+ kgdb-fix-to-kill-breakpoints-on-initmem-after-boot.patch added to -mm tree

+ kgdb-fix-to-kill-breakpoints-on-initmem-after-boot.patch added to -mm tree

[akpm]

The patch titled
     Subject: kgdb: fix to kill breakpoints on initmem after boot
has been added to the -mm tree.  Its filename is
     kgdb-fix-to-kill-breakpoints-on-initmem-after-boot.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/kgdb-fix-to-kill-breakpoints-on-initmem-after-boot.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/kgdb-fix-to-kill-breakpoints-on-initmem-after-boot.patch

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------------------------------------------------------
From: Sumit Garg <sumit.garg@linaro.org>
Subject: 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.

Link: https://lkml.kernel.org/r/20210224081652.587785-1-sumit.garg@linaro.org
Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Suggested-by: Doug Anderson <dianders@chromium.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/kgdb.h      |    2 ++
 init/main.c               |    1 +
 kernel/debug/debug_core.c |   11 +++++++++++
 3 files changed, 14 insertions(+)

--- a/include/linux/kgdb.h~kgdb-fix-to-kill-breakpoints-on-initmem-after-boot
+++ a/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_ */
--- a/init/main.c~kgdb-fix-to-kill-breakpoints-on-initmem-after-boot
+++ a/init/main.c
@@ -1428,6 +1428,7 @@ static int __ref kernel_init(void *unuse
 	async_synchronize_full();
 	kprobe_free_init_mem();
 	ftrace_free_init_mem();
+	kgdb_free_init_mem();
 	free_initmem();
 	mark_readonly();
 
--- a/kernel/debug/debug_core.c~kgdb-fix-to-kill-breakpoints-on-initmem-after-boot
+++ a/kernel/debug/debug_core.c
@@ -455,6 +455,17 @@ setundefined:
 	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)
 {
_

Patches currently in -mm which might be from sumit.garg@linaro.org are

kgdb-fix-to-kill-breakpoints-on-initmem-after-boot.patch