Re: [RFC PATCH] irqchip/sifive-plic: Fix getting wrong chip_data when interrupt is hierarchy

From: Atish Patra
Date: Thu Oct 29 2020 - 17:43:21 EST


On Wed, Oct 28, 2020 at 7:37 PM Greentime Hu <greentime.hu@xxxxxxxxxx> wrote:
>
> This oops is caused by a wrong chip_data and it is because plic_irq_unmask
> uses irq_get_chip_data(irq_data->irq) to get the chip_data. However it may
> get another irq_data with the same irq_data->irq if it is hierarchy.
>
> In this case, it will get irq_data of sifive_gpio_irqchip instead of
> plic_chip so that it will get a wrong chip_data and then the wrong lmask
> of it to cause this oops.
>
> To fix this issue, we can use irq_data_get_irq_chip_data(irq_data) to get
> the correct chip_data of plic_chip.
>
> (gdb) p d
> $11 = (struct irq_data *) 0xffffffe1f695f620
> (gdb) p *d
> $9 = {
> mask = 0,
> irq = 57,
> hwirq = 6,
> common = 0xffffffe1f695f600,
> chip = 0xffffffe0018b5630 <sifive_gpio_irqchip>,
> domain = 0xffffffe1f692c400,
> parent_data = 0xffffffe1f68482c0,
> chip_data = 0xffffffe1f564a820
> }
>
> (gdb) p d
> $6 = (struct irq_data *) 0xffffffe1f68482c0
> (gdb) p *d
> $7 = {
> mask = 0,
> irq = 57,
> hwirq = 29,
> common = 0xffffffe1f695f600,
> chip = 0xffffffe0018b5070 <plic_chip>,
> domain = 0xffffffe1f6635e00,
> parent_data = 0x0,
> chip_data = 0xffffffe1f660f1a0
> }
>
> [ 3.030165] ------------[ cut here ]------------
> [ 3.034614] WARNING: CPU: 1 PID: 1 at drivers/irqchip/irq-sifive-plic.c:125 plic_irq_unmask+0xc4/0x114
> [ 3.043887] Modules linked in:
> [ 3.046932] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 5.9.0 #1
> [ 3.052748] epc: ffffffe000588e90 ra : ffffffe000588e88 sp : ffffffe1f6753940
> [ 3.059869] gp : ffffffe001978f48 tp : ffffffe1f6748000 t0 : ffffffe001995cb0
> [ 3.067080] t1 : ffffffe001995be8 t2 : 73616d61202c343a s0 : ffffffe1f67539a0
> [ 3.074288] s1 : ffffffe1f4968140 a0 : 00000000000000b2 a1 : 0000000000000000
> [ 3.081497] a2 : 00000000000000c2 a3 : 0000000000000000 a4 : 381c5a89432fe900
> [ 3.088707] a5 : 0000000000000004 a6 : 0000000000000000 a7 : 00000000000001aa
> [ 3.095916] s2 : ffffffe1f5901020 s3 : ffffffe00197a0a8 s4 : ffffffe001978b0c
> [ 3.103125] s5 : ffffffe00197a1f0 s6 : 0000000000000008 s7 : ffffffe1f4983c9c
> [ 3.110335] s8 : ffffffe1f4983c68 s9 : ffffffe1f4983c00 s10: ffffffe00000117c
> [ 3.117544] s11: 0000000000000000 t3 : 0000000000000007 t4 : 0000000000000000
> [ 3.124753] t5 : 66666666663a6b73 t6 : ffffffe001988479
> [ 3.130052] status: 0000000200000100 badaddr: ffffffe001978b0c cause: 0000000000000003
> [ 3.137959] ---[ end trace dbc1129f842ecba3 ]---
>
> Fixes: f1ad1133b18f ("irqchip/sifive-plic: Add support for multiple PLICs")
> Signed-off-by: Greentime Hu <greentime.hu@xxxxxxxxxx>
> ---
> drivers/irqchip/irq-sifive-plic.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/irqchip/irq-sifive-plic.c b/drivers/irqchip/irq-sifive-plic.c
> index 4048657ece0a..6f432d2a5ceb 100644
> --- a/drivers/irqchip/irq-sifive-plic.c
> +++ b/drivers/irqchip/irq-sifive-plic.c
> @@ -99,7 +99,7 @@ static inline void plic_irq_toggle(const struct cpumask *mask,
> struct irq_data *d, int enable)
> {
> int cpu;
> - struct plic_priv *priv = irq_get_chip_data(d->irq);
> + struct plic_priv *priv = irq_data_get_irq_chip_data(d);
>
> writel(enable, priv->regs + PRIORITY_BASE + d->hwirq * PRIORITY_PER_ID);
> for_each_cpu(cpu, mask) {
> @@ -115,7 +115,7 @@ static void plic_irq_unmask(struct irq_data *d)
> {
> struct cpumask amask;
> unsigned int cpu;
> - struct plic_priv *priv = irq_get_chip_data(d->irq);
> + struct plic_priv *priv = irq_data_get_irq_chip_data(d);
>
> cpumask_and(&amask, &priv->lmask, cpu_online_mask);
> cpu = cpumask_any_and(irq_data_get_affinity_mask(d),
> @@ -127,7 +127,7 @@ static void plic_irq_unmask(struct irq_data *d)
>
> static void plic_irq_mask(struct irq_data *d)
> {
> - struct plic_priv *priv = irq_get_chip_data(d->irq);
> + struct plic_priv *priv = irq_data_get_irq_chip_data(d);
>
> plic_irq_toggle(&priv->lmask, d, 0);
> }
> @@ -138,7 +138,7 @@ static int plic_set_affinity(struct irq_data *d,
> {
> unsigned int cpu;
> struct cpumask amask;
> - struct plic_priv *priv = irq_get_chip_data(d->irq);
> + struct plic_priv *priv = irq_data_get_irq_chip_data(d);
>
> cpumask_and(&amask, &priv->lmask, mask_val);
>
> --
> 2.28.0
>
>
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Thanks for the fix.

Reviewed-by: Atish Patra <atish.patra@xxxxxxx>

--
Regards,
Atish