Messages in this thread Patch in this message | | | From | YE Chengfeng <> | Subject | [PATCH] i2c: img-scb: Fix img_i2c_isr deadlock issue | Date | Sat, 24 Jun 2023 17:57:31 +0000 |
| |
The softirq img_i2c_isr and timer img_i2c_check_timer could deadlock on the &i2c->lock when img_i2c_isr is preempted by the timer while holding the lock &i2c->lock with spin_lock.
Deadlock scenario: img_i2c_isr -> spin_lock(&i2c->lock); <timer interrupt> -> img_i2c_check_timer -> spin_lock_irqsave(&i2c->lock, flags);
To prevent this deadlock scenario, use spin_lock_bh to disable the bottom half interrupt.
Signed-off-by: Chengfeng Ye <cyeaa@connect.ust.hk> --- drivers/i2c/busses/i2c-img-scb.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/i2c/busses/i2c-img-scb.c b/drivers/i2c/busses/i2c-img-scb.c index 39c479f96eb5..a2b957c3898b 100644 --- a/drivers/i2c/busses/i2c-img-scb.c +++ b/drivers/i2c/busses/i2c-img-scb.c @@ -935,7 +935,7 @@ static irqreturn_t img_i2c_isr(int irq, void *dev_id) img_i2c_wr_rd_fence(i2c); }
- spin_lock(&i2c->lock); + spin_lock_bh(&i2c->lock);
/* Keep track of line status bits received */ i2c->line_status &= ~LINESTAT_INPUT_DATA; @@ -998,7 +998,7 @@ static irqreturn_t img_i2c_isr(int irq, void *dev_id) /* Enable interrupts (int_enable may be altered by changing mode) */ img_i2c_writel(i2c, SCB_INT_MASK_REG, i2c->int_enable);
- spin_unlock(&i2c->lock); + spin_unlock_bh(&i2c->lock);
return IRQ_HANDLED; } -- 2.17.1 | |