| Message ID | 1519661456-30445-1-git-send-email-will.deacon@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, Feb 26, 2018 at 04:10:56PM +0000, Will Deacon wrote: > Commit 6de3f79112cc ("arm_pmu: explicitly enable/disable SPIs at hotplug") > moved all of the arm_pmu IRQ enable/disable calls to the CPU hotplug hooks, > regardless of whether they are implemented as PPIs or SPIs. This can > lead to us sleeping from atomic context due to disable_irq blocking: > Acked-by: Acked-by: Mark Rutland <mark.rutland@arm.com> I think something went wrong here when you applied the tag. ;) Mark.
On Wed, Feb 28, 2018 at 2:57 PM, Mark Rutland <mark.rutland@arm.com> wrote: > On Mon, Feb 26, 2018 at 04:10:56PM +0000, Will Deacon wrote: >> Commit 6de3f79112cc ("arm_pmu: explicitly enable/disable SPIs at hotplug") >> moved all of the arm_pmu IRQ enable/disable calls to the CPU hotplug hooks, >> regardless of whether they are implemented as PPIs or SPIs. This can >> lead to us sleeping from atomic context due to disable_irq blocking: > >> Acked-by: Acked-by: Mark Rutland <mark.rutland@arm.com> > > I think something went wrong here when you applied the tag. ;) In case of respinning: Fixes: 6de3f79112cc26bf ("arm_pmu: explicitly enable/disable SPIs at hotplug") Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
On Wed, Feb 28, 2018 at 03:23:28PM +0100, Geert Uytterhoeven wrote: > On Wed, Feb 28, 2018 at 2:57 PM, Mark Rutland <mark.rutland@arm.com> wrote: > > On Mon, Feb 26, 2018 at 04:10:56PM +0000, Will Deacon wrote: > >> Commit 6de3f79112cc ("arm_pmu: explicitly enable/disable SPIs at hotplug") > >> moved all of the arm_pmu IRQ enable/disable calls to the CPU hotplug hooks, > >> regardless of whether they are implemented as PPIs or SPIs. This can > >> lead to us sleeping from atomic context due to disable_irq blocking: > > > >> Acked-by: Acked-by: Mark Rutland <mark.rutland@arm.com> > > > > I think something went wrong here when you applied the tag. ;) > > In case of respinning: > Fixes: 6de3f79112cc26bf ("arm_pmu: explicitly enable/disable SPIs at hotplug") This is already pushed to fixes/core, so I'll leave it up to Catalin whether he wants to rebase it for that. Will
diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c index 0c2ed11c0603..f63db346c219 100644 --- a/drivers/perf/arm_pmu.c +++ b/drivers/perf/arm_pmu.c @@ -638,7 +638,7 @@ static int arm_perf_teardown_cpu(unsigned int cpu, struct hlist_node *node) if (irq_is_percpu_devid(irq)) disable_percpu_irq(irq); else - disable_irq(irq); + disable_irq_nosync(irq); } per_cpu(cpu_armpmu, cpu) = NULL;
Commit 6de3f79112cc ("arm_pmu: explicitly enable/disable SPIs at hotplug") moved all of the arm_pmu IRQ enable/disable calls to the CPU hotplug hooks, regardless of whether they are implemented as PPIs or SPIs. This can lead to us sleeping from atomic context due to disable_irq blocking: | BUG: sleeping function called from invalid context at kernel/irq/manage.c:112 | in_atomic(): 1, irqs_disabled(): 128, pid: 15, name: migration/1 | no locks held by migration/1/15. | irq event stamp: 192 | hardirqs last enabled at (191): [<00000000803c2507>] | _raw_spin_unlock_irq+0x2c/0x4c | hardirqs last disabled at (192): [<000000007f57ad28>] multi_cpu_stop+0x9c/0x140 | softirqs last enabled at (0): [<0000000004ee1b58>] | copy_process.isra.77.part.78+0x43c/0x1504 | softirqs last disabled at (0): [< (null)>] (null) | CPU: 1 PID: 15 Comm: migration/1 Not tainted 4.16.0-rc3-salvator-x #1651 | Hardware name: Renesas Salvator-X board based on r8a7796 (DT) | Call trace: | dump_backtrace+0x0/0x140 | show_stack+0x14/0x1c | dump_stack+0xb4/0xf0 | ___might_sleep+0x1fc/0x218 | __might_sleep+0x70/0x80 | synchronize_irq+0x40/0xa8 | disable_irq+0x20/0x2c | arm_perf_teardown_cpu+0x80/0xac Since the interrupt is always CPU-affine and this code is running with interrupts disabled, we can just use disable_irq_nosync as we know there isn't a concurrent invocation of the handler to worry about. Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> Tested-by: Geert Uytterhoeven <geert+renesas@glider.be> Acked-by: Acked-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> --- drivers/perf/arm_pmu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)