Andrew Morton wrote:
On Tue, 20 Feb 2007 16:08:11 +0100
20 Feb was a long time ago, sorry. I was hoping to feed the pcmcia patches
through Dominik but I think he's busy with exams or such. So I get to
pretend to be pcmcia maintainer.
"Markus Rechberger" <[email protected]> wrote:
following patch prevents a mutex/semaphore deadlock within the pcmcia
framework when ejecting devices multiple times using pccardctl eject.
For some more details see:
http://lkml.org/lkml/2007/2/19/58
Signed-off-by: Markus Rechberger <[email protected]>
--
Markus Rechberger
Operating System Research Center
AMD Saxony LLC & Co. KG
[pcmcia-pccard-deadlock-fix.diff text/plain (757B)]
index ac00424..c02bf0d 100644
--- a/drivers/pcmcia/cs.c
+++ b/drivers/pcmcia/cs.c
@@ -856,7 +856,8 @@ int pcmcia_eject_card(struct pcmcia_socket *skt)
cs_dbg(skt, 1, "user eject request\n");
- mutex_lock(&skt->skt_mutex);
+ if (!mutex_trylock(&skt->skt_mutex))
+ return -EAGAIN;
do {
if (!(skt->state & SOCKET_PRESENT)) {
ret = -ENODEV;
index 18e111e..b9d3440 100644
--- a/drivers/pcmcia/ds.c
+++ b/drivers/pcmcia/ds.c
@@ -1100,7 +1100,9 @@ static ssize_t pcmcia_store_allow_func_id_match(struct device *dev,
if (!count)
return -EINVAL;
- mutex_lock(&p_dev->socket->skt_mutex);
+ if (!mutex_trylock(&p_dev->socket->skt_mutex))
+ return -EAGAIN;
+
p_dev->allow_func_id_match = 1;
mutex_unlock(&p_dev->socket->skt_mutex);
This is a pretty sad-looking solution. Does it not mean that sometimes
user-initiated actions will mysteriously fail?
The userspace application should return the appropriate error then. It
can really happen any time when someone tries to eject the pcmcia device
(any time as within 1 minute - never in a normal scenario)
Are you able to provide a more detailed description of why/how the deadlock
actually occurs so that perhaps a more robust fix can be implemented?
There's a description about it in following Email:
http://lkml.org/lkml/2007/2/19/58
Markus
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
