This is a note to let you know that I've just added the patch titled net/smc: Fix NULL pointer dereference in smc_pnet_find_ib() to the 5.4-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: net-smc-fix-null-pointer-dereference-in-smc_pnet_fin.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit a0599b243824a2c5fe952d6fbdbe4bddc9635687 Author: Karsten Graul <kgraul@xxxxxxxxxxxxx> Date: Fri Apr 8 17:10:34 2022 +0200 net/smc: Fix NULL pointer dereference in smc_pnet_find_ib() [ Upstream commit d22f4f977236f97e01255a80bca2ea93a8094fc8 ] dev_name() was called with dev.parent as argument but without to NULL-check it before. Solve this by checking the pointer before the call to dev_name(). Fixes: af5f60c7e3d5 ("net/smc: allow PCI IDs as ib device names in the pnet table") Reported-by: syzbot+03e3e228510223dabd34@xxxxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Karsten Graul <kgraul@xxxxxxxxxxxxx> Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/net/smc/smc_pnet.c b/net/smc/smc_pnet.c index 571e6d84da3b..660608202f28 100644 --- a/net/smc/smc_pnet.c +++ b/net/smc/smc_pnet.c @@ -295,8 +295,9 @@ static struct smc_ib_device *smc_pnet_find_ib(char *ib_name) list_for_each_entry(ibdev, &smc_ib_devices.list, list) { if (!strncmp(ibdev->ibdev->name, ib_name, sizeof(ibdev->ibdev->name)) || - !strncmp(dev_name(ibdev->ibdev->dev.parent), ib_name, - IB_DEVICE_NAME_MAX - 1)) { + (ibdev->ibdev->dev.parent && + !strncmp(dev_name(ibdev->ibdev->dev.parent), ib_name, + IB_DEVICE_NAME_MAX - 1))) { goto out; } }