bus: arm-ccn: Fix use of smp_processor_id() in preemptible context

Browse source

commit b18c2b9487 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>

...

This commit is contained in:

Marc Zyngier 2017-10-03 18:14:12 +01:00 • committed by Greg Kroah-Hartman

parent a724b569a5

commit 8741b5ab49

1 changed files with 3 additions and 1 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

4

drivers/bus/arm-ccn.c

View file