From: Sumit Garg sumit.garg@linaro.org
commit d54ce6158e354f5358a547b96299ecd7f3725393 upstream.
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/20210224081652.587785-1-sumit.garg@linaro.org Signed-off-by: Sumit Garg sumit.garg@linaro.org Suggested-by: Doug Anderson dianders@chromium.org Acked-by: Doug Anderson dianders@chromium.org Acked-by: Daniel Thompson daniel.thompson@linaro.org Tested-by: Daniel Thompson daniel.thompson@linaro.org Cc: Masami Hiramatsu mhiramat@kernel.org Cc: Steven Rostedt (VMware) rostedt@goodmis.org Cc: Jason Wessel jason.wessel@windriver.com Cc: Peter Zijlstra peterz@infradead.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.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 +++ b/include/linux/kgdb.h @@ -360,9 +360,11 @@ 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 +++ b/init/main.c @@ -1417,6 +1417,7 @@ 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 +++ b/kernel/debug/debug_core.c @@ -456,6 +456,17 @@ 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) {