@@ -59,16 +59,32 @@ MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS28EA00));
static int w1_strong_pullup = 1;
module_param_named(strong_pullup, w1_strong_pullup, int, 0);
+struct w1_therm_family_data {
+ uint8_t rom[9];
+ atomic_t refcnt;
+};
+
+/* return the address of the refcnt in the family data */
+#define THERM_REFCNT(family_data) \
+ (&((struct w1_therm_family_data*)family_data)->refcnt)
+
static int w1_therm_add_slave(struct w1_slave *sl)
{
- sl->family_data = kzalloc(9, GFP_KERNEL);
+ sl->family_data = kzalloc(sizeof(struct w1_therm_family_data),
+ GFP_KERNEL);
if (!sl->family_data)
return -ENOMEM;
+ atomic_set(THERM_REFCNT(sl->family_data), 1);
return 0;
}
static void w1_therm_remove_slave(struct w1_slave *sl)
{
+ int refcnt = atomic_sub_return(1, THERM_REFCNT(sl->family_data));
+ while(refcnt) {
+ msleep(1000);
+ refcnt = atomic_read(THERM_REFCNT(sl->family_data));
+ }
kfree(sl->family_data);
sl->family_data = NULL;
}
@@ -194,13 +210,22 @@ static ssize_t w1_slave_show(struct device *device,
struct w1_slave *sl = dev_to_w1_slave(device);
struct w1_master *dev = sl->master;
u8 rom[9], crc, verdict, external_power;
- int i, max_trying = 10;
+ int i, ret, max_trying = 10;
ssize_t c = PAGE_SIZE;
+ u8 *family_data = sl->family_data;
+
+ ret = mutex_lock_interruptible(&dev->bus_mutex);
+ if (ret != 0)
+ goto post_unlock;
- i = mutex_lock_interruptible(&dev->bus_mutex);
- if (i != 0)
- return i;
+ if(!sl->family_data)
+ {
+ ret = -ENODEV;
+ goto pre_unlock;
+ }
+ /* prevent the slave from going away in sleep */
+ atomic_inc(THERM_REFCNT(family_data));
memset(rom, 0, sizeof(rom));
while (max_trying--) {
@@ -230,17 +255,19 @@ static ssize_t w1_slave_show(struct device *device,
mutex_unlock(&dev->bus_mutex);
sleep_rem = msleep_interruptible(tm);
- if (sleep_rem != 0)
- return -EINTR;
+ if (sleep_rem != 0) {
+ ret = -EINTR;
+ goto post_unlock;
+ }
- i = mutex_lock_interruptible(&dev->bus_mutex);
- if (i != 0)
- return i;
+ ret = mutex_lock_interruptible(&dev->bus_mutex);
+ if (ret != 0)
+ goto post_unlock;
} else if (!w1_strong_pullup) {
sleep_rem = msleep_interruptible(tm);
if (sleep_rem != 0) {
- mutex_unlock(&dev->bus_mutex);
- return -EINTR;
+ ret = -EINTR;
+ goto pre_unlock;
}
}
@@ -269,19 +296,24 @@ static ssize_t w1_slave_show(struct device *device,
c -= snprintf(buf + PAGE_SIZE - c, c, ": crc=%02x %s\n",
crc, (verdict) ? "YES" : "NO");
if (verdict)
- memcpy(sl->family_data, rom, sizeof(rom));
+ memcpy(family_data, rom, sizeof(rom));
else
dev_warn(device, "Read failed CRC check\n");
for (i = 0; i < 9; ++i)
c -= snprintf(buf + PAGE_SIZE - c, c, "%02x ",
- ((u8 *)sl->family_data)[i]);
+ ((u8 *)family_data)[i]);
c -= snprintf(buf + PAGE_SIZE - c, c, "t=%d\n",
w1_convert_temp(rom, sl->family->fid));
+ ret = PAGE_SIZE - c;
+
+pre_unlock:
mutex_unlock(&dev->bus_mutex);
- return PAGE_SIZE - c;
+post_unlock:
+ atomic_dec(THERM_REFCNT(family_data));
+ return ret;
}
static int __init w1_therm_init(void)
This is a note to let you know that I have just added a patch titled w1_therm reference count family data to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue This patch is scheduled to be released in version 3.19.y-ckt4. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.19.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ------ From b1371761a3d9bd1a93d83711d43a2de39fb1bf7f Mon Sep 17 00:00:00 2001 From: David Fries <David@Fries.net> Date: Fri, 8 May 2015 19:51:50 -0500 Subject: w1_therm reference count family data commit f7134eea05b2fb4a2c0935f8a540539fff01f3eb upstream. A temperature conversion can take 750 ms and when possible the w1_therm slave driver drops the bus_mutex to allow other bus operations, but that includes operations such as a periodic slave search, which can remove this slave when it is no longer detected. If that happens the sl->family_data will be freed and set to NULL causing w1_slave_show to crash when it wakes up. Signed-off-by: David Fries <David@Fries.net> Reported-By: Thorsten Bschorr <thorsten@bschorr.de> Tested-by: Thorsten Bschorr <thorsten@bschorr.de> Acked-by: Evgeniy Polyakov <zbr@ioremap.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- drivers/w1/slaves/w1_therm.c | 62 +++++++++++++++++++++++++++++++++----------- 1 file changed, 47 insertions(+), 15 deletions(-) -- 1.9.1