linux-kernel - Re: [PATCH 1/2] ftrace: Fix NULL pointer dereference in t_probe

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Message-Id: <1567584434.0m0xodpunl.naveen@linux.ibm.com>
Date:   Wed, 04 Sep 2019 13:37:50 +0530
From:   "Naveen N. Rao" <naveen.n.rao@...ux.vnet.ibm.com>
To:     Steven Rostedt <rostedt@...dmis.org>
Cc:     linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: Re: [PATCH 1/2] ftrace: Fix NULL pointer dereference in
 t_probe_next()

Steven Rostedt wrote:
> On Thu,  4 Jul 2019 20:04:41 +0530
> "Naveen N. Rao" <naveen.n.rao@...ux.vnet.ibm.com> wrote:
> 
> 
>>  kernel/trace/ftrace.c | 4 ++++
>>  1 file changed, 4 insertions(+)
>> 
>> diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
>> index 7b037295a1f1..0791eafb693d 100644
>> --- a/kernel/trace/ftrace.c
>> +++ b/kernel/trace/ftrace.c
>> @@ -3093,6 +3093,10 @@ t_probe_next(struct seq_file *m, loff_t *pos)
>>  		hnd = &iter->probe_entry->hlist;
>>  
>>  	hash = iter->probe->ops.func_hash->filter_hash;
>> +
>> +	if (!hash)
>> +		return NULL;
>> +
>>  	size = 1 << hash->size_bits;
>>  
>>   retry:
> 
> OK, I added this, but I'm also adding this on top:

Thanks, the additional comments do make this much clearer.

Regards,
Naveen