pinctrl: mediatek: make devm allocations safer and clearer in mtk_eint_do_init()

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[ Upstream commit 255b721c96 ]

mtk_eint_do_init() allocates several pointer arrays which are then
populated in a per-instance loop and freed on error. The arrays are
currently allocated with devm_kmalloc(), so their entries are left
uninitialised until the per-instance allocations succeed.

On a failure in the middle of the loop, the error path iterates over
the full nbase range and calls devm_kfree() on each element. For
indices which were never initialised, the corresponding array entries
contain stack garbage. If any of those happen to be non-zero,
devm_kfree() will pass them to devres_destroy(), which will WARN
because there is no matching devm_kmalloc() resource for such bogus
pointers.

Improve the robustness and readability by:

  - Using devm_kcalloc() for the pointer arrays so that all entries
    start as NULL, ensuring that only genuinely initialised elements
    may be freed and preventing spurious WARN_ON()s in the error path.
  - Switching the allocations to sizeof(*ptr) / sizeof(**ptr) forms,
    avoiding hard-coded element types and making the code more resilient
    to future type changes.
  - Dropping the redundant NULL checks before devm_kfree(), as
    devm_kfree() safely handles NULL pointers.

The functional behaviour in the successful initialisation path remains
unchanged, while the error handling becomes simpler and less
error-prone.

Reviewed-by: fanggeng <fanggeng@lixiang.com>
Signed-off-by: Liang Jie <liangjie@lixiang.com>
Signed-off-by: Linus Walleij <linusw@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

...

This commit is contained in:

Liang Jie 2025-12-09 18:02:17 +08:00 • committed by Sasha Levin

parent 3842f93e6e

commit 822019d751

1 changed files with 17 additions and 12 deletions

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drivers/pinctrl/mediatek/mtk-eint.c

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