linux-kernel - Re: [PATCH] sys_ioprio

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:	Mon, 21 Aug 2006 00:50:34 +0400
From:	Oleg Nesterov <oleg@...sign.ru>
To:	Jens Axboe <axboe@...e.de>
Cc:	Andrew Morton <akpm@...l.org>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] sys_ioprio_set: don't disable irqs

Question: why do we need to disable irqs in exit_io_context() ?
Why do we need ->alloc_lock to clear io_context->task ?

In other words, could you explain why the patch below is not correct.

Thanks,

Oleg.

--- 2.6.18-rc4/block/ll_rw_blk.c~6_exit	2006-08-20 19:30:10.000000000 +0400
+++ 2.6.18-rc4/block/ll_rw_blk.c	2006-08-20 22:34:46.000000000 +0400
@@ -3580,25 +3580,22 @@ EXPORT_SYMBOL(put_io_context);
 /* Called by the exitting task */
 void exit_io_context(void)
 {
-	unsigned long flags;
 	struct io_context *ioc;
 	struct cfq_io_context *cic;
 
-	local_irq_save(flags);
 	task_lock(current);
 	ioc = current->io_context;
 	current->io_context = NULL;
-	ioc->task = NULL;
 	task_unlock(current);
-	local_irq_restore(flags);
 
+	ioc->task = NULL;
 	if (ioc->aic && ioc->aic->exit)
 		ioc->aic->exit(ioc->aic);
 	if (ioc->cic_root.rb_node != NULL) {
 		cic = rb_entry(rb_first(&ioc->cic_root), struct cfq_io_context, rb_node);
 		cic->exit(ioc);
 	}
- 
+
 	put_io_context(ioc);
 }
 

-
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/