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dmaengine: idxd: Move dma_free_coherent() out of spinlocked context

PATCH In review Rex Zhang 3 participants 4 messages Dec 12, 2023 – Dec 21, 2023

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dmaengine Intel IDXD driver
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Rex Zhang

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#0 lore raw

PATCH 1/1 dmaengine: idxd: Move dma_free_coherent() out of spinlocked context

Task may be rescheduled within dma_free_coherent(). So dma_free_coherent() can't be called between spin_lock() and spin_unlock() to avoid Call Trace:

    Call Trace:
    <TASK>
    dump_stack_lvl+0x37/0x50
    __might_resched+0x16a/0x1c0
    vunmap+0x2c/0x70
    __iommu_dma_free+0x96/0x100
    idxd_device_evl_free+0xd5/0x100 [idxd]
    device_release_driver_internal+0x197/0x200
    unbind_store+0xa1/0xb0
    kernfs_fop_write_iter+0x120/0x1c0
    vfs_write+0x2d3/0x400
    ksys_write+0x63/0xe0
    do_syscall_64+0x44/0xa0
    entry_SYSCALL_64_after_hwframe+0x6e/0xd8

Move it out of the context.

Fixes 244da66cda35 ("dmaengine: idxd: setup event log configuration")
Signed-off-by Rex Zhang <[email protected]>
Reviewed-by Dave Jiang <[email protected]>
Reviewed-by Fenghua Yu <[email protected]>
---
 drivers/dma/idxd/device.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)
drivers/dma/idxd/device.c +8 -1
index 8f754f922217..fa0f880beae6 100644
@@ -802,6 +802,9 @@ static int idxd_device_evl_setup(struct idxd_device *idxd)
 
 static void idxd_device_evl_free(struct idxd_device *idxd)
 {
+	void *evl_log;
+	unsigned int evl_log_size;
+	dma_addr_t evl_dma;
 	union gencfg_reg gencfg;
 	union genctrl_reg genctrl;
 	struct device *dev = &idxd->pdev->dev;

@@ -822,11 +825,15 @@ static void idxd_device_evl_free(struct idxd_device *idxd)
 	iowrite64(0, idxd->reg_base + IDXD_EVLCFG_OFFSET);
 	iowrite64(0, idxd->reg_base + IDXD_EVLCFG_OFFSET + 8);
 
-	dma_free_coherent(dev, evl->log_size, evl->log, evl->dma);
 	bitmap_free(evl->bmap);
+	evl_log = evl->log;
+	evl_log_size = evl->log_size;
+	evl_dma = evl->dma;
 	evl->log = NULL;
 	evl->size = IDXD_EVL_SIZE_MIN;
 	spin_unlock(&evl->lock);
+
+	dma_free_coherent(dev, evl_log_size, evl_log, evl_dma);
 }
 
 static void idxd_group_config_write(struct idxd_group *group)
Signature · 1 line
2.25.1
author
#1 lore raw

PATCH 1/1 dmaengine: idxd: Move dma_free_coherent() out of spinlocked context

Task may be rescheduled within dma_free_coherent(). So dma_free_coherent() can't be called between spin_lock() and spin_unlock() to avoid Call Trace:

    Call Trace:
    <TASK>
    dump_stack_lvl+0x37/0x50
    __might_resched+0x16a/0x1c0
    vunmap+0x2c/0x70
    __iommu_dma_free+0x96/0x100
    idxd_device_evl_free+0xd5/0x100 [idxd]
    device_release_driver_internal+0x197/0x200
    unbind_store+0xa1/0xb0
    kernfs_fop_write_iter+0x120/0x1c0
    vfs_write+0x2d3/0x400
    ksys_write+0x63/0xe0
    do_syscall_64+0x44/0xa0
    entry_SYSCALL_64_after_hwframe+0x6e/0xd8

Move it out of the context.

Fixes 244da66cda35 ("dmaengine: idxd: setup event log configuration")
Signed-off-by Rex Zhang <[email protected]>
Reviewed-by Dave Jiang <[email protected]>
Reviewed-by Fenghua Yu <[email protected]>
---
 drivers/dma/idxd/device.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)
drivers/dma/idxd/device.c +8 -1
index 8f754f922217..fa0f880beae6 100644
@@ -802,6 +802,9 @@ static int idxd_device_evl_setup(struct idxd_device *idxd)
 
 static void idxd_device_evl_free(struct idxd_device *idxd)
 {
+	void *evl_log;
+	unsigned int evl_log_size;
+	dma_addr_t evl_dma;
 	union gencfg_reg gencfg;
 	union genctrl_reg genctrl;
 	struct device *dev = &idxd->pdev->dev;

@@ -822,11 +825,15 @@ static void idxd_device_evl_free(struct idxd_device *idxd)
 	iowrite64(0, idxd->reg_base + IDXD_EVLCFG_OFFSET);
 	iowrite64(0, idxd->reg_base + IDXD_EVLCFG_OFFSET + 8);
 
-	dma_free_coherent(dev, evl->log_size, evl->log, evl->dma);
 	bitmap_free(evl->bmap);
+	evl_log = evl->log;
+	evl_log_size = evl->log_size;
+	evl_dma = evl->dma;
 	evl->log = NULL;
 	evl->size = IDXD_EVL_SIZE_MIN;
 	spin_unlock(&evl->lock);
+
+	dma_free_coherent(dev, evl_log_size, evl_log, evl_dma);
 }
 
 static void idxd_group_config_write(struct idxd_group *group)
Signature · 1 line
2.25.1
maintainer Applied
#2 lore raw
Quoted 16 lines · Rex Zhang

Task may be rescheduled within dma_free_coherent(). So dma_free_coherent() can't be called between spin_lock() and spin_unlock() to avoid Call Trace:

    Call Trace:
    <TASK>
    dump_stack_lvl+0x37/0x50
    __might_resched+0x16a/0x1c0
    vunmap+0x2c/0x70
    __iommu_dma_free+0x96/0x100
    idxd_device_evl_free+0xd5/0x100 [idxd]
    device_release_driver_internal+0x197/0x200
    unbind_store+0xa1/0xb0
    kernfs_fop_write_iter+0x120/0x1c0
    vfs_write+0x2d3/0x400
    ksys_write+0x63/0xe0
    do_syscall_64+0x44/0xa0
    entry_SYSCALL_64_after_hwframe+0x6e/0xd8
Quoted 3 lines

Move it out of the context.

[...]

Applied, thanks!

[1/1] dmaengine: idxd: Move dma_free_coherent() out of spinlocked context

      commit: e271c0ba3f919c48e90c64b703538fbb7865cb63

Best regards,

Signature · 1 line
~Vinod
Reviewed-by on v1 1/1
#3 lore raw
In reply to Rex Zhang
Quoted 16 lines · Rex Zhang

Task may be rescheduled within dma_free_coherent(). So dma_free_coherent() can't be called between spin_lock() and spin_unlock() to avoid Call Trace:

     Call Trace:
     <TASK>
     dump_stack_lvl+0x37/0x50
     __might_resched+0x16a/0x1c0
     vunmap+0x2c/0x70
     __iommu_dma_free+0x96/0x100
     idxd_device_evl_free+0xd5/0x100 [idxd]
     device_release_driver_internal+0x197/0x200
     unbind_store+0xa1/0xb0
     kernfs_fop_write_iter+0x120/0x1c0
     vfs_write+0x2d3/0x400
     ksys_write+0x63/0xe0
     do_syscall_64+0x44/0xa0
     entry_SYSCALL_64_after_hwframe+0x6e/0xd8
Quoted 7 lines

Move it out of the context.

Fixes 244da66cda35 ("dmaengine: idxd: setup event log configuration")
Signed-off-by Rex Zhang <[email protected]>
Reviewed-by Dave Jiang <[email protected]>
Reviewed-by Fenghua Yu <[email protected]>

---

Reviewed-by Lijun Pan <[email protected]>
Quoted 34 lines
  drivers/dma/idxd/device.c | 9 ++++++++-
  1 file changed, 8 insertions(+), 1 deletion(-)
drivers/dma/idxd/device.c +8 -1
index 8f754f922217..fa0f880beae6 100644
@@ -802,6 +802,9 @@ static int idxd_device_evl_setup(struct idxd_device *idxd)
 
  static void idxd_device_evl_free(struct idxd_device *idxd)
  {
+	void *evl_log;
+	unsigned int evl_log_size;
+	dma_addr_t evl_dma;
  	union gencfg_reg gencfg;
  	union genctrl_reg genctrl;
  	struct device *dev = &idxd->pdev->dev;

@@ -822,11 +825,15 @@ static void idxd_device_evl_free(struct idxd_device *idxd)
  	iowrite64(0, idxd->reg_base + IDXD_EVLCFG_OFFSET);
  	iowrite64(0, idxd->reg_base + IDXD_EVLCFG_OFFSET + 8);
 
-	dma_free_coherent(dev, evl->log_size, evl->log, evl->dma);
  	bitmap_free(evl->bmap);
+	evl_log = evl->log;
+	evl_log_size = evl->log_size;
+	evl_dma = evl->dma;
  	evl->log = NULL;
  	evl->size = IDXD_EVL_SIZE_MIN;
  	spin_unlock(&evl->lock);
+
+	dma_free_coherent(dev, evl_log_size, evl_log, evl_dma);
  }
 
  static void idxd_group_config_write(struct idxd_group *group)