From: Jim Cromie <jim.cromie@gmail.com>
To: linux-mm@kvack.org
Cc: gregkh@linuxfoundation.org, linux@rasmusvillemoes.dk,
Jim Cromie <jim.cromie@gmail.com>,
Jason Baron <jbaron@akamai.com>,
linux-kernel@vger.kernel.org
Subject: [PATCH 6/7] dyndbg: add locking around zpool-add loop in zpool-init
Date: Wed, 25 Nov 2020 12:36:25 -0700 [thread overview]
Message-ID: <20201125193626.2266995-7-jim.cromie@gmail.com> (raw)
In-Reply-To: <20201125193626.2266995-1-jim.cromie@gmail.com>
This commit doesnt improve things, last commit was working, next one
still breaks, despite this "fix". I keep it separate to isolate it
and the reasoning for review, which now stated, will be refuted as
needed. ;-)
Locking review:
ddebug_zpool_init(), like other ddebug_*_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 of them; ddebug_change() and 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 | 2 ++
1 file changed, 2 insertions(+)
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 473406b069a7..534d73e45844 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -1195,8 +1195,10 @@ 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),
--
2.28.0
next prev parent reply other threads:[~2020-11-25 19:37 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20201125193626.2266995-1-jim.cromie@gmail.com>
2020-11-25 19:36 ` [PATCH 1/7] dyndbg: move struct _ddebug's display fields to new _ddebug_callsite Jim Cromie
2020-11-25 19:36 ` [PATCH 2/7] dyndbg: count repetition in __dyndbg_callsite fields Jim Cromie
2020-11-25 19:36 ` [PATCH 3/7] dyndbg: add some code to see alignments of linkage data Jim Cromie
2020-11-25 19:36 ` [PATCH 4/7] dyndbg: select ZPOOL,ZS_MALLOC in Kconfig.debug DYNAMIC_DEBUG_CORE Jim Cromie
2020-11-25 19:36 ` [PATCH 5/7] dyndbg: replace __dyndbg_callsite section with a zs-pool copy Jim Cromie
2020-11-25 19:36 ` Jim Cromie [this message]
2020-11-25 19:36 ` [PATCH 7/7] dyndbg: enable 'cache' of active pr_debug callsites Jim Cromie
2020-11-25 20:54 ` Jason Baron
2020-11-25 21:23 ` jim.cromie
2020-08-07 20:09 [PATCH 0/7] dyndbg: WIP diet plan Jim Cromie
2020-08-07 20:09 ` [PATCH 6/7] dyndbg: add locking around zpool-add loop in zpool-init Jim Cromie
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