{
    "data_version": "4.0",
    "data_type": "CVE",
    "data_format": "MITRE",
    "CVE_data_meta": {
        "ID": "CVE-2022-49272",
        "ASSIGNER": "cve@kernel.org",
        "STATE": "PUBLIC"
    },
    "description": {
        "description_data": [
            {
                "lang": "eng",
                "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: pcm: Fix potential AB/BA lock with buffer_mutex and mmap_lock\n\nsyzbot caught a potential deadlock between the PCM\nruntime->buffer_mutex and the mm->mmap_lock.  It was brought by the\nrecent fix to cover the racy read/write and other ioctls, and in that\ncommit, I overlooked a (hopefully only) corner case that may take the\nrevert lock, namely, the OSS mmap.  The OSS mmap operation\nexceptionally allows to re-configure the parameters inside the OSS\nmmap syscall, where mm->mmap_mutex is already held.  Meanwhile, the\ncopy_from/to_user calls at read/write operations also take the\nmm->mmap_lock internally, hence it may lead to a AB/BA deadlock.\n\nA similar problem was already seen in the past and we fixed it with a\nrefcount (in commit b248371628aa).  The former fix covered only the\ncall paths with OSS read/write and OSS ioctls, while we need to cover\nthe concurrent access via both ALSA and OSS APIs now.\n\nThis patch addresses the problem above by replacing the buffer_mutex\nlock in the read/write operations with a refcount similar as we've\nused for OSS.  The new field, runtime->buffer_accessing, keeps the\nnumber of concurrent read/write operations.  Unlike the former\nbuffer_mutex protection, this protects only around the\ncopy_from/to_user() calls; the other codes are basically protected by\nthe PCM stream lock.  The refcount can be a negative, meaning blocked\nby the ioctls.  If a negative value is seen, the read/write aborts\nwith -EBUSY.  In the ioctl side, OTOH, they check this refcount, too,\nand set to a negative value for blocking unless it's already being\naccessed."
            }
        ]
    },
    "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": "73867cb2bc7dfa7fbd219e53a0b68d253d8fda09",
                                            "version_value": "7e9133607e1501c94881be35e118d8f84d96dcb4"
                                        },
                                        {
                                            "version_affected": "<",
                                            "version_name": "b3830197aa7413c65767cf5a1aa8775c83f0dbf7",
                                            "version_value": "40f4cffbe13a51faf136faf5f9ef6847782cd595"
                                        },
                                        {
                                            "version_affected": "<",
                                            "version_name": "08d1807f097a63ea00a7067dad89c1c81cb2115e",
                                            "version_value": "9661bf674d6a82b76e4ae424438a8ce1e3ed855d"
                                        },
                                        {
                                            "version_affected": "<",
                                            "version_name": "8527c8f052fb42091c6569cb928e472376a4a889",
                                            "version_value": "9017201e8d8c6d1472273361389ed431188584a0"
                                        },
                                        {
                                            "version_affected": "<",
                                            "version_name": "47711ff10c7e126702cfa725f6d86ef529d15a5f",
                                            "version_value": "7777744e92a0b30e3e0cce2758d911837011ebd9"
                                        },
                                        {
                                            "version_affected": "<",
                                            "version_name": "4d1b0ace2d56dc27cc4921eda7fae57f77f03eb5",
                                            "version_value": "abedf0d08c79d76da0d6fa0d5dbbc98871dcbc2e"
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                                        {
                                            "version_affected": "<",
                                            "version_name": "dd2f8c684da3e226e5ec7a81c89ff5fd4a957a03",
                                            "version_value": "be9813ad2fc8f0885f5ce6925af0d993ce5da4e5"
                                        },
                                        {
                                            "version_affected": "<",
                                            "version_name": "dca947d4d26dbf925a64a6cfb2ddbc035e831a3d",
                                            "version_value": "bc55cfd5718c7c23e5524582e9fa70b4d10f2433"
                                        },
                                        {
                                            "version_affected": "<",
                                            "version_name": "5.10.109",
                                            "version_value": "5.10.110"
                                        },
                                        {
                                            "version_affected": "<",
                                            "version_name": "5.15.32",
                                            "version_value": "5.15.33"
                                        },
                                        {
                                            "version_affected": "<",
                                            "version_name": "5.16.18",
                                            "version_value": "5.16.19"
                                        },
                                        {
                                            "version_affected": "<",
                                            "version_name": "5.17.1",
                                            "version_value": "5.17.2"
                                        }
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                    }
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    "references": {
        "reference_data": [
            {
                "url": "https://git.kernel.org/stable/c/7e9133607e1501c94881be35e118d8f84d96dcb4",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/7e9133607e1501c94881be35e118d8f84d96dcb4"
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                "url": "https://git.kernel.org/stable/c/40f4cffbe13a51faf136faf5f9ef6847782cd595",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/40f4cffbe13a51faf136faf5f9ef6847782cd595"
            },
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                "url": "https://git.kernel.org/stable/c/9661bf674d6a82b76e4ae424438a8ce1e3ed855d",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/9661bf674d6a82b76e4ae424438a8ce1e3ed855d"
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                "url": "https://git.kernel.org/stable/c/9017201e8d8c6d1472273361389ed431188584a0",
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                "name": "https://git.kernel.org/stable/c/9017201e8d8c6d1472273361389ed431188584a0"
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                "url": "https://git.kernel.org/stable/c/7777744e92a0b30e3e0cce2758d911837011ebd9",
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                "name": "https://git.kernel.org/stable/c/7777744e92a0b30e3e0cce2758d911837011ebd9"
            },
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                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/abedf0d08c79d76da0d6fa0d5dbbc98871dcbc2e"
            },
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                "url": "https://git.kernel.org/stable/c/be9813ad2fc8f0885f5ce6925af0d993ce5da4e5",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/be9813ad2fc8f0885f5ce6925af0d993ce5da4e5"
            },
            {
                "url": "https://git.kernel.org/stable/c/bc55cfd5718c7c23e5524582e9fa70b4d10f2433",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/bc55cfd5718c7c23e5524582e9fa70b4d10f2433"
            }
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