[PATCH 3.16 024/366] rtl8187: Fix NULL pointer dereference in priv->conf_mutex

Ben Hutchings
2018-10-14T23:38:27Z

From: Sudhir Sreedharan <ssreedharan@mvista.com>

commit 7972326a26b5bf8dc2adac575c4e03ee7e9d193a upstream.

This can be reproduced by bind/unbind the driver multiple times
in AM3517 board.

Analysis revealed that rtl8187_start() was invoked before probe
finishes(ie. before the mutex is initialized).

INFO: trying to register non-static key.
the code is fine but needs lockdep annotation.
turning off the locking correctness validator.
CPU: 0 PID: 821 Comm: wpa_supplicant Not tainted 4.9.80-dirty #250
Hardware name: Generic AM3517 (Flattened Device Tree)
[<c010e0d8>] (unwind_backtrace) from [<c010beac>] (show_stack+0x10/0x14)
[<c010beac>] (show_stack) from [<c017401c>] (register_lock_class+0x4f4/0x55c)
[<c017401c>] (register_lock_class) from [<c0176fe0>] (__lock_acquire+0x74/0x1938)
[<c0176fe0>] (__lock_acquire) from [<c0178cfc>] (lock_acquire+0xfc/0x23c)
[<c0178cfc>] (lock_acquire) from [<c08aa2f8>] (mutex_lock_nested+0x50/0x3b0)
[<c08aa2f8>] (mutex_lock_nested) from [<c05f5bf8>] (rtl8187_start+0x2c/0xd54)
[<c05f5bf8>] (rtl8187_start) from [<c082dea0>] (drv_start+0xa8/0x320)
[<c082dea0>] (drv_start) from [<c084d1d4>] (ieee80211_do_open+0x2bc/0x8e4)
[<c084d1d4>] (ieee80211_do_open) from [<c069be94>] (__dev_open+0xb8/0x120)
[<c069be94>] (__dev_open) from [<c069c11c>] (__dev_change_flags+0x88/0x14c)
[<c069c11c>] (__dev_change_flags) from [<c069c1f8>] (dev_change_flags+0x18/0x48)
[<c069c1f8>] (dev_change_flags) from [<c0710b08>] (devinet_ioctl+0x738/0x840)
[<c0710b08>] (devinet_ioctl) from [<c067925c>] (sock_ioctl+0x164/0x2f4)
[<c067925c>] (sock_ioctl) from [<c02883f8>] (do_vfs_ioctl+0x8c/0x9d0)
[<c02883f8>] (do_vfs_ioctl) from [<c0288da8>] (SyS_ioctl+0x6c/0x7c)
[<c0288da8>] (SyS_ioctl) from [<c0107760>] (ret_fast_syscall+0x0/0x1c)
Unable to handle kernel NULL pointer dereference at virtual address 00000000
pgd = cd1ec000
[00000000] *pgd=8d1de831, *pte=00000000, *ppte=00000000
Internal error: Oops: 817 [#1] PREEMPT ARM
Modules linked in:
CPU: 0 PID: 821 Comm: wpa_supplicant Not tainted 4.9.80-dirty #250
Hardware name: Generic AM3517 (Flattened Device Tree)
task: ce73eec0 task.stack: cd1ea000
PC is at mutex_lock_nested+0xe8/0x3b0
LR is at mutex_lock_nested+0xd0/0x3b0

Signed-off-by: Sudhir Sreedharan <ssreedharan@mvista.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
[bwh: Backported to 3.16: adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/net/wireless/rtl818x/rtl8187/dev.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/net/wireless/rtl818x/rtl8187/dev.c
+++ b/drivers/net/wireless/rtl818x/rtl8187/dev.c
@@ -1454,6 +1454,7 @@ static int rtl8187_probe(struct usb_inte
goto err_free_dev;
}
mutex_init(&priv->io_mutex);
+ mutex_init(&priv->conf_mutex);

SET_IEEE80211_DEV(dev, &intf->dev);
usb_set_intfdata(intf, dev);
@@ -1627,7 +1628,6 @@ static int rtl8187_probe(struct usb_inte
printk(KERN_ERR "rtl8187: Cannot register device\n");
goto err_free_dmabuf;
}
- mutex_init(&priv->conf_mutex);
skb_queue_head_init(&priv->b_tx_status.queue);

wiphy_info(dev->wiphy, "hwaddr %pM, %s V%d + %s, rfkill mask %d\n",