arch_check_bp_in_kernelspace() tries to avoid the overflow and does 2 TASK_SIZE checks but it needs OR, not AND. Consider va = TASK_SIZE -1 and len = 2 case.
Note: TASK_SIZE doesn't look right at least on x86, I think it should be replaced by TASK_SIZE_MAX. Signed-off-by: Oleg Nesterov <o...@redhat.com> --- x/arch/arm64/kernel/hw_breakpoint.c +++ x/arch/arm64/kernel/hw_breakpoint.c @@ -293,7 +293,7 @@ int arch_check_bp_in_kernelspace(struct va = info->address; len = get_hbp_len(info->ctrl.len); - return (va >= TASK_SIZE) && ((va + len - 1) >= TASK_SIZE); + return (va >= TASK_SIZE) || ((va + len - 1) >= TASK_SIZE); } /* --- x/arch/arm/kernel/hw_breakpoint.c +++ x/arch/arm/kernel/hw_breakpoint.c @@ -464,7 +464,7 @@ int arch_check_bp_in_kernelspace(struct va = info->address; len = get_hbp_len(info->ctrl.len); - return (va >= TASK_SIZE) && ((va + len - 1) >= TASK_SIZE); + return (va >= TASK_SIZE) || ((va + len - 1) >= TASK_SIZE); } /* --- x/arch/sh/kernel/hw_breakpoint.c +++ x/arch/sh/kernel/hw_breakpoint.c @@ -132,7 +132,7 @@ int arch_check_bp_in_kernelspace(struct va = info->address; len = get_hbp_len(info->len); - return (va >= TASK_SIZE) && ((va + len - 1) >= TASK_SIZE); + return (va >= TASK_SIZE) || ((va + len - 1) >= TASK_SIZE); } int arch_bp_generic_fields(int sh_len, int sh_type, --- x/arch/x86/kernel/hw_breakpoint.c +++ x/arch/x86/kernel/hw_breakpoint.c @@ -200,7 +200,7 @@ int arch_check_bp_in_kernelspace(struct va = info->address; len = get_hbp_len(info->len); - return (va >= TASK_SIZE) && ((va + len - 1) >= TASK_SIZE); + return (va >= TASK_SIZE) || ((va + len - 1) >= TASK_SIZE); } int arch_bp_generic_fields(int x86_len, int x86_type, -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/