The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 140456f994195b568ecd7fc2287a34eadffef3ca Mon Sep 17 00:00:00 2001
From: Andrey Ryabinin <arbn@xxxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxx>
Acked-by: Will Deacon <will@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20210217143004.19165-1-arbn@xxxxxxxxxxxxxxx
Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>
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;
}
