2014-01-31 22:30:09

by Alexey Khoroshilov

[permalink] [raw]
Subject: [PATCH] messages: i2o: fix deadlock in compat_ioctl(I2OGETIOPS)

i2o_cfg_compat_ioctl(I2OGETIOPS) locks i2o_cfg_mutex and then calls
i2o_cfg_ioctl(I2OGETIOPS) that locks i2o_cfg_mutex as well.
A deadlock is guaranteed.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov <[email protected]>
---
drivers/message/i2o/i2o_config.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/message/i2o/i2o_config.c b/drivers/message/i2o/i2o_config.c
index a60c188c2bd9..04bd3b6de401 100644
--- a/drivers/message/i2o/i2o_config.c
+++ b/drivers/message/i2o/i2o_config.c
@@ -754,19 +754,19 @@ static long i2o_cfg_compat_ioctl(struct file *file, unsigned cmd,
unsigned long arg)
{
int ret;
- mutex_lock(&i2o_cfg_mutex);
switch (cmd) {
case I2OGETIOPS:
ret = i2o_cfg_ioctl(file, cmd, arg);
break;
case I2OPASSTHRU32:
+ mutex_lock(&i2o_cfg_mutex);
ret = i2o_cfg_passthru32(file, cmd, arg);
+ mutex_unlock(&i2o_cfg_mutex);
break;
default:
ret = -ENOIOCTLCMD;
break;
}
- mutex_unlock(&i2o_cfg_mutex);
return ret;
}

--
1.8.3.2