From: Xiaoming Ni nixiaoming@huawei.com
[ Upstream commit 3dc709e518b47386e6af937eaec37bb36539edfd ]
When CONFIG_FSL_PMC is set to n, no value is assigned to cpu_up_prepare in the mpc85xx_pm_ops structure. As a result, oops is triggered in smp_85xx_start_cpu().
smp: Bringing up secondary CPUs ... kernel tried to execute user page (0) - exploit attempt? (uid: 0) BUG: Unable to handle kernel instruction fetch (NULL pointer?) Faulting instruction address: 0x00000000 Oops: Kernel access of bad area, sig: 11 [#1] ... NIP [00000000] 0x0 LR [c0021d2c] smp_85xx_kick_cpu+0xe8/0x568 Call Trace: [c1051da8] [c0021cb8] smp_85xx_kick_cpu+0x74/0x568 (unreliable) [c1051de8] [c0011460] __cpu_up+0xc0/0x228 [c1051e18] [c0031bbc] bringup_cpu+0x30/0x224 [c1051e48] [c0031f3c] cpu_up.constprop.0+0x180/0x33c [c1051e88] [c00322e8] bringup_nonboot_cpus+0x88/0xc8 [c1051eb8] [c07e67bc] smp_init+0x30/0x78 [c1051ed8] [c07d9e28] kernel_init_freeable+0x118/0x2a8 [c1051f18] [c00032d8] kernel_init+0x14/0x124 [c1051f38] [c0010278] ret_from_kernel_thread+0x14/0x1c
Fixes: c45361abb918 ("powerpc/85xx: fix timebase sync issue when CONFIG_HOTPLUG_CPU=n") Reported-by: Martin Kennedy hurricos@gmail.com Signed-off-by: Xiaoming Ni nixiaoming@huawei.com Tested-by: Martin Kennedy hurricos@gmail.com Signed-off-by: Michael Ellerman mpe@ellerman.id.au Link: https://lore.kernel.org/r/20211126041153.16926-1-nixiaoming@huawei.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/powerpc/platforms/85xx/smp.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/platforms/85xx/smp.c b/arch/powerpc/platforms/85xx/smp.c index 83f4a6389a282..d7081e9af65c7 100644 --- a/arch/powerpc/platforms/85xx/smp.c +++ b/arch/powerpc/platforms/85xx/smp.c @@ -220,7 +220,7 @@ static int smp_85xx_start_cpu(int cpu) local_irq_save(flags); hard_irq_disable();
- if (qoriq_pm_ops) + if (qoriq_pm_ops && qoriq_pm_ops->cpu_up_prepare) qoriq_pm_ops->cpu_up_prepare(cpu);
/* if cpu is not spinning, reset it */ @@ -292,7 +292,7 @@ static int smp_85xx_kick_cpu(int nr) booting_thread_hwid = cpu_thread_in_core(nr); primary = cpu_first_thread_sibling(nr);
- if (qoriq_pm_ops) + if (qoriq_pm_ops && qoriq_pm_ops->cpu_up_prepare) qoriq_pm_ops->cpu_up_prepare(nr);
/*