Re: kern/60620: Fatal logic inversion in fdtbus_get_u32prop_with_default() breaks usmsc(4) and other FDT drivers

["Nick Hudson via gnats" <gnats-admin%NetBSD.org@localhost>]

The following reply was made to PR kern/60620; it has been noted by GNATS.

From: Nick Hudson <nick.hudson%gmx.co.uk@localhost>
To: gnats-bugs%netbsd.org@localhost,
 kern-bug-people%netbsd.org@localhost,
 gnats-admin%netbsd.org@localhost,
 netbsd-bugs%netbsd.org@localhost
Cc: 
Subject: Re: kern/60620: Fatal logic inversion in
 fdtbus_get_u32prop_with_default() breaks usmsc(4) and other FDT drivers
Date: Wed, 19 Aug 2026 09:01:58 +0100

 On 19/08/2026 06:05, jun%soum.co.jp@localhost via gnats wrote:
 [snip]
 
 > A fatal regression was introduced in sys/dev/fdt/fdt_subr.c (revision =
 1.43)
 > with the implementation of fdtbus_get_u32prop_with_default().
 > The internal logic of of_getprop_uint32() return value checking is =
 inverted:
 > ----------------------------------------------------------------------
 > static int
 > fdtbus_get_u32prop_with_default(int phandle, const char *prop, int =
 dflt)
 > {
 >         uint32_t val;
 >         if (of_getprop_uint32(phandle, prop, &val)) {
 >                 val =3D dflt;
 >         }
 >         return val;
 > }
 
 This isn't a bug.
 
 Also,
 
 $ uname -a
 NetBSD rpi2 11.99.7 NetBSD 11.99.7 (GENERIC) #0: Sun Aug 16 16:46:12 BST =
 2026  =
 nick@Nicks-MacBook-Air.local:/Volumes/Work/netbsd/nick-vchiq/obj.evbarmv7h=
 f-el/sys/arch/evbarm/compile/GENERIC evbarm
 $ gcc -v
 Using built-in specs.
 COLLECT_GCC=3Dgcc
 COLLECT_LTO_WRAPPER=3D/usr/libexec/lto-wrapper
 Target: armv7--netbsdelf-eabihf
 Configured with: =
 /usr/src/tools/gcc/../../external/gpl3/gcc/dist/configure =
 --target=3Darmv7--netbsdelf-eabihf --enable-long-long --enable-threads =
 --with-bugurl=3Dhttp://www.NetBSD.org/support/send-pr.html =
 --with-pkgversion=3D'NetBSD nb1 20250721' --with-system-zlib =
 --enable-__cxa_atexit --enable-libstdcxx-time=3Drt =
 --enable-libstdcxx-threads --with-diagnostics-color=3Dauto-if-env =
 --with-default-libstdcxx-abi=3Dnew =
 --with-isl=3D/var/obj/mknative/evbarm-earmv7hf/usr/src/tooldir.NetBSD-10.0=
 _STABLE-amd64 =
 --with-mpc-lib=3D/var/obj/mknative/evbarm-earmv7hf/usr/src/external/lgpl3/=
 mpc/lib/libmpc =
 --with-mpfr-lib=3D/var/obj/mknative/evbarm-earmv7hf/usr/src/external/lgpl3=
 /mpfr/lib/libmpfr =
 --with-gmp-lib=3D/var/obj/mknative/evbarm-earmv7hf/usr/src/external/lgpl3/=
 gmp/lib/libgmp --with-mpc-include=3D/usr/src/external/lgpl3/mpc/dist/src =
 --with-mpfr-include=3D/usr/src/external/lgpl3/mpfr/dist/src =
 --with-gmp-include=3D/usr/src/external/lgpl3/gmp/lib/libgmp/arch/arm =
 --enable-tls --enable-initfini-array --disable-multilib =
 --disable-libstdcxx-pch --build=3Darmv7--netbsdelf-eabihf =
 --host=3Darmv7--netbsdelf-eabihf =
 --with-sysroot=3D/var/obj/mknative/evbarm-earmv7hf/usr/src/destdir.evbarm
 Thread model: posix
 Supported LTO compression algorithms: zlib
 gcc version 12.5.0 (nb3 20260326)
 $ gcc -Wall -o test_fdt test_fdt_subr.c
 $ ./test_fdt
 =3D=3D=3D FDT Regression Test Bench =3D=3D=3D
 
 [Case 1] Property EXISTS (Expected output: 200)
  - ORIGINAL (Buggy): 200  --> PASS
  - FIXED    (Patch): 200  --> PASS
 
 [Case 2] Property DOES NOT EXIST (Expected output: 100)
  - ORIGINAL (Buggy): 100  --> PASS
  - FIXED    (Patch): 100  --> PASS
 
 =3D=3D=3D Test finished =3D=3D=3D
 $
 
 Will check -current shortly