Re: inconsistent lock/deadlock crash, vanilla 3.3.4, 32bit, tcp

[David Miller]

From: Eric Dumazet <eric.dumazet@xxxxxxxxx>
Date: Sun, 29 Apr 2012 11:21:56 +0200

> From: Eric Dumazet <edumazet@xxxxxxxxxx>
> 
> [PATCH] net: fix sk_sockets_allocated_read_positive
> 
> Denys Fedoryshchenko reported frequent crashes on a proxy server and kindly
> provided a lockdep report that explains it all :
 ...
> Bug is that sk_sockets_allocated_read_positive() calls
> percpu_counter_sum_positive() without BH being disabled.
> 
> This bug was added in commit 180d8cd942ce33
> (foundations of per-cgroup memory pressure controlling.), since previous
> code was using percpu_counter_read_positive() which is IRQ safe.
> 
> In __sk_mem_schedule() we dont need the precise count of allocated
> sockets and can revert to previous behavior.
> 
> Reported-by: Denys Fedoryshchenko <denys@xxxxxxxxxxx>
> Sined-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>

Applied, thanks.
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