[PATCH AUTOSEL 5.1 43/51] platform/mellanox: mlxreg-hotplug: Add devm_free_irq call to remove flow

Sasha Levin
2019-06-26T03:43:26Z

From: Vadim Pasternak <vadimp@mellanox.com>

[ Upstream commit 8c2eb7b6468ad4aa5600aed01aa0715f921a3f8b ]

Add devm_free_irq() call to mlxreg-hotplug remove() for clean release
of devices irq resource. Fix debugobjects warning triggered by rmmod
It prevents of use-after-free memory, related to
mlxreg_hotplug_work_handler.

Issue has been reported as debugobjects warning triggered by
'rmmod mlxtreg-hotplug' flow, while running kernel with
CONFIG_DEBUG_OBJECTS* options.

[ 2489.623551] ODEBUG: free active (active state 0) object type: work_struct hint: mlxreg_hotplug_work_handler+0x0/0x7f0 [mlxreg_hotplug]
[ 2489.637097] WARNING: CPU: 5 PID: 3924 at lib/debugobjects.c:328 debug_print_object+0xfe/0x180
[ 2489.637165] RIP: 0010:debug_print_object+0xfe/0x180
?
[ 2489.637214] Call Trace:
[ 2489.637225] __debug_check_no_obj_freed+0x25e/0x320
[ 2489.637231] kfree+0x82/0x110
[ 2489.637238] release_nodes+0x33c/0x4e0
[ 2489.637242] ? devres_remove_group+0x1b0/0x1b0
[ 2489.637247] device_release_driver_internal+0x146/0x270
[ 2489.637251] driver_detach+0x73/0xe0
[ 2489.637254] bus_remove_driver+0xa1/0x170
[ 2489.637261] __x64_sys_delete_module+0x29e/0x320
[ 2489.637265] ? __ia32_sys_delete_module+0x320/0x320
[ 2489.637268] ? blkcg_exit_queue+0x20/0x20
[ 2489.637273] ? task_work_run+0x7d/0x100
[ 2489.637278] ? exit_to_usermode_loop+0x5b/0xf0
[ 2489.637281] do_syscall_64+0x73/0x160
[ 2489.637287] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 2489.637290] RIP: 0033:0x7f95c3596fd7

The difference in release flow with and with no devm_free_irq is listed
below:

bus: 'platform': remove driver mlxreg-hotplug
mlxreg_hotplug_remove(start)
-> devm_free_irq (with new code)
mlxreg_hotplug_remove (end)
release_nodes (start)
mlxreg-hotplug: DEVRES REL devm_hwmon_release (8 bytes)
device: 'hwmon3': device_unregister
PM: Removing info for No Bus:hwmon3
mlxreg-hotplug: DEVRES REL devm_kzalloc_release (88 bytes)
mlxreg-hotplug: DEVRES REL devm_kzalloc_release (6 bytes)
mlxreg-hotplug: DEVRES REL devm_kzalloc_release (5 bytes)
mlxreg-hotplug: DEVRES REL devm_kzalloc_release (5 bytes)
mlxreg-hotplug: DEVRES REL devm_kzalloc_release (5 bytes)
mlxreg-hotplug: DEVRES REL devm_kzalloc_release (5 bytes)
mlxreg-hotplug: DEVRES REL devm_kzalloc_release (5 bytes)
mlxreg-hotplug: DEVRES REL devm_kzalloc_release (5 bytes)
mlxreg-hotplug: DEVRES REL devm_kzalloc_release (5 bytes)
mlxreg-hotplug: DEVRES REL devm_kzalloc_release (5 bytes)
mlxreg-hotplug: DEVRES REL devm_kzalloc_release (5 bytes)
mlxreg-hotplug: DEVRES REL devm_kzalloc_release (5 bytes)
mlxreg-hotplug: DEVRES REL devm_irq_release (16 bytes) (no new code)
mlxreg-hotplug: DEVRES REL devm_kzalloc_release (1376 bytes)
------------[ cut here ]------------ (no new code):
ODEBUG: free active (active state 0) object type: work_struct hint: mlxreg_hotplug_work_handler

release_nodes(end)
driver: 'mlxreg-hotplug': driver_release

Fixes: 1f976f6978bf ("platform/x86: Move Mellanox platform hotplug driver to platform/mellanox")
Signed-off-by: Vadim Pasternak <vadimp@mellanox.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/platform/mellanox/mlxreg-hotplug.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/platform/mellanox/mlxreg-hotplug.c b/drivers/platform/mellanox/mlxreg-hotplug.c
index 687ce6817d0d..f85a1b9d129b 100644
--- a/drivers/platform/mellanox/mlxreg-hotplug.c
+++ b/drivers/platform/mellanox/mlxreg-hotplug.c
@@ -694,6 +694,7 @@ static int mlxreg_hotplug_remove(struct platform_device *pdev)

/* Clean interrupts setup. */
mlxreg_hotplug_unset_irq(priv);
+ devm_free_irq(&pdev->dev, priv->irq, priv);

return 0;
}
--
2.20.1