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pinctrl: use non-devm kmalloc versions for free functions
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When a pinctrl driver gets interrupted during its probe process
(returning -EPROBE_DEFER), the devres system cleans up all allocated
resources. During this process it calls pinmux_generic_free_functions()
and pinctrl_generic_free_groups(), which in turn use managed kmalloc
calls for temporarily allocating some memory. Now those calls seem to
get added to the devres list, but are apparently not covered by the
cleanup process, because this is actually just running and iterating the
existing list. This leads to those mallocs being left with the device,
which the devres manager complains about when the driver eventually gets
probed again:
[    0.825239] ------------[ cut here ]------------
[    0.825256] WARNING: CPU: 1 PID: 89 at drivers/base/dd.c:349 driver_probe_device+0x2ac/0x2e8
[    0.825258] Modules linked in:
[    0.825262]
[    0.825270] CPU: 1 PID: 89 Comm: kworker/1:1 Not tainted 4.11.0 torvalds#307
[    0.825272] Hardware name: Pine64+ (DT)
[    0.825283] Workqueue: events deferred_probe_work_func
[    0.825288] task: ffff80007c19c100 task.stack: ffff80007c16c000
[    0.825292] PC is at driver_probe_device+0x2ac/0x2e8
[    0.825296] LR is at driver_probe_device+0x108/0x2e8
[    0.825300] pc : [<ffff000008559234>] lr : [<ffff000008559090>] pstate: 20000045
....
This warning is triggered because the devres list is not empty. In this
case the allocations were using 0 bytes, so no real leaks, but still this
ugly warning.
Looking more closely at these *cleanup* functions, devm_kzalloc() is actually
not needed, because the memory is just allocated temporarily and can be
freed just before returning from this function.
So fix this issue by using the bog standard kcalloc() call instead of
devm_kzalloc() and kfree()ing the memory at the end.

This fixes above warnings on boot, which can be observed on *some* builds
for the Pine64, where the pinctrl driver gets loaded early, but it missing
resources, so gets deferred and is loaded again (successfully) later.
kernelci caught this as well [1].

Signed-off-by: Andre Przywara <[email protected]>

[1] https://storage.kernelci.org/net-next/master/v4.11-rc8-2122-gc08bac03d289/arm64/defconfig/lab-baylibre-seattle/boot-sun50i-a64-pine64-plus.html
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Andre-ARM authored and 0day robot committed May 4, 2017
1 parent 1aa2faf commit 9de6950
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Showing 2 changed files with 6 additions and 4 deletions.
5 changes: 3 additions & 2 deletions drivers/pinctrl/core.c
Original file line number Diff line number Diff line change
Expand Up @@ -690,8 +690,8 @@ static void pinctrl_generic_free_groups(struct pinctrl_dev *pctldev)
void **slot;
int i = 0;

indices = devm_kzalloc(pctldev->dev, sizeof(*indices) *
pctldev->num_groups, GFP_KERNEL);
indices = kcalloc(pctldev->num_groups, sizeof(*indices),
GFP_KERNEL);
if (!indices)
return;

Expand All @@ -704,6 +704,7 @@ static void pinctrl_generic_free_groups(struct pinctrl_dev *pctldev)
radix_tree_delete(&pctldev->pin_group_tree, indices[i]);
devm_kfree(pctldev->dev, group);
}
kfree(indices);

pctldev->num_groups = 0;
}
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5 changes: 3 additions & 2 deletions drivers/pinctrl/pinmux.c
Original file line number Diff line number Diff line change
Expand Up @@ -836,8 +836,8 @@ void pinmux_generic_free_functions(struct pinctrl_dev *pctldev)
void **slot;
int i = 0;

indices = devm_kzalloc(pctldev->dev, sizeof(*indices) *
pctldev->num_functions, GFP_KERNEL);
indices = kcalloc(pctldev->num_functions, sizeof(*indices),
GFP_KERNEL);
if (!indices)
return;

Expand All @@ -850,6 +850,7 @@ void pinmux_generic_free_functions(struct pinctrl_dev *pctldev)
radix_tree_delete(&pctldev->pin_function_tree, indices[i]);
devm_kfree(pctldev->dev, function);
}
kfree(indices);

pctldev->num_functions = 0;
}
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