[PATCH 4.9 60/70] iommu/ipmmu-vmsa: Fix allocation in atomic context

Greg Kroah-Hartman
2018-09-17T22:58:50Z

From: Geert Uytterhoeven <geert+renesas@glider.be>

[ Upstream commit 46583e8c48c5a094ba28060615b3a7c8c576690f ]

When attaching a device to an IOMMU group with
CONFIG_DEBUG_ATOMIC_SLEEP=y:

BUG: sleeping function called from invalid context at mm/slab.h:421
in_atomic(): 1, irqs_disabled(): 128, pid: 61, name: kworker/1:1
...
Call trace:
...
arm_lpae_alloc_pgtable+0x114/0x184
arm_64_lpae_alloc_pgtable_s1+0x2c/0x128
arm_32_lpae_alloc_pgtable_s1+0x40/0x6c
alloc_io_pgtable_ops+0x60/0x88
ipmmu_attach_device+0x140/0x334

ipmmu_attach_device() takes a spinlock, while arm_lpae_alloc_pgtable()
allocates memory using GFP_KERNEL. Originally, the ipmmu-vmsa driver
had its own custom page table allocation implementation using
GFP_ATOMIC, hence the spinlock was fine.

Fix this by replacing the spinlock by a mutex, like the arm-smmu driver
does.

Fixes: f20ed39f53145e45 ("iommu/ipmmu-vmsa: Use the ARM LPAE page table allocator")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/iommu/ipmmu-vmsa.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)

--- a/drivers/iommu/ipmmu-vmsa.c
+++ b/drivers/iommu/ipmmu-vmsa.c
@@ -44,7 +44,7 @@ struct ipmmu_vmsa_domain {
struct io_pgtable_ops *iop;

unsigned int context_id;
- spinlock_t lock; /* Protects mappings */
+ struct mutex mutex; /* Protects mappings */
};

struct ipmmu_vmsa_archdata {
@@ -464,7 +464,7 @@ static struct iommu_domain *ipmmu_domain
if (!domain)
return NULL;

- spin_lock_init(&domain->lock);
+ mutex_init(&domain->mutex);

return &domain->io_domain;
}
@@ -488,7 +488,6 @@ static int ipmmu_attach_device(struct io
struct ipmmu_vmsa_archdata *archdata = dev->archdata.iommu;
struct ipmmu_vmsa_device *mmu = archdata->mmu;
struct ipmmu_vmsa_domain *domain = to_vmsa_domain(io_domain);
- unsigned long flags;
unsigned int i;
int ret = 0;

@@ -497,7 +496,7 @@ static int ipmmu_attach_device(struct io
return -ENXIO;
}

- spin_lock_irqsave(&domain->lock, flags);
+ mutex_lock(&domain->mutex);

if (!domain->mmu) {
/* The domain hasn't been used yet, initialize it. */
@@ -513,7 +512,7 @@ static int ipmmu_attach_device(struct io
ret = -EINVAL;
}

- spin_unlock_irqrestore(&domain->lock, flags);
+ mutex_unlock(&domain->mutex);

if (ret < 0)
return ret;