[BUG] net/w5500: two latent code defects (build break with NETDEV_STATISTICS; wrong d_private)

[ricardgb]

Disclaimer: This report was prepared with AI assistance (Claude Code). I reviewed it, verified the code citations against master myself, and validated the behaviour on real hardware where noted before filing.

Line numbers vs drivers/net/w5500.c at master 50f91ef502.

1. NETDEV_RXERRORS(&priv->dev) references variables that do not exist

l. 1351, in w5500_receive():

NETDEV_RXERRORS(&priv->dev);

Neither priv nor a field named dev exists in this function — the
variable is self and the field is w_dev. This compiles today only
because NETDEV_RXERRORS() expands to nothing without
CONFIG_NETDEV_STATISTICS; enabling statistics breaks the build.

Fix: NETDEV_RXERRORS(&self->w_dev);

2. d_private set to the device array instead of the instance

l. 2069, in w5500_initialize():

self->w_dev.d_private = g_w5500;   /* Used to recover private state from dev */

Should be self. Harmless for device 0 (g_w5500 == &g_w5500[0]), wrong
for any devno > 0 — every callback that recovers the driver state via
dev->d_private would operate on device 0's state.

Fix: self->w_dev.d_private = self;

Both fixes are included in the reference branch:
https://github.com/ricardgb/nuttx/tree/w5500-driver-fixes

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Disclosure: found during an AI-assisted (Claude Code) audit, verified by
me by reading the cited lines against master.