{"id":"CVE-2024-50275","revision":"29513a72bb384316882bae1eb6195bce","records":[{"revision":"29513a72bb384316882bae1eb6195bce","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2024-50275","aliases":[],"title":"arm64/sve: Discard stale CPU state when handling SVE traps","description":"In the Linux kernel, the following vulnerability has been resolved:\n\narm64/sve: Discard stale CPU state when handling SVE traps\n\nThe logic for handling SVE traps manipulates saved FPSIMD/SVE state\nincorrectly, and a race with preemption can result in a task having\nTIF_SVE set and TIF_FOREIGN_FPSTATE clear even though the live CPU state\nis stale (e.g. with SVE traps enabled). This has been observed to result\nin warnings from do_sve_acc() where SVE traps are not expected while\nTIF_SVE is set:\n\n| if (test_and_set_thread_flag(TIF_SVE))\n| WARN_ON(1); /* SVE access shouldn't have trapped */\n\nWarnings of this form have been reported intermittently, e.g.\n\n https://lore.kernel.org/linux-arm-kernel/CA+G9fYtEGe_DhY2Ms7+L7NKsLYUomGsgqpdBj+QwDLeSg=JhGg@mail.gmail.com/\n https://lore.kernel.org/linux-arm-kernel/000000000000511e9a060ce5a45c@google.com/\n\nThe race can occur when the SVE trap handler is preempted before and\nafter manipulating the saved FPSIMD/SVE state, starting and ending on\nthe same CPU, e.g.\n\n| void do_sve_acc(unsigned long esr, struct pt_regs *regs)\n| {\n| // Trap on CPU 0 with TIF_SVE clear, SVE 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| if (test_and_set_thread_flag(TIF_SVE))\n| WARN_ON(1); /* SVE access shouldn't have trapped */\n|\n| sve_init_regs() {\n| if (!test_thread_flag(TIF_FOREIGN_FPSTATE)) {\n| ...\n| } else {\n| fpsimd_to_sve(current);\n| current->thread.fp_type = FP_STATE_SVE;\n| }\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 SVE 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.","state":0,"publishedAt":"2024-11-19T01:30:15.293+00:00","modifiedAt":"2026-10-15T21:41:45.687+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 \"arch/arm64/kernel/fpsimd.c\"\n ],\n \"versions\": [\n {\n \"version\": \"cccb78ce89c45a4414db712be4986edfb92434bd\",\n \"lessThan\": \"51d3d80a6dc314982a9a0aeb0961085922a1aa15\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"cccb78ce89c45a4414db712be4986edfb92434bd\",\n \"lessThan\": \"de529504b3274d57caf8f66800b714b0d3ee235a\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"cccb78ce89c45a4414db712be4986edfb92434bd\",\n \"lessThan\": \"51d11ea0250d6ee461987403bbfd4b2abb5613a7\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"cccb78ce89c45a4414db712be4986edfb92434bd\",\n \"lessThan\": \"fa9ce027b3ce37a2bb173bf2553b5caa438fd8c9\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"cccb78ce89c45a4414db712be4986edfb92434bd\",\n \"lessThan\": \"751ecf6afd6568adc98f2a6052315552c0483d18\",\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 \"arch/arm64/kernel/fpsimd.c\"\n ],\n \"versions\": [\n {\n \"version\": \"5.13\",\n \"status\": \"affected\"\n },\n {\n \"version\": \"0\",\n \"lessThan\": \"5.13\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.15.174\",\n \"lessThanOrEqual\": \"5.15.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.1.120\",\n \"lessThanOrEqual\": \"6.1.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.6.61\",\n \"lessThanOrEqual\": \"6.6.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.11.8\",\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:L/A:H","score":7.3,"severity":"HIGH"}],"references":["https://git.kernel.org/stable/c/51d3d80a6dc314982a9a0aeb0961085922a1aa15","https://git.kernel.org/stable/c/de529504b3274d57caf8f66800b714b0d3ee235a","https://git.kernel.org/stable/c/51d11ea0250d6ee461987403bbfd4b2abb5613a7","https://git.kernel.org/stable/c/fa9ce027b3ce37a2bb173bf2553b5caa438fd8c9","https://git.kernel.org/stable/c/751ecf6afd6568adc98f2a6052315552c0483d18"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2024-50275","license":"CVE Program Terms of Use","key":"cve-program:CVE-2024-50275","identifiers":["CVE-2024-50275"]},"retained":false,"historicalAffected":[]}],"coverage":[]}