Re: powerpc/4xx: Fix error return path in ppc4xx_msi_probe()

[Michael Ellerman]

On Tue, 2018-07-31 at 01:44:14 UTC, Guenter Roeck wrote:
> An arbitrary error in ppc4xx_msi_probe() quite likely results in a
> crash similar to the following, seen after dma_alloc_coherent()
> returned an error.
> 
> Unable to handle kernel paging request for data at address 0x00000000
> Faulting instruction address: 0xc001bff0
> Oops: Kernel access of bad area, sig: 11 [#1]
> BE Canyonlands
> Modules linked in:
> CPU: 0 PID: 1 Comm: swapper Tainted: G        W
> 4.18.0-rc6-00010-gff33d1030a6c #1
> NIP:  c001bff0 LR: c001c418 CTR: c01faa7c
> REGS: cf82db40 TRAP: 0300   Tainted: G        W
> (4.18.0-rc6-00010-gff33d1030a6c)
> MSR:  00029000 <CE,EE,ME>  CR: 28002024  XER: 00000000
> DEAR: 00000000 ESR: 00000000
> GPR00: c001c418 cf82dbf0 cf828000 cf8de400 00000000 00000000 000000c4 000000c4
> GPR08: c0481ea4 00000000 00000000 000000c4 22002024 00000000 c00025e8 00000000
> GPR16: 00000000 00000000 00000000 00000000 00000000 00000000 c0492380 0000004a
> GPR24: 00029000 0000000c 00000000 cf8de410 c0494d60 c0494d60 cf8bebc0 00000001
> NIP [c001bff0] ppc4xx_of_msi_remove+0x48/0xa0
> LR [c001c418] ppc4xx_msi_probe+0x294/0x3b8
> Call Trace:
> [cf82dbf0] [00029000] 0x29000 (unreliable)
> [cf82dc10] [c001c418] ppc4xx_msi_probe+0x294/0x3b8
> [cf82dc70] [c0209fbc] platform_drv_probe+0x40/0x9c
> [cf82dc90] [c0208240] driver_probe_device+0x2a8/0x350
> [cf82dcc0] [c0206204] bus_for_each_drv+0x60/0xac
> [cf82dcf0] [c0207e88] __device_attach+0xe8/0x160
> [cf82dd20] [c02071e0] bus_probe_device+0xa0/0xbc
> [cf82dd40] [c02050c8] device_add+0x404/0x5c4
> [cf82dd90] [c0288978] of_platform_device_create_pdata+0x88/0xd8
> [cf82ddb0] [c0288b70] of_platform_bus_create+0x134/0x220
> [cf82de10] [c0288bcc] of_platform_bus_create+0x190/0x220
> [cf82de70] [c0288cf4] of_platform_bus_probe+0x98/0xec
> [cf82de90] [c0449650] __machine_initcall_canyonlands_ppc460ex_device_probe+0x38/0x54
> [cf82dea0] [c0002404] do_one_initcall+0x40/0x188
> [cf82df00] [c043daec] kernel_init_freeable+0x130/0x1d0
> [cf82df30] [c0002600] kernel_init+0x18/0x104
> [cf82df40] [c000c23c] ret_from_kernel_thread+0x14/0x1c
> Instruction dump:
> 90010024 813d0024 2f890000 83c30058 41bd0014 48000038 813d0024 7f89f800
> 409d002c 813e000c 57ea103a 3bff0001 <7c69502e> 2f830000 419effe0 4803b26d
> ---[ end trace 8cf551077ecfc42a ]---
> 
> Fix it up. Specifically,
> 
> - Return valid error codes from ppc4xx_setup_pcieh_hw(), have it clean
>   up after itself, and only access hardware after all possible error
>   conditions have been handled.
> - Use devm_kzalloc() instead of kzalloc() in ppc4xx_msi_probe()
> 
> Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/6e0495c2e8ac39b1aad0a4588fe644

cheers