# DF-2845 — build.log (reconstructed from the orchestrating session's captured output)

The guest wedged in ddb after the INVARIANTS panic run before /tmp/kbuild*.log
could be re-fetched over ssh; the lines below are the verbatim command outputs
captured by the audit session that drove the builds.

## Trigger code — KLD variant (first attempt; NOT loadable on this snapshot)
  $ cd /root/baddrain && sh build.sh
  cc -O2 -pipe -D_KERNEL -Wall -Wredundant-decls -Wnested-externs
     -Wstrict-prototypes -Wmissing-prototypes -Wpointer-arith -Wcast-qual
     -Wold-style-definition -Wmissing-include-dirs -Wno-pointer-sign -Winit-self
     -Wundef -Wno-unused-but-set-variable -std=gnu11 -Werror -DKLD_MODULE
     -nostdinc [...] -c baddrain.c
  cc -Wl,--build-id=sha1 -nostdlib -Wl,--hash-style=sysv -r -Wl,-d -o baddrain.ko baddrain.o
  -rw-r--r-- 1 root wheel 5104 Sep 2 07:28 baddrain.ko

  NOTE: kldload of ANY module freshly built by this snapshot's toolchain
  (cc 8.3 [DragonFly] 2019) crashes the prebuilt Jul-2026 kernel's module
  loader (Fatal trap 9 GPF at strcmp+0x10 during linker metadata parse,
  before MOD_LOAD runs; a minimal hello-world KLD does the same).  Stock
  /boot/kernel/*.ko modules load fine.  The PoC was therefore compiled
  INTO custom kernels instead — see df2845_test.c.

## Kernel builds (in-guest, native toolchain)

  $ cd /usr/src && make nativekernel KERNCONF=DF2845_NOINV -j6   [unpatched, no INVARIANTS]
  BUILD_RC=0
  --------------------------------------------------------------
  >>> Kernel build for DF2845_NOINV completed on Wed Sep  2 07:47:26 UTC 2026
  --------------------------------------------------------------
  $ cp /usr/obj/usr/src/sys/DF2845_NOINV/kernel.stripped /boot/kernel/kernel
  INSTALLED-NOINV
  (booted: DragonFly 6.5-DEVELOPMENT #0: Wed Sep  2 07:44:03 UTC 2026
   root@dfbsd:/usr/obj/usr/src/sys/DF2845_NOINV x86_64)

  $ cd /usr/src && patch -p0 < /root/fix.diff    [fix applied to sys/kern/subr_sbuf.c]
  Hunk #1 succeeded at 333. done
  $ make nativekernel KERNCONF=DF2845_NOINV -j6  [patched, no INVARIANTS]
  BUILD_RC=0
  INSTALLED-FIXED
  (booted: DragonFly 6.5-DEVELOPMENT #1: Wed Sep  2 07:54:44 UTC 2026)

  $ cd /usr/src && patch -R -p0 < /root/fix.diff [reverted]
  $ make nativekernel KERNCONF=DF2845_INV -j6    [unpatched, WITH INVARIANTS]
  BUILD_RC=0
  INSTALLED-INV
  (booted and panicked on trigger at ~08:09 UTC 2026)