linux-kernel - Re: [PATCH 00/13] Re: Scalability requirements for sysv ipc

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 15 Apr 2008 08:13:27 +0200
From:	Nadia Derbey <Nadia.Derbey@...l.net>
To:	Manfred Spraul <manfred@...orfullife.com>
Cc:	Peter Zijlstra <peterz@...radead.org>, efault@....de,
	linux-kernel@...r.kernel.org, paulmck@...ux.vnet.ibm.com,
	akpm@...ux-foundation.org, xemul@...nvz.org
Subject: Re: [PATCH 00/13] Re: Scalability requirements for sysv ipc

Manfred Spraul wrote:
> Nadia Derbey wrote:
> 
>>
>> Well, 1 interface changes, 1 is added and another one went away:
>>
>> 1) for the preload part (it becomes like the radix-tree preload part):
>>
>> int idr_pre_get(struct idr *, gfp_t);
>> would become
>> int idr_pre_get(gfp_t);
>>
> Btw, that's one point I didn't understand about the idr code:
> Is it interrupt-safe? It uses spin_lock_irqsave and gfp_t, this implies 
> that it could be called from all contexts.
> 
> But the prealloc made me a bit nervous: does it handle idr_pre_get(); 
> interrupt with another idr_pre_get(), add, pre_get_end, interrupt ends, 
> ... correctly?

I don't know if I'm answering your question, but after allocating, 
idr_pre_get() calls free_layer() which is the routine that inserts the 
allocated memory into the idr free list. And free_layer() calls 
spin_lock_ir_save() to protect this free list modification. So it should 
be safe?

> 
> If it's only intended to be called from process context I would remove 
> the _irqsave and perhaps add an assert(!in_interrupt())

Well, I guess it might be called from any context, since the 
kmem_cache_alloc is called with the gfp_mask routine's parameter?


Regards,
Nadia
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/