[PATCH 0/2] can: m_can_platform: Bug fix of kernel panic for

From: Pankaj Sharma
Date: Tue Nov 19 2019 - 05:21:39 EST


The current code is failing while clock prepare enable because of not
getting proper clock from platform device.

[ 0.852089] Call trace:
[ 0.854516] 0xffff0000fa22a668
[ 0.857638] clk_prepare+0x20/0x34
[ 0.861019] m_can_runtime_resume+0x2c/0xe4
[ 0.865180] pm_generic_runtime_resume+0x28/0x38
[ 0.869770] __rpm_callback+0x16c/0x1bc
[ 0.873583] rpm_callback+0x24/0x78
[ 0.877050] rpm_resume+0x428/0x560
[ 0.880517] __pm_runtime_resume+0x7c/0xa8
[ 0.884593] m_can_clk_start.isra.9.part.10+0x1c/0xa8
[ 0.889618] m_can_class_register+0x138/0x370
[ 0.893950] m_can_plat_probe+0x120/0x170
[ 0.897939] platform_drv_probe+0x4c/0xa0
[ 0.901924] really_probe+0xd8/0x31c
[ 0.905477] driver_probe_device+0x58/0xe8
[ 0.909551] device_driver_attach+0x68/0x70
[ 0.913711] __driver_attach+0x9c/0xf8
[ 0.917437] bus_for_each_dev+0x50/0xa0
[ 0.921251] driver_attach+0x20/0x28
[ 0.924804] bus_add_driver+0x148/0x1fc
[ 0.928617] driver_register+0x6c/0x124
[ 0.932431] __platform_driver_register+0x48/0x50
[ 0.937113] m_can_plat_driver_init+0x18/0x20
[ 0.941446] do_one_initcall+0x4c/0x19c
[ 0.945259] kernel_init_freeable+0x1d0/0x280
[ 0.949591] kernel_init+0x10/0x100
[ 0.953057] ret_from_fork+0x10/0x18
[ 0.956614] Code: 00000000 00000000 00000000 00000000 (fa22a668)
[ 0.962681] ---[ end trace 881f71bd609de763 ]---
[ 0.967301] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b

A device driver for CAN controller hardware registers itself with the
Linux network layer as a network device. So, the driver data for m_can
should ideally be of type net_device.

Further even when passing the proper net device in probe function the
code was hanging because of the function m_can_runtime_resume() getting
recursively called from m_can_class_resume().

Pankaj Sharma (2):
can: m_can_platform: set net_device structure as driver data
can: m_can_platform: remove unnecessary m_can_class_resume() call

drivers/net/can/m_can/m_can_platform.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)

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2.7.4