[PATCH v2 0/3] Fix i2c mux module refcount issues

Herve Codina
2023-10-19T10:10:28Z

Hi,

Some i2c mux drivers wrongly use the pair of_find_i2c_adapter_by_node()
/ i2c_put_adapter() to lock the parent adapter.

Indeed, i2c_put_adapter() decrements the module refcount while
of_find_i2c_adapter_by_node() does not increment it. This leads to an
overflow over zero of the parent adapter user counter.

Identified mux drivers impacted are:
- i2c-mux-gpmux
- i2c-demux-pinctrl
- i2c-mux-pinctrl

Commit 48e9743dd648 ("i2c: core: add and export of_get_i2c_adapter_by_node()
interface") introduces of_get_i2c_adapter_by_node() to correctly handle
this refcount issue.

This series fixes the 3 identified mux drivers replacing the
of_find_i2c_adapter_by_node() call by an of_get_i2c_adapter_by_node()
call.

Compare to the previous iteration
https://lore.kernel.org/linux-kernel/20231019073533.386563-1-herve.codina@bootlin.com/
This v2 series:
- Fixes commit log message
- Add Fixes and Acked-by tags

Best regards,
Hervé

Changes v1 -> v2:
- All patches
Fix commit log
Add relevant Fixes tag
Add 'Acked-by: Peter Rosin <peda@axentia.se>'

Herve Codina (3):
i2c: muxes: i2c-mux-pinctrl: Use of_get_i2c_adapter_by_node()
i2c: muxes: i2c-demux-pinctrl: Use of_get_i2c_adapter_by_node()
i2c: muxes: i2c-mux-gpmux: Use of_get_i2c_adapter_by_node()

drivers/i2c/muxes/i2c-demux-pinctrl.c | 2 +-
drivers/i2c/muxes/i2c-mux-gpmux.c | 2 +-
drivers/i2c/muxes/i2c-mux-pinctrl.c | 2 +-
3 files changed, 3 insertions(+), 3 deletions(-)

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2.41.0