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| author |   Cédric Le Goater <clg@kaod.org> | 2017-08-08 11:02:49 +0200 |
|---|---|---|
| committer |   Michael Ellerman <mpe@ellerman.id.au> | 2017-08-24 15:20:18 +1000 |
| commit | a9dadc1c512807f955f0799e85830b420da47932 (patch) | |
| tree | 6f16eee2805cb407005d0edcb4d121ce25fdd444 /arch/powerpc/sysdev/xive | |
| parent | powerpc/64: Optimise set/clear of CTRL[RUN] (runlatch) (diff) | |
| download | linux-dev-a9dadc1c512807f955f0799e85830b420da47932.tar.xz linux-dev-a9dadc1c512807f955f0799e85830b420da47932.zip | |
powerpc/xive: Fix the size of the cpumask used in xive_find_target_in_mask()
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>
Diffstat (limited to 'arch/powerpc/sysdev/xive')
| -rw-r--r-- | arch/powerpc/sysdev/xive/common.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/powerpc/sysdev/xive/common.c b/arch/powerpc/sysdev/xive/common.c index 0db4c45bc561..558df6542b1a 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 */ |