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authorCédric Le Goater <clg@kaod.org>2017-08-08 11:02:49 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-11-02 09:54:50 +0100
commit0cdddc6f88f999a240d64127feea404b5cc11acf (patch)
parent5ee110383f15b2cef1e47f82cf7e0066274c5269 (diff)
powerpc/xive: Fix the size of the cpumask used in xive_find_target_in_mask()
commit a9dadc1c512807f955f0799e85830b420da47932 upstream. When called from xive_irq_startup(), the size of the cpumask can be larger than nr_cpu_ids. This can result in a WARN_ON such as: WARNING: CPU: 10 PID: 1 at ../arch/powerpc/sysdev/xive/common.c:476 xive_find_target_in_mask+0x110/0x2f0 ... NIP [c00000000008a310] xive_find_target_in_mask+0x110/0x2f0 LR [c00000000008a2e4] xive_find_target_in_mask+0xe4/0x2f0 Call Trace: xive_find_target_in_mask+0x74/0x2f0 (unreliable) xive_pick_irq_target.isra.1+0x200/0x230 xive_irq_startup+0x60/0x180 irq_startup+0x70/0xd0 __setup_irq+0x7bc/0x880 request_threaded_irq+0x14c/0x2c0 request_event_sources_irqs+0x100/0x180 __machine_initcall_pseries_init_ras_IRQ+0x104/0x134 do_one_initcall+0x68/0x1d0 kernel_init_freeable+0x290/0x374 kernel_init+0x24/0x170 ret_from_kernel_thread+0x5c/0x74 This happens because we're being called with our affinity mask set to irq_default_affinity. That in turn was populated using cpumask_setall(), which sets NR_CPUs worth of bits, not nr_cpu_ids worth. Finally cpumask_weight() will return > nr_cpu_ids when passed a mask which has > nr_cpu_ids bits set. Fix it by limiting the value returned by cpumask_weight(). Signed-off-by: Cédric Le Goater <clg@kaod.org> [mpe: Add change log details on actual cause] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Cc: Stewart Smith <stewart@linux.vnet.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/powerpc/sysdev/xive/common.c b/arch/powerpc/sysdev/xive/common.c
index 6595462b1fc8..6e0c9dee724f 100644
--- a/arch/powerpc/sysdev/xive/common.c
+++ b/arch/powerpc/sysdev/xive/common.c
@@ -447,7 +447,7 @@ static int xive_find_target_in_mask(const struct cpumask *mask,
int cpu, first, num, i;
/* Pick up a starting point CPU in the mask based on fuzz */
- num = cpumask_weight(mask);
+ num = min_t(int, cpumask_weight(mask), nr_cpu_ids);
first = fuzz % num;
/* Locate it */