I've been doing an overhaul of the w1 netlink system and have a patch outstanding to address this issue. It requires patches already accepted in gregkh char-misc-next.
w1: fix netlink refcnt leak on error path I avoided the issue by checking the length before taking any references to avoid adding another goto target. Actually the changes in char-misc-next removed one goto target so with my patch series that routine only has one jump target, much easier to track what's going on than having three. Accepted patches (still need to apply the refcnt patch) git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git char-misc-next Here's my current set of patches on top of char-misc-next. 7cf8baf26cdc2c27bcff562e9b2328ac891dc3a5 https://github.com/dfries/linux.git w1_rework For my setup I have 14 ds18b20 one wire temperature sensors inside and outside of my house connected to the ds2490 USB dongle that I have a program talking over netlink to read every 30 seconds. I'm curious what's your setup? I would appreciate it if I could get some testers on the w1_rework branch and verify it doesn't break anything with other programs. The biggest user visible changes from the w1_rework branch are. w1: new netlink commands, add/remove/list slaves w1: process w1 netlink commands in w1_process thread w1: reply only to the requester portid ds2490 hardware search, much faster search in general, 23 seconds to .3 seconds w1: fix netlink refcnt leak on error path w1: optional bundling of netlink kernel replies With all these changes the program is no longer blocked when issuing commands because the w1_process thread now executes them. That's a pretty big deal if your program has something else to do while waiting for a reply. Then there's the optional bundling, so I can now send one netlink packet which will request a conversion or read a previous conversion for all temperature sensors and the kernel will reply with one netlink packet with all the status or results, instead of something like 56 individual packets. On Sun, Mar 09, 2014 at 12:08:48AM +0100, Richard Weinberger wrote: > If userspace sends a w1 message of length 0 we leak > the refcount. > > Signed-off-by: Richard Weinberger <rich...@nod.at> > --- > drivers/w1/w1_netlink.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/w1/w1_netlink.c b/drivers/w1/w1_netlink.c > index 40788c9..7131777 100644 > --- a/drivers/w1/w1_netlink.c > +++ b/drivers/w1/w1_netlink.c > @@ -355,7 +355,7 @@ static void w1_cn_callback(struct cn_msg *msg, struct > netlink_skb_parms *nsp) > > err = 0; > if (!mlen) > - goto out_cont; > + goto out_dec; > > mutex_lock(&dev->mutex); > > @@ -384,10 +384,11 @@ static void w1_cn_callback(struct cn_msg *msg, struct > netlink_skb_parms *nsp) > mlen -= cmd->len + sizeof(struct w1_netlink_cmd); > } > out_up: > + mutex_unlock(&dev->mutex); > +out_dec: > atomic_dec(&dev->refcnt); > if (sl) > atomic_dec(&sl->refcnt); > - mutex_unlock(&dev->mutex); > out_cont: > if (!cmd || err) > w1_netlink_send_error(msg, m, cmd, err); > -- > 1.8.4.2 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- David Fries <da...@fries.net> PGP pub CB1EE8F0 http://fries.net/~david/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
