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SubjectRe: [syzbot] KASAN: slab-out-of-bounds Read in do_wait_for_common
On Mon, 19 Jul 2021 06:42:25 -0700
syzbot <syzbot+cc699626e48a6ebaf295@syzkaller.appspotmail.com> wrote:

> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: 8096acd7442e Merge tag 'net-5.14-rc2' of
> git://git.kernel... git tree: upstream
> console output:
> https://syzkaller.appspot.com/x/log.txt?x=167ca94a300000 kernel
> config: https://syzkaller.appspot.com/x/.config?x=5294764a378649cb
> dashboard link:
> https://syzkaller.appspot.com/bug?extid=cc699626e48a6ebaf295
> compiler: Debian clang version 11.0.1-2 syz repro:
> https://syzkaller.appspot.com/x/repro.syz?x=14d68024300000 C
> reproducer: https://syzkaller.appspot.com/x/repro.c?x=16e4f180300000
>
> IMPORTANT: if you fix the issue, please add the following tag to the
> commit: Reported-by:
> syzbot+cc699626e48a6ebaf295@syzkaller.appspotmail.com
>
> ==================================================================
> BUG: KASAN: slab-out-of-bounds in debug_spin_lock_before
> kernel/locking/spinlock_debug.c:83 [inline] BUG: KASAN:
> slab-out-of-bounds in do_raw_spin_lock+0x4f5/0x8e0
> kernel/locking/spinlock_debug.c:112 Read of size 4 at addr
> ffff88802b46ce14 by task kworker/0:6/8471
>

I don't see any reason behind doing clean up stuff in firmware
callback. In my prevoius patch to this driver I fixed memory leak and, I
believed, that this approach won't trigger anything else...

Let's just call device_release_driver() under parent lock in case of
firmware load failure and see if it works.

#syz test
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master


With regards,
Pavel Skripkin
From 754dff1a4e90cf0b41ab4dc3a06226738385476f Mon Sep 17 00:00:00 2001
From: Pavel Skripkin <paskripkin@gmail.com>
Date: Tue, 20 Jul 2021 14:05:02 +0300
Subject: [PATCH] staging: rtl8712: rewrite error handling

/* .... */

Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
---
drivers/staging/rtl8712/hal_init.c | 30 ++++++++++++------
drivers/staging/rtl8712/usb_intf.c | 50 +++++++++++++-----------------
2 files changed, 42 insertions(+), 38 deletions(-)

diff --git a/drivers/staging/rtl8712/hal_init.c b/drivers/staging/rtl8712/hal_init.c
index 22974277afa0..4eff3fdecdb8 100644
--- a/drivers/staging/rtl8712/hal_init.c
+++ b/drivers/staging/rtl8712/hal_init.c
@@ -29,21 +29,31 @@
#define FWBUFF_ALIGN_SZ 512
#define MAX_DUMP_FWSZ (48 * 1024)

+static void rtl871x_load_fw_fail(struct _adapter *adapter)
+{
+ struct usb_device *udev = adapter->dvobjpriv.pusbdev;
+ struct device *dev = &udev->dev;
+ struct device *parent = dev->parent;
+
+ complete(&adapter->rtl8712_fw_ready);
+
+ dev_err(&udev->dev, "r8712u: Firmware request failed\n");
+
+ if (parent)
+ device_lock(parent);
+
+ device_release_driver(dev);
+
+ if (parent)
+ device_unlock(parent);
+}
+
static void rtl871x_load_fw_cb(const struct firmware *firmware, void *context)
{
struct _adapter *adapter = context;

if (!firmware) {
- struct usb_device *udev = adapter->dvobjpriv.pusbdev;
- struct usb_interface *usb_intf = adapter->pusb_intf;
-
- dev_err(&udev->dev, "r8712u: Firmware request failed\n");
- usb_put_dev(udev);
- usb_set_intfdata(usb_intf, NULL);
- r8712_free_drv_sw(adapter);
- adapter->dvobj_deinit(adapter);
- complete(&adapter->rtl8712_fw_ready);
- free_netdev(adapter->pnetdev);
+ rtl871x_load_fw_fail(adapter);
return;
}
adapter->fw = firmware;
diff --git a/drivers/staging/rtl8712/usb_intf.c b/drivers/staging/rtl8712/usb_intf.c
index 2434b13c8b12..6440febfd08d 100644
--- a/drivers/staging/rtl8712/usb_intf.c
+++ b/drivers/staging/rtl8712/usb_intf.c
@@ -591,35 +591,29 @@ static void r871xu_dev_remove(struct usb_interface *pusb_intf)
{
struct net_device *pnetdev = usb_get_intfdata(pusb_intf);
struct usb_device *udev = interface_to_usbdev(pusb_intf);
+ struct _adapter *padapter = netdev_priv(pnetdev);
+
+ /* never exit with a firmware callback pending */
+ wait_for_completion(&padapter->rtl8712_fw_ready);
+ usb_set_intfdata(pusb_intf, NULL);
+ release_firmware(padapter->fw);
+ if (drvpriv.drv_registered)
+ padapter->surprise_removed = true;
+ if (pnetdev->reg_state != NETREG_UNINITIALIZED)
+ unregister_netdev(pnetdev); /* will call netdev_close() */
+ flush_scheduled_work();
+ udelay(1);
+ /* Stop driver mlme relation timer */
+ r8712_stop_drv_timers(padapter);
+ r871x_dev_unload(padapter);
+ r8712_free_drv_sw(padapter);
+ free_netdev(pnetdev);
+
+ /* decrease the reference count of the usb device structure
+ * when disconnect
+ */
+ usb_put_dev(udev);

- if (pnetdev) {
- struct _adapter *padapter = netdev_priv(pnetdev);
-
- /* never exit with a firmware callback pending */
- wait_for_completion(&padapter->rtl8712_fw_ready);
- pnetdev = usb_get_intfdata(pusb_intf);
- usb_set_intfdata(pusb_intf, NULL);
- if (!pnetdev)
- goto firmware_load_fail;
- release_firmware(padapter->fw);
- if (drvpriv.drv_registered)
- padapter->surprise_removed = true;
- if (pnetdev->reg_state != NETREG_UNINITIALIZED)
- unregister_netdev(pnetdev); /* will call netdev_close() */
- flush_scheduled_work();
- udelay(1);
- /* Stop driver mlme relation timer */
- r8712_stop_drv_timers(padapter);
- r871x_dev_unload(padapter);
- r8712_free_drv_sw(padapter);
- free_netdev(pnetdev);
-
- /* decrease the reference count of the usb device structure
- * when disconnect
- */
- usb_put_dev(udev);
- }
-firmware_load_fail:
/* If we didn't unplug usb dongle and remove/insert module, driver
* fails on sitesurvey for the first time when device is up.
* Reset usb port for sitesurvey fail issue.
--
2.32.0
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