Re: [PATCH] tcp: Replace infinite loop on recvmsg bug with proper crash

From: Julius Werner
Date: Tue Nov 06 2012 - 20:51:09 EST


> We've had reports of this WARN against the Fedora kernel for a while.
> Had this been immediately followed by a BUG(), we'd have never seen those traces at all,
> and just got "my machine just locked up" reports instead.
>
> The proper fix here is to find out why we're getting into this state.

Are you sure you don't mean the WARN below that ("recvmsg bug 2")
instead? I don't think this one can happen without eventually running
into the syslog overflow issue I described.

I agree that the underlying cause must be fixed too, but as we will
always have bugs in the kernel I think proper handling when it does
happen is also important (and filling the hard disk with junk is
obviously not the best approach). If you think a full panic is too
extreme, I have an alternative version of this patch that logs the
WARN once, closes the socket, and returns EBADFD from the syscall...
would you think that is more appropriate?
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