From 911476ef3c585da9fdf156fd7aaa7455455daf76 Mon Sep 17 00:00:00 2001 From: Jason Gunthorpe Date: Mon, 26 Jun 2023 12:13:11 -0300 Subject: iommu: Fix crash during syfs iommu_groups/N/type The err_restore_domain flow was accidently inserted into the success path in commit 1000dccd5d13 ("iommu: Allow IOMMU_RESV_DIRECT to work on ARM"). It should only happen if iommu_create_device_direct_mappings() fails. This caused the domains the be wrongly changed and freed whenever the sysfs is used, resulting in an oops: BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP NOPTI CPU: 1 PID: 3417 Comm: avocado Not tainted 6.4.0-rc4-next-20230602 #3 Hardware name: Dell Inc. PowerEdge R6515/07PXPY, BIOS 2.3.6 07/06/2021 RIP: 0010:__iommu_attach_device+0xc/0xa0 Code: c0 c3 cc cc cc cc 48 89 f0 c3 cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 44 00 00 41 54 55 48 8b 47 08 <48> 8b 00 48 85 c0 74 74 48 89 f5 e8 64 12 49 00 41 89 c4 85 c0 74 RSP: 0018:ffffabae0220bd48 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff9ac04f70e410 RCX: 0000000000000001 RDX: ffff9ac044db20c0 RSI: ffff9ac044fa50d0 RDI: ffff9ac04f70e410 RBP: ffff9ac044fa50d0 R08: 1000000100209001 R09: 00000000000002dc R10: 0000000000000000 R11: 0000000000000000 R12: ffff9ac043d54700 R13: ffff9ac043d54700 R14: 0000000000000001 R15: 0000000000000001 FS: 00007f02e30ae000(0000) GS:ffff9afeb2440000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 000000012afca006 CR4: 0000000000770ee0 PKRU: 55555554 Call Trace: ? __die+0x24/0x70 ? page_fault_oops+0x82/0x150 ? __iommu_queue_command_sync+0x80/0xc0 ? exc_page_fault+0x69/0x150 ? asm_exc_page_fault+0x26/0x30 ? __iommu_attach_device+0xc/0xa0 ? __iommu_attach_device+0x1c/0xa0 __iommu_device_set_domain+0x42/0x80 __iommu_group_set_domain_internal+0x5d/0x160 iommu_setup_default_domain+0x318/0x400 iommu_group_store_type+0xb1/0x200 kernfs_fop_write_iter+0x12f/0x1c0 vfs_write+0x2a2/0x3b0 ksys_write+0x63/0xe0 do_syscall_64+0x3f/0x90 entry_SYSCALL_64_after_hwframe+0x6e/0xd8 RIP: 0033:0x7f02e2f14a6f Reorganize the error flow so that the success branch and error branches are clearer. Fixes: 1000dccd5d13 ("iommu: Allow IOMMU_RESV_DIRECT to work on ARM") Reported-by: Dheeraj Kumar Srivastava Tested-by: Vasant Hegde Signed-off-by: Jason Gunthorpe Reviewed-by: Lu Baolu Reviewed-by: Kevin Tian Link: https://lore.kernel.org/r/0-v1-5bd8cc969d9e+1f1-iommu_set_def_fix_jgg@nvidia.com Signed-off-by: Joerg Roedel --- drivers/iommu/iommu.c | 27 ++++++++++++++------------- 1 file changed, 14 insertions(+), 13 deletions(-) (limited to 'drivers') diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index da340f11c5f5..caaf563d38ae 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -2891,14 +2891,11 @@ static int iommu_setup_default_domain(struct iommu_group *group, ret = __iommu_group_set_domain_internal( group, dom, IOMMU_SET_DOMAIN_MUST_SUCCEED); if (WARN_ON(ret)) - goto out_free; + goto out_free_old; } else { ret = __iommu_group_set_domain(group, dom); - if (ret) { - iommu_domain_free(dom); - group->default_domain = old_dom; - return ret; - } + if (ret) + goto err_restore_def_domain; } /* @@ -2911,20 +2908,24 @@ static int iommu_setup_default_domain(struct iommu_group *group, for_each_group_device(group, gdev) { ret = iommu_create_device_direct_mappings(dom, gdev->dev); if (ret) - goto err_restore; + goto err_restore_domain; } } -err_restore: - if (old_dom) { +out_free_old: + if (old_dom) + iommu_domain_free(old_dom); + return ret; + +err_restore_domain: + if (old_dom) __iommu_group_set_domain_internal( group, old_dom, IOMMU_SET_DOMAIN_MUST_SUCCEED); +err_restore_def_domain: + if (old_dom) { iommu_domain_free(dom); - old_dom = NULL; + group->default_domain = old_dom; } -out_free: - if (old_dom) - iommu_domain_free(old_dom); return ret; } -- cgit v1.2.3