{"dataType": "CVE_RECORD", "dataVersion": "5.1", "cveMetadata": {"cveId": "CVE-2025-38170", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T04:51:23.991Z", "datePublished": "2025-07-03T08:36:09.012Z", "dateUpdated": "2025-07-28T04:14:10.966Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2025-07-28T04:14:10.966Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\narm64/fpsimd: Discard stale CPU state when handling SME traps\n\nThe logic for handling SME traps manipulates saved FPSIMD/SVE/SME state\nincorrectly, and a race with preemption can result in a task having\nTIF_SME set and TIF_FOREIGN_FPSTATE clear even though the live CPU state\nis stale (e.g. with SME traps enabled). This can result in warnings from\ndo_sme_acc() where SME traps are not expected while TIF_SME is set:\n\n| /* With TIF_SME userspace shouldn't generate any traps */\n| if (test_and_set_thread_flag(TIF_SME))\n| WARN_ON(1);\n\nThis is very similar to the SVE issue we fixed in commit:\n\n 751ecf6afd6568ad (\"arm64/sve: Discard stale CPU state when handling SVE traps\")\n\nThe race can occur when the SME trap handler is preempted before and\nafter manipulating the saved FPSIMD/SVE/SME state, starting and ending on\nthe same CPU, e.g.\n\n| void do_sme_acc(unsigned long esr, struct pt_regs *regs)\n| {\n| // Trap on CPU 0 with TIF_SME clear, SME traps enabled\n| // task->fpsimd_cpu is 0.\n| // per_cpu_ptr(&fpsimd_last_state, 0) is task.\n|\n| ...\n|\n| // Preempted; migrated from CPU 0 to CPU 1.\n| // TIF_FOREIGN_FPSTATE is set.\n|\n| get_cpu_fpsimd_context();\n|\n| /* With TIF_SME userspace shouldn't generate any traps */\n| if (test_and_set_thread_flag(TIF_SME))\n| WARN_ON(1);\n|\n| if (!test_thread_flag(TIF_FOREIGN_FPSTATE)) {\n| unsigned long vq_minus_one =\n| sve_vq_from_vl(task_get_sme_vl(current)) - 1;\n| sme_set_vq(vq_minus_one);\n|\n| fpsimd_bind_task_to_cpu();\n| }\n|\n| put_cpu_fpsimd_context();\n|\n| // Preempted; migrated from CPU 1 to CPU 0.\n| // task->fpsimd_cpu is still 0\n| // If per_cpu_ptr(&fpsimd_last_state, 0) is still task then:\n| // - Stale HW state is reused (with SME traps enabled)\n| // - TIF_FOREIGN_FPSTATE is cleared\n| // - A return to userspace skips HW state restore\n| }\n\nFix the case where the state is not live and TIF_FOREIGN_FPSTATE is set\nby calling fpsimd_flush_task_state() to detach from the saved CPU\nstate. This ensures that a subsequent context switch will not reuse the\nstale CPU state, and will instead set TIF_FOREIGN_FPSTATE, forcing the\nnew state to be reloaded from memory prior to a return to userspace.\n\nNote: this was originallly posted as [1].\n\n[ Rutland: rewrite commit message ]"}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["arch/arm64/kernel/fpsimd.c"], "versions": [{"version": "8bd7f91c03d886f41d35f6108078d20be5a4a1bd", "lessThan": "de89368de3894a8db27caeb8fd902ba1c49f696a", "status": "affected", "versionType": "git"}, {"version": "8bd7f91c03d886f41d35f6108078d20be5a4a1bd", "lessThan": "43be952e885476dafb74aa832c0847b2f4f650c6", "status": "affected", "versionType": "git"}, {"version": "8bd7f91c03d886f41d35f6108078d20be5a4a1bd", "lessThan": "6103f9ba51a59afb5a0f32299c837377c5a5a693", "status": "affected", "versionType": "git"}, {"version": "8bd7f91c03d886f41d35f6108078d20be5a4a1bd", "lessThan": "c4a4786d93e99517d6f10ed56b9ffba4ce88d3b3", "status": "affected", "versionType": "git"}, {"version": "8bd7f91c03d886f41d35f6108078d20be5a4a1bd", "lessThan": "d3eaab3c70905c5467e5c4ea403053d67505adeb", "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/arm64/kernel/fpsimd.c"], "versions": [{"version": "5.19", "status": "affected"}, {"version": "0", "lessThan": "5.19", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.142", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.94", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.34", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.15.3", "lessThanOrEqual": "6.15.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.16", "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": "5.19", "versionEndExcluding": "6.1.142"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.19", "versionEndExcluding": "6.6.94"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.19", "versionEndExcluding": "6.12.34"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.19", "versionEndExcluding": "6.15.3"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.19", "versionEndExcluding": "6.16"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/de89368de3894a8db27caeb8fd902ba1c49f696a"}, {"url": "https://git.kernel.org/stable/c/43be952e885476dafb74aa832c0847b2f4f650c6"}, {"url": "https://git.kernel.org/stable/c/6103f9ba51a59afb5a0f32299c837377c5a5a693"}, {"url": "https://git.kernel.org/stable/c/c4a4786d93e99517d6f10ed56b9ffba4ce88d3b3"}, {"url": "https://git.kernel.org/stable/c/d3eaab3c70905c5467e5c4ea403053d67505adeb"}], "title": "arm64/fpsimd: Discard stale CPU state when handling SME traps", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\narm64/fpsimd: Discard stale CPU state when handling SME traps\n\nThe logic for handling SME traps manipulates saved FPSIMD/SVE/SME state\nincorrectly, and a race with preemption can result in a task having\nTIF_SME set and TIF_FOREIGN_FPSTATE clear even though the live CPU state\nis stale (e.g. with SME traps enabled). This can result in warnings from\ndo_sme_acc() where SME traps are not expected while TIF_SME is set:\n\n| /* With TIF_SME userspace shouldn't generate any traps */\n| if (test_and_set_thread_flag(TIF_SME))\n| WARN_ON(1);\n\nThis is very similar to the SVE issue we fixed in commit:\n\n 751ecf6afd6568ad (\"arm64/sve: Discard stale CPU state when handling SVE traps\")\n\nThe race can occur when the SME trap handler is preempted before and\nafter manipulating the saved FPSIMD/SVE/SME state, starting and ending on\nthe same CPU, e.g.\n\n| void do_sme_acc(unsigned long esr, struct pt_regs *regs)\n| {\n| // Trap on CPU 0 with TIF_SME clear, SME traps enabled\n| // task->fpsimd_cpu is 0.\n| // per_cpu_ptr(&fpsimd_last_state, 0) is task.\n|\n| ...\n|\n| // Preempted; migrated from CPU 0 to CPU 1.\n| // TIF_FOREIGN_FPSTATE is set.\n|\n| get_cpu_fpsimd_context();\n|\n| /* With TIF_SME userspace shouldn't generate any traps */\n| if (test_and_set_thread_flag(TIF_SME))\n| WARN_ON(1);\n|\n| if (!test_thread_flag(TIF_FOREIGN_FPSTATE)) {\n| unsigned long vq_minus_one =\n| sve_vq_from_vl(task_get_sme_vl(current)) - 1;\n| sme_set_vq(vq_minus_one);\n|\n| fpsimd_bind_task_to_cpu();\n| }\n|\n| put_cpu_fpsimd_context();\n|\n| // Preempted; migrated from CPU 1 to CPU 0.\n| // task->fpsimd_cpu is still 0\n| // If per_cpu_ptr(&fpsimd_last_state, 0) is still task then:\n| // - Stale HW state is reused (with SME traps enabled)\n| // - TIF_FOREIGN_FPSTATE is cleared\n| // - A return to userspace skips HW state restore\n| }\n\nFix the case where the state is not live and TIF_FOREIGN_FPSTATE is set\nby calling fpsimd_flush_task_state() to detach from the saved CPU\nstate. This ensures that a subsequent context switch will not reuse the\nstale CPU state, and will instead set TIF_FOREIGN_FPSTATE, forcing the\nnew state to be reloaded from memory prior to a return to userspace.\n\nNote: this was originallly posted as [1].\n\n[ Rutland: rewrite commit message ]"}, {"lang": "es", "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: arm64/fpsimd: Descartar estado de CPU obsoleto al manejar trampas de SME La l\u00f3gica para manejar trampas de SME manipula incorrectamente el estado FPSIMD/SVE/SME guardado, y una ejecuci\u00f3n con preempci\u00f3n puede dar como resultado que una tarea tenga TIF_SME establecido y TIF_FOREIGN_FPSTATE borrado incluso si el estado de CPU en vivo est\u00e1 obsoleto (por ejemplo, con trampas de SME habilitadas). Esto puede dar como resultado advertencias de do_sme_acc() donde no se esperan trampas de SME mientras TIF_SME est\u00e9 establecido: | /* Con TIF_SME, el espacio de usuario no deber\u00eda generar ninguna trampa */ | if (test_and_set_thread_flag(TIF_SME)) | WARN_ON(1); Esto es muy similar al problema de SVE que corregimos en el commit: 751ecf6afd6568ad (\"arm64/sve: descartar estado de CPU obsoleto al manejar trampas de SVE\") La ejecuci\u00f3n puede ocurrir cuando el controlador de trampas de SME se interrumpe antes y despu\u00e9s de manipular el estado FPSIMD/SVE/SME guardado, comenzando y terminando en la misma CPU, por ejemplo, | void do_sme_acc(unsigned long esr, struct pt_regs *regs) | { | // Trampa en la CPU 0 con TIF_SME limpio, trampas de SME habilitadas | // task->fpsimd_cpu es 0. | // per_cpu_ptr(&fpsimd_last_state, 0) es la tarea. | | ... | | // Interrumpido; migrado de la CPU 0 a la CPU 1. | // TIF_FOREIGN_FPSTATE est\u00e1 configurado. | | get_cpu_fpsimd_context(); | | /* Con TIF_SME el espacio de usuario no deber\u00eda generar ninguna trampa */ | if (test_and_set_thread_flag(TIF_SME)) | WARN_ON(1); | | if (!test_thread_flag(TIF_FOREIGN_FPSTATE)) { | unsigned long vq_minus_one = | sve_vq_from_vl(task_get_sme_vl(current)) - 1; | sme_set_vq(vq_minus_one); | | fpsimd_bind_task_to_cpu(); | } | | put_cpu_fpsimd_context(); | | // Interrumpido; migrado de la CPU 1 a la CPU 0. | // task->fpsimd_cpu sigue siendo 0 | // Si per_cpu_ptr(&fpsimd_last_state, 0) sigue siendo tarea, entonces: | // - Se reutiliza el estado de hardware obsoleto (con las trampas de SME habilitadas) | // - Se borra TIF_FOREIGN_FPSTATE | // - Al regresar al espacio de usuario, se omite la restauraci\u00f3n del estado de hardware | } Se soluciona el caso en el que el estado no est\u00e1 activo y TIF_FOREIGN_FPSTATE se establece llamando a fpsimd_flush_task_state() para separarlo del estado de CPU guardado. Esto garantiza que un cambio de contexto posterior no reutilice el estado de CPU obsoleto, sino que establezca TIF_FOREIGN_FPSTATE, forzando la recarga del nuevo estado desde la memoria antes de regresar al espacio de usuario. Nota: esto se public\u00f3 originalmente como [1]. [Rutland: reescribir el mensaje de confirmaci\u00f3n]"}], "id": "CVE-2025-38170", "lastModified": "2025-07-03T15:13:53.147", "metrics": {}, "published": "2025-07-03T09:15:32.643", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/43be952e885476dafb74aa832c0847b2f4f650c6"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/6103f9ba51a59afb5a0f32299c837377c5a5a693"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/c4a4786d93e99517d6f10ed56b9ffba4ce88d3b3"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/d3eaab3c70905c5467e5c4ea403053d67505adeb"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/de89368de3894a8db27caeb8fd902ba1c49f696a"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Awaiting Analysis"}

{"bugzilla": {"description": "kernel: arm64/fpsimd: Discard stale CPU state when handling SME traps", "id": "2376091", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2376091"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.0", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H", "status": "draft"}, "details": ["In the Linux kernel, the following vulnerability has been resolved:\narm64/fpsimd: Discard stale CPU state when handling SME traps\nThe logic for handling SME traps manipulates saved FPSIMD/SVE/SME state\nincorrectly, and a race with preemption can result in a task having\nTIF_SME set and TIF_FOREIGN_FPSTATE clear even though the live CPU state\nis stale (e.g. with SME traps enabled). This can result in warnings from\ndo_sme_acc() where SME traps are not expected while TIF_SME is set:\n| /* With TIF_SME userspace shouldn't generate any traps */\n| if (test_and_set_thread_flag(TIF_SME))\n| WARN_ON(1);\nThis is very similar to the SVE issue we fixed in commit:\n751ecf6afd6568ad (\"arm64/sve: Discard stale CPU state when handling SVE traps\")\nThe race can occur when the SME trap handler is preempted before and\nafter manipulating the saved FPSIMD/SVE/SME state, starting and ending on\nthe same CPU, e.g.\n| void do_sme_acc(unsigned long esr, struct pt_regs *regs)\n| {\n| // Trap on CPU 0 with TIF_SME clear, SME traps enabled\n| // task->fpsimd_cpu is 0.\n| // per_cpu_ptr(&fpsimd_last_state, 0) is task.\n|\n| ...\n|\n| // Preempted; migrated from CPU 0 to CPU 1.\n| // TIF_FOREIGN_FPSTATE is set.\n|\n| get_cpu_fpsimd_context();\n|\n| /* With TIF_SME userspace shouldn't generate any traps */\n| if (test_and_set_thread_flag(TIF_SME))\n| WARN_ON(1);\n|\n| if (!test_thread_flag(TIF_FOREIGN_FPSTATE)) {\n| unsigned long vq_minus_one =\n| sve_vq_from_vl(task_get_sme_vl(current)) - 1;\n| sme_set_vq(vq_minus_one);\n|\n| fpsimd_bind_task_to_cpu();\n| }\n|\n| put_cpu_fpsimd_context();\n|\n| // Preempted; migrated from CPU 1 to CPU 0.\n| // task->fpsimd_cpu is still 0\n| // If per_cpu_ptr(&fpsimd_last_state, 0) is still task then:\n| // - Stale HW state is reused (with SME traps enabled)\n| // - TIF_FOREIGN_FPSTATE is cleared\n| // - A return to userspace skips HW state restore\n| }\nFix the case where the state is not live and TIF_FOREIGN_FPSTATE is set\nby calling fpsimd_flush_task_state() to detach from the saved CPU\nstate. This ensures that a subsequent context switch will not reuse the\nstale CPU state, and will instead set TIF_FOREIGN_FPSTATE, forcing the\nnew state to be reloaded from memory prior to a return to userspace.\nNote: this was originallly posted as [1].\n[ Rutland: rewrite commit message ]"], "name": "CVE-2025-38170", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"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": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2025-07-03T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2025-38170\nhttps://nvd.nist.gov/vuln/detail/CVE-2025-38170\nhttps://lore.kernel.org/linux-cve-announce/2025070342-CVE-2025-38170-0f47@gregkh/T"], "threat_severity": "Moderate"}