{"id":"CVE-2024-50082","revision":"da07939c32f04288ad7c8588eb633279","records":[{"revision":"da07939c32f04288ad7c8588eb633279","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2024-50082","aliases":[],"title":"blk-rq-qos: fix crash on rq_qos_wait vs. rq_qos_wake_function race","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nblk-rq-qos: fix crash on rq_qos_wait vs. rq_qos_wake_function race\n\nWe're seeing crashes from rq_qos_wake_function that look like this:\n\n  BUG: unable to handle page fault for address: ffffafe180a40084\n  #PF: supervisor write access in kernel mode\n  #PF: error_code(0x0002) - not-present page\n  PGD 100000067 P4D 100000067 PUD 10027c067 PMD 10115d067 PTE 0\n  Oops: Oops: 0002 [#1] PREEMPT SMP PTI\n  CPU: 17 UID: 0 PID: 0 Comm: swapper/17 Not tainted 6.12.0-rc3-00013-geca631b8fe80 #11\n  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014\n  RIP: 0010:_raw_spin_lock_irqsave+0x1d/0x40\n  Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 0f 1f 44 00 00 41 54 9c 41 5c fa 65 ff 05 62 97 30 4c 31 c0 ba 01 00 00 00 <f0> 0f b1 17 75 0a 4c 89 e0 41 5c c3 cc cc cc cc 89 c6 e8 2c 0b 00\n  RSP: 0018:ffffafe180580ca0 EFLAGS: 00010046\n  RAX: 0000000000000000 RBX: ffffafe180a3f7a8 RCX: 0000000000000011\n  RDX: 0000000000000001 RSI: 0000000000000003 RDI: ffffafe180a40084\n  RBP: 0000000000000000 R08: 00000000001e7240 R09: 0000000000000011\n  R10: 0000000000000028 R11: 0000000000000888 R12: 0000000000000002\n  R13: ffffafe180a40084 R14: 0000000000000000 R15: 0000000000000003\n  FS:  0000000000000000(0000) GS:ffff9aaf1f280000(0000) knlGS:0000000000000000\n  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n  CR2: ffffafe180a40084 CR3: 000000010e428002 CR4: 0000000000770ef0\n  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\n  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400\n  PKRU: 55555554\n  Call Trace:\n   <IRQ>\n   try_to_wake_up+0x5a/0x6a0\n   rq_qos_wake_function+0x71/0x80\n   __wake_up_common+0x75/0xa0\n   __wake_up+0x36/0x60\n   scale_up.part.0+0x50/0x110\n   wb_timer_fn+0x227/0x450\n   ...\n\nSo rq_qos_wake_function() calls wake_up_process(data->task), which calls\ntry_to_wake_up(), which faults in raw_spin_lock_irqsave(&p->pi_lock).\n\np comes from data->task, and data comes from the waitqueue entry, which\nis stored on the waiter's stack in rq_qos_wait(). Analyzing the core\ndump with drgn, I found that the waiter had already woken up and moved\non to a completely unrelated code path, clobbering what was previously\ndata->task. Meanwhile, the waker was passing the clobbered garbage in\ndata->task to wake_up_process(), leading to the crash.\n\nWhat's happening is that in between rq_qos_wake_function() deleting the\nwaitqueue entry and calling wake_up_process(), rq_qos_wait() is finding\nthat it already got a token and returning. The race looks like this:\n\nrq_qos_wait()                           rq_qos_wake_function()\n==============================================================\nprepare_to_wait_exclusive()\n                                        data->got_token = true;\n                                        list_del_init(&curr->entry);\nif (data.got_token)\n        break;\nfinish_wait(&rqw->wait, &data.wq);\n  ^- returns immediately because\n     list_empty_careful(&wq_entry->entry)\n     is true\n... return, go do something else ...\n                                        wake_up_process(data->task)\n                                          (NO LONGER VALID!)-^\n\nNormally, finish_wait() is supposed to synchronize against the waker.\nBut, as noted above, it is returning immediately because the waitqueue\nentry has already been removed from the waitqueue.\n\nThe bug is that rq_qos_wake_function() is accessing the waitqueue entry\nAFTER deleting it. Note that autoremove_wake_function() wakes the waiter\nand THEN deletes the waitqueue entry, which is the proper order.\n\nFix it by swapping the order. We also need to use\nlist_del_init_careful() to match the list_empty_careful() in\nfinish_wait().","state":0,"publishedAt":"2024-10-29T00:50:24.667+00:00","modifiedAt":"2026-10-15T21:41:45.546+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"block/blk-rq-qos.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"38cfb5a45ee013bfab5d1ae4c4738815e744b440\",\n                            \"lessThan\": \"d04b72c9ef2b0689bfc1057d21c4aeed087c329f\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"38cfb5a45ee013bfab5d1ae4c4738815e744b440\",\n                            \"lessThan\": \"3bc6d0f8b70a9101456cf02ab99acb75254e1852\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"38cfb5a45ee013bfab5d1ae4c4738815e744b440\",\n                            \"lessThan\": \"455a469758e57a6fe070e3e342db12e4a629e0eb\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"38cfb5a45ee013bfab5d1ae4c4738815e744b440\",\n                            \"lessThan\": \"b5e900a3612b69423a0e1b0ab67841a1fb4af80f\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"38cfb5a45ee013bfab5d1ae4c4738815e744b440\",\n                            \"lessThan\": \"4c5b123ab289767afe940389dbb963c5c05e594e\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"38cfb5a45ee013bfab5d1ae4c4738815e744b440\",\n                            \"lessThan\": \"04f283fc16c8d5db641b6bffd2d8310aa7eccebc\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"38cfb5a45ee013bfab5d1ae4c4738815e744b440\",\n                            \"lessThan\": \"e972b08b91ef48488bae9789f03cfedb148667fb\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"block/blk-rq-qos.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"4.19\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"4.19\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.4.285\",\n                            \"lessThanOrEqual\": \"5.4.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.10.228\",\n                            \"lessThanOrEqual\": \"5.10.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.15.169\",\n                            \"lessThanOrEqual\": \"5.15.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.1.114\",\n                            \"lessThanOrEqual\": \"6.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.58\",\n                            \"lessThanOrEqual\": \"6.6.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.11.5\",\n                            \"lessThanOrEqual\": \"6.11.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8,"severity":"HIGH"}],"references":["https://git.kernel.org/stable/c/d04b72c9ef2b0689bfc1057d21c4aeed087c329f","https://git.kernel.org/stable/c/3bc6d0f8b70a9101456cf02ab99acb75254e1852","https://git.kernel.org/stable/c/455a469758e57a6fe070e3e342db12e4a629e0eb","https://git.kernel.org/stable/c/b5e900a3612b69423a0e1b0ab67841a1fb4af80f","https://git.kernel.org/stable/c/4c5b123ab289767afe940389dbb963c5c05e594e","https://git.kernel.org/stable/c/04f283fc16c8d5db641b6bffd2d8310aa7eccebc","https://git.kernel.org/stable/c/e972b08b91ef48488bae9789f03cfedb148667fb"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2024-50082","license":"CVE Program Terms of Use","key":"cve-program:CVE-2024-50082","identifiers":["CVE-2024-50082"]},"retained":false,"historicalAffected":[]}],"coverage":[]}