| { |
| "containers": { |
| "cna": { |
| "providerMetadata": { |
| "orgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038" |
| }, |
| "descriptions": [ |
| { |
| "lang": "en", |
| "value": "In the Linux kernel, the following vulnerability has been resolved:\n\npowerpc/smp: do not decrement idle task preempt count in CPU offline\n\nWith PREEMPT_COUNT=y, when a CPU is offlined and then onlined again, we\nget:\n\nBUG: scheduling while atomic: swapper/1/0/0x00000000\nno locks held by swapper/1/0.\nCPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.15.0-rc2+ #100\nCall Trace:\n dump_stack_lvl+0xac/0x108\n __schedule_bug+0xac/0xe0\n __schedule+0xcf8/0x10d0\n schedule_idle+0x3c/0x70\n do_idle+0x2d8/0x4a0\n cpu_startup_entry+0x38/0x40\n start_secondary+0x2ec/0x3a0\n start_secondary_prolog+0x10/0x14\n\nThis is because powerpc's arch_cpu_idle_dead() decrements the idle task's\npreempt count, for reasons explained in commit a7c2bb8279d2 (\"powerpc:\nRe-enable preemption before cpu_die()\"), specifically \"start_secondary()\nexpects a preempt_count() of 0.\"\n\nHowever, since commit 2c669ef6979c (\"powerpc/preempt: Don't touch the idle\ntask's preempt_count during hotplug\") and commit f1a0a376ca0c (\"sched/core:\nInitialize the idle task with preemption disabled\"), that justification no\nlonger holds.\n\nThe idle task isn't supposed to re-enable preemption, so remove the\nvestigial preempt_enable() from the CPU offline path.\n\nTested with pseries and powernv in qemu, and pseries on PowerVM." |
| } |
| ], |
| "affected": [ |
| { |
| "product": "Linux", |
| "vendor": "Linux", |
| "defaultStatus": "unaffected", |
| "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", |
| "programFiles": [ |
| "arch/powerpc/kernel/smp.c" |
| ], |
| "versions": [ |
| { |
| "version": "bdf4d33e8342b90386156204e1da0cdfdb4bf146", |
| "lessThan": "53770a411559cf7bc0906d1df319cc533d2f4f58", |
| "status": "affected", |
| "versionType": "git" |
| }, |
| { |
| "version": "2c669ef6979c370f98d4b876e54f19613c81e075", |
| "lessThan": "3ea0b497a7a2fff6a4b7090310c9f52c91975934", |
| "status": "affected", |
| "versionType": "git" |
| }, |
| { |
| "version": "2c669ef6979c370f98d4b876e54f19613c81e075", |
| "lessThan": "787252a10d9422f3058df9a4821f389e5326c440", |
| "status": "affected", |
| "versionType": "git" |
| }, |
| { |
| "version": "2b6148ef2bd6d8ddc76e7873114f7769b6aa25f0", |
| "status": "affected", |
| "versionType": "git" |
| }, |
| { |
| "version": "20a015e948b825afb47855de2efce7cae7c2608f", |
| "status": "affected", |
| "versionType": "git" |
| } |
| ] |
| }, |
| { |
| "product": "Linux", |
| "vendor": "Linux", |
| "defaultStatus": "affected", |
| "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", |
| "programFiles": [ |
| "arch/powerpc/kernel/smp.c" |
| ], |
| "versions": [ |
| { |
| "version": "5.14", |
| "status": "affected" |
| }, |
| { |
| "version": "0", |
| "lessThan": "5.14", |
| "status": "unaffected", |
| "versionType": "semver" |
| }, |
| { |
| "version": "5.10.76", |
| "lessThanOrEqual": "5.10.*", |
| "status": "unaffected", |
| "versionType": "semver" |
| }, |
| { |
| "version": "5.14.15", |
| "lessThanOrEqual": "5.14.*", |
| "status": "unaffected", |
| "versionType": "semver" |
| }, |
| { |
| "version": "5.15", |
| "lessThanOrEqual": "*", |
| "status": "unaffected", |
| "versionType": "original_commit_for_fix" |
| } |
| ] |
| } |
| ], |
| "cpeApplicability": [ |
| { |
| "nodes": [ |
| { |
| "operator": "OR", |
| "negate": false, |
| "cpeMatch": [ |
| { |
| "vulnerable": true, |
| "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", |
| "versionStartIncluding": "5.10.50", |
| "versionEndExcluding": "5.10.76" |
| }, |
| { |
| "vulnerable": true, |
| "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", |
| "versionStartIncluding": "5.14", |
| "versionEndExcluding": "5.14.15" |
| }, |
| { |
| "vulnerable": true, |
| "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", |
| "versionStartIncluding": "5.14", |
| "versionEndExcluding": "5.15" |
| }, |
| { |
| "vulnerable": true, |
| "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", |
| "versionStartIncluding": "5.12.17" |
| }, |
| { |
| "vulnerable": true, |
| "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", |
| "versionStartIncluding": "5.13.2" |
| } |
| ] |
| } |
| ] |
| } |
| ], |
| "references": [ |
| { |
| "url": "https://git.kernel.org/stable/c/53770a411559cf7bc0906d1df319cc533d2f4f58" |
| }, |
| { |
| "url": "https://git.kernel.org/stable/c/3ea0b497a7a2fff6a4b7090310c9f52c91975934" |
| }, |
| { |
| "url": "https://git.kernel.org/stable/c/787252a10d9422f3058df9a4821f389e5326c440" |
| } |
| ], |
| "title": "powerpc/smp: do not decrement idle task preempt count in CPU offline", |
| "x_generator": { |
| "engine": "bippy-1.2.0" |
| } |
| } |
| }, |
| "cveMetadata": { |
| "assignerOrgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038", |
| "cveID": "CVE-2021-47454", |
| "requesterUserId": "gregkh@kernel.org", |
| "serial": "1", |
| "state": "PUBLISHED" |
| }, |
| "dataType": "CVE_RECORD", |
| "dataVersion": "5.0" |
| } |
