CVE-2021-47185

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At the same time, the workqueue will do the\nflush_to_ldisc to pop data in a loop until there is no more data left.\nWhen the sender and workqueue running in different core, the sender sends\ndata fastly in full time which will result in workqueue doing work in loop\nfor a long time and occuring softlockup in flush_to_ldisc with kernel\nconfigured without preempt. So I add need_resched check and cond_resched\nin the flush_to_ldisc loop to avoid it."}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["drivers/tty/tty_buffer.c"], "versions": [{"version": "81de916f19cf5f1437c0b9ed817364f0f7c81961", "lessThan": "0380f643f3a7a61b0845cdc738959c2ad5735d61", "status": "affected", "versionType": "git"}, {"version": "81de916f19cf5f1437c0b9ed817364f0f7c81961", "lessThan": "b1ffc16ec05ae40d82b6e373322d62e9d6b54fbc", "status": "affected", "versionType": "git"}, {"version": "81de916f19cf5f1437c0b9ed817364f0f7c81961", "lessThan": "4c1623651a0936ee197859824cdae6ebbd04d3ed", "status": "affected", "versionType": "git"}, {"version": "81de916f19cf5f1437c0b9ed817364f0f7c81961", "lessThan": "4f300f47dbcf9c3d4b2ea76c8554c8f360400725", "status": "affected", "versionType": "git"}, {"version": "81de916f19cf5f1437c0b9ed817364f0f7c81961", "lessThan": "d491c84df5c469dd9621863b6a770b3428137063", "status": "affected", "versionType": "git"}, {"version": "81de916f19cf5f1437c0b9ed817364f0f7c81961", "lessThan": "77e9fed33056f2a88eba9dd4d2d5412f0c7d1f41", "status": "affected", "versionType": "git"}, {"version": "81de916f19cf5f1437c0b9ed817364f0f7c81961", "lessThan": "5c34486f04700f1ba04907231dce0cc2705c2d7d", "status": "affected", "versionType": "git"}, {"version": "81de916f19cf5f1437c0b9ed817364f0f7c81961", "lessThan": "3968ddcf05fb4b9409cd1859feb06a5b0550a1c1", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["drivers/tty/tty_buffer.c"], "versions": [{"version": "3.0", "status": "affected"}, {"version": "0", "lessThan": "3.0", "status": "unaffected", "versionType": "semver"}, {"version": "4.4.293", "lessThanOrEqual": "4.4.*", "status": "unaffected", "versionType": "semver"}, {"version": "4.9.291", "lessThanOrEqual": "4.9.*", "status": "unaffected", "versionType": "semver"}, {"version": "4.14.256", "lessThanOrEqual": "4.14.*", "status": "unaffected", "versionType": "semver"}, {"version": "4.19.218", "lessThanOrEqual": "4.19.*", "status": "unaffected", "versionType": "semver"}, {"version": "5.4.162", "lessThanOrEqual": "5.4.*", "status": "unaffected", "versionType": "semver"}, {"version": "5.10.82", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver"}, {"version": "5.15.5", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver"}, {"version": "5.16", "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": "3.0", "versionEndExcluding": "4.4.293"}, {"vulnerable": true, "criteria": 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"https://git.kernel.org/stable/c/0380f643f3a7a61b0845cdc738959c2ad5735d61", "tags": ["x_transferred"]}, {"url": "https://git.kernel.org/stable/c/b1ffc16ec05ae40d82b6e373322d62e9d6b54fbc", "tags": ["x_transferred"]}, {"url": "https://git.kernel.org/stable/c/4c1623651a0936ee197859824cdae6ebbd04d3ed", "tags": ["x_transferred"]}, {"url": "https://git.kernel.org/stable/c/4f300f47dbcf9c3d4b2ea76c8554c8f360400725", "tags": ["x_transferred"]}, {"url": "https://git.kernel.org/stable/c/d491c84df5c469dd9621863b6a770b3428137063", "tags": ["x_transferred"]}, {"url": "https://git.kernel.org/stable/c/77e9fed33056f2a88eba9dd4d2d5412f0c7d1f41", "tags": ["x_transferred"]}, {"url": "https://git.kernel.org/stable/c/5c34486f04700f1ba04907231dce0cc2705c2d7d", "tags": ["x_transferred"]}, {"url": "https://git.kernel.org/stable/c/3968ddcf05fb4b9409cd1859feb06a5b0550a1c1", "tags": ["x_transferred"]}]}]}}

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"shortName": "CISA-ADP", "dateUpdated": "2024-05-23T19:01:23.742Z"}}], "cna": {"title": "tty: tty_buffer: Fix the softlockup issue in flush_to_ldisc", "affected": [{"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "81de916f19cf5f1437c0b9ed817364f0f7c81961", "lessThan": "0380f643f3a7a61b0845cdc738959c2ad5735d61", "versionType": "git"}, {"status": "affected", "version": "81de916f19cf5f1437c0b9ed817364f0f7c81961", "lessThan": "b1ffc16ec05ae40d82b6e373322d62e9d6b54fbc", "versionType": "git"}, {"status": "affected", "version": "81de916f19cf5f1437c0b9ed817364f0f7c81961", "lessThan": "4c1623651a0936ee197859824cdae6ebbd04d3ed", "versionType": "git"}, {"status": "affected", "version": "81de916f19cf5f1437c0b9ed817364f0f7c81961", "lessThan": "4f300f47dbcf9c3d4b2ea76c8554c8f360400725", "versionType": "git"}, {"status": "affected", "version": "81de916f19cf5f1437c0b9ed817364f0f7c81961", "lessThan": "d491c84df5c469dd9621863b6a770b3428137063", "versionType": "git"}, {"status": "affected", "version": "81de916f19cf5f1437c0b9ed817364f0f7c81961", "lessThan": "77e9fed33056f2a88eba9dd4d2d5412f0c7d1f41", "versionType": "git"}, {"status": "affected", "version": "81de916f19cf5f1437c0b9ed817364f0f7c81961", "lessThan": "5c34486f04700f1ba04907231dce0cc2705c2d7d", "versionType": "git"}, {"status": "affected", "version": "81de916f19cf5f1437c0b9ed817364f0f7c81961", "lessThan": "3968ddcf05fb4b9409cd1859feb06a5b0550a1c1", "versionType": "git"}], "programFiles": ["drivers/tty/tty_buffer.c"], "defaultStatus": "unaffected"}, {"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "3.0"}, {"status": "unaffected", "version": "0", "lessThan": "3.0", "versionType": "semver"}, {"status": "unaffected", "version": "4.4.293", "versionType": "semver", "lessThanOrEqual": "4.4.*"}, {"status": "unaffected", "version": "4.9.291", "versionType": "semver", "lessThanOrEqual": "4.9.*"}, {"status": "unaffected", "version": "4.14.256", "versionType": "semver", "lessThanOrEqual": "4.14.*"}, {"status": "unaffected", "version": "4.19.218", "versionType": "semver", "lessThanOrEqual": "4.19.*"}, {"status": "unaffected", "version": "5.4.162", "versionType": "semver", "lessThanOrEqual": "5.4.*"}, {"status": "unaffected", "version": "5.10.82", "versionType": "semver", "lessThanOrEqual": "5.10.*"}, {"status": "unaffected", "version": "5.15.5", "versionType": "semver", "lessThanOrEqual": "5.15.*"}, {"status": "unaffected", "version": "5.16", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*"}], "programFiles": ["drivers/tty/tty_buffer.c"], "defaultStatus": "affected"}], "references": [{"url": "https://git.kernel.org/stable/c/0380f643f3a7a61b0845cdc738959c2ad5735d61"}, {"url": "https://git.kernel.org/stable/c/b1ffc16ec05ae40d82b6e373322d62e9d6b54fbc"}, {"url": "https://git.kernel.org/stable/c/4c1623651a0936ee197859824cdae6ebbd04d3ed"}, {"url": "https://git.kernel.org/stable/c/4f300f47dbcf9c3d4b2ea76c8554c8f360400725"}, {"url": "https://git.kernel.org/stable/c/d491c84df5c469dd9621863b6a770b3428137063"}, {"url": "https://git.kernel.org/stable/c/77e9fed33056f2a88eba9dd4d2d5412f0c7d1f41"}, {"url": "https://git.kernel.org/stable/c/5c34486f04700f1ba04907231dce0cc2705c2d7d"}, {"url": "https://git.kernel.org/stable/c/3968ddcf05fb4b9409cd1859feb06a5b0550a1c1"}], "x_generator": {"engine": "bippy-1.2.0"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntty: tty_buffer: Fix the softlockup issue in flush_to_ldisc\n\nWhen running ltp testcase(ltp/testcases/kernel/pty/pty04.c) with arm64, there is a soft lockup,\nwhich look like this one:\n\n Workqueue: events_unbound flush_to_ldisc\n Call trace:\n dump_backtrace+0x0/0x1ec\n show_stack+0x24/0x30\n dump_stack+0xd0/0x128\n panic+0x15c/0x374\n watchdog_timer_fn+0x2b8/0x304\n __run_hrtimer+0x88/0x2c0\n __hrtimer_run_queues+0xa4/0x120\n hrtimer_interrupt+0xfc/0x270\n arch_timer_handler_phys+0x40/0x50\n handle_percpu_devid_irq+0x94/0x220\n __handle_domain_irq+0x88/0xf0\n gic_handle_irq+0x84/0xfc\n el1_irq+0xc8/0x180\n slip_unesc+0x80/0x214 [slip]\n tty_ldisc_receive_buf+0x64/0x80\n tty_port_default_receive_buf+0x50/0x90\n flush_to_ldisc+0xbc/0x110\n process_one_work+0x1d4/0x4b0\n worker_thread+0x180/0x430\n kthread+0x11c/0x120\n\nIn the testcase pty04, The first process call the write syscall to send\ndata to the pty master. At the same time, the workqueue will do the\nflush_to_ldisc to pop data in a loop until there is no more data left.\nWhen the sender and workqueue running in different core, the sender sends\ndata fastly in full time which will result in workqueue doing work in loop\nfor a long time and occuring softlockup in flush_to_ldisc with kernel\nconfigured without preempt. So I add need_resched check and cond_resched\nin the flush_to_ldisc loop to avoid it."}], "cpeApplicability": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "4.4.293", "versionStartIncluding": "3.0"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "4.9.291", "versionStartIncluding": "3.0"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "4.14.256", "versionStartIncluding": "3.0"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "4.19.218", "versionStartIncluding": "3.0"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "5.4.162", "versionStartIncluding": "3.0"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "5.10.82", "versionStartIncluding": "3.0"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "5.15.5", "versionStartIncluding": "3.0"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "5.16", "versionStartIncluding": "3.0"}], "operator": "OR"}]}], "providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2025-12-18T11:35:51.324Z"}}}, "cveMetadata": {"cveId": "CVE-2021-47185", "state": "PUBLISHED", "dateUpdated": "2025-12-18T11:35:51.324Z", "dateReserved": "2024-03-25T09:12:14.113Z", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "datePublished": "2024-04-10T18:56:25.671Z", "assignerShortName": "Linux"}, "dataVersion": "5.2"}

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"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "2128A085-4C0C-4C1E-9E9C-0DD868E2170F", "versionEndExcluding": "5.15.5", "versionStartIncluding": "5.11", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntty: tty_buffer: Fix the softlockup issue in flush_to_ldisc\n\nWhen running ltp testcase(ltp/testcases/kernel/pty/pty04.c) with arm64, there is a soft lockup,\nwhich look like this one:\n\n Workqueue: events_unbound flush_to_ldisc\n Call trace:\n dump_backtrace+0x0/0x1ec\n show_stack+0x24/0x30\n dump_stack+0xd0/0x128\n panic+0x15c/0x374\n watchdog_timer_fn+0x2b8/0x304\n __run_hrtimer+0x88/0x2c0\n __hrtimer_run_queues+0xa4/0x120\n hrtimer_interrupt+0xfc/0x270\n arch_timer_handler_phys+0x40/0x50\n handle_percpu_devid_irq+0x94/0x220\n __handle_domain_irq+0x88/0xf0\n gic_handle_irq+0x84/0xfc\n el1_irq+0xc8/0x180\n slip_unesc+0x80/0x214 [slip]\n tty_ldisc_receive_buf+0x64/0x80\n tty_port_default_receive_buf+0x50/0x90\n flush_to_ldisc+0xbc/0x110\n process_one_work+0x1d4/0x4b0\n worker_thread+0x180/0x430\n kthread+0x11c/0x120\n\nIn the testcase pty04, The first process call the write syscall to send\ndata to the pty master. At the same time, the workqueue will do the\nflush_to_ldisc to pop data in a loop until there is no more data left.\nWhen the sender and workqueue running in different core, the sender sends\ndata fastly in full time which will result in workqueue doing work in loop\nfor a long time and occuring softlockup in flush_to_ldisc with kernel\nconfigured without preempt. So I add need_resched check and cond_resched\nin the flush_to_ldisc loop to avoid it."}, {"lang": "es", "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: tty: tty_buffer: soluciona el problema de bloqueo suave en flush_to_ldisc Al ejecutar ltp testcase(ltp/testcases/kernel/pty/pty04.c) con arm64, hay un bloqueo suave, que se parece a este: Workqueue: events_unbound flush_to_ldisc Rastreo de llamadas: dump_backtrace+0x0/0x1ec show_stack+0x24/0x30 dump_stack+0xd0/0x128 panic+0x15c/0x374 watchdog_timer_fn+0x2b8/0x304 __run_hrtimer+0x88/0x2c0 __hrtimer_run_queues+0xa4/0x120 hrtimer_interrupt+0xfc/0x270 arch_timer_handler_phys+0x40/0x50 handle_percpu_devid_irq+0x94/0x220 __handle_domain_irq+0x88/0xf0 gic_handle_irq+0x84/0xfc el1_irq+0xc8/0x180 slip_unesc+0x80/0x214 [slip] tty_ldisc_receive_buf+0x64/0x80 tty_port_default_receive_buf+0x50/0x90 flush_to_ldisc+0xbc/0x110 process_one_work+0x1d4/0x4b0 worker_thread+0x180/0x430 kthread+0x11c/0x120 En el caso de prueba pty04, el primer proceso llama a la escritura Llamada al sistema para enviar datos al maestro pty. Al mismo tiempo, la cola de trabajo ejecutar\u00e1 el comando flush_to_ldisc para extraer los datos en un bucle hasta que no queden m\u00e1s datos. Cuando el remitente y la cola de trabajo se ejecutan en n\u00facleos diferentes, el remitente env\u00eda datos r\u00e1pidamente en tiempo completo, lo que har\u00e1 que la cola de trabajo realice el trabajo en bucle durante mucho tiempo y se produzca un bloqueo suave en flush_to_ldisc con el n\u00facleo configurado sin interrupci\u00f3n. Por lo tanto, agrego la comprobaci\u00f3n need_resched y cond_resched en el bucle flush_to_ldisc para evitarlo."}], "id": "CVE-2021-47185", "lastModified": "2026-06-17T04:16:51.590", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 4.4, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "HIGH", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 0.8, "impactScore": 3.6, "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2021-47185", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2024-04-15T14:53:32.237242Z", "version": "2.0.3"}}]}, "published": "2024-04-10T19:15:47.383", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/0380f643f3a7a61b0845cdc738959c2ad5735d61"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/3968ddcf05fb4b9409cd1859feb06a5b0550a1c1"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/4c1623651a0936ee197859824cdae6ebbd04d3ed"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/4f300f47dbcf9c3d4b2ea76c8554c8f360400725"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/5c34486f04700f1ba04907231dce0cc2705c2d7d"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/77e9fed33056f2a88eba9dd4d2d5412f0c7d1f41"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/b1ffc16ec05ae40d82b6e373322d62e9d6b54fbc"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/d491c84df5c469dd9621863b6a770b3428137063"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/0380f643f3a7a61b0845cdc738959c2ad5735d61"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/3968ddcf05fb4b9409cd1859feb06a5b0550a1c1"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/4c1623651a0936ee197859824cdae6ebbd04d3ed"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/4f300f47dbcf9c3d4b2ea76c8554c8f360400725"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/5c34486f04700f1ba04907231dce0cc2705c2d7d"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/77e9fed33056f2a88eba9dd4d2d5412f0c7d1f41"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/b1ffc16ec05ae40d82b6e373322d62e9d6b54fbc"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/d491c84df5c469dd9621863b6a770b3428137063"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-667"}], "source": "nvd@nist.gov", "type": "Primary"}]}

{"affected_release": [{"advisory": "RHSA-2024:3627", "cpe": "cpe:/a:redhat:enterprise_linux:8::nfv", "package": "kernel-rt-0:4.18.0-553.5.1.rt7.346.el8_10", "product_name": "Red Hat Enterprise Linux 8", "release_date": "2024-06-05T00:00:00Z"}, {"advisory": "RHSA-2024:3618", "cpe": "cpe:/o:redhat:enterprise_linux:8", "package": "kernel-0:4.18.0-553.5.1.el8_10", "product_name": "Red Hat Enterprise Linux 8", "release_date": "2024-06-05T00:00:00Z"}, {"advisory": "RHSA-2024:9315", "cpe": "cpe:/a:redhat:enterprise_linux:9", "package": "kernel-0:5.14.0-503.11.1.el9_5", "product_name": "Red Hat Enterprise Linux 9", "release_date": "2024-11-12T00:00:00Z"}, {"advisory": "RHSA-2024:9315", "cpe": "cpe:/o:redhat:enterprise_linux:9", "package": "kernel-0:5.14.0-503.11.1.el9_5", "product_name": "Red Hat Enterprise Linux 9", "release_date": "2024-11-12T00:00:00Z"}], "bugzilla": {"description": "kernel: tty: tty_buffer: Fix the softlockup issue in flush_to_ldisc", "id": "2274624", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2274624"}, "csaw": false, "cvss3": {"cvss3_base_score": "4.4", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H", "status": "verified"}, "cwe": "CWE-1050", "details": ["In the Linux kernel, the following vulnerability has been resolved:\ntty: tty_buffer: Fix the softlockup issue in flush_to_ldisc\nWhen running ltp testcase(ltp/testcases/kernel/pty/pty04.c) with arm64, there is a soft lockup,\nwhich look like this one:\nWorkqueue: events_unbound flush_to_ldisc\nCall trace:\ndump_backtrace+0x0/0x1ec\nshow_stack+0x24/0x30\ndump_stack+0xd0/0x128\npanic+0x15c/0x374\nwatchdog_timer_fn+0x2b8/0x304\n__run_hrtimer+0x88/0x2c0\n__hrtimer_run_queues+0xa4/0x120\nhrtimer_interrupt+0xfc/0x270\narch_timer_handler_phys+0x40/0x50\nhandle_percpu_devid_irq+0x94/0x220\n__handle_domain_irq+0x88/0xf0\ngic_handle_irq+0x84/0xfc\nel1_irq+0xc8/0x180\nslip_unesc+0x80/0x214 [slip]\ntty_ldisc_receive_buf+0x64/0x80\ntty_port_default_receive_buf+0x50/0x90\nflush_to_ldisc+0xbc/0x110\nprocess_one_work+0x1d4/0x4b0\nworker_thread+0x180/0x430\nkthread+0x11c/0x120\nIn the testcase pty04, The first process call the write syscall to send\ndata to the pty master. At the same time, the workqueue will do the\nflush_to_ldisc to pop data in a loop until there is no more data left.\nWhen the sender and workqueue running in different core, the sender sends\ndata fastly in full time which will result in workqueue doing work in loop\nfor a long time and occuring softlockup in flush_to_ldisc with kernel\nconfigured without preempt. So I add need_resched check and cond_resched\nin the flush_to_ldisc loop to avoid it."], "name": "CVE-2021-47185", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Out of support scope", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Out of support scope", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2024-04-10T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2021-47185\nhttps://nvd.nist.gov/vuln/detail/CVE-2021-47185\nhttps://lore.kernel.org/linux-cve-announce/2024041033-CVE-2021-47185-c363@gregkh/T"], "threat_severity": "Low"}

{}