diff --git a/arch/arm64/kernel/hw_breakpoint.c b/arch/arm64/kernel/hw_breakpoint.c index bba85c8f8037..46465d9fbc4d 100644 --- a/arch/arm64/kernel/hw_breakpoint.c +++ b/arch/arm64/kernel/hw_breakpoint.c @@ -163,6 +163,20 @@ enum hw_breakpoint_ops { HW_BREAKPOINT_RESTORE }; +static int is_compat_bp(struct perf_event *bp) +{ + struct task_struct *tsk = bp->hw.target; + + /* + * tsk can be NULL for per-cpu (non-ptrace) breakpoints. + * In this case, use the native interface, since we don't have + * the notion of a "compat CPU" and could end up relying on + * deprecated behaviour if we use unaligned watchpoints in + * AArch64 state. + */ + return tsk && is_compat_thread(task_thread_info(tsk)); +} + /** * hw_breakpoint_slot_setup - Find and setup a perf slot according to * operations @@ -420,7 +434,7 @@ static int arch_build_bp_info(struct perf_event *bp) * Watchpoints can be of length 1, 2, 4 or 8 bytes. */ if (info->ctrl.type == ARM_BREAKPOINT_EXECUTE) { - if (is_compat_task()) { + if (is_compat_bp(bp)) { if (info->ctrl.len != ARM_BREAKPOINT_LEN_2 && info->ctrl.len != ARM_BREAKPOINT_LEN_4) return -EINVAL; @@ -477,7 +491,7 @@ int arch_validate_hwbkpt_settings(struct perf_event *bp) * AArch32 tasks expect some simple alignment fixups, so emulate * that here. */ - if (is_compat_task()) { + if (is_compat_bp(bp)) { if (info->ctrl.len == ARM_BREAKPOINT_LEN_8) alignment_mask = 0x7; else