linux-stable/net/rfkill
Johannes Berg 4799357688 net: rfkill: reduce data->mtx scope in rfkill_fop_open
commit f2ac54ebf8 upstream.

In syzbot runs, lockdep reports that there's a (potential)
deadlock here of data->mtx being locked recursively. This
isn't really a deadlock since they are different instances,
but lockdep cannot know, and teaching it would be far more
difficult than other fixes.

At the same time we don't even really _need_ the mutex to
be locked in rfkill_fop_open(), since we're modifying only
a completely fresh instance of 'data' (struct rfkill_data)
that's not yet added to the global list.

However, to avoid any reordering etc. within the globally
locked section, and to make the code look more symmetric,
we should still lock the data->events list manipulation,
but also need to lock _only_ that. So do that.

Reported-by: syzbot+509238e523e032442b80@syzkaller.appspotmail.com
Fixes: 2c3dfba4cf ("rfkill: sync before userspace visibility/changes")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-10-25 12:16:30 +02:00
..
core.c net: rfkill: reduce data->mtx scope in rfkill_fop_open 2023-10-25 12:16:30 +02:00
input.c rfkill: use DEFINE_SPINLOCK() for spinlock 2021-04-08 10:16:53 +02:00
Kconfig treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
Makefile treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
rfkill-gpio.c net: rfkill: gpio: prevent value glitch during probe 2023-10-25 12:16:14 +02:00
rfkill.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00