diff options
| author | Marc Zyngier <marc.zyngier@arm.com> | 2017-10-03 18:14:12 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-12-14 09:28:15 +0100 |
| commit | 793eed33da5fd9745f8b62e2a93b4b4a3e36caa3 (patch) | |
| tree | dd515879bd566feae1b8142eb2091d9dca4d1b71 /drivers/bus | |
| parent | 595aca74c67a2a6ffa78c3760a0c3027b90c36a7 (diff) | |
bus: arm-ccn: Fix use of smp_processor_id() in preemptible context
commit b18c2b9487d8e797fc0a757e57ac3645348c5fba upstream.
Booting a DEBUG_PREEMPT enabled kernel on a CCN-based system
results in the following splat:
[...]
arm-ccn e8000000.ccn: No access to interrupts, using timer.
BUG: using smp_processor_id() in preemptible [00000000] code: swapper/0/1
caller is debug_smp_processor_id+0x1c/0x28
CPU: 1 PID: 1 Comm: swapper/0 Not tainted 4.13.0 #6111
Hardware name: AMD Seattle/Seattle, BIOS 17:08:23 Jun 26 2017
Call trace:
[<ffff000008089e78>] dump_backtrace+0x0/0x278
[<ffff00000808a22c>] show_stack+0x24/0x30
[<ffff000008bc3bc4>] dump_stack+0x8c/0xb0
[<ffff00000852b534>] check_preemption_disabled+0xfc/0x100
[<ffff00000852b554>] debug_smp_processor_id+0x1c/0x28
[<ffff000008551bd8>] arm_ccn_probe+0x358/0x4f0
[...]
as we use smp_processor_id() in the wrong context.
Turn this into a get_cpu()/put_cpu() that extends over the CPU hotplug
registration, making sure that we don't race against a CPU down operation.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Pawel Moll <pawel.moll@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/bus')
| -rw-r--r-- | drivers/bus/arm-ccn.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/bus/arm-ccn.c b/drivers/bus/arm-ccn.c index 45dfcc80523b..96d50e4b38c6 100644 --- a/drivers/bus/arm-ccn.c +++ b/drivers/bus/arm-ccn.c @@ -1301,7 +1301,7 @@ static int arm_ccn_pmu_init(struct arm_ccn *ccn) } /* Pick one CPU which we will use to collect data from CCN... */ - cpumask_set_cpu(smp_processor_id(), &ccn->dt.cpu); + cpumask_set_cpu(get_cpu(), &ccn->dt.cpu); /* Also make sure that the overflow interrupt is handled by this CPU */ if (ccn->irq) { @@ -1318,10 +1318,12 @@ static int arm_ccn_pmu_init(struct arm_ccn *ccn) cpuhp_state_add_instance_nocalls(CPUHP_AP_PERF_ARM_CCN_ONLINE, &ccn->dt.node); + put_cpu(); return 0; error_pmu_register: error_set_affinity: + put_cpu(); error_choose_name: ida_simple_remove(&arm_ccn_pmu_ida, ccn->dt.id); for (i = 0; i < ccn->num_xps; i++) |