kgdb: fix to kill breakpoints on initmem after boot

Currently breakpoints in kernel .init.text section are not handled correctly while allowing to remove them even after corresponding pages have been freed. Fix it via killing .init.text section breakpoints just prior to initmem pages being freed. Doug: "HW breakpoints aren't handled by this patch but it's probably not such a big deal". Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Sumit Garg <[email protected]> Suggested-by: Doug Anderson <[email protected]> Acked-by: Doug Anderson <[email protected]> Acked-by: Daniel Thompson <[email protected]> Tested-by: Daniel Thompson <[email protected]> Cc: Masami Hiramatsu <[email protected]> Cc: Steven Rostedt (VMware) <[email protected]> Cc: Jason Wessel <[email protected]> Cc: Peter Zijlstra <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
josf · Feb 26, 2021 · d54ce61 · d54ce61
1 parent db7fbf4
commit d54ce61
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diff --git a/include/linux/kgdb.h b/include/linux/kgdb.h
@@ -359,9 +359,11 @@ extern atomic_t			kgdb_active;
 extern bool dbg_is_early;
 extern void __init dbg_late_init(void);
 extern void kgdb_panic(const char *msg);
+extern void kgdb_free_init_mem(void);
 #else /* ! CONFIG_KGDB */
 #define in_dbg_master() (0)
 #define dbg_late_init()
 static inline void kgdb_panic(const char *msg) {}
+static inline void kgdb_free_init_mem(void) { }
 #endif /* ! CONFIG_KGDB */
 #endif /* _KGDB_H_ */
diff --git a/init/main.c b/init/main.c
@@ -1426,6 +1426,7 @@ static int __ref kernel_init(void *unused)
 	async_synchronize_full();
 	kprobe_free_init_mem();
 	ftrace_free_init_mem();
+	kgdb_free_init_mem();
 	free_initmem();
 	mark_readonly();
 

diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c
@@ -455,6 +455,17 @@ int dbg_remove_all_break(void)
 	return 0;
 }
 
+void kgdb_free_init_mem(void)
+{
+	int i;
+
+	/* Clear init memory breakpoints. */
+	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+		if (init_section_contains((void *)kgdb_break[i].bpt_addr, 0))
+			kgdb_break[i].state = BP_UNDEFINED;
+	}
+}
+
 #ifdef CONFIG_KGDB_KDB
 void kdb_dump_stack_on_cpu(int cpu)
 {