This is a note to let you know that I've just added the patch titled ata: libata-transport: fix double ata_host_put() in ata_tport_add() 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: ata-libata-transport-fix-double-ata_host_put-in-ata_.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 d40afcb6312043bedb0248ff87f4091032e958d5 Author: Yang Yingliang <yangyingliang@xxxxxxxxxx> Date: Tue Nov 8 21:40:01 2022 +0800 ata: libata-transport: fix double ata_host_put() in ata_tport_add() [ Upstream commit 8c76310740807ade5ecdab5888f70ecb6d35732e ] In the error path in ata_tport_add(), when calling put_device(), ata_tport_release() is called, it will put the refcount of 'ap->host'. And then ata_host_put() is called again, the refcount is decreased to 0, ata_host_release() is called, all ports are freed and set to null. When unbinding the device after failure, ata_host_stop() is called to release the resources, it leads a null-ptr-deref(), because all the ports all freed and null. Unable to handle kernel NULL pointer dereference at virtual address 0000000000000008 CPU: 7 PID: 18671 Comm: modprobe Kdump: loaded Tainted: G E 6.1.0-rc3+ #8 pstate: 80400009 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : ata_host_stop+0x3c/0x84 [libata] lr : release_nodes+0x64/0xd0 Call trace: ata_host_stop+0x3c/0x84 [libata] release_nodes+0x64/0xd0 devres_release_all+0xbc/0x1b0 device_unbind_cleanup+0x20/0x70 really_probe+0x158/0x320 __driver_probe_device+0x84/0x120 driver_probe_device+0x44/0x120 __driver_attach+0xb4/0x220 bus_for_each_dev+0x78/0xdc driver_attach+0x2c/0x40 bus_add_driver+0x184/0x240 driver_register+0x80/0x13c __pci_register_driver+0x4c/0x60 ahci_pci_driver_init+0x30/0x1000 [ahci] Fix this by removing redundant ata_host_put() in the error path. Fixes: 2623c7a5f279 ("libata: add refcounting to ata_host") Signed-off-by: Yang Yingliang <yangyingliang@xxxxxxxxxx> Signed-off-by: Damien Le Moal <damien.lemoal@xxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/ata/libata-transport.c b/drivers/ata/libata-transport.c index 93d6920cd86c..2b1e3403570c 100644 --- a/drivers/ata/libata-transport.c +++ b/drivers/ata/libata-transport.c @@ -317,7 +317,6 @@ int ata_tport_add(struct device *parent, tport_err: transport_destroy_device(dev); put_device(dev); - ata_host_put(ap->host); return error; }