2023-07-07 09:07:23

by Chengfeng Ye

[permalink] [raw]

Subject: [PATCH v2] i2c: bcm-iproc: Fix bcm_iproc_i2c_isr deadlock issue

---

iproc_i2c_rd_reg() and iproc_i2c_wr_reg() are called from both
interrupt context (e.g. bcm_iproc_i2c_isr) and process context
(e.g. bcm_iproc_i2c_suspend). Therefore, interrupts should be
disabled to avoid potential deadlock. To prevent this scenario,
use spin_lock_irqsave().

Fixes: 9a1038728037 ("i2c: iproc: add NIC I2C support")
Signed-off-by: Chengfeng Ye <[email protected]>
---
drivers/i2c/busses/i2c-bcm-iproc.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/busses/i2c-bcm-iproc.c b/drivers/i2c/busses/i2c-bcm-iproc.c
index 85d8a6b04885..30a2a3200bed 100644
--- a/drivers/i2c/busses/i2c-bcm-iproc.c
+++ b/drivers/i2c/busses/i2c-bcm-iproc.c
@@ -233,13 +233,14 @@ static inline u32 iproc_i2c_rd_reg(struct bcm_iproc_i2c_dev *iproc_i2c,
u32 offset)
{
u32 val;
+ unsigned long flags;

if (iproc_i2c->idm_base) {
- spin_lock(&iproc_i2c->idm_lock);
+ spin_lock_irqsave(&iproc_i2c->idm_lock, flags);
writel(iproc_i2c->ape_addr_mask,
iproc_i2c->idm_base + IDM_CTRL_DIRECT_OFFSET);
val = readl(iproc_i2c->base + offset);
- spin_unlock(&iproc_i2c->idm_lock);
+ spin_unlock_irqrestore(&iproc_i2c->idm_lock, flags);
} else {
val = readl(iproc_i2c->base + offset);
}
@@ -250,12 +251,14 @@ static inline u32 iproc_i2c_rd_reg(struct bcm_iproc_i2c_dev *iproc_i2c,
static inline void iproc_i2c_wr_reg(struct bcm_iproc_i2c_dev *iproc_i2c,
u32 offset, u32 val)
{
+ unsigned long flags;
+
if (iproc_i2c->idm_base) {
- spin_lock(&iproc_i2c->idm_lock);
+ spin_lock_irqsave(&iproc_i2c->idm_lock, flags);
writel(iproc_i2c->ape_addr_mask,
iproc_i2c->idm_base + IDM_CTRL_DIRECT_OFFSET);
writel(val, iproc_i2c->base + offset);
- spin_unlock(&iproc_i2c->idm_lock);
+ spin_unlock_irqrestore(&iproc_i2c->idm_lock, flags);
} else {
writel(val, iproc_i2c->base + offset);
}
--
2.17.1

2023-07-07 16:39:20

by Ray Jui

[permalink] [raw]

Subject: Re: [PATCH v2] i2c: bcm-iproc: Fix bcm_iproc_i2c_isr deadlock issue

---

On 7/7/2023 1:49 AM, Chengfeng Ye wrote:
> iproc_i2c_rd_reg() and iproc_i2c_wr_reg() are called from both
> interrupt context (e.g. bcm_iproc_i2c_isr) and process context
> (e.g. bcm_iproc_i2c_suspend). Therefore, interrupts should be
> disabled to avoid potential deadlock. To prevent this scenario,
> use spin_lock_irqsave().
>
> Fixes: 9a1038728037 ("i2c: iproc: add NIC I2C support")
> Signed-off-by: Chengfeng Ye <[email protected]>
> ---
> drivers/i2c/busses/i2c-bcm-iproc.c | 11 +++++++----
> 1 file changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-bcm-iproc.c b/drivers/i2c/busses/i2c-bcm-iproc.c
> index 85d8a6b04885..30a2a3200bed 100644
> --- a/drivers/i2c/busses/i2c-bcm-iproc.c
> +++ b/drivers/i2c/busses/i2c-bcm-iproc.c
> @@ -233,13 +233,14 @@ static inline u32 iproc_i2c_rd_reg(struct bcm_iproc_i2c_dev *iproc_i2c,
> u32 offset)
> {
> u32 val;
> + unsigned long flags;
>
> if (iproc_i2c->idm_base) {
> - spin_lock(&iproc_i2c->idm_lock);
> + spin_lock_irqsave(&iproc_i2c->idm_lock, flags);
> writel(iproc_i2c->ape_addr_mask,
> iproc_i2c->idm_base + IDM_CTRL_DIRECT_OFFSET);
> val = readl(iproc_i2c->base + offset);
> - spin_unlock(&iproc_i2c->idm_lock);
> + spin_unlock_irqrestore(&iproc_i2c->idm_lock, flags);
> } else {
> val = readl(iproc_i2c->base + offset);
> }
> @@ -250,12 +251,14 @@ static inline u32 iproc_i2c_rd_reg(struct bcm_iproc_i2c_dev *iproc_i2c,
> static inline void iproc_i2c_wr_reg(struct bcm_iproc_i2c_dev *iproc_i2c,
> u32 offset, u32 val)
> {
> + unsigned long flags;
> +
> if (iproc_i2c->idm_base) {
> - spin_lock(&iproc_i2c->idm_lock);
> + spin_lock_irqsave(&iproc_i2c->idm_lock, flags);
> writel(iproc_i2c->ape_addr_mask,
> iproc_i2c->idm_base + IDM_CTRL_DIRECT_OFFSET);
> writel(val, iproc_i2c->base + offset);
> - spin_unlock(&iproc_i2c->idm_lock);
> + spin_unlock_irqrestore(&iproc_i2c->idm_lock, flags);
> } else {
> writel(val, iproc_i2c->base + offset);
> }

Acked-by: Ray Jui <[email protected]>

Thanks, Chengfeng.

---

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2023-07-27 21:23:18

by Andi Shyti

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Subject: Re: [PATCH v2] i2c: bcm-iproc: Fix bcm_iproc_i2c_isr deadlock issue

---

Hi Chengfeng,

On Fri, Jul 07, 2023 at 08:49:41AM +0000, Chengfeng Ye wrote:
> iproc_i2c_rd_reg() and iproc_i2c_wr_reg() are called from both
> interrupt context (e.g. bcm_iproc_i2c_isr) and process context
> (e.g. bcm_iproc_i2c_suspend). Therefore, interrupts should be
> disabled to avoid potential deadlock. To prevent this scenario,
> use spin_lock_irqsave().
>
> Fixes: 9a1038728037 ("i2c: iproc: add NIC I2C support")
> Signed-off-by: Chengfeng Ye <[email protected]>

Reviewed-by: Andi Shyti <[email protected]>

Thanks,
Andi

2023-08-14 16:32:53

by Wolfram Sang

[permalink] [raw]

Subject: Re: [PATCH v2] i2c: bcm-iproc: Fix bcm_iproc_i2c_isr deadlock issue

---

On Fri, Jul 07, 2023 at 08:49:41AM +0000, Chengfeng Ye wrote:
> iproc_i2c_rd_reg() and iproc_i2c_wr_reg() are called from both
> interrupt context (e.g. bcm_iproc_i2c_isr) and process context
> (e.g. bcm_iproc_i2c_suspend). Therefore, interrupts should be
> disabled to avoid potential deadlock. To prevent this scenario,
> use spin_lock_irqsave().
>
> Fixes: 9a1038728037 ("i2c: iproc: add NIC I2C support")
> Signed-off-by: Chengfeng Ye <[email protected]>

Applied to for-current, thanks!

---

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