[PATCH v8 19/27] arm64/hwbp/ksw: integrate KStackWatch handler support
From: Jinchao Wang <hidden>
Date: 2025-11-10 16:38:06
Also in:
linux-doc, linux-mm, linux-perf-users, lkml, llvm, workflows
Subsystem:
arm pmu profiling and debugging, arm64 port (aarch64 architecture), memory management, the rest · Maintainers:
Will Deacon, Mark Rutland, Catalin Marinas, Andrew Morton, Linus Torvalds
Add support for identifying KStackWatch watchpoints in the ARM64 hardware breakpoint handler. When a watchpoint belongs to KStackWatch, the handler bypasses single-step re-arming to allow proper recovery. Introduce is_ksw_watch_handler() to detect KStackWatch-managed breakpoints and use it in watchpoint_report() under CONFIG_KSTACKWATCH. Signed-off-by: Jinchao Wang <redacted> --- arch/arm64/kernel/hw_breakpoint.c | 7 +++++++ include/linux/kstackwatch.h | 2 ++ mm/kstackwatch/watch.c | 8 ++++++++ 3 files changed, 17 insertions(+)
diff --git a/arch/arm64/kernel/hw_breakpoint.c b/arch/arm64/kernel/hw_breakpoint.c
index bd7d23d7893d..7abcd988c5c2 100644
--- a/arch/arm64/kernel/hw_breakpoint.c
+++ b/arch/arm64/kernel/hw_breakpoint.c@@ -14,6 +14,9 @@ #include <linux/errno.h> #include <linux/hw_breakpoint.h> #include <linux/kprobes.h> +#ifdef CONFIG_KSTACKWATCH +#include <linux/kstackwatch.h> +#endif #include <linux/perf_event.h> #include <linux/ptrace.h> #include <linux/smp.h>
@@ -738,6 +741,10 @@ static int watchpoint_report(struct perf_event *wp, unsigned long addr, struct pt_regs *regs) { int step = is_default_overflow_handler(wp); +#ifdef CONFIG_KSTACKWATCH + if (is_ksw_watch_handler(wp)) + step = 1; +#endif struct arch_hw_breakpoint *info = counter_arch_bp(wp); info->trigger = addr;
diff --git a/include/linux/kstackwatch.h b/include/linux/kstackwatch.h
index afedd9823de9..ce3882acc5dc 100644
--- a/include/linux/kstackwatch.h
+++ b/include/linux/kstackwatch.h@@ -53,6 +53,8 @@ struct ksw_watchpoint { struct llist_node node; // for atomic watch_on and off struct list_head list; // for cpu online and offline }; + +bool is_ksw_watch_handler(struct perf_event *event); int ksw_watch_init(void); void ksw_watch_exit(void); int ksw_watch_get(struct ksw_watchpoint **out_wp);
diff --git a/mm/kstackwatch/watch.c b/mm/kstackwatch/watch.c
index 99184f63d7e3..c2aa912bf4c4 100644
--- a/mm/kstackwatch/watch.c
+++ b/mm/kstackwatch/watch.c@@ -64,6 +64,14 @@ static void ksw_watch_handler(struct perf_event *bp, panic("Stack corruption detected"); } +bool is_ksw_watch_handler(struct perf_event *event) +{ + perf_overflow_handler_t overflow_handler = event->overflow_handler; + + if (unlikely(overflow_handler == ksw_watch_handler)) + return true; + return false; +} static void ksw_watch_on_local_cpu(void *info) { struct ksw_watchpoint *wp = info;
--
2.43.0