This is a note to let you know that I've just added the patch titled iommu/amd: Fix sleeping in atomic in increase_address_space() to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: iommu-amd-fix-sleeping-in-atomic-in-increase_address_space.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 140456f994195b568ecd7fc2287a34eadffef3ca Mon Sep 17 00:00:00 2001 From: Andrey Ryabinin <arbn@xxxxxxxxxxxxxxx> Date: Wed, 17 Feb 2021 17:30:04 +0300 Subject: iommu/amd: Fix sleeping in atomic in increase_address_space() From: Andrey Ryabinin <arbn@xxxxxxxxxxxxxxx> 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@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> Signed-off-by: Andrey Ryabinin <arbn@xxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- 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 @@ -1469,25 +1469,27 @@ static bool increase_address_space(struc bool ret = false; u64 *pte; + pte = (void *)get_zeroed_page(gfp); + if (!pte) + return false; + spin_lock_irqsave(&domain->lock, flags); if (address <= PM_LEVEL_SIZE(domain->mode) || WARN_ON_ONCE(domain->mode == PAGE_MODE_6_LEVEL)) 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; + pte = NULL; ret = true; out: spin_unlock_irqrestore(&domain->lock, flags); + free_page((unsigned long)pte); return ret; } Patches currently in stable-queue which might be from arbn@xxxxxxxxxxxxxxx are queue-5.4/iommu-amd-fix-sleeping-in-atomic-in-increase_address_space.patch