diff options
| -rw-r--r-- | arch/x86/kernel/ptrace.c | 14 | ||||
| -rw-r--r-- | tools/testing/selftests/x86/fsgsbase.c | 22 |
2 files changed, 16 insertions, 20 deletions
diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c index 71691a8310e7..0fdbe89d0754 100644 --- a/arch/x86/kernel/ptrace.c +++ b/arch/x86/kernel/ptrace.c @@ -369,12 +369,22 @@ static int putreg(struct task_struct *child, case offsetof(struct user_regs_struct,fs_base): if (value >= TASK_SIZE_MAX) return -EIO; - x86_fsbase_write_task(child, value); + /* + * When changing the FS base, use do_arch_prctl_64() + * to set the index to zero and to set the base + * as requested. + */ + if (child->thread.fsbase != value) + return do_arch_prctl_64(child, ARCH_SET_FS, value); return 0; case offsetof(struct user_regs_struct,gs_base): + /* + * Exactly the same here as the %fs handling above. + */ if (value >= TASK_SIZE_MAX) return -EIO; - x86_gsbase_write_task(child, value); + if (child->thread.gsbase != value) + return do_arch_prctl_64(child, ARCH_SET_GS, value); return 0; #endif } diff --git a/tools/testing/selftests/x86/fsgsbase.c b/tools/testing/selftests/x86/fsgsbase.c index 5ab4c60c100e..15a329da59fa 100644 --- a/tools/testing/selftests/x86/fsgsbase.c +++ b/tools/testing/selftests/x86/fsgsbase.c @@ -489,25 +489,11 @@ static void test_ptrace_write_gsbase(void) * selector value is changed or not by the GSBASE write in * a ptracer. */ - if (gs != *shared_scratch) { - nerrs++; - printf("[FAIL]\tGS changed to %lx\n", gs); - - /* - * On older kernels, poking a nonzero value into the - * base would zero the selector. On newer kernels, - * this behavior has changed -- poking the base - * changes only the base and, if FSGSBASE is not - * available, this may have no effect. - */ - if (gs == 0) - printf("\tNote: this is expected behavior on older kernels.\n"); - } else if (have_fsgsbase && (base != 0xFF)) { - nerrs++; - printf("[FAIL]\tGSBASE changed to %lx\n", base); + if (gs == 0 && base == 0xFF) { + printf("[OK]\tGS was reset as expected\n"); } else { - printf("[OK]\tGS remained 0x%hx%s", *shared_scratch, have_fsgsbase ? " and GSBASE changed to 0xFF" : ""); - printf("\n"); + nerrs++; + printf("[FAIL]\tGS=0x%lx, GSBASE=0x%lx (should be 0, 0xFF)\n", gs, base); } } |