From f22e52b89e036fd12b9374212da8b5d4a447bd1e Mon Sep 17 00:00:00 2001 From: Stefan Richter Date: Sat, 16 Aug 2008 00:15:16 +0200 Subject: ieee1394: raw1394: make write() thread-safe Application programs should use a libraw1394 handle only in a single thread. The raw1394 driver was apparently relying on this, because it did nothing to protect its fi->state variable from corruption due to concurrent accesses. We now serialize the fi->state accesses. This affects the write() path. We re-use the state_mutex which was introduced to protect fi->iso_state accesses in the ioctl() path. These paths and accesses are independent of each other, hence separate mutexes could be used. But I don't see much benefit in that. Signed-off-by: Stefan Richter --- drivers/ieee1394/raw1394.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'drivers/ieee1394') diff --git a/drivers/ieee1394/raw1394.c b/drivers/ieee1394/raw1394.c index d1594427601f9..2cf4ae75becaf 100644 --- a/drivers/ieee1394/raw1394.c +++ b/drivers/ieee1394/raw1394.c @@ -2268,6 +2268,8 @@ static ssize_t raw1394_write(struct file *file, const char __user * buffer, return -EFAULT; } + mutex_lock(&fi->state_mutex); + switch (fi->state) { case opened: retval = state_opened(fi, req); @@ -2282,6 +2284,8 @@ static ssize_t raw1394_write(struct file *file, const char __user * buffer, break; } + mutex_unlock(&fi->state_mutex); + if (retval < 0) { free_pending_request(req); } else { -- cgit 1.2.3-korg