{ "schema_version": "1.6.1", "id": "RPI-CVE-2024-50275", "modified": "2026-10-09T11:39:44Z", "upstream": [ "CVE-2024-50275" ], "published": "2024-11-19T01:35:04Z", "summary": "arm64/sve: Discard stale CPU state when handling SVE traps", "details": "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.", "severity": [ { "type": "CVSS_V3", "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:H" } ], "affected": [ { "package": { "ecosystem": "Raspberry Pi OS:12", "name": "linux" }, "versions": [ "1:6.1.21-1+rpt1", "1:6.1.47-1+rpt2", "1:6.1.47-1+rpt4", "1:6.1.54-1+rpt2", "1:6.1.58-1+rpt2", "1:6.1.63-1+rpt1", "1:6.1.73-1+rpt1", "1:6.6.20-1+rpt1", "1:6.6.28-1+rpt1", "1:6.6.31-1+rpt1", "1:6.6.47-1+rpt1", "1:6.6.51-1+rpt1", "1:6.6.51-1+rpt2", "1:6.6.51-1+rpt3" ], "ecosystem_specific": { "binaries": [ { "binary_name": "linux-image-6.1.0-rpi1-rpi-v8", "binary_version": "1:6.1.21-1+rpt1" }, { "binary_name": "linux-image-6.1.0-rpi2-rpi-v8", "binary_version": "1:6.1.47-1+rpt2" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-2712", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v6", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v7", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v8", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi4-rpi-2712", "binary_version": "1:6.1.54-1+rpt2" }, { "binary_name": "linux-image-6.1.0-rpi4-rpi-v8", "binary_version": "1:6.1.54-1+rpt2" }, { "binary_name": "linux-image-6.1.0-rpi6-rpi-2712", "binary_version": "1:6.1.58-1+rpt2" }, { "binary_name": "linux-image-6.1.0-rpi6-rpi-v8", "binary_version": "1:6.1.58-1+rpt2" }, { "binary_name": "linux-image-6.1.0-rpi7-rpi-2712", "binary_version": "1:6.1.63-1+rpt1" }, { "binary_name": "linux-image-6.1.0-rpi7-rpi-v8", "binary_version": "1:6.1.63-1+rpt1" }, { "binary_name": "linux-image-6.1.0-rpi8-rpi-2712", "binary_version": "1:6.1.73-1+rpt1" }, { "binary_name": "linux-image-6.1.0-rpi8-rpi-v8", "binary_version": "1:6.1.73-1+rpt1" }, { "binary_name": "linux-image-6.6.20+rpt-rpi-2712", "binary_version": "1:6.6.20-1+rpt1" }, { "binary_name": "linux-image-6.6.20+rpt-rpi-v8", "binary_version": "1:6.6.20-1+rpt1" }, { "binary_name": "linux-image-6.6.28+rpt-rpi-2712", "binary_version": "1:6.6.28-1+rpt1" }, { "binary_name": "linux-image-6.6.28+rpt-rpi-v8", "binary_version": "1:6.6.28-1+rpt1" }, { "binary_name": "linux-image-6.6.31+rpt-rpi-2712", "binary_version": "1:6.6.31-1+rpt1" }, { "binary_name": "linux-image-6.6.31+rpt-rpi-v8", "binary_version": "1:6.6.31-1+rpt1" }, { "binary_name": "linux-image-6.6.47+rpt-rpi-2712", "binary_version": "1:6.6.47-1+rpt1" }, { "binary_name": "linux-image-6.6.47+rpt-rpi-v8", "binary_version": "1:6.6.47-1+rpt1" }, { "binary_name": "linux-image-6.6.51+rpt-rpi-2712", "binary_version": "1:6.6.51-1+rpt1" }, { "binary_name": "linux-image-6.6.51+rpt-rpi-v8", "binary_version": "1:6.6.51-1+rpt1" }, { "binary_name": "linux-image-6.6.51+rpt-rpi-2712", "binary_version": "1:6.6.51-1+rpt2" }, { "binary_name": "linux-image-6.6.51+rpt-rpi-v8", "binary_version": "1:6.6.51-1+rpt2" }, { "binary_name": "linux-image-6.6.51+rpt-rpi-2712", "binary_version": "1:6.6.51-1+rpt3" }, { "binary_name": "linux-image-6.6.51+rpt-rpi-v8", "binary_version": "1:6.6.51-1+rpt3" } ] }, "database_specific": { "per_version": { "1:6.1.21-1+rpt1": { "linux_commit": "0afb5e98488aed7017b9bf321b575d0177feb7ed", "upstream_version": "6.1.21", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.1.120" }, "1:6.1.47-1+rpt2": { "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e", "upstream_version": "6.1.47", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.1.120" }, "1:6.1.47-1+rpt4": { "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e", "upstream_version": "6.1.47", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.1.120", "compiled_filter": false }, "1:6.1.54-1+rpt2": { "linux_commit": "2906f7abdc03d4a92b6b0e2e0c87ea2a9dffe8f7", "upstream_version": "6.1.54", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.1.120" }, "1:6.1.58-1+rpt2": { "linux_commit": "ccf1586ad0663fa91238ac56abf6340d6d740d18", "upstream_version": "6.1.58", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.1.120" }, "1:6.1.63-1+rpt1": { "linux_commit": null, "upstream_version": "6.1.63", "assessment": "upstream version (no usable Linux commit)", "upstream_fixed": "6.1.120" }, "1:6.1.73-1+rpt1": { "linux_commit": null, "upstream_version": "6.1.73", "assessment": "upstream version (no usable Linux commit)", "upstream_fixed": "6.1.120" }, "1:6.6.20-1+rpt1": { "linux_commit": "6f16847710cc0502450788b9f12f0a14d3429668", "upstream_version": "6.6.20", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.6.61" }, "1:6.6.28-1+rpt1": { "linux_commit": "0c341f47adc3578cd5f817aa20ee2b7f9ae6b23e", "upstream_version": "6.6.28", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.6.61" }, "1:6.6.31-1+rpt1": { "linux_commit": "c1432b4bae5b6582f4d32ba381459f33c34d1424", "upstream_version": "6.6.31", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.6.61" }, "1:6.6.47-1+rpt1": { "linux_commit": "cf64a1dfecc2dc418efdd61701c1a4b185ab4761", "upstream_version": "6.6.47", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.6.61" }, "1:6.6.51-1+rpt1": { "linux_commit": "0094eba3f2a4338cfa6854b0b5104d02ba0fa01f", "upstream_version": "6.6.51", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.6.61" }, "1:6.6.51-1+rpt2": { "linux_commit": "82a50e430ef1d6eb37d78e25aa572c1f6ea56160", "upstream_version": "6.6.51", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.6.61" }, "1:6.6.51-1+rpt3": { "linux_commit": "5aeecea9f4a45248bcf564dec924965e066a7bfd", "upstream_version": "6.6.51", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.6.61" } } } } ], "references": [ { "type": "ADVISORY", "url": "https://www.cve.org/CVERecord?id=CVE-2024-50275" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/51d3d80a6dc314982a9a0aeb0961085922a1aa15" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/de529504b3274d57caf8f66800b714b0d3ee235a" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/51d11ea0250d6ee461987403bbfd4b2abb5613a7" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/fa9ce027b3ce37a2bb173bf2553b5caa438fd8c9" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/751ecf6afd6568adc98f2a6052315552c0483d18" } ], "database_specific": { "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git", "upstream_modified": "2026-08-05T11:52:36Z", "severity": { "source": "kernel CNA", "cvss_v3_score": 7.3, "cvss_v3_severity": "High", "scenario": "AV:L - The vulnerable code is the EL0 SVE access trap handler, reached only by a local process on the machine executing an SVE instruction. No network or remote input is involved.\nAC:L - The attacker controls both halves of the race \u2014 both windows around get/put_cpu_fpsimd_context() are fully preemptible, and the attacker can force preemption and CPU0\u2192CPU1\u2192CPU0 migration by oversubscribing a restricted affinity mask, while re-arming the SVE trap indefinitely (any syscall saves state as FPSIMD, clearing TIF_SVE and re-enabling the trap).\nPR:L - Only the ability to run unprivileged code is needed; el0_sve_acc()/do_sve_acc() perform no capability, namespace, or credential check of any kind.\nUI:N - The attacking process triggers the trap and the race entirely on its own; no action by any other user is required.\nS:U - The impact stays within the kernel/OS security authority \u2014 corrupted FP/SVE state tracking and kernel warnings on the same host, with no VM, IOMMU, or hypervisor boundary crossed.\nC:H - Skipping sve_flush_live() leaves SVE predicate registers P0-P15 and FFR from a previously running task's SVE context in the register file while the kernel treats them as the current task's live SVE state, so they are saved into thread.sve_state and copied to userspace by preserve_sve_context() (or read via ptrace NT_ARM_SVE) \u2014 a cross-process disclosure of up to 17 \u00d7 VL/8 bytes, ~4 KB on max-VL hardware.\nI:L - Foreign SVE predicate/FFR contents are injected into the task's architectural state and the correctly converted in-memory state is silently discarded, but the WARN_ON(sve_get_vl() != vl) guard in fpsimd_save_user_state() blocks the mismatched-VL out-of-bounds save, so there is no arbitrary-write or control-flow primitive.\nA:H - The stale state reliably produces the WARN_ON(1) splat in do_sve_acc() \u2014 a kernel panic on the many panic_on_warn deployments (CI, hardened, cloud, Android) \u2014 and the VL-mismatch path additionally force-SIGKILLs the task; an unprivileged user can trigger this in a tight loop." } } }