Ben Greear reported:
> I see lots of instability as soon as I load up the carl9710 NIC.
> My application is going to be poking at it's debugfs files...
>
> BUG: KASAN: slab-out-of-bounds in carl9170_debugfs_read+0xd5/0x2a0
> [carl9170] at addr 0xffff8801bc1208b0
> Read of size 8 by task btserver/5888
> =======================================================================
> BUG kmalloc-256 (Tainted: G W ): kasan: bad access detected
> -----------------------------------------------------------------------
>
> INFO: Allocated in seq_open+0x50/0x100 age=2690 cpu=2 pid=772
>...
This breakage was caused by the introduction of intermediate
fops in debugfs by commit 9fd4dcece43a
("debugfs: prevent access to possibly dead file_operations at file open")
Thankfully, the original/real fops are still available in d_fsdata.
Reported-by: Ben Greear <greearb@xxxxxxxxxxxxxxx>
Signed-off-by: Christian Lamparter <chunkeey@xxxxxxxxx>
Cc: stable <stable@xxxxxxxxxxxxxxx> # 4.7+
---
drivers/net/wireless/ath/carl9170/debug.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/net/wireless/ath/carl9170/debug.c b/drivers/net/wireless/ath/carl9170/debug.c
index 6808db4..ec3a64e 100644
--- a/drivers/net/wireless/ath/carl9170/debug.c
+++ b/drivers/net/wireless/ath/carl9170/debug.c
@@ -75,7 +75,8 @@ static ssize_t carl9170_debugfs_read(struct file *file, char __user *userbuf,
if (!ar)
return -ENODEV;
- dfops = container_of(file->f_op, struct carl9170_debugfs_fops, fops);
+ dfops = container_of(debugfs_real_fops(file),
+ struct carl9170_debugfs_fops, fops);
if (!dfops->read)
return -ENOSYS;
@@ -127,7 +128,8 @@ static ssize_t carl9170_debugfs_write(struct file *file,
if (!ar)
return -ENODEV;
- dfops = container_of(file->f_op, struct carl9170_debugfs_fops, fops);
+ dfops = container_of(debugfs_real_fops(file),
+ struct carl9170_debugfs_fops, fops);
if (!dfops->write)
return -ENOSYS;
--
2.9.3
