe@...nel.org>, <rick.p.edgecombe@...el.com>,
<kirill.shutemov@...ux.intel.com>, <jithu.joseph@...el.com>,
<kai.huang@...el.com>, <kan.liang@...ux.intel.com>,
<daniel.sneddon@...ux.intel.com>, <pbonzini@...hat.com>,
<sandipan.das@....com>, <ilpo.jarvinen@...ux.intel.com>,
<peternewman@...gle.com>, <maciej.wieczor-retman@...el.com>,
<linux-doc@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
<eranian@...gle.com>, <james.morse@....com>
Subject: Re: [PATCH v6 22/22] x86/resctrl: Introduce interface to modify
assignment states of the groups
Hi Babu,
On 8/21/24 1:11 PM, Moger, Babu wrote:
> On 8/16/24 17:33, Reinette Chatre wrote:
>> On 8/6/24 3:00 PM, Babu Moger wrote:
...
>>> +
>>> +static int rdtgroup_str_to_mon_state(char *flag)
>>> +{
>>> + int i, mon_state = 0;
>>> +
>>> + for (i = 0; i < strlen(flag); i++) {
>>> + switch (*(flag + i)) {
>>> + case 't':
>>> + mon_state |= ASSIGN_TOTAL;
>>> + break;
>>> + case 'l':
>>> + mon_state |= ASSIGN_LOCAL;
>>> + break;
>>> + case '_':
>>> + mon_state = ASSIGN_NONE;
>>> + break;
>>
>> It looks like this supports flags like "_lt", treating it as assigning
>> both local and total. I expect this should remove all flags instead?
>
> This is a cobination of flags.
> "_lt" This will assign both local and total.
> "lt_" This with remove both the flags.
>
> It seems alright to me. Do you want me to change the bahaviour here?
This looks like undefined behavior to me. A request to set individual flags
and also clear all flags looks like a contradiction to me.
>
>
>>
>>> + default:
>>> + break;
>>> + }
>>> + }
>>> +
>>> + return mon_state;
>>> +}
>>
>> hmmm ... so you removed assigning mon_state to ASSIGN_NONE from default,
>> but that did not change what this function returns since ASSIGN_NONE is 0
>> and mon_state is initialized to 0. Unknown flags should cause error so
>> that it is possible to add flags in the future. Above prevents us from
>> ever adding new flags.
>
> May be I am missing something here. How about this?
>
> enum {
> ASSIGN_NONE = 0,
> ASSIGN_TOTAL,
> ASSIGN_LOCAL,
> ASSIGN_INVALID,
> };
>
>
> static int rdtgroup_str_to_mon_state(char *flag)
> {
> int i, mon_state = ASSIGN_NONE;
>
> for (i = 0; i < strlen(flag); i++) {
> switch (*(flag + i)) {
> case 't':
> mon_state |= ASSIGN_TOTAL;
> break;
> case 'l':
> mon_state |= ASSIGN_LOCAL;
> break;
> case '_':
> mon_state = ASSIGN_NONE;
> break;
> default:
> mon_state = ASSIGN_INVALID;
> goto out_done;
> }
> }
>
> :out_done:
> return mon_state;
> }
>
> Then handle the ASSIGN_INVALID from the caller. Is that what you think?
Why not return an error?
>
>>
>>> +
>>> +static struct rdtgroup *rdtgroup_find_grp(enum rdt_group_type rtype,
>>> char *p_grp, char *c_grp)
>>
>> rdtgroup_find_grp() -> rdtgroup_find_grp_by_name()?
>>
>>> +{
>>> + struct rdtgroup *rdtg, *crg;
>>> +
>>> + if (rtype == RDTCTRL_GROUP && *p_grp == '\0') {
>>> + return &rdtgroup_default;
>>> + } else if (rtype == RDTCTRL_GROUP) {
>>> + list_for_each_entry(rdtg, &rdt_all_groups, rdtgroup_list)
>>> + if (!strcmp(p_grp, rdtg->kn->name))
>>> + return rdtg;
>>> + } else if (rtype == RDTMON_GROUP) {
>>> + list_for_each_entry(rdtg, &rdt_all_groups, rdtgroup_list) {
>>> + if (!strcmp(p_grp, rdtg->kn->name)) {
>>> + list_for_each_entry(crg, &rdtg->mon.crdtgrp_list,
>>> + mon.crdtgrp_list) {
>>> + if (!strcmp(c_grp, crg->kn->name))
>>> + return crg;
>>> + }
>>> + }
>>> + }
>>> + }
>>> +
>>> + return NULL;
>>> +}
>>> +
>>> +static int rdtgroup_process_flags(struct rdt_resource *r,
>>> + enum rdt_group_type rtype,
>>> + char *p_grp, char *c_grp, char *tok)
>>> +{
>>> + int op, mon_state, assign_state, unassign_state;
>>> + char *dom_str, *id_str, *op_str;
>>> + struct rdt_mon_domain *d;
>>> + struct rdtgroup *rdtgrp;
>>> + unsigned long dom_id;
>>> + int ret, found = 0;
>>> +
>>> + rdtgrp = rdtgroup_find_grp(rtype, p_grp, c_grp);
>>> +
>>> + if (!rdtgrp) {
>>> + rdt_last_cmd_puts("Not a valid resctrl group\n");
>>> + return -EINVAL;
>>> + }
>>> +
>>> +next:
>>> + if (!tok || tok[0] == '\0')
>>> + return 0;
>>> +
>>> + /* Start processing the strings for each domain */
>>> + dom_str = strim(strsep(&tok, ";"));
>>> +
>>> + op_str = strpbrk(dom_str, "=+-");
>>> +
>>> + if (op_str) {
>>> + op = *op_str;
>>> + } else {
>>> + rdt_last_cmd_puts("Missing operation =, +, -, _ character\n");
>>> + return -EINVAL;
>>> + }
>>> +
>>> + id_str = strsep(&dom_str, "=+-");
>>> +
>>> + /* Check for domain id '*' which means all domains */
>>> + if (id_str && *id_str == '*') {
>>> + d = NULL;
>>> + goto check_state;
>>> + } else if (!id_str || kstrtoul(id_str, 10, &dom_id)) {
>>> + rdt_last_cmd_puts("Missing domain id\n");
>>> + return -EINVAL;
>>> + }
>>> +
>>> + /* Verify if the dom_id is valid */
>>> + list_for_each_entry(d, &r->mon_domains, hdr.list) {
>>> + if (d->hdr.id == dom_id) {
>>> + found = 1;
>>> + break;
>>> + }
>>> + }
>>> +
>>> + if (!found) {
>>> + rdt_last_cmd_printf("Invalid domain id %ld\n", dom_id);
>>> + return -EINVAL;
>>> + }
>>> +
>>> +check_state:
>>> + mon_state = rdtgroup_str_to_mon_state(dom_str);
>>
>> Function should return error and exit here.
>
> No. This is case to skip checking for domain when '*' is passed to apply
> assignment to all the domains.
Using "*" for a domain still requires valid flags, no?
Reinette
Powered by blists - more mailing lists