This is a note to let you know that I've just added the patch titled i2c: i801: Use PCI bus rescan mutex to protect P2SB access to the 5.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: i2c-i801-use-pci-bus-rescan-mutex-to-protect-p2sb-ac.patch and it can be found in the queue-5.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 8ea75b453dd9b4e3479f7174d21970aaa803dd2a Author: Heiner Kallweit <hkallweit1@xxxxxxxxx> Date: Sun Sep 5 17:59:42 2021 +0200 i2c: i801: Use PCI bus rescan mutex to protect P2SB access [ Upstream commit 7d6b61c394a42b8385858bb9e306d48a0112823c ] As pointed out by Andy in [0] using a local mutex here isn't strictly wrong but not sufficient. We should hold the PCI rescan lock for P2SB operations. [0] https://www.spinics.net/lists/linux-i2c/msg52717.html Fixes: 1a987c69ce2c ("i2c: i801: make p2sb_spinlock a mutex") Reported-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxx> Signed-off-by: Heiner Kallweit <hkallweit1@xxxxxxxxx> Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxx> Reviewed-by: Jean Delvare <jdelvare@xxxxxxx> Signed-off-by: Wolfram Sang <wsa@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c index 89ae78ef1a1cc..1f929e6c30bea 100644 --- a/drivers/i2c/busses/i2c-i801.c +++ b/drivers/i2c/busses/i2c-i801.c @@ -1493,7 +1493,6 @@ static struct platform_device * i801_add_tco_spt(struct i801_priv *priv, struct pci_dev *pci_dev, struct resource *tco_res) { - static DEFINE_MUTEX(p2sb_mutex); struct resource *res; unsigned int devfn; u64 base64_addr; @@ -1506,7 +1505,7 @@ i801_add_tco_spt(struct i801_priv *priv, struct pci_dev *pci_dev, * enumerated by the PCI subsystem, so we need to unhide/hide it * to lookup the P2SB BAR. */ - mutex_lock(&p2sb_mutex); + pci_lock_rescan_remove(); devfn = PCI_DEVFN(PCI_SLOT(pci_dev->devfn), 1); @@ -1524,7 +1523,7 @@ i801_add_tco_spt(struct i801_priv *priv, struct pci_dev *pci_dev, /* Hide the P2SB device, if it was hidden before */ if (hidden) pci_bus_write_config_byte(pci_dev->bus, devfn, 0xe1, hidden); - mutex_unlock(&p2sb_mutex); + pci_unlock_rescan_remove(); res = &tco_res[1]; if (pci_dev->device == PCI_DEVICE_ID_INTEL_DNV_SMBUS)