From 0834d627fbea00c1444075eb3e448e1974da452d Mon Sep 17 00:00:00 2001 From: Michael Ellerman Date: Fri, 30 Mar 2018 23:27:25 +1100 Subject: [PATCH] powerpc/mpic: Check if cpu_possible() in mpic_physmask() In mpic_physmask() we loop over all CPUs up to 32, then get the hard SMP processor id of that CPU. Currently that's possibly walking off the end of the paca array, but in a future patch we will change the paca array to be an array of pointers, and in that case we will get a NULL for missing CPUs and oops. eg: Unable to handle kernel paging request for data at address 0x88888888888888b8 Faulting instruction address: 0xc00000000004e380 Oops: Kernel access of bad area, sig: 11 [#1] ... NIP .mpic_set_affinity+0x60/0x1a0 LR .irq_do_set_affinity+0x48/0x100 Fix it by checking the CPU is possible, this also fixes the code if there are gaps in the CPU numbering which probably never happens on mpic systems but who knows. Debugged-by: Nicholas Piggin Signed-off-by: Michael Ellerman --- arch/powerpc/sysdev/mpic.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/powerpc/sysdev/mpic.c b/arch/powerpc/sysdev/mpic.c index 73067805300a..1d4e0ef658d3 100644 --- a/arch/powerpc/sysdev/mpic.c +++ b/arch/powerpc/sysdev/mpic.c @@ -626,7 +626,7 @@ static inline u32 mpic_physmask(u32 cpumask) int i; u32 mask = 0; - for (i = 0; i < min(32, NR_CPUS); ++i, cpumask >>= 1) + for (i = 0; i < min(32, NR_CPUS) && cpu_possible(i); ++i, cpumask >>= 1) mask |= (cpumask & 1) << get_hard_smp_processor_id(i); return mask; } -- 2.30.2