Messages in this thread | | | From | Rainer Weikusat <> | Subject | Re: [PATCH net] af_unix: Guard against other == sk in unix_dgram_sendmsg | Date | Fri, 12 Feb 2016 20:59:57 +0000 |
| |
Ben Hutchings <ben@decadent.org.uk> writes: > On Fri, 2016-02-12 at 20:17 +0000, Rainer Weikusat wrote:
[...]
>>>> I don't think this should apply when >>>> receiving and sending sockets are identical. But that's just my >>>> opinion. The other option would be to avoid the unix_state_double_lock >>>> for sk == other. >>> >>> Given that unix_state_double_lock() already handles sk == other, I'm >>> not sure why you think it needs to be avoided. >> >> Because the whole complication of restarting the operation after locking >> both sk and other because other had to be unlocked before calling >> unix_state_double_lock is useless for this case:
[...]
> Well of course it's useless, but it's also harmless.
As is adding a
for (i = 0; i < 1000000; ++i);
between any two statements. And this isn't even entirely true as the pointless double-lock will then require "did we pointlessly doube-lock" checks elsewhere. I think it should be possible to do this in a simpler way by not pointlessly double-locking (this may be wrong but it's worth a try).
> If we really wanted to optimise this we could also skip unlocking if > other < sk.
I wouldn't want to hardcode assumptions about the unix_state_double_lock algorithm in functions using it.
| |