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Received: from DS7PR12MB6048.namprd12.prod.outlook.com (2603:10b6:8:9f::5) by SN7PR12MB6671.namprd12.prod.outlook.com (2603:10b6:806:26d::12) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.6521.23; Fri, 23 Jun 2023 04:38:51 +0000 Received: from DS7PR12MB6048.namprd12.prod.outlook.com ([fe80::7cbf:236a:55b:2c99]) by DS7PR12MB6048.namprd12.prod.outlook.com ([fe80::7cbf:236a:55b:2c99%4]) with mapi id 15.20.6521.026; Fri, 23 Jun 2023 04:38:51 +0000 Message-ID: Date: Fri, 23 Jun 2023 10:08:39 +0530 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.8.1 Subject: Re: [PATCH v2 iommu/next] iommu: Fix default domain setup Content-Language: en-US To: Jason Gunthorpe Cc: Baolu Lu , iommu@lists.linux.dev, joro@8bytes.org, suravee.suthikulpanit@amd.com, Dheeraj Kumar Srivastava References: <20230619084945.6427-1-vasant.hegde@amd.com> <13d072e5-df86-d3c8-6742-e52b66fd96a4@linux.intel.com> <13b8b3a8-4dc5-7e61-4e0b-f545a3679a8a@amd.com> From: Vasant Hegde In-Reply-To: Content-Type: text/plain; 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>>>>> + group->default_domain = old_dom; >>>>> iommu_domain_free(dom); >>>>> old_dom = NULL; >>>>> } >>>> >>>> The err_restore branch doesn't work if old_dom is NULL. We have no means >>>> to restore a group from a successful first-time attaching to NULL >>>> attaching. >>> >>> Yes, this is what I fixed in my alternative version >> >> Not really. Even your version has > > I though what Baolu means is that it crashes in some of the cases. > >> +err_restore_domain: >> + if (old_dom) >> >> >> Only first time we will have old_dom is NULL and this functions returns error >> code. iommu_probe_device()/bus_iommu_probe() handler error path properly and >> frees resources. So I think this is fine. > > Yes, the design is to leave it as-is and know that the error unwind > will fail to attach the device and free the domain after > release. There is a comment explaining this. > >> @Jason, >> I'm fine with your version of patch as well. Are you going to send proper >> patch -OR- do you want me to respin? > > I was hoping you'd test it and can you share the oops message? This has been tested. Sorry. I should have mentioned it explicitly. One of the call trace without this fix: [ 350.334395] BUG: kernel NULL pointer dereference, address: 0000000000000000 [ 350.341356] #PF: supervisor read access in kernel mode [ 350.346494] #PF: error_code(0x0000) - not-present page [ 350.351625] PGD 0 P4D 0 [ 350.354164] Oops: 0000 [#1] PREEMPT SMP NOPTI [ 350.358523] CPU: 1 PID: 3417 Comm: avocado Not tainted 6.4.0-rc4-next-20230602 #3 [ 350.366003] Hardware name: Dell Inc. PowerEdge R6515/07PXPY, BIOS 2.3.6 07/06/2021 [ 350.373567] RIP: 0010:__iommu_attach_device+0xc/0xa0 [ 350.378533] 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 [ 350.397269] RSP: 0018:ffffabae0220bd48 EFLAGS: 00010246 [ 350.402488] RAX: 0000000000000000 RBX: ffff9ac04f70e410 RCX: 0000000000000001 [ 350.409620] RDX: ffff9ac044db20c0 RSI: ffff9ac044fa50d0 RDI: ffff9ac04f70e410 [ 350.416751] RBP: ffff9ac044fa50d0 R08: 1000000100209001 R09: 00000000000002dc [ 350.423875] R10: 0000000000000000 R11: 0000000000000000 R12: ffff9ac043d54700 [ 350.431001] R13: ffff9ac043d54700 R14: 0000000000000001 R15: 0000000000000001 [ 350.438133] FS: 00007f02e30ae000(0000) GS:ffff9afeb2440000(0000) knlGS:0000000000000000 [ 350.446217] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 350.451956] CR2: 0000000000000000 CR3: 000000012afca006 CR4: 0000000000770ee0 [ 350.459086] PKRU: 55555554 [ 350.461792] Call Trace: [ 350.464235] [ 350.466335] ? __die+0x24/0x70 [ 350.469392] ? page_fault_oops+0x82/0x150 [ 350.473404] ? __iommu_queue_command_sync+0x80/0xc0 [ 350.478283] ? exc_page_fault+0x69/0x150 [ 350.482210] ? asm_exc_page_fault+0x26/0x30 [ 350.486396] ? __iommu_attach_device+0xc/0xa0 [ 350.490756] ? __iommu_attach_device+0x1c/0xa0 [ 350.495201] __iommu_device_set_domain+0x42/0x80 [ 350.499820] __iommu_group_set_domain_internal+0x5d/0x160 [ 350.505220] iommu_setup_default_domain+0x318/0x400 [ 350.510097] iommu_group_store_type+0xb1/0x200 [ 350.514536] kernfs_fop_write_iter+0x12f/0x1c0 [ 350.518982] vfs_write+0x2a2/0x3b0 [ 350.522389] ksys_write+0x63/0xe0 [ 350.525707] do_syscall_64+0x3f/0x90 [ 350.529284] entry_SYSCALL_64_after_hwframe+0x6e/0xd8 [ 350.534338] RIP: 0033:0x7f02e2f14a6f [ 350.537918] Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 19 c0 f7 ff 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 5c c0 f7 ff 48 [ 350.556663] RSP: 002b:00007ffe5451b6e0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 [ 350.564226] RAX: ffffffffffffffda RBX: 000055f381c20a20 RCX: 00007f02e2f14a6f [ 350.571352] RDX: 0000000000000008 RSI: 000055f382f36220 RDI: 000000000000000d [ 350.578485] RBP: 000055f3829e0340 R08: 0000000000000000 R09: 0000000000000000 [ 350.585615] R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000008 [ 350.592740] R13: 00007f02e30adf80 R14: 000000000000000d R15: 000055f382f36220 [ 350.599865] [ 350.602057] Modules linked in: xt_CHECKSUM xt_MASQUERADE xt_conntrack ipt_REJECT nf_reject_ipv4 nft_compat nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 nf_tables nfnetlink bridge stp llc binfmt_misc ipmi_ssif vfat fat intel_rapl_msr intel_rapl_common amd64_edac edac_mce_amd kvm_amd kvm irqbypass acpi_ipmi rapl wmi_bmof acpi_cpufreq ccp sg k10temp ipmi_si acpi_power_meter squashfs loop dm_multipath ipmi_devintf ipmi_msghandler ramoops reed_solomon fuse ip_tables ext4 mbcache jbd2 raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor xor async_tx raid6_pq libcrc32c raid1 raid0 linear dm_mod sd_mod t10_pi crc64_rocksoft_generic crc64_rocksoft crc64 mgag200 i2c_algo_bit drm_shmem_helper crct10dif_pclmul crc32_pclmul ahci drm_kms_helper crc32c_intel libahci ghash_clmulni_intel mpt3sas sha512_ssse3 drm tg3 raid_class libata i2c_piix4 scsi_transport_sas wmi [ 350.679856] CR2: 0000000000000000 [ 350.683174] ---[ end trace 0000000000000000 ]--- [ 350.687791] RIP: 0010:__iommu_attach_device+0xc/0xa0 [ 350.692758] 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 [ 350.711495] RSP: 0018:ffffabae0220bd48 EFLAGS: 00010246 [ 350.716721] RAX: 0000000000000000 RBX: ffff9ac04f70e410 RCX: 0000000000000001 [ 350.723844] RDX: ffff9ac044db20c0 RSI: ffff9ac044fa50d0 RDI: ffff9ac04f70e410 [ 350.730968] RBP: ffff9ac044fa50d0 R08: 1000000100209001 R09: 00000000000002dc [ 350.738092] R10: 0000000000000000 R11: 0000000000000000 R12: ffff9ac043d54700 [ 350.745215] R13: ffff9ac043d54700 R14: 0000000000000001 R15: 0000000000000001 [ 350.752339] FS: 00007f02e30ae000(0000) GS:ffff9afeb2440000(0000) knlGS:0000000000000000 [ 350.760417] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 350.766154] CR2: 0000000000000000 CR3: 000000012afca006 CR4: 0000000000770ee0 [ 350.773279] PKRU: 55555554 [ 350.775989] Kernel panic - not syncing: Fatal exception [ 351.399507] Kernel Offset: 0x2fe00000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) [ 351.410284] ---[ end Kernel panic - not syncing: Fatal exception ]--- -Vasant