gsd-2024-26687
Vulnerability from gsd
Modified
2024-02-20 06:02
Details
In the Linux kernel, the following vulnerability has been resolved: xen/events: close evtchn after mapping cleanup shutdown_pirq and startup_pirq are not taking the irq_mapping_update_lock because they can't due to lock inversion. Both are called with the irq_desc->lock being taking. The lock order, however, is first irq_mapping_update_lock and then irq_desc->lock. This opens multiple races: - shutdown_pirq can be interrupted by a function that allocates an event channel: CPU0 CPU1 shutdown_pirq { xen_evtchn_close(e) __startup_pirq { EVTCHNOP_bind_pirq -> returns just freed evtchn e set_evtchn_to_irq(e, irq) } xen_irq_info_cleanup() { set_evtchn_to_irq(e, -1) } } Assume here event channel e refers here to the same event channel number. After this race the evtchn_to_irq mapping for e is invalid (-1). - __startup_pirq races with __unbind_from_irq in a similar way. Because __startup_pirq doesn't take irq_mapping_update_lock it can grab the evtchn that __unbind_from_irq is currently freeing and cleaning up. In this case even though the event channel is allocated, its mapping can be unset in evtchn_to_irq. The fix is to first cleanup the mappings and then close the event channel. In this way, when an event channel gets allocated it's potential previous evtchn_to_irq mappings are guaranteed to be unset already. This is also the reverse order of the allocation where first the event channel is allocated and then the mappings are setup. On a 5.10 kernel prior to commit 3fcdaf3d7634 ("xen/events: modify internal [un]bind interfaces"), we hit a BUG like the following during probing of NVMe devices. The issue is that during nvme_setup_io_queues, pci_free_irq is called for every device which results in a call to shutdown_pirq. With many nvme devices it's therefore likely to hit this race during boot because there will be multiple calls to shutdown_pirq and startup_pirq are running potentially in parallel. ------------[ cut here ]------------ blkfront: xvda: barrier or flush: disabled; persistent grants: enabled; indirect descriptors: enabled; bounce buffer: enabled kernel BUG at drivers/xen/events/events_base.c:499! invalid opcode: 0000 [#1] SMP PTI CPU: 44 PID: 375 Comm: kworker/u257:23 Not tainted 5.10.201-191.748.amzn2.x86_64 #1 Hardware name: Xen HVM domU, BIOS 4.11.amazon 08/24/2006 Workqueue: nvme-reset-wq nvme_reset_work RIP: 0010:bind_evtchn_to_cpu+0xdf/0xf0 Code: 5d 41 5e c3 cc cc cc cc 44 89 f7 e8 2b 55 ad ff 49 89 c5 48 85 c0 0f 84 64 ff ff ff 4c 8b 68 30 41 83 fe ff 0f 85 60 ff ff ff <0f> 0b 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 0f 1f 44 00 00 RSP: 0000:ffffc9000d533b08 EFLAGS: 00010046 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000006 RDX: 0000000000000028 RSI: 00000000ffffffff RDI: 00000000ffffffff RBP: ffff888107419680 R08: 0000000000000000 R09: ffffffff82d72b00 R10: 0000000000000000 R11: 0000000000000000 R12: 00000000000001ed R13: 0000000000000000 R14: 00000000ffffffff R15: 0000000000000002 FS: 0000000000000000(0000) GS:ffff88bc8b500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 0000000002610001 CR4: 00000000001706e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: ? show_trace_log_lvl+0x1c1/0x2d9 ? show_trace_log_lvl+0x1c1/0x2d9 ? set_affinity_irq+0xdc/0x1c0 ? __die_body.cold+0x8/0xd ? die+0x2b/0x50 ? do_trap+0x90/0x110 ? bind_evtchn_to_cpu+0xdf/0xf0 ? do_error_trap+0x65/0x80 ? bind_evtchn_to_cpu+0xdf/0xf0 ? exc_invalid_op+0x4e/0x70 ? bind_evtchn_to_cpu+0xdf/0xf0 ? asm_exc_invalid_op+0x12/0x20 ? bind_evtchn_to_cpu+0xdf/0x ---truncated---
Aliases


To clipboard 

{
  "gsd": {
    "metadata": {
      "exploitCode": "unknown",
      "remediation": "unknown",
      "reportConfidence": "confirmed",
      "type": "vulnerability"
    },
    "osvSchema": {
      "aliases": [
        "CVE-2024-26687"
      ],
      "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nxen/events: close evtchn after mapping cleanup\n\nshutdown_pirq and startup_pirq are not taking the\nirq_mapping_update_lock because they can\u0027t due to lock inversion. Both\nare called with the irq_desc-\u003elock being taking. The lock order,\nhowever, is first irq_mapping_update_lock and then irq_desc-\u003elock.\n\nThis opens multiple races:\n- shutdown_pirq can be interrupted by a function that allocates an event\n  channel:\n\n  CPU0                        CPU1\n  shutdown_pirq {\n    xen_evtchn_close(e)\n                              __startup_pirq {\n                                EVTCHNOP_bind_pirq\n                                  -\u003e returns just freed evtchn e\n                                set_evtchn_to_irq(e, irq)\n                              }\n    xen_irq_info_cleanup() {\n      set_evtchn_to_irq(e, -1)\n    }\n  }\n\n  Assume here event channel e refers here to the same event channel\n  number.\n  After this race the evtchn_to_irq mapping for e is invalid (-1).\n\n- __startup_pirq races with __unbind_from_irq in a similar way. Because\n  __startup_pirq doesn\u0027t take irq_mapping_update_lock it can grab the\n  evtchn that __unbind_from_irq is currently freeing and cleaning up. In\n  this case even though the event channel is allocated, its mapping can\n  be unset in evtchn_to_irq.\n\nThe fix is to first cleanup the mappings and then close the event\nchannel. In this way, when an event channel gets allocated it\u0027s\npotential previous evtchn_to_irq mappings are guaranteed to be unset already.\nThis is also the reverse order of the allocation where first the event\nchannel is allocated and then the mappings are setup.\n\nOn a 5.10 kernel prior to commit 3fcdaf3d7634 (\"xen/events: modify internal\n[un]bind interfaces\"), we hit a BUG like the following during probing of NVMe\ndevices. The issue is that during nvme_setup_io_queues, pci_free_irq\nis called for every device which results in a call to shutdown_pirq.\nWith many nvme devices it\u0027s therefore likely to hit this race during\nboot because there will be multiple calls to shutdown_pirq and\nstartup_pirq are running potentially in parallel.\n\n  ------------[ cut here ]------------\n  blkfront: xvda: barrier or flush: disabled; persistent grants: enabled; indirect descriptors: enabled; bounce buffer: enabled\n  kernel BUG at drivers/xen/events/events_base.c:499!\n  invalid opcode: 0000 [#1] SMP PTI\n  CPU: 44 PID: 375 Comm: kworker/u257:23 Not tainted 5.10.201-191.748.amzn2.x86_64 #1\n  Hardware name: Xen HVM domU, BIOS 4.11.amazon 08/24/2006\n  Workqueue: nvme-reset-wq nvme_reset_work\n  RIP: 0010:bind_evtchn_to_cpu+0xdf/0xf0\n  Code: 5d 41 5e c3 cc cc cc cc 44 89 f7 e8 2b 55 ad ff 49 89 c5 48 85 c0 0f 84 64 ff ff ff 4c 8b 68 30 41 83 fe ff 0f 85 60 ff ff ff \u003c0f\u003e 0b 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 0f 1f 44 00 00\n  RSP: 0000:ffffc9000d533b08 EFLAGS: 00010046\n  RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000006\n  RDX: 0000000000000028 RSI: 00000000ffffffff RDI: 00000000ffffffff\n  RBP: ffff888107419680 R08: 0000000000000000 R09: ffffffff82d72b00\n  R10: 0000000000000000 R11: 0000000000000000 R12: 00000000000001ed\n  R13: 0000000000000000 R14: 00000000ffffffff R15: 0000000000000002\n  FS:  0000000000000000(0000) GS:ffff88bc8b500000(0000) knlGS:0000000000000000\n  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n  CR2: 0000000000000000 CR3: 0000000002610001 CR4: 00000000001706e0\n  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\n  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400\n  Call Trace:\n   ? show_trace_log_lvl+0x1c1/0x2d9\n   ? show_trace_log_lvl+0x1c1/0x2d9\n   ? set_affinity_irq+0xdc/0x1c0\n   ? __die_body.cold+0x8/0xd\n   ? die+0x2b/0x50\n   ? do_trap+0x90/0x110\n   ? bind_evtchn_to_cpu+0xdf/0xf0\n   ? do_error_trap+0x65/0x80\n   ? bind_evtchn_to_cpu+0xdf/0xf0\n   ? exc_invalid_op+0x4e/0x70\n   ? bind_evtchn_to_cpu+0xdf/0xf0\n   ? asm_exc_invalid_op+0x12/0x20\n   ? bind_evtchn_to_cpu+0xdf/0x\n---truncated---",
      "id": "GSD-2024-26687",
      "modified": "2024-02-20T06:02:29.077587Z",
      "schema_version": "1.4.0"
    }
  },
  "namespaces": {
    "cve.org": {
      "CVE_data_meta": {
        "ASSIGNER": "cve@kernel.org",
        "ID": "CVE-2024-26687",
        "STATE": "PUBLIC"
      },
      "affects": {
        "vendor": {
          "vendor_data": [
            {
              "product": {
                "product_data": [
                  {
                    "product_name": "Linux",
                    "version": {
                      "version_data": [
                        {
                          "version_affected": "\u003c",
                          "version_name": "d46a78b05c0e",
                          "version_value": "9470f5b2503c"
                        },
                        {
                          "version_value": "not down converted",
                          "x_cve_json_5_version_data": {
                            "defaultStatus": "affected",
                            "versions": [
                              {
                                "status": "affected",
                                "version": "2.6.37"
                              },
                              {
                                "lessThan": "2.6.37",
                                "status": "unaffected",
                                "version": "0",
                                "versionType": "custom"
                              },
                              {
                                "lessThanOrEqual": "5.4.*",
                                "status": "unaffected",
                                "version": "5.4.274",
                                "versionType": "custom"
                              },
                              {
                                "lessThanOrEqual": "5.10.*",
                                "status": "unaffected",
                                "version": "5.10.215",
                                "versionType": "custom"
                              },
                              {
                                "lessThanOrEqual": "5.15.*",
                                "status": "unaffected",
                                "version": "5.15.154",
                                "versionType": "custom"
                              },
                              {
                                "lessThanOrEqual": "6.1.*",
                                "status": "unaffected",
                                "version": "6.1.81",
                                "versionType": "custom"
                              },
                              {
                                "lessThanOrEqual": "6.6.*",
                                "status": "unaffected",
                                "version": "6.6.19",
                                "versionType": "custom"
                              },
                              {
                                "lessThanOrEqual": "6.7.*",
                                "status": "unaffected",
                                "version": "6.7.6",
                                "versionType": "custom"
                              },
                              {
                                "lessThanOrEqual": "*",
                                "status": "unaffected",
                                "version": "6.8",
                                "versionType": "original_commit_for_fix"
                              }
                            ]
                          }
                        }
                      ]
                    }
                  }
                ]
              },
              "vendor_name": "Linux"
            }
          ]
        }
      },
      "data_format": "MITRE",
      "data_type": "CVE",
      "data_version": "4.0",
      "description": {
        "description_data": [
          {
            "lang": "eng",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nxen/events: close evtchn after mapping cleanup\n\nshutdown_pirq and startup_pirq are not taking the\nirq_mapping_update_lock because they can\u0027t due to lock inversion. Both\nare called with the irq_desc-\u003elock being taking. The lock order,\nhowever, is first irq_mapping_update_lock and then irq_desc-\u003elock.\n\nThis opens multiple races:\n- shutdown_pirq can be interrupted by a function that allocates an event\n  channel:\n\n  CPU0                        CPU1\n  shutdown_pirq {\n    xen_evtchn_close(e)\n                              __startup_pirq {\n                                EVTCHNOP_bind_pirq\n                                  -\u003e returns just freed evtchn e\n                                set_evtchn_to_irq(e, irq)\n                              }\n    xen_irq_info_cleanup() {\n      set_evtchn_to_irq(e, -1)\n    }\n  }\n\n  Assume here event channel e refers here to the same event channel\n  number.\n  After this race the evtchn_to_irq mapping for e is invalid (-1).\n\n- __startup_pirq races with __unbind_from_irq in a similar way. Because\n  __startup_pirq doesn\u0027t take irq_mapping_update_lock it can grab the\n  evtchn that __unbind_from_irq is currently freeing and cleaning up. In\n  this case even though the event channel is allocated, its mapping can\n  be unset in evtchn_to_irq.\n\nThe fix is to first cleanup the mappings and then close the event\nchannel. In this way, when an event channel gets allocated it\u0027s\npotential previous evtchn_to_irq mappings are guaranteed to be unset already.\nThis is also the reverse order of the allocation where first the event\nchannel is allocated and then the mappings are setup.\n\nOn a 5.10 kernel prior to commit 3fcdaf3d7634 (\"xen/events: modify internal\n[un]bind interfaces\"), we hit a BUG like the following during probing of NVMe\ndevices. The issue is that during nvme_setup_io_queues, pci_free_irq\nis called for every device which results in a call to shutdown_pirq.\nWith many nvme devices it\u0027s therefore likely to hit this race during\nboot because there will be multiple calls to shutdown_pirq and\nstartup_pirq are running potentially in parallel.\n\n  ------------[ cut here ]------------\n  blkfront: xvda: barrier or flush: disabled; persistent grants: enabled; indirect descriptors: enabled; bounce buffer: enabled\n  kernel BUG at drivers/xen/events/events_base.c:499!\n  invalid opcode: 0000 [#1] SMP PTI\n  CPU: 44 PID: 375 Comm: kworker/u257:23 Not tainted 5.10.201-191.748.amzn2.x86_64 #1\n  Hardware name: Xen HVM domU, BIOS 4.11.amazon 08/24/2006\n  Workqueue: nvme-reset-wq nvme_reset_work\n  RIP: 0010:bind_evtchn_to_cpu+0xdf/0xf0\n  Code: 5d 41 5e c3 cc cc cc cc 44 89 f7 e8 2b 55 ad ff 49 89 c5 48 85 c0 0f 84 64 ff ff ff 4c 8b 68 30 41 83 fe ff 0f 85 60 ff ff ff \u003c0f\u003e 0b 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 0f 1f 44 00 00\n  RSP: 0000:ffffc9000d533b08 EFLAGS: 00010046\n  RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000006\n  RDX: 0000000000000028 RSI: 00000000ffffffff RDI: 00000000ffffffff\n  RBP: ffff888107419680 R08: 0000000000000000 R09: ffffffff82d72b00\n  R10: 0000000000000000 R11: 0000000000000000 R12: 00000000000001ed\n  R13: 0000000000000000 R14: 00000000ffffffff R15: 0000000000000002\n  FS:  0000000000000000(0000) GS:ffff88bc8b500000(0000) knlGS:0000000000000000\n  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n  CR2: 0000000000000000 CR3: 0000000002610001 CR4: 00000000001706e0\n  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\n  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400\n  Call Trace:\n   ? show_trace_log_lvl+0x1c1/0x2d9\n   ? show_trace_log_lvl+0x1c1/0x2d9\n   ? set_affinity_irq+0xdc/0x1c0\n   ? __die_body.cold+0x8/0xd\n   ? die+0x2b/0x50\n   ? do_trap+0x90/0x110\n   ? bind_evtchn_to_cpu+0xdf/0xf0\n   ? do_error_trap+0x65/0x80\n   ? bind_evtchn_to_cpu+0xdf/0xf0\n   ? exc_invalid_op+0x4e/0x70\n   ? bind_evtchn_to_cpu+0xdf/0xf0\n   ? asm_exc_invalid_op+0x12/0x20\n   ? bind_evtchn_to_cpu+0xdf/0x\n---truncated---"
          }
        ]
      },
      "generator": {
        "engine": "bippy-d175d3acf727"
      },
      "problemtype": {
        "problemtype_data": [
          {
            "description": [
              {
                "lang": "eng",
                "value": "n/a"
              }
            ]
          }
        ]
      },
      "references": {
        "reference_data": [
          {
            "name": "https://git.kernel.org/stable/c/9470f5b2503cae994098dea9682aee15b313fa44",
            "refsource": "MISC",
            "url": "https://git.kernel.org/stable/c/9470f5b2503cae994098dea9682aee15b313fa44"
          },
          {
            "name": "https://git.kernel.org/stable/c/0fc88aeb2e32b76db3fe6a624b8333dbe621b8fd",
            "refsource": "MISC",
            "url": "https://git.kernel.org/stable/c/0fc88aeb2e32b76db3fe6a624b8333dbe621b8fd"
          },
          {
            "name": "https://git.kernel.org/stable/c/ea592baf9e41779fe9a0424c03dd2f324feca3b3",
            "refsource": "MISC",
            "url": "https://git.kernel.org/stable/c/ea592baf9e41779fe9a0424c03dd2f324feca3b3"
          },
          {
            "name": "https://git.kernel.org/stable/c/585a344af6bcac222608a158fc2830ff02712af5",
            "refsource": "MISC",
            "url": "https://git.kernel.org/stable/c/585a344af6bcac222608a158fc2830ff02712af5"
          },
          {
            "name": "https://git.kernel.org/stable/c/20980195ec8d2e41653800c45c8c367fa1b1f2b4",
            "refsource": "MISC",
            "url": "https://git.kernel.org/stable/c/20980195ec8d2e41653800c45c8c367fa1b1f2b4"
          },
          {
            "name": "https://git.kernel.org/stable/c/9be71aa12afa91dfe457b3fb4a444c42b1ee036b",
            "refsource": "MISC",
            "url": "https://git.kernel.org/stable/c/9be71aa12afa91dfe457b3fb4a444c42b1ee036b"
          },
          {
            "name": "https://git.kernel.org/stable/c/fa765c4b4aed2d64266b694520ecb025c862c5a9",
            "refsource": "MISC",
            "url": "https://git.kernel.org/stable/c/fa765c4b4aed2d64266b694520ecb025c862c5a9"
          }
        ]
      }
    },
    "nvd.nist.gov": {
      "cve": {
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nxen/events: close evtchn after mapping cleanup\n\nshutdown_pirq and startup_pirq are not taking the\nirq_mapping_update_lock because they can\u0027t due to lock inversion. Both\nare called with the irq_desc-\u003elock being taking. The lock order,\nhowever, is first irq_mapping_update_lock and then irq_desc-\u003elock.\n\nThis opens multiple races:\n- shutdown_pirq can be interrupted by a function that allocates an event\n  channel:\n\n  CPU0                        CPU1\n  shutdown_pirq {\n    xen_evtchn_close(e)\n                              __startup_pirq {\n                                EVTCHNOP_bind_pirq\n                                  -\u003e returns just freed evtchn e\n                                set_evtchn_to_irq(e, irq)\n                              }\n    xen_irq_info_cleanup() {\n      set_evtchn_to_irq(e, -1)\n    }\n  }\n\n  Assume here event channel e refers here to the same event channel\n  number.\n  After this race the evtchn_to_irq mapping for e is invalid (-1).\n\n- __startup_pirq races with __unbind_from_irq in a similar way. Because\n  __startup_pirq doesn\u0027t take irq_mapping_update_lock it can grab the\n  evtchn that __unbind_from_irq is currently freeing and cleaning up. In\n  this case even though the event channel is allocated, its mapping can\n  be unset in evtchn_to_irq.\n\nThe fix is to first cleanup the mappings and then close the event\nchannel. In this way, when an event channel gets allocated it\u0027s\npotential previous evtchn_to_irq mappings are guaranteed to be unset already.\nThis is also the reverse order of the allocation where first the event\nchannel is allocated and then the mappings are setup.\n\nOn a 5.10 kernel prior to commit 3fcdaf3d7634 (\"xen/events: modify internal\n[un]bind interfaces\"), we hit a BUG like the following during probing of NVMe\ndevices. The issue is that during nvme_setup_io_queues, pci_free_irq\nis called for every device which results in a call to shutdown_pirq.\nWith many nvme devices it\u0027s therefore likely to hit this race during\nboot because there will be multiple calls to shutdown_pirq and\nstartup_pirq are running potentially in parallel.\n\n  ------------[ cut here ]------------\n  blkfront: xvda: barrier or flush: disabled; persistent grants: enabled; indirect descriptors: enabled; bounce buffer: enabled\n  kernel BUG at drivers/xen/events/events_base.c:499!\n  invalid opcode: 0000 [#1] SMP PTI\n  CPU: 44 PID: 375 Comm: kworker/u257:23 Not tainted 5.10.201-191.748.amzn2.x86_64 #1\n  Hardware name: Xen HVM domU, BIOS 4.11.amazon 08/24/2006\n  Workqueue: nvme-reset-wq nvme_reset_work\n  RIP: 0010:bind_evtchn_to_cpu+0xdf/0xf0\n  Code: 5d 41 5e c3 cc cc cc cc 44 89 f7 e8 2b 55 ad ff 49 89 c5 48 85 c0 0f 84 64 ff ff ff 4c 8b 68 30 41 83 fe ff 0f 85 60 ff ff ff \u003c0f\u003e 0b 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 0f 1f 44 00 00\n  RSP: 0000:ffffc9000d533b08 EFLAGS: 00010046\n  RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000006\n  RDX: 0000000000000028 RSI: 00000000ffffffff RDI: 00000000ffffffff\n  RBP: ffff888107419680 R08: 0000000000000000 R09: ffffffff82d72b00\n  R10: 0000000000000000 R11: 0000000000000000 R12: 00000000000001ed\n  R13: 0000000000000000 R14: 00000000ffffffff R15: 0000000000000002\n  FS:  0000000000000000(0000) GS:ffff88bc8b500000(0000) knlGS:0000000000000000\n  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n  CR2: 0000000000000000 CR3: 0000000002610001 CR4: 00000000001706e0\n  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\n  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400\n  Call Trace:\n   ? show_trace_log_lvl+0x1c1/0x2d9\n   ? show_trace_log_lvl+0x1c1/0x2d9\n   ? set_affinity_irq+0xdc/0x1c0\n   ? __die_body.cold+0x8/0xd\n   ? die+0x2b/0x50\n   ? do_trap+0x90/0x110\n   ? bind_evtchn_to_cpu+0xdf/0xf0\n   ? do_error_trap+0x65/0x80\n   ? bind_evtchn_to_cpu+0xdf/0xf0\n   ? exc_invalid_op+0x4e/0x70\n   ? bind_evtchn_to_cpu+0xdf/0xf0\n   ? asm_exc_invalid_op+0x12/0x20\n   ? bind_evtchn_to_cpu+0xdf/0x\n---truncated---"
          },
          {
            "lang": "es",
            "value": "En el kernel de Linux, se resolvi\u00f3 la siguiente vulnerabilidad: xen/events: cierre evtchn despu\u00e9s de la limpieza del mapeo. Shutdown_pirq y startup_pirq no est\u00e1n tomando irq_mapping_update_lock porque no pueden hacerlo debido a la inversi\u00f3n de bloqueo. Ambos se llaman con el irq_desc-\u0026gt;lock en curso. Sin embargo, el orden de bloqueo es primero irq_mapping_update_lock y luego irq_desc-\u0026gt;lock. Esto abre m\u00faltiples ejecuci\u00f3ns: - Shutdown_pirq puede ser interrumpido por una funci\u00f3n que asigna un canal de evento: CPU0 CPU1 Shutdown_pirq { xen_evtchn_close(e) __startup_pirq { EVTCHNOP_bind_pirq -\u0026gt; devuelve el evtchn e set_evtchn_to_irq(e, irq) reci\u00e9n liberado} xen_irq_info_cleanup() { set_evtchn_to_irq( e, -1) } } Supongamos que aqu\u00ed el canal de eventos e se refiere aqu\u00ed al mismo n\u00famero de canal de eventos. Despu\u00e9s de esta ejecuci\u00f3n, el mapeo evtchn_to_irq para e no es v\u00e1lido (-1). - __startup_pirq compite con __unbind_from_irq de manera similar. Debido a que __startup_pirq no toma irq_mapping_update_lock, puede tomar el evtchn que __unbind_from_irq est\u00e1 liberando y limpiando actualmente. En este caso, aunque el canal de eventos est\u00e9 asignado, su asignaci\u00f3n se puede desarmar en evtchn_to_irq. La soluci\u00f3n es limpiar primero las asignaciones y luego cerrar el canal de eventos. De esta manera, cuando se asigna un canal de eventos, se garantiza que sus posibles asignaciones anteriores de evtchn_to_irq ya no estar\u00e1n configuradas. Este es tambi\u00e9n el orden inverso de la asignaci\u00f3n donde primero se asigna el canal de evento y luego se configuran las asignaciones. En un kernel 5.10 antes de commit 3fcdaf3d7634 (\"xen/events: modificar interfaces internas [un]bind\"), encontramos un ERROR como el siguiente durante el sondeo de dispositivos NVMe. El problema es que durante nvme_setup_io_queues, se llama a pci_free_irq para cada dispositivo, lo que resulta en una llamada a Shutdown_pirq. Por lo tanto, con muchos dispositivos nvme es probable que alcance esta ejecuci\u00f3n durante el arranque porque habr\u00e1 m\u00faltiples llamadas a Shutdown_pirq y startup_pirq que se ejecutan potencialmente en paralelo. ------------[ cortar aqu\u00ed ]------------ blkfront: xvda: barrera o descarga: deshabilitado; subvenciones persistentes: habilitadas; descriptores indirectos: habilitado; b\u00fafer de rebote: \u00a1ERROR del kernel habilitado en drivers/xen/events/events_base.c:499! c\u00f3digo de operaci\u00f3n no v\u00e1lido: 0000 [#1] SMP PTI CPU: 44 PID: 375 Comm: kworker/u257:23 No contaminado 5.10.201-191.748.amzn2.x86_64 #1 Nombre de hardware: Xen HVM domU, BIOS 4.11.amazon 24/08 /2006 Cola de trabajo: nvme-reset-wq nvme_reset_work RIP: 0010:bind_evtchn_to_cpu+0xdf/0xf0 C\u00f3digo: 5d 41 5e c3 cc cc cc cc 44 89 f7 e8 2b 55 ad ff 49 89 c5 48 85 c0 0f 84 64 ff ff ff 4c 8b 68 30 41 83 fe ff 0f 85 60 ff ff ff \u0026lt;0f\u0026gt; 0b 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 0f 1f 44 00 00 RSP: 0000:ffffc9000d533b08 EFLAGS: 00010046 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000006 RDX: 0000000000000028 RSI: 00000000ffffffff RDI: 00000000ffffffff RBP: ffff888107419680 R08: 00000000000 00000 R09: ffffffff82d72b00 R10: 00000000000000000 R11: 0000000000000000 R12: 00000000000001ed R13: 00000000000000000 R14: 00000000ffffffff R15 : 0000000000000002 FS: 0000000000000000(0000) GS:ffff88bc8b500000( 0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000000000000 CR3: 0000000002610001 CR4: 000000000017 06e0 DR0: 0000000000000000 DR1: 00000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Seguimiento de llamadas: ? show_trace_log_lvl+0x1c1/0x2d9? show_trace_log_lvl+0x1c1/0x2d9? set_affinity_irq+0xdc/0x1c0? __die_body.cold+0x8/0xd ? morir+0x2b/0x50 ? do_trap+0x90/0x110? bind_evtchn_to_cpu+0xdf/0xf0? do_error_trap+0x65/0x80? bind_evtchn_to_cpu+0xdf/0xf0? exc_invalid_op+0x4e/0x70? bind_evtchn_to_cpu+0xdf/0xf0? asm_exc_invalid_op+0x12/0x20? bind_evtchn_to_cpu+0xdf/0x ---truncado---"
          }
        ],
        "id": "CVE-2024-26687",
        "lastModified": "2024-04-13T12:15:11.463",
        "metrics": {},
        "published": "2024-04-03T15:15:52.313",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/0fc88aeb2e32b76db3fe6a624b8333dbe621b8fd"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/20980195ec8d2e41653800c45c8c367fa1b1f2b4"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/585a344af6bcac222608a158fc2830ff02712af5"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/9470f5b2503cae994098dea9682aee15b313fa44"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/9be71aa12afa91dfe457b3fb4a444c42b1ee036b"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/ea592baf9e41779fe9a0424c03dd2f324feca3b3"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/fa765c4b4aed2d64266b694520ecb025c862c5a9"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Awaiting Analysis"
      }
    }
  }
}


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