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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/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>
This commit is contained in:
Sumit Garg 2021-02-25 17:22:38 -08:00 committed by Linus Torvalds
parent db7fbf492d
commit d54ce6158e
3 changed files with 14 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
include/linux/kgdb.h
View File

@ -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_ */

1
init/main.c
View File

@ -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();

11
kernel/debug/debug_core.c
View File

@ -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)
{