patch "bus: mhi: pci_generic: Fix possible use-after-free in" added to char-misc-linus

This is a note to let you know that I've just added the patch titled

bus: mhi: pci_generic: Fix possible use-after-free in

to my char-misc git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From 0b67808ade8893a1b3608ddd74fac7854786c919 Mon Sep 17 00:00:00 2001
From: Wei Yongjun <[email protected]>
Date: Sun, 6 Jun 2021 21:07:40 +0530
Subject: bus: mhi: pci_generic: Fix possible use-after-free in
mhi_pci_remove()

This driver's remove path calls del_timer(). However, that function does not wait until the timer handler finishes. This means that the timer handler may still be running after the driver's remove function has finished, which would result in a use-after-free.

Fix by calling del_timer_sync(), which makes sure the timer handler has finished, and unable to re-schedule itself.

---
 drivers/bus/mhi/pci_generic.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index 8c7f6576e421..0a6619ad292c 100644
@@ -708,7 +708,7 @@ static void mhi_pci_remove(struct pci_dev *pdev)
 	struct mhi_pci_device *mhi_pdev = pci_get_drvdata(pdev);
 	struct mhi_controller *mhi_cntrl = &mhi_pdev->mhi_cntrl;
 
-	del_timer(&mhi_pdev->health_check_timer);
+	del_timer_sync(&mhi_pdev->health_check_timer);
 	cancel_work_sync(&mhi_pdev->recovery_work);
 
 	if (test_and_clear_bit(MHI_PCI_DEV_STARTED, &mhi_pdev->status)) {

2.32.0