md/r5cache: call mddev_lock/unlock() in r5c_journal_mode_show (a72cbf83) · Commits · 戴 / test

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 <songliubraving@fb.com> Reported-by:

Stephen Rothwell <sfr@canb.auug.org.au> Reported-by:

kbuild test robot <fengguang.wu@intel.com> Signed-off-by:

Shaohua Li <shli@fb.com>

drivers/md/raid5-cache.c

+10 −2

Original line number	Diff line number	Diff line
		@@ -2529,11 +2529,18 @@ 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;

		if (!conf->log)
		ret = mddev_lock(mddev);
		if (ret)
		return ret;

		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 +2558,7 @@ static ssize_t r5c_journal_mode_show(struct mddev mddev, char page)
		default:
		ret = 0;
		}
		mddev_unlock(mddev);
		return ret;
		}

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