{ "containers": { "cna": { "providerMetadata": { "orgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038" }, "descriptions": [ { "lang": "en", "value": "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 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 \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()." } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "block/blk-rq-qos.c" ], "versions": [ { "version": "38cfb5a45ee0", "lessThan": "3bc6d0f8b70a", "status": "affected", "versionType": "git" }, { "version": "38cfb5a45ee0", "lessThan": "455a469758e5", "status": "affected", "versionType": "git" }, { "version": "38cfb5a45ee0", "lessThan": "b5e900a3612b", "status": "affected", "versionType": "git" }, { "version": "38cfb5a45ee0", "lessThan": "4c5b123ab289", "status": "affected", "versionType": "git" }, { "version": "38cfb5a45ee0", "lessThan": "04f283fc16c8", "status": "affected", "versionType": "git" }, { "version": "38cfb5a45ee0", "lessThan": "e972b08b91ef", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "block/blk-rq-qos.c" ], "versions": [ { "version": "4.19", "status": "affected" }, { "version": "0", "lessThan": "4.19", "status": "unaffected", "versionType": "custom" }, { "version": "5.10.228", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "custom" }, { "version": "5.15.169", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "custom" }, { "version": "6.1.114", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "custom" }, { "version": "6.6.58", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "custom" }, { "version": "6.11.5", "lessThanOrEqual": "6.11.*", "status": "unaffected", "versionType": "custom" }, { "version": "6.12-rc4", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/3bc6d0f8b70a9101456cf02ab99acb75254e1852" }, { "url": "https://git.kernel.org/stable/c/455a469758e57a6fe070e3e342db12e4a629e0eb" }, { "url": "https://git.kernel.org/stable/c/b5e900a3612b69423a0e1b0ab67841a1fb4af80f" }, { "url": "https://git.kernel.org/stable/c/4c5b123ab289767afe940389dbb963c5c05e594e" }, { "url": "https://git.kernel.org/stable/c/04f283fc16c8d5db641b6bffd2d8310aa7eccebc" }, { "url": "https://git.kernel.org/stable/c/e972b08b91ef48488bae9789f03cfedb148667fb" } ], "title": "blk-rq-qos: fix crash on rq_qos_wait vs. rq_qos_wake_function race", "x_generator": { "engine": "bippy-c9c4e1df01b2" } } }, "cveMetadata": { "assignerOrgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038", "cveID": "CVE-2024-50082", "requesterUserId": "gregkh@kernel.org", "serial": "1", "state": "PUBLISHED" }, "dataType": "CVE_RECORD", "dataVersion": "5.0" }