From e7757563e621522f5cd862b3aff473aedf8b66c0 Mon Sep 17 00:00:00 2001 From: Xiaoming Ni Date: Fri, 26 Nov 2021 12:11:53 +0800 Subject: [PATCH] powerpc/85xx: fix oops when CONFIG_FSL_PMC=n 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(). [ 0.627233] smp: Bringing up secondary CPUs ... [ 0.681659] kernel tried to execute user page (0) - exploit attempt? (uid: 0) [ 0.766618] BUG: Unable to handle kernel instruction fetch (NULL pointer?) [ 0.848899] Faulting instruction address: 0x00000000 [ 0.908273] Oops: Kernel access of bad area, sig: 11 [#1] ... [ 1.758220] NIP [00000000] 0x0 [ 1.794688] LR [c0021d2c] smp_85xx_kick_cpu+0xe8/0x568 [ 1.856126] Call Trace: [ 1.885295] [c1051da8] [c0021cb8] smp_85xx_kick_cpu+0x74/0x568 (unreliable) [ 1.968633] [c1051de8] [c0011460] __cpu_up+0xc0/0x228 [ 2.029038] [c1051e18] [c0031bbc] bringup_cpu+0x30/0x224 [ 2.092572] [c1051e48] [c0031f3c] cpu_up.constprop.0+0x180/0x33c [ 2.164443] [c1051e88] [c00322e8] bringup_nonboot_cpus+0x88/0xc8 [ 2.236326] [c1051eb8] [c07e67bc] smp_init+0x30/0x78 [ 2.295698] [c1051ed8] [c07d9e28] kernel_init_freeable+0x118/0x2a8 [ 2.369641] [c1051f18] [c00032d8] kernel_init+0x14/0x124 [ 2.433176] [c1051f38] [c0010278] ret_from_kernel_thread+0x14/0x1c Fixes: c45361abb9185b ("powerpc/85xx: fix timebase sync issue when CONFIG_HOTPLUG_CPU=n") Link: https://lore.kernel.org/lkml/CANA18Uyba4kMJQrbCSZVTFep2Exe5izE45whNJgwwUvNSEcNLg@mail.gmail.com/ Reported-by: Martin Kennedy Signed-off-by: Xiaoming Ni Tested-by: Martin Kennedy Cc: stable@vger.kernel.org --- 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); /*