This is a note to let you know that I've just added the patch titled
opp: Fix use-after-free in lazy_opp_tables after probe deferral
to the 6.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
opp-fix-use-after-free-in-lazy_opp_tables-after-probe-deferral.patch
and it can be found in the queue-6.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From b2a2ab039bd58f51355e33d7d3fc64605d7f870d Mon Sep 17 00:00:00 2001
From: Stephan Gerhold <stephan.gerhold@xxxxxxxxxxxxxxx>
Date: Tue, 30 May 2023 17:54:46 +0200
Subject: opp: Fix use-after-free in lazy_opp_tables after probe deferral
From: Stephan Gerhold <stephan.gerhold@xxxxxxxxxxxxxxx>
commit b2a2ab039bd58f51355e33d7d3fc64605d7f870d upstream.
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@xxxxxxxxxxxxxxx
Suggested-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
Fixes: 7eba0c7641b0 ("opp: Allow lazy-linking of required-opps")
Signed-off-by: Stephan Gerhold <stephan.gerhold@xxxxxxxxxxxxxxx>
Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/opp/core.c | 3 +++
1 file changed, 3 insertions(+)
--- a/drivers/opp/core.c
+++ b/drivers/opp/core.c
@@ -1358,7 +1358,10 @@ static struct opp_table *_allocate_opp_t
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);
Patches currently in stable-queue which might be from stephan.gerhold@xxxxxxxxxxxxxxx are
queue-6.4/opp-fix-use-after-free-in-lazy_opp_tables-after-probe-deferral.patch
