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authorRex Zhang <rex.zhang@intel.com>2024-04-05 01:39:49 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2024-05-02 17:35:33 +0300
commitc9b732a9f73eadc638abdcf0a6d39bc7a0c1af5f (patch)
tree66f6a9c2970e50de402d9f396b30ba30e7ca9bee
parent2232eb36cb8fff11eb61f5368f6a3d29286dc070 (diff)
downloadlinux-c9b732a9f73eadc638abdcf0a6d39bc7a0c1af5f.tar.xz
dmaengine: idxd: Convert spinlock to mutex to lock evl workqueue
[ Upstream commit d5638de827cff0fce77007e426ec0ffdedf68a44 ] drain_workqueue() cannot be called safely in a spinlocked context due to possible task rescheduling. In the multi-task scenario, calling queue_work() while drain_workqueue() will lead to a Call Trace as pushing a work on a draining workqueue is not permitted in spinlocked context. Call Trace: <TASK> ? __warn+0x7d/0x140 ? __queue_work+0x2b2/0x440 ? report_bug+0x1f8/0x200 ? handle_bug+0x3c/0x70 ? exc_invalid_op+0x18/0x70 ? asm_exc_invalid_op+0x1a/0x20 ? __queue_work+0x2b2/0x440 queue_work_on+0x28/0x30 idxd_misc_thread+0x303/0x5a0 [idxd] ? __schedule+0x369/0xb40 ? __pfx_irq_thread_fn+0x10/0x10 ? irq_thread+0xbc/0x1b0 irq_thread_fn+0x21/0x70 irq_thread+0x102/0x1b0 ? preempt_count_add+0x74/0xa0 ? __pfx_irq_thread_dtor+0x10/0x10 ? __pfx_irq_thread+0x10/0x10 kthread+0x103/0x140 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x31/0x50 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1b/0x30 </TASK> The current implementation uses a spinlock to protect event log workqueue and will lead to the Call Trace due to potential task rescheduling. To address the locking issue, convert the spinlock to mutex, allowing the drain_workqueue() to be called in a safe mutex-locked context. This change ensures proper synchronization when accessing the event log workqueue, preventing potential Call Trace and improving the overall robustness of the code. Fixes: c40bd7d9737b ("dmaengine: idxd: process user page faults for completion record") Signed-off-by: Rex Zhang <rex.zhang@intel.com> Reviewed-by: Dave Jiang <dave.jiang@intel.com> Reviewed-by: Fenghua Yu <fenghua.yu@intel.com> Reviewed-by: Lijun Pan <lijun.pan@intel.com> Link: https://lore.kernel.org/r/20240404223949.2885604-1-fenghua.yu@intel.com Signed-off-by: Vinod Koul <vkoul@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
-rw-r--r--drivers/dma/idxd/cdev.c5
-rw-r--r--drivers/dma/idxd/debugfs.c4
-rw-r--r--drivers/dma/idxd/device.c8
-rw-r--r--drivers/dma/idxd/idxd.h2
-rw-r--r--drivers/dma/idxd/init.c2
-rw-r--r--drivers/dma/idxd/irq.c4
6 files changed, 12 insertions, 13 deletions
diff --git a/drivers/dma/idxd/cdev.c b/drivers/dma/idxd/cdev.c
index e5a94a93a3cc..59456f21778b 100644
--- a/drivers/dma/idxd/cdev.c
+++ b/drivers/dma/idxd/cdev.c
@@ -342,7 +342,7 @@ static void idxd_cdev_evl_drain_pasid(struct idxd_wq *wq, u32 pasid)
if (!evl)
return;
- spin_lock(&evl->lock);
+ mutex_lock(&evl->lock);
status.bits = ioread64(idxd->reg_base + IDXD_EVLSTATUS_OFFSET);
t = status.tail;
h = status.head;
@@ -354,9 +354,8 @@ static void idxd_cdev_evl_drain_pasid(struct idxd_wq *wq, u32 pasid)
set_bit(h, evl->bmap);
h = (h + 1) % size;
}
- spin_unlock(&evl->lock);
-
drain_workqueue(wq->wq);
+ mutex_unlock(&evl->lock);
}
static int idxd_cdev_release(struct inode *node, struct file *filep)
diff --git a/drivers/dma/idxd/debugfs.c b/drivers/dma/idxd/debugfs.c
index f3f25ee676f3..ad4245cb301d 100644
--- a/drivers/dma/idxd/debugfs.c
+++ b/drivers/dma/idxd/debugfs.c
@@ -66,7 +66,7 @@ static int debugfs_evl_show(struct seq_file *s, void *d)
if (!evl || !evl->log)
return 0;
- spin_lock(&evl->lock);
+ mutex_lock(&evl->lock);
evl_status.bits = ioread64(idxd->reg_base + IDXD_EVLSTATUS_OFFSET);
t = evl_status.tail;
@@ -87,7 +87,7 @@ static int debugfs_evl_show(struct seq_file *s, void *d)
dump_event_entry(idxd, s, i, &count, processed);
}
- spin_unlock(&evl->lock);
+ mutex_unlock(&evl->lock);
return 0;
}
diff --git a/drivers/dma/idxd/device.c b/drivers/dma/idxd/device.c
index ecfdf4a8f1f8..c41ef195eeb9 100644
--- a/drivers/dma/idxd/device.c
+++ b/drivers/dma/idxd/device.c
@@ -775,7 +775,7 @@ static int idxd_device_evl_setup(struct idxd_device *idxd)
goto err_alloc;
}
- spin_lock(&evl->lock);
+ mutex_lock(&evl->lock);
evl->log = addr;
evl->dma = dma_addr;
evl->log_size = size;
@@ -796,7 +796,7 @@ static int idxd_device_evl_setup(struct idxd_device *idxd)
gencfg.evl_en = 1;
iowrite32(gencfg.bits, idxd->reg_base + IDXD_GENCFG_OFFSET);
- spin_unlock(&evl->lock);
+ mutex_unlock(&evl->lock);
return 0;
err_alloc:
@@ -819,7 +819,7 @@ static void idxd_device_evl_free(struct idxd_device *idxd)
if (!gencfg.evl_en)
return;
- spin_lock(&evl->lock);
+ mutex_lock(&evl->lock);
gencfg.evl_en = 0;
iowrite32(gencfg.bits, idxd->reg_base + IDXD_GENCFG_OFFSET);
@@ -836,7 +836,7 @@ static void idxd_device_evl_free(struct idxd_device *idxd)
evl_dma = evl->dma;
evl->log = NULL;
evl->size = IDXD_EVL_SIZE_MIN;
- spin_unlock(&evl->lock);
+ mutex_unlock(&evl->lock);
dma_free_coherent(dev, evl_log_size, evl_log, evl_dma);
}
diff --git a/drivers/dma/idxd/idxd.h b/drivers/dma/idxd/idxd.h
index d0f5db6cf1ed..df91472f0f5b 100644
--- a/drivers/dma/idxd/idxd.h
+++ b/drivers/dma/idxd/idxd.h
@@ -293,7 +293,7 @@ struct idxd_driver_data {
struct idxd_evl {
/* Lock to protect event log access. */
- spinlock_t lock;
+ struct mutex lock;
void *log;
dma_addr_t dma;
/* Total size of event log = number of entries * entry size. */
diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
index 4954adc6bb60..264c4e47d7cc 100644
--- a/drivers/dma/idxd/init.c
+++ b/drivers/dma/idxd/init.c
@@ -354,7 +354,7 @@ static int idxd_init_evl(struct idxd_device *idxd)
if (!evl)
return -ENOMEM;
- spin_lock_init(&evl->lock);
+ mutex_init(&evl->lock);
evl->size = IDXD_EVL_SIZE_MIN;
idxd_name = dev_name(idxd_confdev(idxd));
diff --git a/drivers/dma/idxd/irq.c b/drivers/dma/idxd/irq.c
index 348aa21389a9..8dc029c86551 100644
--- a/drivers/dma/idxd/irq.c
+++ b/drivers/dma/idxd/irq.c
@@ -363,7 +363,7 @@ static void process_evl_entries(struct idxd_device *idxd)
evl_status.bits = 0;
evl_status.int_pending = 1;
- spin_lock(&evl->lock);
+ mutex_lock(&evl->lock);
/* Clear interrupt pending bit */
iowrite32(evl_status.bits_upper32,
idxd->reg_base + IDXD_EVLSTATUS_OFFSET + sizeof(u32));
@@ -380,7 +380,7 @@ static void process_evl_entries(struct idxd_device *idxd)
evl_status.head = h;
iowrite32(evl_status.bits_lower32, idxd->reg_base + IDXD_EVLSTATUS_OFFSET);
- spin_unlock(&evl->lock);
+ mutex_unlock(&evl->lock);
}
irqreturn_t idxd_misc_thread(int vec, void *data)