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

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

From: Jun Ebihara <[email protected]>
To: [email protected]
Cc: [email protected], [email protected], [email protected]
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 17:48:20 +0900

 Thanx! 20260818180311Z seems fine!
 
 $ ./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
 armv7$ uname -a
 NetBSD armv7 11.99.7 NetBSD 11.99.7 (GENERIC) #0: Tue Aug 18 18:03:11
 UTC 2026  [email protected]:/usr/src/sys/arch/evbarm/compile/GENER=
 IC
 evbarm
 
 2026=E5=B9=B48=E6=9C=8819=E6=97=A5(=E6=B0=B4) 17:05 Nick Hudson via gnats <=
 [email protected]>:
 >
 > The following reply was made to PR kern/60620; it has been noted by GNATS=
 .
 >
 > From: Nick Hudson <[email protected]>
 > To: [email protected],
 >  [email protected],
 >  [email protected],
 >  [email protected]
 > 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, [email protected] via gnats wrote:
 >  [snip]
 >
 >  > A fatal regression was introduced in sys/dev/fdt/fdt_subr.c (revision =
 =3D
 >  1.43)
 >  > with the implementation of fdtbus_get_u32prop_with_default().
 >  > The internal logic of of_getprop_uint32() return value checking is =3D
 >  inverted:
 >  > ----------------------------------------------------------------------
 >  > static int
 >  > fdtbus_get_u32prop_with_default(int phandle, const char *prop, int =3D
 >  dflt)
 >  > {
 >  >         uint32_t val;
 >  >         if (of_getprop_uint32(phandle, prop, &val)) {
 >  >                 val =3D3D 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=
  =3D
 >  2026  =3D
 >  [email protected]:/Volumes/Work/netbsd/nick-vchiq/obj.evbarmv=
 7h=3D
 >  f-el/sys/arch/evbarm/compile/GENERIC evbarm
 >  $ gcc -v
 >  Using built-in specs.
 >  COLLECT_GCC=3D3Dgcc
 >  COLLECT_LTO_WRAPPER=3D3D/usr/libexec/lto-wrapper
 >  Target: armv7--netbsdelf-eabihf
 >  Configured with: =3D
 >  /usr/src/tools/gcc/../../external/gpl3/gcc/dist/configure =3D
 >  --target=3D3Darmv7--netbsdelf-eabihf --enable-long-long --enable-threads=
  =3D
 >  --with-bugurl=3D3Dhttp://www.NetBSD.org/support/send-pr.html =3D
 >  --with-pkgversion=3D3D'NetBSD nb1 20250721' --with-system-zlib =3D
 >  --enable-__cxa_atexit --enable-libstdcxx-time=3D3Drt =3D
 >  --enable-libstdcxx-threads --with-diagnostics-color=3D3Dauto-if-env =3D
 >  --with-default-libstdcxx-abi=3D3Dnew =3D
 >  --with-isl=3D3D/var/obj/mknative/evbarm-earmv7hf/usr/src/tooldir.NetBSD-=
 10.0=3D
 >  _STABLE-amd64 =3D
 >  --with-mpc-lib=3D3D/var/obj/mknative/evbarm-earmv7hf/usr/src/external/lg=
 pl3/=3D
 >  mpc/lib/libmpc =3D
 >  --with-mpfr-lib=3D3D/var/obj/mknative/evbarm-earmv7hf/usr/src/external/l=
 gpl3=3D
 >  /mpfr/lib/libmpfr =3D
 >  --with-gmp-lib=3D3D/var/obj/mknative/evbarm-earmv7hf/usr/src/external/lg=
 pl3/=3D
 >  gmp/lib/libgmp --with-mpc-include=3D3D/usr/src/external/lgpl3/mpc/dist/s=
 rc =3D
 >  --with-mpfr-include=3D3D/usr/src/external/lgpl3/mpfr/dist/src =3D
 >  --with-gmp-include=3D3D/usr/src/external/lgpl3/gmp/lib/libgmp/arch/arm =
 =3D
 >  --enable-tls --enable-initfini-array --disable-multilib =3D
 >  --disable-libstdcxx-pch --build=3D3Darmv7--netbsdelf-eabihf =3D
 >  --host=3D3Darmv7--netbsdelf-eabihf =3D
 >  --with-sysroot=3D3D/var/obj/mknative/evbarm-earmv7hf/usr/src/destdir.evb=
 arm
 >  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
 >  =3D3D=3D3D=3D3D FDT Regression Test Bench =3D3D=3D3D=3D3D
 >
 >  [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
 >
 >  =3D3D=3D3D=3D3D Test finished =3D3D=3D3D=3D3D
 >  $
 >
 >  Will check -current shortly
 >
 
 
 --=20
 Jun Ebihara