{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2022-49266", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-02-26T01:49:39.297Z", "datePublished": "2025-02-26T01:56:15.709Z", "dateUpdated": "2026-05-23T15:21:48.745Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-05-23T15:21:48.745Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nblock: fix rq-qos breakage from skipping rq_qos_done_bio()\n\na647a524a467 (\"block: don't call rq_qos_ops->done_bio if the bio isn't\ntracked\") made bio_endio() skip rq_qos_done_bio() if BIO_TRACKED is not set.\nWhile this fixed a potential oops, it also broke blk-iocost by skipping the\ndone_bio callback for merged bios.\n\nBefore, whether a bio goes through rq_qos_throttle() or rq_qos_merge(),\nrq_qos_done_bio() would be called on the bio on completion with BIO_TRACKED\ndistinguishing the former from the latter. rq_qos_done_bio() is not called\nfor bios which wenth through rq_qos_merge(). This royally confuses\nblk-iocost as the merged bios never finish and are considered perpetually\nin-flight.\n\nOne reliably reproducible failure mode is an intermediate cgroup geting\nstuck active preventing its children from being activated due to the\nleaf-only rule, leading to loss of control. The following is from\nresctl-bench protection scenario which emulates isolating a web server like\nworkload from a memory bomb run on an iocost configuration which should\nyield a reasonable level of protection.\n\n # cat /sys/block/nvme2n1/device/model\n Samsung SSD 970 PRO 512GB\n # cat /sys/fs/cgroup/io.cost.model\n 259:0 ctrl=user model=linear rbps=834913556 rseqiops=93622 rrandiops=102913 wbps=618985353 wseqiops=72325 wrandiops=71025\n # cat /sys/fs/cgroup/io.cost.qos\n 259:0 enable=1 ctrl=user rpct=95.00 rlat=18776 wpct=95.00 wlat=8897 min=60.00 max=100.00\n # resctl-bench -m 29.6G -r out.json run protection::scenario=mem-hog,loops=1\n ...\n Memory Hog Summary\n ==================\n\n IO Latency: R p50=242u:336u/2.5m p90=794u:1.4m/7.5m p99=2.7m:8.0m/62.5m max=8.0m:36.4m/350m\n W p50=221u:323u/1.5m p90=709u:1.2m/5.5m p99=1.5m:2.5m/9.5m max=6.9m:35.9m/350m\n\n Isolation and Request Latency Impact Distributions:\n\n min p01 p05 p10 p25 p50 p75 p90 p95 p99 max mean stdev\n isol% 15.90 15.90 15.90 40.05 57.24 59.07 60.01 74.63 74.63 90.35 90.35 58.12 15.82\n lat-imp% 0 0 0 0 0 4.55 14.68 15.54 233.5 548.1 548.1 53.88 143.6\n\n Result: isol=58.12:15.82% lat_imp=53.88%:143.6 work_csv=100.0% missing=3.96%\n\nThe isolation result of 58.12% is close to what this device would show\nwithout any IO control.\n\nFix it by introducing a new flag BIO_QOS_MERGED to mark merged bios and\ncalling rq_qos_done_bio() on them too. For consistency and clarity, rename\nBIO_TRACKED to BIO_QOS_THROTTLED. The flag checks are moved into\nrq_qos_done_bio() so that it's next to the code paths that set the flags.\n\nWith the patch applied, the above same benchmark shows:\n\n # resctl-bench -m 29.6G -r out.json run protection::scenario=mem-hog,loops=1\n ...\n Memory Hog Summary\n ==================\n\n IO Latency: R p50=123u:84.4u/985u p90=322u:256u/2.5m p99=1.6m:1.4m/9.5m max=11.1m:36.0m/350m\n W p50=429u:274u/995u p90=1.7m:1.3m/4.5m p99=3.4m:2.7m/11.5m max=7.9m:5.9m/26.5m\n\n Isolation and Request Latency Impact Distributions:\n\n min p01 p05 p10 p25 p50 p75 p90 p95 p99 max mean stdev\n isol% 84.91 84.91 89.51 90.73 92.31 94.49 96.36 98.04 98.71 100.0 100.0 94.42 2.81\n lat-imp% 0 0 0 0 0 2.81 5.73 11.11 13.92 17.53 22.61 4.10 4.68\n\n Result: isol=94.42:2.81% lat_imp=4.10%:4.68 work_csv=58.34% missing=0%" } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "block/bio.c", "block/blk-iolatency.c", "block/blk-rq-qos.h", "include/linux/blk_types.h" ], "versions": [ { "version": "a647a524a46736786c95cdb553a070322ca096e3", "lessThan": "af9452dfdba4bf7359ef7645eee2d243a1df0649", "status": "affected", "versionType": "git" }, { "version": "a647a524a46736786c95cdb553a070322ca096e3", "lessThan": "dbd20bb904ad5731aaca8d009367a930d6ada111", "status": "affected", "versionType": "git" }, { "version": "a647a524a46736786c95cdb553a070322ca096e3", "lessThan": "09737db4c891eba25e6f6383a7c38afd4acc883f", "status": "affected", "versionType": "git" }, { "version": "a647a524a46736786c95cdb553a070322ca096e3", "lessThan": "aa1b46dcdc7baaf5fec0be25782ef24b26aa209e", "status": "affected", "versionType": "git" }, { "version": "db60edbfff332a6a5477c367af8125f034570989", "status": "affected", "versionType": "git" }, { "version": "004b8f8a691205a93d9e80d98b786b2b97424d6e", "status": "affected", "versionType": "git" }, { "version": "5.10.241", "lessThan": "5.11", "status": "affected", "versionType": "semver" }, { "version": "5.14.11", "lessThan": "5.15", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "block/bio.c", "block/blk-iolatency.c", "block/blk-rq-qos.h", "include/linux/blk_types.h" ], "versions": [ { "version": "5.15", "status": "affected" }, { "version": "0", "lessThan": "5.15", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.54", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.16.19", "lessThanOrEqual": "5.16.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.17.2", "lessThanOrEqual": "5.17.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.18", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "5.15.54" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "5.16.19" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "5.17.2" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "5.18" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.10.241" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.14.11" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/af9452dfdba4bf7359ef7645eee2d243a1df0649" }, { "url": "https://git.kernel.org/stable/c/dbd20bb904ad5731aaca8d009367a930d6ada111" }, { "url": "https://git.kernel.org/stable/c/09737db4c891eba25e6f6383a7c38afd4acc883f" }, { "url": "https://git.kernel.org/stable/c/aa1b46dcdc7baaf5fec0be25782ef24b26aa209e" } ], "title": "block: fix rq-qos breakage from skipping rq_qos_done_bio()", "x_generator": { "engine": "bippy-1.2.0" } } } }