{"id":"DEBIAN-CVE-2024-50275","details":"In the Linux kernel, the following vulnerability has been resolved:  arm64/sve: Discard stale CPU state when handling SVE traps  The logic for handling SVE traps manipulates saved FPSIMD/SVE state incorrectly, and a race with preemption can result in a task having TIF_SVE set and TIF_FOREIGN_FPSTATE clear even though the live CPU state is stale (e.g. with SVE traps enabled). This has been observed to result in warnings from do_sve_acc() where SVE traps are not expected while TIF_SVE is set:  |         if (test_and_set_thread_flag(TIF_SVE)) |                 WARN_ON(1); /* SVE access shouldn't have trapped */  Warnings of this form have been reported intermittently, e.g.    https://lore.kernel.org/linux-arm-kernel/CA+G9fYtEGe_DhY2Ms7+L7NKsLYUomGsgqpdBj+QwDLeSg=JhGg@mail.gmail.com/   https://lore.kernel.org/linux-arm-kernel/000000000000511e9a060ce5a45c@google.com/  The race can occur when the SVE trap handler is preempted before and after manipulating the saved FPSIMD/SVE state, starting and ending on the same CPU, e.g.  | void do_sve_acc(unsigned long esr, struct pt_regs *regs) | { |         // Trap on CPU 0 with TIF_SVE clear, SVE traps enabled |         // task-\u003efpsimd_cpu is 0. |         // per_cpu_ptr(&fpsimd_last_state, 0) is task. | |         ... | |         // Preempted; migrated from CPU 0 to CPU 1. |         // TIF_FOREIGN_FPSTATE is set. | |         get_cpu_fpsimd_context(); | |         if (test_and_set_thread_flag(TIF_SVE)) |                 WARN_ON(1); /* SVE access shouldn't have trapped */ | |         sve_init_regs() { |                 if (!test_thread_flag(TIF_FOREIGN_FPSTATE)) { |                         ... |                 } else { |                         fpsimd_to_sve(current); |                         current-\u003ethread.fp_type = FP_STATE_SVE; |                 } |         } | |         put_cpu_fpsimd_context(); | |         // Preempted; migrated from CPU 1 to CPU 0. |         // task-\u003efpsimd_cpu is still 0 |         // If per_cpu_ptr(&fpsimd_last_state, 0) is still task then: |         // - Stale HW state is reused (with SVE traps enabled) |         // - TIF_FOREIGN_FPSTATE is cleared |         // - A return to userspace skips HW state restore | }  Fix the case where the state is not live and TIF_FOREIGN_FPSTATE is set by calling fpsimd_flush_task_state() to detach from the saved CPU state. This ensures that a subsequent context switch will not reuse the stale CPU state, and will instead set TIF_FOREIGN_FPSTATE, forcing the new state to be reloaded from memory prior to a return to userspace.","modified":"2026-09-15T09:03:15.691915205Z","published":"2024-11-19T02:16:29.760Z","upstream":["CVE-2024-50275"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2024-50275"}],"affected":[{"package":{"name":"linux","ecosystem":"Debian:12","purl":"pkg:deb/debian/linux?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.1.123-1"}]}],"versions":["6.1.106-1","6.1.106-2","6.1.106-3","6.1.112-1","6.1.115-1","6.1.119-1","6.1.27-1","6.1.37-1","6.1.38-1","6.1.38-2","6.1.38-2~bpo11+1","6.1.38-3","6.1.38-4","6.1.38-4~bpo11+1","6.1.52-1","6.1.55-1","6.1.55-1~bpo11+1","6.1.64-1","6.1.66-1","6.1.67-1","6.1.69-1","6.1.69-1~bpo11+1","6.1.76-1","6.1.76-1~bpo11+1","6.1.82-1","6.1.85-1","6.1.90-1","6.1.90-1~bpo11+1","6.1.94-1","6.1.94-1~bpo11+1","6.1.98-1","6.1.99-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2024-50275.json"}},{"package":{"name":"linux","ecosystem":"Debian:13","purl":"pkg:deb/debian/linux?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.11.9-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2024-50275.json"}},{"package":{"name":"linux","ecosystem":"Debian:14","purl":"pkg:deb/debian/linux?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.11.9-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2024-50275.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H"}]}