| Message ID | 20220412112300.106640-1-duoming@zju.edu.cn (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | None | expand |
diff --git a/drivers/nfc/nfcmrvl/fw_dnld.c b/drivers/nfc/nfcmrvl/fw_dnld.c index c22a4556db5..8188d466a01 100644 --- a/drivers/nfc/nfcmrvl/fw_dnld.c +++ b/drivers/nfc/nfcmrvl/fw_dnld.c @@ -116,7 +116,10 @@ static void fw_dnld_over(struct nfcmrvl_private *priv, u32 error) nfcmrvl_chip_halt(priv); } - nfc_fw_download_done(priv->ndev->nfc_dev, priv->fw_dnld.name, error); + spin_lock_irq(&priv->fw_dnld.lock); + if (priv->ndev->nfc_dev->fw_download_in_progress) + nfc_fw_download_done(priv->ndev->nfc_dev, priv->fw_dnld.name, error); + spin_unlock_irq(&priv->fw_dnld.lock); } static void fw_dnld_timeout(struct timer_list *t)
There are potential double free bug in nfc_fw_download_done(). The timer handler fw_dnld_timeout() and work item fw_dnld_rx_work() could both reach in fw_dnld_over() and nfc_fw_download_done() is not protected by any lock, which leads to double free. The race between fw_dnld_rx_work() and fw_dnld_timeout() can be shown as below: (Thread 1) | (Thread 2) fw_dnld_timeout | fw_dnld_rx_work | fw_dnld_over fw_dnld_over | nfc_fw_download_done nfc_fw_download_done | nfc_genl_fw_download_done nfc_genl_fw_download_done| nlmsg_free(msg) //(1) nlmsg_free(msg) //(2) | ... ... | The nlmsg_free() will deallocate sk_buff in position (1), but nlmsg_free will be deallocated again in position (2), which leads to double free. This patch adds spin_lock_irq() and check in fw_dnld_over() in order to synchronize among different threads that call fw_dnld_over(). So the double free bug could be prevented. Fixes: 3194c6870158e3 ("NFC: nfcmrvl: add firmware download support") Signed-off-by: Duoming Zhou <duoming@zju.edu.cn> Reviewed-by: Lin Ma <linma@zju.edu.cn> --- Changes in V2: - Fix the check in spin_lock_irq. drivers/nfc/nfcmrvl/fw_dnld.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)