On Mon, Aug 7, 2017 at 11:39 AM, Marcelo Ricardo Leitner
<marcelo.leitner@xxxxxxxxx> wrote:
> On Sun, Aug 06, 2017 at 06:14:39PM +1200, Xin Long wrote:
>> On Sun, Aug 6, 2017 at 5:08 AM, Marcelo Ricardo Leitner
>> <marcelo.leitner@xxxxxxxxx> wrote:
>> > On Sat, Aug 05, 2017 at 08:31:09PM +0800, Xin Long wrote:
>> >> Chen Wei found a kernel call trace when modprobe sctp_probe with
>> >> bufsize set with a huge value.
>> >>
>> >> It's because in sctpprobe_init when alloc memory for sctpw.fifo,
>> >> the size is got from userspace. If it is too large, kernel will
>> >> fail and give a warning.
>> >
>> > Yes but sctp_probe can only be loaded by an admin and it would happen
>> > only during modprobe. It's different from the commit mentioned below, on
>> > which any user could trigger it.
>> yeah, in this way it's different, I think generally it's acceptable to have
>> this kinda warning call trace by admin.
>>
>> But it could get the feedback from the return value and the warning
>> call trace seems not useful. sometimes users may be confused
>
> users or admins?
admins.
>
>> with this call trace. So it may be better not to dump the warning ?
>>
>> Or you think it can be helpful if we leave it here ?
>
> I'm afraid we may be exagerating here. There are several other ways that
> an admin can trigger scary warnings, this one is no special. I'd rather
> leave this one to the mm defaults instead.
OK, I'm all for that.
>
>>
>> >
>> >>
>> >> As there will be a fallback allocation later, this patch is just
>> >> to fail silently and return ret, just as commit 0ccc22f425e5
>> >> ("sit: use __GFP_NOWARN for user controlled allocation") did.
>> >>
>> >> Reported-by: Chen Wei <weichen@xxxxxxxxxx>
>> >> Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx>
>> >> ---
>> >> net/sctp/probe.c | 2 +-
>> >> 1 file changed, 1 insertion(+), 1 deletion(-)
>> >>
>> >> diff --git a/net/sctp/probe.c b/net/sctp/probe.c
>> >> index 6cc2152..5bf3164 100644
>> >> --- a/net/sctp/probe.c
>> >> +++ b/net/sctp/probe.c
>> >> @@ -210,7 +210,7 @@ static __init int sctpprobe_init(void)
>> >>
>> >> init_waitqueue_head(&sctpw.wait);
>> >> spin_lock_init(&sctpw.lock);
>> >> - if (kfifo_alloc(&sctpw.fifo, bufsize, GFP_KERNEL))
>> >> + if (kfifo_alloc(&sctpw.fifo, bufsize, GFP_KERNEL | __GFP_NOWARN))
>> >> return ret;
>> >>
>> >> if (!proc_create(procname, S_IRUSR, init_net.proc_net,
>> >> --
>> >> 2.1.0
>> >>
>> >> --
>> >> To unsubscribe from this list: send the line "unsubscribe linux-sctp" in
>> >> the body of a message to majordomo@xxxxxxxxxxxxxxx
>> >> More majordomo info at http://vger.kernel.org/majordomo-info.html
>> >>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-sctp" in
>> the body of a message to majordomo@xxxxxxxxxxxxxxx
>> More majordomo info at http://vger.kernel.org/majordomo-info.html
>>
--
To unsubscribe from this list: send the line "unsubscribe linux-sctp" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
