This is a note to let you know that I've just added the patch titled
iio: trigger: sysfs: fix use-after-free on remove
to my char-misc git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
>From 78601726d4a59a291acc5a52da1d3a0a6831e4e8 Mon Sep 17 00:00:00 2001
From: Vincent Whitchurch <vincent.whitchurch@xxxxxxxx>
Date: Thu, 19 May 2022 11:19:25 +0200
Subject: iio: trigger: sysfs: fix use-after-free on remove
Ensure that the irq_work has completed before the trigger is freed.
==================================================================
BUG: KASAN: use-after-free in irq_work_run_list
Read of size 8 at addr 0000000064702248 by task python3/25
Call Trace:
irq_work_run_list
irq_work_tick
update_process_times
tick_sched_handle
tick_sched_timer
__hrtimer_run_queues
hrtimer_interrupt
Allocated by task 25:
kmem_cache_alloc_trace
iio_sysfs_trig_add
dev_attr_store
sysfs_kf_write
kernfs_fop_write_iter
new_sync_write
vfs_write
ksys_write
sys_write
Freed by task 25:
kfree
iio_sysfs_trig_remove
dev_attr_store
sysfs_kf_write
kernfs_fop_write_iter
new_sync_write
vfs_write
ksys_write
sys_write
==================================================================
Fixes: f38bc926d022 ("staging:iio:sysfs-trigger: Use irq_work to properly active trigger")
Signed-off-by: Vincent Whitchurch <vincent.whitchurch@xxxxxxxx>
Reviewed-by: Lars-Peter Clausen <lars@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20220519091925.1053897-1-vincent.whitchurch@xxxxxxxx
Cc: <Stable@xxxxxxxxxxxxxxx>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
---
drivers/iio/trigger/iio-trig-sysfs.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/iio/trigger/iio-trig-sysfs.c b/drivers/iio/trigger/iio-trig-sysfs.c
index 2a4b75897910..3d911c24b265 100644
--- a/drivers/iio/trigger/iio-trig-sysfs.c
+++ b/drivers/iio/trigger/iio-trig-sysfs.c
@@ -191,6 +191,7 @@ static int iio_sysfs_trigger_remove(int id)
}
iio_trigger_unregister(t->trig);
+ irq_work_sync(&t->work);
iio_trigger_free(t->trig);
list_del(&t->l);
--
2.36.1
