summary: no fix here. Locking review: ddebug_zpool_init(), like other *_init() routines, does not run under a lock (that we control). Unlike them, it runs later, at late_init. I dont know whether this is pertinent to the kernel panic. ddebug_callsite_get/put() are called as a pair under mutex-lock for all 3 callsite users; dynamic_emit_prefix() does its own ABBA-ish LGPU (Lock-Get-Put-Unlock), as does ddebug_change(). ddebug_proc_show() does GP, ddebug_proc_start|stop() wrap it with LU. ddebug_add_module() does LU to protect list_add(), HEAD~x added ddebug_zpool_add() inside that protection. This commit adds locking to ddebug_zpool_init(), around the loop of ddebug_zpool_add(), to match the locking in ddebug_add_module(). Signed-off-by: Jim Cromie <jim.cromie@gmail.com> --- lib/dynamic_debug.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c index 9c51f24a9c66..716231a98910 100644 --- a/lib/dynamic_debug.c +++ b/lib/dynamic_debug.c @@ -1187,8 +1187,10 @@ static void __init ddebug_zpool_init(void) } /* add-module normally does this, but not in time for builtins */ + mutex_lock(&ddebug_lock); for (iter = __start___dyndbg; iter < __stop___dyndbg; iter++) ddebug_zpool_add(iter); + mutex_unlock(&ddebug_lock); v2pr_info("total pages: %lu compaction: %lu\n", zs_get_total_pages(dd_callsite_zpool), @@ -1285,4 +1287,3 @@ early_initcall(dynamic_debug_init); /* Debugfs setup must be done later */ fs_initcall(dynamic_debug_init_control); - -- 2.26.2