From b2a2ab039bd58f51355e33d7d3fc64605d7f870d Mon Sep 17 00:00:00 2001
From: Stephan Gerhold <stephan.gerhold@kernkonzept.com>
Date: Tue, 30 May 2023 17:54:46 +0200
Subject: [PATCH] opp: Fix use-after-free in lazy_opp_tables after probe deferral
Git-commit: b2a2ab039bd58f51355e33d7d3fc64605d7f870d
Patch-mainline: v6.5-rc1
References: git-fixes

When dev_pm_opp_of_find_icc_paths() in _allocate_opp_table() returns
-EPROBE_DEFER, the opp_table is freed again, to wait until all the
interconnect paths are available.

However, if the OPP table is using required-opps then it may already
have been added to the global lazy_opp_tables list. The error path
does not remove the opp_table from the list again.

This can cause crashes later when the provider of the required-opps
is added, since we will iterate over OPP tables that have already been
freed. E.g.:

  Unable to handle kernel NULL pointer dereference when read
  CPU: 0 PID: 7 Comm: kworker/0:0 Not tainted 6.4.0-rc3
  PC is at _of_add_opp_table_v2 (include/linux/of.h:949
  drivers/opp/of.c:98 drivers/opp/of.c:344 drivers/opp/of.c:404
  drivers/opp/of.c:1032) -> lazy_link_required_opp_table()

Fix this by calling _of_clear_opp_table() to remove the opp_table from
the list and clear other allocated resources. While at it, also add the
missing mutex_destroy() calls in the error path.

Cc: stable@vger.kernel.org
Suggested-by: Viresh Kumar <viresh.kumar@linaro.org>
Fixes: 7eba0c7641b0 ("opp: Allow lazy-linking of required-opps")
Signed-off-by: Stephan Gerhold <stephan.gerhold@kernkonzept.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/opp/core.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/opp/core.c b/drivers/opp/core.c
index 85cbc8de407c..7046487dc6f4 100644
--- a/drivers/opp/core.c
+++ b/drivers/opp/core.c
@@ -1358,7 +1358,10 @@ static struct opp_table *_allocate_opp_table(struct device *dev, int index)
 	return opp_table;
 
 remove_opp_dev:
+	_of_clear_opp_table(opp_table);
 	_remove_opp_dev(opp_dev, opp_table);
+	mutex_destroy(&opp_table->genpd_virt_dev_lock);
+	mutex_destroy(&opp_table->lock);
 err:
 	kfree(opp_table);
 	return ERR_PTR(ret);
-- 
2.35.3