Kuppuswamy Sathyanarayanan cd74de676a drivers: base: Fix NULL pointer exception in __platform_driver_probe() if a driver developer is foolish ... [ Upstream commit 388bcc6ecc ] If platform bus driver registration is failed then, accessing platform bus spin lock (&drv->driver.bus->p->klist_drivers.k_lock) in __platform_driver_probe() without verifying the return value __platform_driver_register() can lead to NULL pointer exception. So check the return value before attempting the spin lock. One such example is below: For a custom usecase, I have intentionally failed the platform bus registration and I expected all the platform device/driver registrations to fail gracefully. But I came across this panic issue. [ 1.331067] BUG: kernel NULL pointer dereference, address: 00000000000000c8 [ 1.331118] #PF: supervisor write access in kernel mode [ 1.331163] #PF: error_code(0x0002) - not-present page [ 1.331208] PGD 0 P4D 0 [ 1.331233] Oops: 0002 [#1] PREEMPT SMP [ 1.331268] CPU: 3 PID: 1 Comm: swapper/0 Tainted: G W 5.6.0-00049-g670d35fb0144 #165 [ 1.331341] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 [ 1.331406] RIP: 0010:_raw_spin_lock+0x15/0x30 [ 1.331588] RSP: 0000:ffffc9000001be70 EFLAGS: 00010246 [ 1.331632] RAX: 0000000000000000 RBX: 00000000000000c8 RCX: 0000000000000001 [ 1.331696] RDX: 0000000000000001 RSI: 0000000000000092 RDI: 0000000000000000 [ 1.331754] RBP: 00000000ffffffed R08: 0000000000000501 R09: 0000000000000001 [ 1.331817] R10: ffff88817abcc520 R11: 0000000000000670 R12: 00000000ffffffed [ 1.331881] R13: ffffffff82dbc268 R14: ffffffff832f070a R15: 0000000000000000 [ 1.331945] FS: 0000000000000000(0000) GS:ffff88817bd80000(0000) knlGS:0000000000000000 [ 1.332008] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1.332062] CR2: 00000000000000c8 CR3: 000000000681e001 CR4: 00000000003606e0 [ 1.332126] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 1.332189] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 1.332252] Call Trace: [ 1.332281] __platform_driver_probe+0x92/0xee [ 1.332323] ? rtc_dev_init+0x2b/0x2b [ 1.332358] cmos_init+0x37/0x67 [ 1.332396] do_one_initcall+0x7d/0x168 [ 1.332428] kernel_init_freeable+0x16c/0x1c9 [ 1.332473] ? rest_init+0xc0/0xc0 [ 1.332508] kernel_init+0x5/0x100 [ 1.332543] ret_from_fork+0x1f/0x30 [ 1.332579] CR2: 00000000000000c8 [ 1.332616] ---[ end trace 3bd87f12e9010b87 ]--- [ 1.333549] note: swapper/0[1] exited with preempt_count 1 [ 1.333592] Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000009 [ 1.333736] Kernel Offset: disabled Note, this can only be triggered if a driver errors out from this call, which should never happen. If it does, the driver needs to be fixed. Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> Link: https://lore.kernel.org/r/20200408214003.3356-1-sathyanarayanan.kuppuswamy@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>		2020-06-25 15:32:55 +02:00
..
firmware_loader	firmware: fix a double abort case with fw_load_sysfs_fallback	2020-04-17 10:48:42 +02:00
power	driver core: Remove device link creation limitation	2020-03-20 11:55:58 +01:00
regmap	soundwire: fix regmap dependencies and align with other serial links	2019-10-07 18:57:27 +02:00
test
arch_topology.c	Revert "base: arch_topology: fix section mismatch build warnings"	2018-03-15 14:36:20 +01:00
attribute_container.c
base.h	driver core: Establish order of operations for device_add and device_del via bitflag	2019-08-09 17:52:28 +02:00
bus.c	kobject: return error code if writing /sys/.../uevent fails	2019-02-12 19:47:06 +01:00
cacheinfo.c	drivers: base: cacheinfo: Ensure cpu hotplug work is done before Intel RDT	2019-07-21 09:03:03 +02:00
class.c
component.c	component: Silence bind error on -EPROBE_DEFER	2020-05-27 17:37:33 +02:00
container.c
core.c	driver core: Fix creation of device links with PM-runtime flags	2020-03-20 11:55:58 +01:00
cpu.c	x86/speculation: Add Special Register Buffer Data Sampling (SRBDS) mitigation	2020-06-10 21:35:01 +02:00
dd.c	driver core: Add device link flag DL_FLAG_AUTOPROBE_CONSUMER	2020-03-20 11:55:58 +01:00
devcon.c	drivers: base: Unified device connection lookup	2018-03-22 13:10:29 +01:00
devcoredump.c
devres.c	devres: Align data[] to ARCH_KMALLOC_MINALIGN	2019-02-12 19:46:56 +01:00
devtmpfs.c	kernel: add ksys_unshare() helper; remove in-kernel calls to sys_unshare()	2018-04-02 20:16:06 +02:00
driver.c	driver-core: return EINVAL error instead of BUG_ON()	2018-05-25 18:18:45 +02:00
firmware.c
hypervisor.c
init.c	base: fix order of OF initialization	2018-07-07 17:54:29 +02:00
isa.c
Kconfig	firmware_loader: move kconfig FW_LOADER entries to its own file	2018-05-14 16:43:10 +02:00
Makefile	dma-mapping: move all DMA mapping code to kernel/dma	2018-06-14 08:50:37 +02:00
map.c
memory.c	mm/memory_hotplug: fix try_offline_node()	2020-01-29 16:43:27 +01:00
module.c
node.c	drivers/base/node.c: simplify unregister_memory_block_under_nodes()	2020-01-29 16:43:26 +01:00
pinctrl.c
platform-msi.c	platform-msi: Free descriptors in platform_msi_domain_free()	2019-01-09 17:38:42 +01:00
platform.c	drivers: base: Fix NULL pointer exception in __platform_driver_probe() if a driver developer is foolish	2020-06-25 15:32:55 +02:00
property.c	device property: Get rid of union aliasing	2018-05-17 12:47:21 +02:00
soc.c	base: soc: Export soc_device_register/unregister APIs	2019-10-05 13:09:37 +02:00
syscore.c
topology.c
transport_class.c