From: Greg Kroah-Hartman gregkh@linuxfoundation.org
From: Andrey Ryabinin arbn@yandex-team.com
commit 140456f994195b568ecd7fc2287a34eadffef3ca upstream.
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 Signed-off-by: Andrey Ryabinin arbn@yandex-team.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/iommu/amd_iommu.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)
--- a/drivers/iommu/amd_iommu.c +++ b/drivers/iommu/amd_iommu.c @@ -1348,24 +1348,26 @@ static void increase_address_space(struc unsigned long flags; u64 *pte;
+ pte = (void *)get_zeroed_page(gfp); + if (!pte) + return; + spin_lock_irqsave(&domain->lock, flags);
if (WARN_ON_ONCE(domain->mode == PAGE_MODE_6_LEVEL)) /* address space already 64 bit large */ goto out;
- pte = (void *)get_zeroed_page(gfp); - if (!pte) - goto out; - *pte = PM_LEVEL_PDE(domain->mode, iommu_virt_to_phys(domain->pt_root)); domain->pt_root = pte; domain->mode += 1; domain->updated = true; + pte = NULL;
out: spin_unlock_irqrestore(&domain->lock, flags); + free_page((unsigned long)pte);
return; }