5.15-stable review patch. If anyone has any objections, please let me know.
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From: Rex Zhang rex.zhang@intel.com
[ Upstream commit c0409dd3d151f661e7e57b901a81a02565df163c ]
In idxd_cmd_exec(), wait_event_lock_irq() explicitly calls spin_unlock_irq()/spin_lock_irq(). If the interrupt is on before entering wait_event_lock_irq(), it will become off status after wait_event_lock_irq() is called. Later, wait_for_completion() may go to sleep but irq is disabled. The scenario is warned in might_sleep().
Fix it by using spin_lock_irqsave() instead of the primitive spin_lock() to save the irq status before entering wait_event_lock_irq() and using spin_unlock_irqrestore() instead of the primitive spin_unlock() to restore the irq status before entering wait_for_completion().
Before the change: idxd_cmd_exec() { interrupt is on spin_lock() // interrupt is on wait_event_lock_irq() spin_unlock_irq() // interrupt is enabled ... spin_lock_irq() // interrupt is disabled spin_unlock() // interrupt is still disabled wait_for_completion() // report "BUG: sleeping function // called from invalid context... // in_atomic() irqs_disabled()" }
After applying spin_lock_irqsave(): idxd_cmd_exec() { interrupt is on spin_lock_irqsave() // save the on state // interrupt is disabled wait_event_lock_irq() spin_unlock_irq() // interrupt is enabled ... spin_lock_irq() // interrupt is disabled spin_unlock_irqrestore() // interrupt is restored to on wait_for_completion() // No Call trace }
Fixes: f9f4082dbc56 ("dmaengine: idxd: remove interrupt disable for cmd_lock") Signed-off-by: Rex Zhang rex.zhang@intel.com Signed-off-by: Lijun Pan lijun.pan@intel.com Reviewed-by: Dave Jiang dave.jiang@intel.com Reviewed-by: Fenghua Yu fenghua.yu@intel.com Link: https://lore.kernel.org/r/20230916060619.3744220-1-rex.zhang@intel.com Signed-off-by: Vinod Koul vkoul@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/dma/idxd/device.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/dma/idxd/device.c b/drivers/dma/idxd/device.c index 535f021911c55..f2cfefc505a8c 100644 --- a/drivers/dma/idxd/device.c +++ b/drivers/dma/idxd/device.c @@ -490,6 +490,7 @@ static void idxd_cmd_exec(struct idxd_device *idxd, int cmd_code, u32 operand, union idxd_command_reg cmd; DECLARE_COMPLETION_ONSTACK(done); u32 stat; + unsigned long flags;
if (idxd_device_is_halted(idxd)) { dev_warn(&idxd->pdev->dev, "Device is HALTED!\n"); @@ -503,7 +504,7 @@ static void idxd_cmd_exec(struct idxd_device *idxd, int cmd_code, u32 operand, cmd.operand = operand; cmd.int_req = 1;
- spin_lock(&idxd->cmd_lock); + spin_lock_irqsave(&idxd->cmd_lock, flags); wait_event_lock_irq(idxd->cmd_waitq, !test_bit(IDXD_FLAG_CMD_RUNNING, &idxd->flags), idxd->cmd_lock); @@ -520,7 +521,7 @@ static void idxd_cmd_exec(struct idxd_device *idxd, int cmd_code, u32 operand, * After command submitted, release lock and go to sleep until * the command completes via interrupt. */ - spin_unlock(&idxd->cmd_lock); + spin_unlock_irqrestore(&idxd->cmd_lock, flags); wait_for_completion(&done); stat = ioread32(idxd->reg_base + IDXD_CMDSTS_OFFSET); spin_lock(&idxd->cmd_lock);