On Wed, Feb 17, 2021 at 06:10:02PM +0000, Will Deacon wrote:

...

drivers/iommu/amd/iommu.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)

Acked-by: Will Deacon will@kernel.org

Applied for v5.12, thanks.

There were some conflicts which I resolved, can you please check the result, Andrey? The updated patch is attached.

From 140456f994195b568ecd7fc2287a34eadffef3ca Mon Sep 17 00:00:00 2001

From: Andrey Ryabinin arbn@yandex-team.com Date: Wed, 17 Feb 2021 17:30:04 +0300 Subject: [PATCH] iommu/amd: Fix sleeping in atomic in increase_address_space()

increase_address_space() calls get_zeroed_page(gfp) under spin_lock with disabled interrupts. gfp flags passed to increase_address_space() may allow sleeping, so it comes to this:

BUG: sleeping function called from invalid context at mm/page_alloc.c:4342 in_atomic(): 1, irqs_disabled(): 1, pid: 21555, name: epdcbbf1qnhbsd8

Call Trace: dump_stack+0x66/0x8b ___might_sleep+0xec/0x110 __alloc_pages_nodemask+0x104/0x300 get_zeroed_page+0x15/0x40 iommu_map_page+0xdd/0x3e0 amd_iommu_map+0x50/0x70 iommu_map+0x106/0x220 vfio_iommu_type1_ioctl+0x76e/0x950 [vfio_iommu_type1] do_vfs_ioctl+0xa3/0x6f0 ksys_ioctl+0x66/0x70 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x4e/0x100 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fix this by moving get_zeroed_page() out of spin_lock/unlock section.

Fixes: 754265bcab ("iommu/amd: Fix race in increase_address_space()") Signed-off-by: Andrey Ryabinin arbn@yandex-team.com Acked-by: Will Deacon will@kernel.org Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20210217143004.19165-1-arbn@yandex-team.com Signed-off-by: Joerg Roedel jroedel@suse.de --- drivers/iommu/amd/io_pgtable.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/iommu/amd/io_pgtable.c b/drivers/iommu/amd/io_pgtable.c index 1c4961e05c12..bb0ee5c9fde7 100644 --- a/drivers/iommu/amd/io_pgtable.c +++ b/drivers/iommu/amd/io_pgtable.c @@ -182,6 +182,10 @@ static bool increase_address_space(struct protection_domain *domain, bool ret = true; u64 *pte;

+ pte = (void *)get_zeroed_page(gfp); + if (!pte) + return false; + spin_lock_irqsave(&domain->lock, flags);

if (address <= PM_LEVEL_SIZE(domain->iop.mode)) @@ -191,10 +195,6 @@ static bool increase_address_space(struct protection_domain *domain, if (WARN_ON_ONCE(domain->iop.mode == PAGE_MODE_6_LEVEL)) goto out;

- pte = (void *)get_zeroed_page(gfp); - if (!pte) - goto out; - *pte = PM_LEVEL_PDE(domain->iop.mode, iommu_virt_to_phys(domain->iop.root));

domain->iop.root = pte; @@ -208,10 +208,12 @@ static bool increase_address_space(struct protection_domain *domain, */ amd_iommu_domain_set_pgtable(domain, pte, domain->iop.mode);

+ pte = NULL; ret = true;

out: spin_unlock_irqrestore(&domain->lock, flags); + free_page((unsigned long)pte);

return ret; }