pinctrl: generic: serialise pinctrl_generic_dt_node_to_map()

Browse source

pinctrl_generic_add_group() documents that the caller must take care of
locking, and pinmux_generic_add_function() needs it too, but
pinctrl_generic_dt_node_to_map() calls them without holding
pctldev->mutex, and the core caller in create_pinctrl() does not take it
either.

The driver core calls pinctrl_bind_pins() before probing a device, so
two devices that reference the same pin controller can run
pinctrl_generic_dt_node_to_map() on one pctldev at the same time.

Both `add` functions take the new selector from pctldev->num_groups or
pctldev->num_functions, and radix_tree_insert() at that index.
Two racing callers can read the same selector before either
has inserted, so the second insert collides and fails:

  k1-pinctrl d401e000.pinctrl:
  error -EEXIST: error adding function pcie2-0-cfg
  k1-pinctrl d401e000.pinctrl:
  does not have pin group pcie0-0-cfg.pcie0-0-pins

leaving one consumer without its pin configuration.

This was hit on a SpacemiT K3 board, where PCIe devices probe in parallel
against the single shared pin controller.

Take pctldev->mutex across the whole function, so that the groups and the
function referring are in a single critical section.

Fixes: 43722575e5 ("pinctrl: add generic functions + pins mapper")
Signed-off-by: Sarah Emery <sarah.emery@canonical.com>
Signed-off-by: Linus Walleij <linusw@kernel.org>

...

This commit is contained in:

Sarah Emery 2026-08-28 17:58:17 +02:00 • committed by Linus Walleij

parent 692f32609a

commit 51ae996594

1 changed files with 4 additions and 0 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

4

drivers/pinctrl/pinctrl-generic.c

View file