[PATCH 5.10 216/491] PM: runtime: Fix a race condition related to device removal

Greg Kroah-Hartman
2026-04-13T16:53:21Z

From: Bart Van Assche <bvanassche@acm.org>

[ Upstream commit 29ab768277617452d88c0607c9299cdc63b6e9ff ]

The following code in pm_runtime_work() may dereference the dev->parent
pointer after the parent device has been freed:

/* Maybe the parent is now able to suspend. */
if (parent && !parent->power.ignore_children) {
spin_unlock(&dev->power.lock);

spin_lock(&parent->power.lock);
rpm_idle(parent, RPM_ASYNC);
spin_unlock(&parent->power.lock);

spin_lock(&dev->power.lock);
}

Fix this by inserting a flush_work() call in pm_runtime_remove().

Without this patch blktest block/001 triggers the following complaint
sporadically:

BUG: KASAN: slab-use-after-free in lock_acquire+0x70/0x160
Read of size 1 at addr ffff88812bef7198 by task kworker/u553:1/3081
Workqueue: pm pm_runtime_work
Call Trace:
<TASK>
dump_stack_lvl+0x61/0x80
print_address_description.constprop.0+0x8b/0x310
print_report+0xfd/0x1d7
kasan_report+0xd8/0x1d0
__kasan_check_byte+0x42/0x60
lock_acquire.part.0+0x38/0x230
lock_acquire+0x70/0x160
_raw_spin_lock+0x36/0x50
rpm_suspend+0xc6a/0xfe0
rpm_idle+0x578/0x770
pm_runtime_work+0xee/0x120
process_one_work+0xde3/0x1410
worker_thread+0x5eb/0xfe0
kthread+0x37b/0x480
ret_from_fork+0x6cb/0x920
ret_from_fork_asm+0x11/0x20
</TASK>

Allocated by task 4314:
kasan_save_stack+0x2a/0x50
kasan_save_track+0x18/0x40
kasan_save_alloc_info+0x3d/0x50
__kasan_kmalloc+0xa0/0xb0
__kmalloc_noprof+0x311/0x990
scsi_alloc_target+0x122/0xb60 [scsi_mod]
__scsi_scan_target+0x101/0x460 [scsi_mod]
scsi_scan_channel+0x179/0x1c0 [scsi_mod]
scsi_scan_host_selected+0x259/0x2d0 [scsi_mod]
store_scan+0x2d2/0x390 [scsi_mod]
dev_attr_store+0x43/0x80
sysfs_kf_write+0xde/0x140
kernfs_fop_write_iter+0x3ef/0x670
vfs_write+0x506/0x1470
ksys_write+0xfd/0x230
__x64_sys_write+0x76/0xc0
x64_sys_call+0x213/0x1810
do_syscall_64+0xee/0xfc0
entry_SYSCALL_64_after_hwframe+0x4b/0x53

Freed by task 4314:
kasan_save_stack+0x2a/0x50
kasan_save_track+0x18/0x40
kasan_save_free_info+0x3f/0x50
__kasan_slab_free+0x67/0x80
kfree+0x225/0x6c0
scsi_target_dev_release+0x3d/0x60 [scsi_mod]
device_release+0xa3/0x220
kobject_cleanup+0x105/0x3a0
kobject_put+0x72/0xd0
put_device+0x17/0x20
scsi_device_dev_release+0xacf/0x12c0 [scsi_mod]
device_release+0xa3/0x220
kobject_cleanup+0x105/0x3a0
kobject_put+0x72/0xd0
put_device+0x17/0x20
scsi_device_put+0x7f/0xc0 [scsi_mod]
sdev_store_delete+0xa5/0x120 [scsi_mod]
dev_attr_store+0x43/0x80
sysfs_kf_write+0xde/0x140
kernfs_fop_write_iter+0x3ef/0x670
vfs_write+0x506/0x1470
ksys_write+0xfd/0x230
__x64_sys_write+0x76/0xc0
x64_sys_call+0x213/0x1810

Reported-by: Ming Lei <ming.lei@redhat.com>
Closes: https://lore.kernel.org/all/ZxdNvLNI8QaOfD2d@fedora/
Reported-by: syzbot+6c905ab800f20cf4086c@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/68c13942.050a0220.2ff435.000b.GAE@google.com/
Fixes: 5e928f77a09a ("PM: Introduce core framework for run-time PM of I/O devices (rev. 17)")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://patch.msgid.link/20260312182720.2776083-1-bvanassche@acm.org
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/base/power/runtime.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index d15d033be2c97..ec14c3089e329 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -1776,6 +1776,7 @@ void pm_runtime_reinit(struct device *dev)
void pm_runtime_remove(struct device *dev)
{
__pm_runtime_disable(dev, false);
+ flush_work(&dev->power.work);
pm_runtime_reinit(dev);
}

--
2.51.0