This is a note to let you know that I've just added the patch titled nfc: fix segfault in nfc_genl_dump_devices_done to the 4.4-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: nfc-fix-segfault-in-nfc_genl_dump_devices_done.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From fd79a0cbf0b2e34bcc45b13acf962e2032a82203 Mon Sep 17 00:00:00 2001 From: Tadeusz Struk <tadeusz.struk@xxxxxxxxxx> Date: Wed, 8 Dec 2021 10:27:42 -0800 Subject: nfc: fix segfault in nfc_genl_dump_devices_done From: Tadeusz Struk <tadeusz.struk@xxxxxxxxxx> commit fd79a0cbf0b2e34bcc45b13acf962e2032a82203 upstream. When kmalloc in nfc_genl_dump_devices() fails then nfc_genl_dump_devices_done() segfaults as below KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f] CPU: 0 PID: 25 Comm: kworker/0:1 Not tainted 5.16.0-rc4-01180-g2a987e65025e-dirty #5 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-6.fc35 04/01/2014 Workqueue: events netlink_sock_destruct_work RIP: 0010:klist_iter_exit+0x26/0x80 Call Trace: <TASK> class_dev_iter_exit+0x15/0x20 nfc_genl_dump_devices_done+0x3b/0x50 genl_lock_done+0x84/0xd0 netlink_sock_destruct+0x8f/0x270 __sk_destruct+0x64/0x3b0 sk_destruct+0xa8/0xd0 __sk_free+0x2e8/0x3d0 sk_free+0x51/0x90 netlink_sock_destruct_work+0x1c/0x20 process_one_work+0x411/0x710 worker_thread+0x6fd/0xa80 Link: https://syzkaller.appspot.com/bug?id=fc0fa5a53db9edd261d56e74325419faf18bd0df Reported-by: syzbot+f9f76f4a0766420b4a02@xxxxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Tadeusz Struk <tadeusz.struk@xxxxxxxxxx> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20211208182742.340542-1-tadeusz.struk@xxxxxxxxxx Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/nfc/netlink.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/net/nfc/netlink.c +++ b/net/nfc/netlink.c @@ -632,8 +632,10 @@ static int nfc_genl_dump_devices_done(st { struct class_dev_iter *iter = (struct class_dev_iter *) cb->args[0]; - nfc_device_iter_exit(iter); - kfree(iter); + if (iter) { + nfc_device_iter_exit(iter); + kfree(iter); + } return 0; } Patches currently in stable-queue which might be from tadeusz.struk@xxxxxxxxxx are queue-4.4/nfc-fix-segfault-in-nfc_genl_dump_devices_done.patch