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>
Cc: <stable@xxxxxxxxxxxxxxx>
---
drivers/iommu/amd/iommu.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
index f0adbc48fd17..9256f84f5ebf 100644
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -1502,6 +1502,10 @@ 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);
amd_iommu_domain_get_pgtable(domain, &pgtable);
@@ -1513,10 +1517,6 @@ static bool increase_address_space(struct protection_domain *domain,
if (WARN_ON_ONCE(pgtable.mode == PAGE_MODE_6_LEVEL))
goto out;
- pte = (void *)get_zeroed_page(gfp);
- if (!pte)
- goto out;
-
*pte = PM_LEVEL_PDE(pgtable.mode, iommu_virt_to_phys(pgtable.root));
pgtable.root = pte;
@@ -1530,10 +1530,12 @@ static bool increase_address_space(struct protection_domain *domain,
*/
amd_iommu_domain_set_pgtable(domain, pte, pgtable.mode);
+ pte = NULL;
ret = true;
out:
spin_unlock_irqrestore(&domain->lock, flags);
+ free_page((unsigned long)pte);
return ret;
}
--
2.26.2
