{
    "data_version": "4.0",
    "data_type": "CVE",
    "data_format": "MITRE",
    "CVE_data_meta": {
        "ID": "CVE-2024-26687",
        "ASSIGNER": "cve@kernel.org",
        "STATE": "PUBLIC"
    },
    "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't due to lock inversion. Both\nare called with the irq_desc->lock being taking. The lock order,\nhowever, is first irq_mapping_update_lock and then irq_desc->lock.\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                                  -> 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't 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's\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's 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 <0f> 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---"
            }
        ]
    },
    "problemtype": {
        "problemtype_data": [
            {
                "description": [
                    {
                        "lang": "eng",
                        "value": "n/a"
                    }
                ]
            }
        ]
    },
    "affects": {
        "vendor": {
            "vendor_data": [
                {
                    "vendor_name": "Linux",
                    "product": {
                        "product_data": [
                            {
                                "product_name": "Linux",
                                "version": {
                                    "version_data": [
                                        {
                                            "version_affected": "<",
                                            "version_name": "d46a78b05c0e",
                                            "version_value": "9470f5b2503c"
                                        },
                                        {
                                            "version_value": "not down converted",
                                            "x_cve_json_5_version_data": {
                                                "versions": [
                                                    {
                                                        "version": "2.6.37",
                                                        "status": "affected"
                                                    },
                                                    {
                                                        "version": "0",
                                                        "lessThan": "2.6.37",
                                                        "status": "unaffected",
                                                        "versionType": "custom"
                                                    },
                                                    {
                                                        "version": "5.4.274",
                                                        "lessThanOrEqual": "5.4.*",
                                                        "status": "unaffected",
                                                        "versionType": "custom"
                                                    },
                                                    {
                                                        "version": "5.10.215",
                                                        "lessThanOrEqual": "5.10.*",
                                                        "status": "unaffected",
                                                        "versionType": "custom"
                                                    },
                                                    {
                                                        "version": "5.15.154",
                                                        "lessThanOrEqual": "5.15.*",
                                                        "status": "unaffected",
                                                        "versionType": "custom"
                                                    },
                                                    {
                                                        "version": "6.1.81",
                                                        "lessThanOrEqual": "6.1.*",
                                                        "status": "unaffected",
                                                        "versionType": "custom"
                                                    },
                                                    {
                                                        "version": "6.6.19",
                                                        "lessThanOrEqual": "6.6.*",
                                                        "status": "unaffected",
                                                        "versionType": "custom"
                                                    },
                                                    {
                                                        "version": "6.7.6",
                                                        "lessThanOrEqual": "6.7.*",
                                                        "status": "unaffected",
                                                        "versionType": "custom"
                                                    },
                                                    {
                                                        "version": "6.8",
                                                        "lessThanOrEqual": "*",
                                                        "status": "unaffected",
                                                        "versionType": "original_commit_for_fix"
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                                                "defaultStatus": "affected"
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    "references": {
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            {
                "url": "https://git.kernel.org/stable/c/9470f5b2503cae994098dea9682aee15b313fa44",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/9470f5b2503cae994098dea9682aee15b313fa44"
            },
            {
                "url": "https://git.kernel.org/stable/c/0fc88aeb2e32b76db3fe6a624b8333dbe621b8fd",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/0fc88aeb2e32b76db3fe6a624b8333dbe621b8fd"
            },
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                "url": "https://git.kernel.org/stable/c/ea592baf9e41779fe9a0424c03dd2f324feca3b3",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/ea592baf9e41779fe9a0424c03dd2f324feca3b3"
            },
            {
                "url": "https://git.kernel.org/stable/c/585a344af6bcac222608a158fc2830ff02712af5",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/585a344af6bcac222608a158fc2830ff02712af5"
            },
            {
                "url": "https://git.kernel.org/stable/c/20980195ec8d2e41653800c45c8c367fa1b1f2b4",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/20980195ec8d2e41653800c45c8c367fa1b1f2b4"
            },
            {
                "url": "https://git.kernel.org/stable/c/9be71aa12afa91dfe457b3fb4a444c42b1ee036b",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/9be71aa12afa91dfe457b3fb4a444c42b1ee036b"
            },
            {
                "url": "https://git.kernel.org/stable/c/fa765c4b4aed2d64266b694520ecb025c862c5a9",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/fa765c4b4aed2d64266b694520ecb025c862c5a9"
            },
            {
                "url": "https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html",
                "refsource": "MISC",
                "name": "https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html"
            }
        ]
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