{"id":"CVE-2022-50488","summary":"block, bfq: fix possible uaf for 'bfqq-\u003ebic'","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nblock, bfq: fix possible uaf for 'bfqq-\u003ebic'\n\nOur test report a uaf for 'bfqq-\u003ebic' in 5.10:\n\n==================================================================\nBUG: KASAN: use-after-free in bfq_select_queue+0x378/0xa30\n\nCPU: 6 PID: 2318352 Comm: fsstress Kdump: loaded Not tainted 5.10.0-60.18.0.50.h602.kasan.eulerosv2r11.x86_64 #1\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.1-0-ga5cab58-20220320_160524-szxrtosci10000 04/01/2014\nCall Trace:\n bfq_select_queue+0x378/0xa30\n bfq_dispatch_request+0xe8/0x130\n blk_mq_do_dispatch_sched+0x62/0xb0\n __blk_mq_sched_dispatch_requests+0x215/0x2a0\n blk_mq_sched_dispatch_requests+0x8f/0xd0\n __blk_mq_run_hw_queue+0x98/0x180\n __blk_mq_delay_run_hw_queue+0x22b/0x240\n blk_mq_run_hw_queue+0xe3/0x190\n blk_mq_sched_insert_requests+0x107/0x200\n blk_mq_flush_plug_list+0x26e/0x3c0\n blk_finish_plug+0x63/0x90\n __iomap_dio_rw+0x7b5/0x910\n iomap_dio_rw+0x36/0x80\n ext4_dio_read_iter+0x146/0x190 [ext4]\n ext4_file_read_iter+0x1e2/0x230 [ext4]\n new_sync_read+0x29f/0x400\n vfs_read+0x24e/0x2d0\n ksys_read+0xd5/0x1b0\n do_syscall_64+0x33/0x40\n entry_SYSCALL_64_after_hwframe+0x61/0xc6\n\nCommit 3bc5e683c67d (\"bfq: Split shared queues on move between cgroups\")\nchanges that move process to a new cgroup will allocate a new bfqq to\nuse, however, the old bfqq and new bfqq can point to the same bic:\n\n1) Initial state, two process with io in the same cgroup.\n\nProcess 1       Process 2\n (BIC1)          (BIC2)\n  |  Λ            |  Λ\n  |  |            |  |\n  V  |            V  |\n  bfqq1           bfqq2\n\n2) bfqq1 is merged to bfqq2.\n\nProcess 1       Process 2\n (BIC1)          (BIC2)\n  |               |\n   \\-------------\\|\n                  V\n  bfqq1           bfqq2(coop)\n\n3) Process 1 exit, then issue new io(denoce IOA) from Process 2.\n\n (BIC2)\n  |  Λ\n  |  |\n  V  |\n  bfqq2(coop)\n\n4) Before IOA is completed, move Process 2 to another cgroup and issue io.\n\nProcess 2\n (BIC2)\n   Λ\n   |\\--------------\\\n   |                V\n  bfqq2           bfqq3\n\nNow that BIC2 points to bfqq3, while bfqq2 and bfqq3 both point to BIC2.\nIf all the requests are completed, and Process 2 exit, BIC2 will be\nfreed while there is no guarantee that bfqq2 will be freed before BIC2.\n\nFix the problem by clearing bfqq-\u003ebic while bfqq is detached from bic.","modified":"2026-10-28T02:31:01.925958574Z","published":"2025-10-04T15:43:42.352Z","related":["SUSE-SU-2025:4111-1","SUSE-SU-2025:4135-1","SUSE-SU-2025:4139-1","SUSE-SU-2025:4149-1","SUSE-SU-2025:4188-1","SUSE-SU-2025:4320-1","SUSE-SU-2026:0475-1","SUSE-SU-2026:0495-1"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/50xxx/CVE-2022-50488.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/094f3d9314d67691cb21ba091c1b528f6e3c4893"},{"type":"WEB","url":"https://git.kernel.org/stable/c/5533742c7cb1bc9b1f0bf401cc397d44a3a9e07a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/64dc8c732f5c2b406cc752e6aaa1bd5471159cab"},{"type":"WEB","url":"https://git.kernel.org/stable/c/761564d93c8265f65543acf0a576b32d66bfa26a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b22fd72bfebda3956efc4431b60ddfc0a51e03e0"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/50xxx/CVE-2022-50488.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2022-50488"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"4dfc12f8c94c8052e975060f595938f75e8b7165"},{"fixed":"5533742c7cb1bc9b1f0bf401cc397d44a3a9e07a"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"81b7d0c717a487ec50e2924a773ff501ee40f0d5"},{"fixed":"094f3d9314d67691cb21ba091c1b528f6e3c4893"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"3bc5e683c67d94bd839a1da2e796c15847b51b69"},{"fixed":"b22fd72bfebda3956efc4431b60ddfc0a51e03e0"},{"fixed":"761564d93c8265f65543acf0a576b32d66bfa26a"},{"fixed":"64dc8c732f5c2b406cc752e6aaa1bd5471159cab"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"5.10.121"},{"fixed":"5.10.175"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"5.15.46"},{"fixed":"5.15.86"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"5.4.198"},{"fixed":"5.5"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"5.17.14"},{"fixed":"5.18"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"5.18.3"},{"fixed":"5.19"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"31326bf551269fb9bafa84ca99172b8340e5d8f8"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"43c51b86dbe551cff5d39b88aa2f41d29479f9c4"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"8615f6c0c9e7cf0ca90b6b5408784d797cbe5621"}]}],"versions":["v5.10.174","v5.10.173","v5.10.172","v5.10.171","v5.10.170","v5.10.169","v5.10.168","v5.10.167","v5.10.166","v5.10.165","v5.10.164","v5.10.163","v5.10.162","v5.10.161","v5.10.160","v5.10.159","v5.10.158","v5.10.157","v5.10.156","v5.10.155","v5.10.154","v5.10.153","v5.10.152","v5.10.151","v5.10.150","v5.10.149","v5.10.148","v5.10.147","v5.10.146","v5.10.145","v5.10.144","v5.10.143","v5.10.142","v5.10.141","v5.10.140","v5.10.139","v5.10.138","v5.10.137","v5.10.136","v5.10.135","v5.10.134","v5.10.133","v5.10.132","v5.10.131","v5.10.130","v5.10.129","v5.10.128","v5.10.127","v5.10.126","v5.10.125","v5.10.124","v5.10.123","v5.10.122","v5.10.121","v5.15.85","v5.15.84","v5.15.83","v5.15.82","v5.15.81","v5.15.80","v5.15.79","v5.15.78","v5.15.77","v5.15.76","v5.15.75","v5.15.74","v5.15.73","v5.15.72","v5.15.71","v5.15.70","v5.15.69","v5.15.68","v5.15.67","v5.15.66","v5.15.65","v5.15.64","v5.15.63","v5.15.62","v5.15.61","v5.15.60","v5.15.59","v5.15.58","v5.15.57","v5.15.56","v5.15.55","v5.15.54","v5.15.53","v5.15.52","v5.15.51","v5.15.50","v5.15.49","v5.15.48","v5.15.47","v5.15.46","v5.4.302","v5.4.301","v5.4.300","v5.4.299","v5.4.298","v5.4.297","v5.4.296","v5.4.295","v5.4.294","v5.4.293","v5.4.292","v5.4.291","v5.4.290","v5.4.289","v5.4.288","v5.4.287","v5.4.286","v5.4.285","v5.4.284","v5.4.283","v5.4.282","v5.4.281","v5.4.280","v5.4.279","v5.4.278","v5.4.277","v5.4.276","v5.4.275","v5.4.274","v5.4.273","v5.4.272","v5.4.271","v5.4.270","v5.4.269","v5.4.268","v5.4.267","v5.4.266","v5.4.265","v5.4.264","v5.4.263","v5.4.262","v5.4.261","v5.4.260","v5.4.259","v5.4.258","v5.4.257","v5.4.256","v5.4.255","v5.4.254","v5.4.253","v5.4.252","v5.4.251","v5.4.250","v5.4.249","v5.4.248","v5.4.247","v5.4.246","v5.4.245","v5.4.244","v5.4.243","v5.4.242","v5.4.241","v5.4.240","v5.4.239","v5.4.238","v5.4.237","v5.4.236","v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