[PATCH v2] md/r5cache: call mddev_lock/unlock() in r5c_journal_mode_show
From: Song Liu <hidden>
Date: 2017-08-09 05:56:52
Subsystem:
software raid (multiple disks) support, the rest · Maintainers:
Song Liu, Yu Kuai, Linus Torvalds
In r5c_journal_mode_show(), it is necessary to call mddev_lock() before accessing conf and conf->log. Otherwise, the conf->log may change (and become NULL). Signed-off-by: Song Liu <redacted> Reported-by: Stephen Rothwell <redacted> Reported-by: kbuild test robot <redacted> --- drivers/md/raid5-cache.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c
index 2dcbafa..b6f3702 100644
--- a/drivers/md/raid5-cache.c
+++ b/drivers/md/raid5-cache.c@@ -2529,11 +2529,19 @@ static void r5l_write_super(struct r5l_log *log, sector_t cp) static ssize_t r5c_journal_mode_show(struct mddev *mddev, char *page) { - struct r5conf *conf = mddev->private; + struct r5conf *conf; int ret; + int err; - if (!conf->log) + err = mddev_lock(mddev); + if (err) + return err; + + conf = mddev->private; + if (!conf || !conf->log) { + mddev_unlock(mddev); return 0; + } switch (conf->log->r5c_journal_mode) { case R5C_JOURNAL_MODE_WRITE_THROUGH:
@@ -2551,6 +2559,7 @@ static ssize_t r5c_journal_mode_show(struct mddev *mddev, char *page) default: ret = 0; } + mddev_unlock(mddev); return ret; }
--
2.9.3