{"id":"CVE-2021-46938","details":"In the Linux kernel, the following vulnerability has been resolved:\n\ndm rq: fix double free of blk_mq_tag_set in dev remove after table load fails\n\nWhen loading a device-mapper table for a request-based mapped device,\nand the allocation/initialization of the blk_mq_tag_set for the device\nfails, a following device remove will cause a double free.\n\nE.g. (dmesg):\n  device-mapper: core: Cannot initialize queue for request-based dm-mq mapped device\n  device-mapper: ioctl: unable to set up device queue for new table.\n  Unable to handle kernel pointer dereference in virtual kernel address space\n  Failing address: 0305e098835de000 TEID: 0305e098835de803\n  Fault in home space mode while using kernel ASCE.\n  AS:000000025efe0007 R3:0000000000000024\n  Oops: 0038 ilc:3 [#1] SMP\n  Modules linked in: ... lots of modules ...\n  Supported: Yes, External\n  CPU: 0 PID: 7348 Comm: multipathd Kdump: loaded Tainted: G        W      X    5.3.18-53-default #1 SLE15-SP3\n  Hardware name: IBM 8561 T01 7I2 (LPAR)\n  Krnl PSW : 0704e00180000000 000000025e368eca (kfree+0x42/0x330)\n             R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:2 PM:0 RI:0 EA:3\n  Krnl GPRS: 000000000000004a 000000025efe5230 c1773200d779968d 0000000000000000\n             000000025e520270 000000025e8d1b40 0000000000000003 00000007aae10000\n             000000025e5202a2 0000000000000001 c1773200d779968d 0305e098835de640\n             00000007a8170000 000003ff80138650 000000025e5202a2 000003e00396faa8\n  Krnl Code: 000000025e368eb8: c4180041e100       lgrl    %r1,25eba50b8\n             000000025e368ebe: ecba06b93a55       risbg   %r11,%r10,6,185,58\n            #000000025e368ec4: e3b010000008       ag      %r11,0(%r1)\n            \u003e000000025e368eca: e310b0080004       lg      %r1,8(%r11)\n             000000025e368ed0: a7110001           tmll    %r1,1\n             000000025e368ed4: a7740129           brc     7,25e369126\n             000000025e368ed8: e320b0080004       lg      %r2,8(%r11)\n             000000025e368ede: b904001b           lgr     %r1,%r11\n  Call Trace:\n   [\u003c000000025e368eca\u003e] kfree+0x42/0x330\n   [\u003c000000025e5202a2\u003e] blk_mq_free_tag_set+0x72/0xb8\n   [\u003c000003ff801316a8\u003e] dm_mq_cleanup_mapped_device+0x38/0x50 [dm_mod]\n   [\u003c000003ff80120082\u003e] free_dev+0x52/0xd0 [dm_mod]\n   [\u003c000003ff801233f0\u003e] __dm_destroy+0x150/0x1d0 [dm_mod]\n   [\u003c000003ff8012bb9a\u003e] dev_remove+0x162/0x1c0 [dm_mod]\n   [\u003c000003ff8012a988\u003e] ctl_ioctl+0x198/0x478 [dm_mod]\n   [\u003c000003ff8012ac8a\u003e] dm_ctl_ioctl+0x22/0x38 [dm_mod]\n   [\u003c000000025e3b11ee\u003e] ksys_ioctl+0xbe/0xe0\n   [\u003c000000025e3b127a\u003e] __s390x_sys_ioctl+0x2a/0x40\n   [\u003c000000025e8c15ac\u003e] system_call+0xd8/0x2c8\n  Last Breaking-Event-Address:\n   [\u003c000000025e52029c\u003e] blk_mq_free_tag_set+0x6c/0xb8\n  Kernel panic - not syncing: Fatal exception: panic_on_oops\n\nWhen allocation/initialization of the blk_mq_tag_set fails in\ndm_mq_init_request_queue(), it is uninitialized/freed, but the pointer\nis not reset to NULL; so when dev_remove() later gets into\ndm_mq_cleanup_mapped_device() it sees the pointer and tries to\nuninitialize and free it again.\n\nFix this by setting the pointer to NULL in dm_mq_init_request_queue()\nerror-handling. Also set it to NULL in dm_mq_cleanup_mapped_device().","modified":"2026-03-15T21:45:10.229071Z","published":"2024-02-27T19:04:05.823Z","related":["SUSE-SU-2024:1454-1","SUSE-SU-2024:1465-1","SUSE-SU-2024:1489-1","SUSE-SU-2024:1643-1","SUSE-SU-2024:1646-1","SUSE-SU-2024:1870-1"],"references":[{"type":"FIX","url":"https://git.kernel.org/stable/c/b42c0a33dfdd451d9be62dd5de58c39f2750b6e3"},{"type":"FIX","url":"https://git.kernel.org/stable/c/d757bf4c69cda3c3ab7f775dfabbf5a80e2f6f9d"},{"type":"FIX","url":"https://git.kernel.org/stable/c/1cb02dc76f4c0a2749a02b26469512d6984252e9"},{"type":"FIX","url":"https://git.kernel.org/stable/c/6086f957416a6e87236c06079fcaba7a3998aeca"},{"type":"FIX","url":"https://git.kernel.org/stable/c/772b9f59657665af3b68d24d12b9d172d31f0dfb"},{"type":"FIX","url":"https://git.kernel.org/stable/c/8ae0185255eaf05bd66f4215c81e99bf01140fd9"},{"type":"FIX","url":"https://git.kernel.org/stable/c/8e947c8f4a5620df77e43c9c75310dc510250166"},{"type":"FIX","url":"https://git.kernel.org/stable/c/a992a283c0b77d0a7c2c348add0e6a21fb1dab67"}],"affected":[{"database_specific":{"unresolved_ranges":[{"events":[{"introduced":"4.6.0"},{"fixed":"4.9.269"}]},{"events":[{"introduced":"4.10.0"},{"fixed":"4.14.233"}]},{"events":[{"introduced":"4.15.0"},{"fixed":"4.19.191"}]},{"events":[{"introduced":"4.20.0"},{"fixed":"5.4.118"}]},{"events":[{"introduced":"5.5.0"},{"fixed":"5.10.36"}]},{"events":[{"introduced":"5.11.0"},{"fixed":"5.11.20"}]},{"events":[{"introduced":"5.12.0"},{"fixed":"5.12.3"}]}],"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-46938.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"}]}