From: "Paul E. McKenney" <paulmck@us.ibm.com>
To: Suzanne Wood <suzannew@cs.pdx.edu>
Cc: linux-kernel@vger.kernel.org, SteveW@ACM.org, walpole@cs.pdx.edu
Subject: Re: rcu read-side protection
Date: Tue, 16 Aug 2005 19:01:57 -0700 [thread overview]
Message-ID: <20050817020156.GF1319@us.ibm.com> (raw)
In-Reply-To: <000f01c5a2bf$f8e752d0$6401a8c0@woodworkxi42l4>
On Tue, Aug 16, 2005 at 05:09:29PM -0700, Suzanne Wood wrote:
[ . . . ]
> A read-side critical section is marked to protect the dereference of the
> dn_ptr and assignment to dn_db which is a pointer to a dn_dev. (struct
> net_device is defined in /linux/netdevice.h and its dn_ptr in
> /include/net/dn_dev.h) Should this rcu-protection be extended to the line
> following rcu_read_lock()? Even though use_long is a simple char, it
> appears to be a member of an rcu-protected structure.
Looks to me that this could indeed be a problem -- the structure
pointed to by dn_db could potentially be freed immediately after the
rcu_read_unlock(), unless there is some other non-obvious locking
mechanism protecting it. In which case, why the rcu_read_lock()
and rcu_read_unlock()...
Thanx, Paul
next prev parent reply other threads:[~2005-08-17 2:01 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-08-17 0:09 rcu read-side protection Suzanne Wood
2005-08-17 2:01 ` Paul E. McKenney [this message]
2005-08-17 8:25 ` Steven Whitehouse
2005-08-17 14:14 ` Paul E. McKenney
2005-08-17 14:45 ` Steven Whitehouse
2005-08-17 15:21 ` Patrick Caulfield
2005-08-17 19:05 ` David S. Miller
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