linux-kernel - Re: 2.6.23-rc6-mm1: IPC: sleeping function called ...

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, 18 Sep 2007 03:27:27 -0700
From:	Andrew Morton <akpm@...ux-foundation.org>
To:	Alexey Dobriyan <adobriyan@...ru>
Cc:	nadia.derbey@...l.net, linux-kernel@...r.kernel.org
Subject: Re: 2.6.23-rc6-mm1: IPC: sleeping function called ...

On Tue, 18 Sep 2007 13:17:28 +0400 Alexey Dobriyan <adobriyan@...ru> wrote:

> I'm getting tons of this, and X fails to start
> 
> CONFIG_SYSVIPC=y
> CONFIG_SYSVIPC_SYSCTL=y
> # CONFIG_PREEMPT_NONE is not set
> # CONFIG_PREEMPT_VOLUNTARY is not set
> CONFIG_PREEMPT=y
> CONFIG_PREEMPT_BKL=y
> CONFIG_DEBUG_PREEMPT=y
> 
> BUG: sleeping function called from invalid context at kernel/rwsem.c:47
> in_atomic():1, irqs_disabled():0

OK, this fixes the locking here:

--- a/ipc/util.c~ipc-integrate-ipc_checkid-into-ipc_lock-fix-2
+++ a/ipc/util.c
@@ -295,7 +295,6 @@ int ipc_addid(struct ipc_ids* ids, struc

 	spin_lock_init(&new->lock);
 	new->deleted = 0;
-	rcu_read_lock();
 	spin_lock(&new->lock);
 	return id;
 }
@@ -691,7 +690,7 @@ struct kern_ipc_perm *ipc_lock(struct ip
 		rcu_read_unlock();
 		return ERR_PTR(-EINVAL);
 	}
-
+	rcu_read_unlock();
 	return out;
 }

_

But I'm not very confident in what's happening in there.  The patches take
away a _lot_ of the RCU locking, and it's unlear what's protecting the idr
tree.  Is it rcu, or is it the mutex?  The code seems confused and the
comments are all wrong.
-
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/