{"id":"CVE-2021-47435","details":"In the Linux kernel, the following vulnerability has been resolved:\n\ndm: fix mempool NULL pointer race when completing IO\n\ndm_io_dec_pending() calls end_io_acct() first and will then dec md\nin-flight pending count. But if a task is swapping DM table at same\ntime this can result in a crash due to mempool-\u003eelements being NULL:\n\ntask1                             task2\ndo_resume\n -\u003edo_suspend\n  -\u003edm_wait_for_completion\n                                  bio_endio\n\t\t\t\t   -\u003eclone_endio\n\t\t\t\t    -\u003edm_io_dec_pending\n\t\t\t\t     -\u003eend_io_acct\n\t\t\t\t      -\u003ewakeup task1\n -\u003edm_swap_table\n  -\u003e__bind\n   -\u003e__bind_mempools\n    -\u003ebioset_exit\n     -\u003emempool_exit\n                                     -\u003efree_io\n\n[ 67.330330] Unable to handle kernel NULL pointer dereference at\nvirtual address 0000000000000000\n......\n[ 67.330494] pstate: 80400085 (Nzcv daIf +PAN -UAO)\n[ 67.330510] pc : mempool_free+0x70/0xa0\n[ 67.330515] lr : mempool_free+0x4c/0xa0\n[ 67.330520] sp : ffffff8008013b20\n[ 67.330524] x29: ffffff8008013b20 x28: 0000000000000004\n[ 67.330530] x27: ffffffa8c2ff40a0 x26: 00000000ffff1cc8\n[ 67.330535] x25: 0000000000000000 x24: ffffffdada34c800\n[ 67.330541] x23: 0000000000000000 x22: ffffffdada34c800\n[ 67.330547] x21: 00000000ffff1cc8 x20: ffffffd9a1304d80\n[ 67.330552] x19: ffffffdada34c970 x18: 000000b312625d9c\n[ 67.330558] x17: 00000000002dcfbf x16: 00000000000006dd\n[ 67.330563] x15: 000000000093b41e x14: 0000000000000010\n[ 67.330569] x13: 0000000000007f7a x12: 0000000034155555\n[ 67.330574] x11: 0000000000000001 x10: 0000000000000001\n[ 67.330579] x9 : 0000000000000000 x8 : 0000000000000000\n[ 67.330585] x7 : 0000000000000000 x6 : ffffff80148b5c1a\n[ 67.330590] x5 : ffffff8008013ae0 x4 : 0000000000000001\n[ 67.330596] x3 : ffffff80080139c8 x2 : ffffff801083bab8\n[ 67.330601] x1 : 0000000000000000 x0 : ffffffdada34c970\n[ 67.330609] Call trace:\n[ 67.330616] mempool_free+0x70/0xa0\n[ 67.330627] bio_put+0xf8/0x110\n[ 67.330638] dec_pending+0x13c/0x230\n[ 67.330644] clone_endio+0x90/0x180\n[ 67.330649] bio_endio+0x198/0x1b8\n[ 67.330655] dec_pending+0x190/0x230\n[ 67.330660] clone_endio+0x90/0x180\n[ 67.330665] bio_endio+0x198/0x1b8\n[ 67.330673] blk_update_request+0x214/0x428\n[ 67.330683] scsi_end_request+0x2c/0x300\n[ 67.330688] scsi_io_completion+0xa0/0x710\n[ 67.330695] scsi_finish_command+0xd8/0x110\n[ 67.330700] scsi_softirq_done+0x114/0x148\n[ 67.330708] blk_done_softirq+0x74/0xd0\n[ 67.330716] __do_softirq+0x18c/0x374\n[ 67.330724] irq_exit+0xb4/0xb8\n[ 67.330732] __handle_domain_irq+0x84/0xc0\n[ 67.330737] gic_handle_irq+0x148/0x1b0\n[ 67.330744] el1_irq+0xe8/0x190\n[ 67.330753] lpm_cpuidle_enter+0x4f8/0x538\n[ 67.330759] cpuidle_enter_state+0x1fc/0x398\n[ 67.330764] cpuidle_enter+0x18/0x20\n[ 67.330772] do_idle+0x1b4/0x290\n[ 67.330778] cpu_startup_entry+0x20/0x28\n[ 67.330786] secondary_start_kernel+0x160/0x170\n\nFix this by:\n1) Establishing pointers to 'struct dm_io' members in\ndm_io_dec_pending() so that they may be passed into end_io_acct()\n_after_ free_io() is called.\n2) Moving end_io_acct() after free_io().","modified":"2026-03-15T22:43:13.024398Z","published":"2024-05-22T07:15:08.790Z","related":["SUSE-SU-2024:1979-1","SUSE-SU-2024:1983-1","SUSE-SU-2024:2008-1","SUSE-SU-2024:2010-1","SUSE-SU-2024:2011-1","SUSE-SU-2024:2019-1","SUSE-SU-2024:2184-1","SUSE-SU-2024:2185-1","SUSE-SU-2024:2189-1","SUSE-SU-2024:2190-1"],"references":[{"type":"FIX","url":"https://git.kernel.org/stable/c/d208b89401e073de986dc891037c5a668f5d5d95"},{"type":"FIX","url":"https://git.kernel.org/stable/c/d29c78d3f9c5d2604548c1065bf1ec212728ea61"},{"type":"FIX","url":"https://git.kernel.org/stable/c/d35aef9c60d310eff3eaddacce301efe877e2b7c"},{"type":"FIX","url":"https://git.kernel.org/stable/c/6e506f07c5b561d673dd0b0d8f7f420cc48024fb"},{"type":"FIX","url":"https://git.kernel.org/stable/c/9e07272cca2ed76f7f6073f4444b1143828c8d87"},{"type":"FIX","url":"https://git.kernel.org/stable/c/9fb7cd5c7fef0f1c982e3cd27745a0dec260eaed"},{"type":"FIX","url":"https://git.kernel.org/stable/c/ad1393b92e5059218d055bfec8f4946d85ad04c4"}],"affected":[{"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-47435.json","unresolved_ranges":[{"events":[{"introduced":"0"},{"fixed":"4.9.313"}]},{"events":[{"introduced":"4.10"},{"fixed":"4.14.278"}]},{"events":[{"introduced":"4.15"},{"fixed":"4.19.242"}]},{"events":[{"introduced":"4.20"},{"fixed":"5.4.193"}]},{"events":[{"introduced":"5.5"},{"fixed":"5.10.113"}]},{"events":[{"introduced":"5.11"},{"fixed":"5.14.14"}]},{"events":[{"introduced":"0"},{"last_affected":"5.15-rc1"}]},{"events":[{"introduced":"0"},{"last_affected":"5.15-rc2"}]},{"events":[{"introduced":"0"},{"last_affected":"5.15-rc3"}]},{"events":[{"introduced":"0"},{"last_affected":"5.15-rc4"}]},{"events":[{"introduced":"0"},{"last_affected":"5.15-rc5"}]}]}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H"}]}