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Date: Wed, 30 Aug 2006 18:57:59 +0400 From: Oleg Nesterov <oleg@...sign.ru> To: Roman Zippel <zippel@...ux-m68k.org> Cc: Kirill Korotaev <dev@...ru>, Andrew Morton <akpm@...l.org>, Linux Kernel Mailing List <linux-kernel@...r.kernel.org>, Alan Cox <alan@...rguk.ukuu.org.uk>, Christoph Hellwig <hch@...radead.org>, Pavel Emelianov <xemul@...nvz.org>, Andrey Savochkin <saw@...ru>, devel@...nvz.org, Rik van Riel <riel@...hat.com>, Andi Kleen <ak@...e.de>, Alexey Dobriyan <adobriyan@...l.ru>, Matt Helsley <matthltc@...ibm.com>, CKRM-Tech <ckrm-tech@...ts.sourceforge.net> Subject: Re: [PATCH 1/7] introduce atomic_dec_and_lock_irqsave() On 08/30, Roman Zippel wrote: > Hi, > > On Tue, 29 Aug 2006, Kirill Korotaev wrote: > > > --- ./kernel/user.c.dlirq 2006-07-10 12:39:20.000000000 +0400 > > +++ ./kernel/user.c 2006-08-28 11:08:56.000000000 +0400 > > @@ -108,15 +108,12 @@ void free_uid(struct user_struct *up) > > if (!up) > > return; > > > > - local_irq_save(flags); > > - if (atomic_dec_and_lock(&up->__count, &uidhash_lock)) { > > + if (atomic_dec_and_lock_irqsave(&up->__count, &uidhash_lock, flags)) { > > uid_hash_remove(up); > > spin_unlock_irqrestore(&uidhash_lock, flags); > > key_put(up->uid_keyring); > > key_put(up->session_keyring); > > kmem_cache_free(uid_cachep, up); > > - } else { > > - local_irq_restore(flags); > > } > > } > > Why does this need protection against interrupts? uidhash_lock can be taken from irq context. For example, delayed_put_task_struct() does __put_task_struct()->free_uid(). Oleg. - 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/
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