Messages in this thread Patch in this message | | | From | Jim Cromie <> | Subject | [PATCH 6/7] dyndbg: add locking around zpool-add loop in zpool-init | Date | Fri, 7 Aug 2020 14:09:53 -0600 |
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This commit doesnt improve things, last commit was working, next one still breaks, despite this "fix". I keep it separate for the following review, which now stated, will be refuted as needed. ;-)
Locking review:
ddebug_zpool_init(), like other *_init() routines, does no locking itself. Unlike them, it runs later, at late_init. This patch doesnt fix the kernel panic that HEAD+1 does.
ddebug_callsite_get/put() are called as a pair under mutex-lock for all 3 callsite users, 2: ddebug_change(), dynamic_emit_prefix(), do their own ABBA-ish LGPU (Lock-Get-Put-Unlock).
ddebug_proc_show() does the GP part, and is wrapped by ddebug_proc_start|stop() with LU.
ddebug_add_module() does LU to protect list_add(), HEAD~1 added ddebug_zpool_add() loop 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 fdf52a26a504..701d3d1fb7e7 100644 --- a/lib/dynamic_debug.c +++ b/lib/dynamic_debug.c @@ -1182,8 +1182,10 @@ 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), @@ -1280,4 +1282,3 @@ early_initcall(dynamic_debug_init); /* Debugfs setup must be done later */ fs_initcall(dynamic_debug_init_control); - -- 2.26.2
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