From: Pavel Skripkin <paskripkin@gmail.com>
To: Larry.Finger@lwfinger.net, florian.c.schilhabel@googlemail.com,
gregkh@linuxfoundation.org
Cc: linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org,
Pavel Skripkin <paskripkin@gmail.com>
Subject: [PATCH 3/3] staging: rtl8712: fix memory leak in rtl871x_load_fw_cb
Date: Mon, 14 Jun 2021 01:00:19 +0300 [thread overview]
Message-ID: <81e68fe0194499cc2e7692d35bc4dcf167827d8f.1623620630.git.paskripkin@gmail.com> (raw)
In-Reply-To: <cover.1623620630.git.paskripkin@gmail.com>
There is a leak in rtl8712 driver.
The problem was in non-freed adapter data if
firmware load failed.
This leak can be reproduced with this code:
https://syzkaller.appspot.com/text?tag=ReproC&x=16612f02d00000,
Autoload must fail (to not hit memory leak reported by syzkaller)
There are 2 possible ways how rtl871x_load_fw_cb() and
r871xu_dev_remove() can be called (in case of fw load error).
1st case:
r871xu_dev_remove() then rtl871x_load_fw_cb()
In this case r871xu_dev_remove() will wait for
completion and then will jump to the end, because
rtl871x_load_fw_cb() set intfdata to NULL:
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;
... clean up code here ...
}
2nd case:
rtl871x_load_fw_cb() then r871xu_dev_remove()
In this case pnetdev (from code snippet above) will
be zero (because rtl871x_load_fw_cb() set it to NULL)
And clean up code won't be executed again.
So, in all cases we need to free adapted data in rtl871x_load_fw_cb(),
because disconnect function cannot take care of it. And there won't be
any race conditions, because complete() call happens after setting
intfdata to NULL.
In previous patch I moved out free_netdev() from r8712_free_drv_sw()
and that's why now it's possible to free adapter data and then call
complete.
Fixes: 8c213fa59199 ("staging: r8712u: Use asynchronous firmware loading")
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
---
drivers/staging/rtl8712/hal_init.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/staging/rtl8712/hal_init.c b/drivers/staging/rtl8712/hal_init.c
index 715f1fe8b472..22974277afa0 100644
--- a/drivers/staging/rtl8712/hal_init.c
+++ b/drivers/staging/rtl8712/hal_init.c
@@ -40,7 +40,10 @@ static void rtl871x_load_fw_cb(const struct firmware *firmware, void *context)
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);
return;
}
adapter->fw = firmware;
--
2.32.0
prev parent reply other threads:[~2021-06-13 22:00 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-13 21:59 [PATCH 0/3] staging: rtl8712: code improvment and bug fixes Pavel Skripkin
2021-06-13 22:00 ` [PATCH 1/3] staging: rtl8712: remove redundant check in r871xu_drv_init Pavel Skripkin
2021-06-13 22:00 ` [PATCH 2/3] staging: rtl8712: fix error handling " Pavel Skripkin
2021-06-13 22:00 ` Pavel Skripkin [this message]
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