linux_dsm_epyc7002/drivers/base
Kuppuswamy Sathyanarayanan 388bcc6ecc drivers: base: Fix NULL pointer exception in __platform_driver_probe() if a driver developer is foolish
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>
2020-05-05 16:52:07 +02:00
..
firmware_loader firmware_loader: move fw_fallback_config to a private kernel symbol namespace 2020-04-28 21:05:42 +02:00
power PM: sleep: core: Switch back to async_schedule_dev() 2020-04-22 16:36:18 +02:00
regmap
test Driver core changes for 5.6-rc1 2020-01-29 10:18:20 -08:00
arch_topology.c arm64 updates for 5.7: 2020-03-31 10:05:01 -07:00
attribute_container.c
base.h
bus.c
cacheinfo.c
class.c
component.c component: allow missing unbind callback 2020-03-18 14:13:33 +01:00
container.c
core.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 2020-03-31 17:29:33 -07:00
cpu.c CPU (hotplug) updates: 2020-03-30 18:06:39 -07:00
dd.c driver core: Add missing '\n' in log messages 2020-04-28 21:05:42 +02:00
devcon.c
devcoredump.c
devres.c
devtmpfs.c Merge branch 'merge.nfs-fs_parse.1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-02-08 13:26:41 -08:00
driver.c
firmware.c
hypervisor.c
init.c
isa.c
Kconfig
Makefile
map.c
memory.c mm/memory_hotplug: allow to specify a default online_type 2020-04-07 10:43:41 -07:00
module.c
node.c mm/sparse: rename pfn_present() to pfn_in_present_section() 2020-04-02 09:35:30 -07:00
pinctrl.c
platform-msi.c
platform.c drivers: base: Fix NULL pointer exception in __platform_driver_probe() if a driver developer is foolish 2020-05-05 16:52:07 +02:00
property.c device property: Export fwnode_get_name() 2020-03-16 07:47:58 +01:00
soc.c driver/base/soc: Use kobj_to_dev() API 2020-04-28 21:05:42 +02:00
swnode.c Revert "software node: Simplify software_node_release() function" 2020-03-04 22:31:44 +01:00
syscore.c
topology.c
transport_class.c