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Subject: Re: [RFC PATCH v1.9 13/14] livepatch: add /proc/<pid>/patch_status
To: Josh Poimboeuf <jpoimboe@redhat.com>, Jiri Kosina <jikos@kernel.org>,
        Jessica Yu <jeyu@redhat.com>, Miroslav Benes <mbenes@suse.cz>
References: <cover.1458933243.git.jpoimboe@redhat.com>
 <9de6283945f99958dfd7fac0f24fcce98d5410a6.1458933243.git.jpoimboe@redhat.com>
 <56FCEEFA.3030309@suse.cz>
Cc: linux-kernel@vger.kernel.org, live-patching@vger.kernel.org,
        Vojtech Pavlik <vojtech@suse.com>
From: Jiri Slaby <jslaby@suse.cz>
Message-ID: <56FCF079.8070708@suse.cz>
Date: Thu, 31 Mar 2016 11:40:09 +0200
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On 03/31/2016, 11:33 AM, Jiri Slaby wrote:
> On 03/25/2016, 08:35 PM, Josh Poimboeuf wrote:
>> Expose the per-task klp_universe value so users can determine which
>> tasks are holding up completion of a patching operation.
>>
>> Call it "patch_status" rather than "universe": it's at least more
>> descriptive for the average user.
>>
>> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
>> ---
>>  fs/proc/base.c | 12 ++++++++++++
>>  1 file changed, 12 insertions(+)
>>
>> diff --git a/fs/proc/base.c b/fs/proc/base.c
>> index b1755b2..f90998b 100644
>> --- a/fs/proc/base.c
>> +++ b/fs/proc/base.c
>> @@ -2801,6 +2801,15 @@ static int proc_pid_personality(struct seq_file *m, struct pid_namespace *ns,
>>  	return err;
>>  }
>>  
>> +#ifdef CONFIG_LIVEPATCH
>> +static int proc_pid_patch_status(struct seq_file *m, struct pid_namespace *ns,
>> +				 struct pid *pid, struct task_struct *task)
>> +{
>> +	seq_printf(m, "%d\n", task->klp_universe);
>> +	return 0;
>> +}
>> +#endif /* CONFIG_LIVEPATCH */
>> +
>>  /*
>>   * Thread groups
>>   */
>> @@ -2900,6 +2909,9 @@ static const struct pid_entry tgid_base_stuff[] = {
>>  	REG("timers",	  S_IRUGO, proc_timers_operations),
>>  #endif
>>  	REG("timerslack_ns", S_IRUGO|S_IWUGO, proc_pid_set_timerslack_ns_operations),
>> +#ifdef CONFIG_LIVEPATCH
>> +	ONE("patch_status",  S_IRUSR, proc_pid_patch_status),
>> +#endif
> 
> I think we want to know the state about all tasks, not only group
> leaders. This should go to tid_base_stuff.

Or loop over all tasks here by for_each_thread(task, t) and check them all.

> thanks,
-- 
js
suse labs