I have kernel 2.4.26 and I applied the grsecurity patch. When I am recompiling (make bzImage) I get this error:
gcc -E -C -P -I/usr/src/linux-2.4.26/include -D__KERNEL__ -imacros /usr/src/linux-2.4.26/include/linux/config.h -imacros /usr/src/linux-2.4.26/include/asm-i386/segment.h -imacros /usr/src/linux-2.4.26/include/asm-i386/page.h -Ui386 arch/i386/vmlinux.lds.S >arch/i386/vmlinux.lds
ld -m elf_i386 -T /usr/src/linux-2.4.26/arch/i386/vmlinux.lds -e stext arch/i386/kernel/head.o arch/i386/kernel/init_task.o init/main.o init/version.o init/do_mounts.o \
--start-group \
arch/i386/kernel/kernel.o arch/i386/mm/mm.o kernel/kernel.o mm/mm.o fs/fs.o ipc/ipc.o \
drivers/parport/driver.o drivers/char/char.o drivers/block/block.o drivers/misc/misc.o drivers/net/net.o drivers/char/agp/agp.o drivers/char/drm/drm.o drivers/ide/idedriver.o drivers/cdrom/driver.o drivers/pci/driver.o drivers/pcmcia/pcmcia.o drivers/net/pcmcia/pcmcia_net.o drivers/pnp/pnp.o drivers/video/video.o drivers/media/media.o drivers/input/inputdrv.o crypto/crypto.o \
net/network.o \
grsecurity/grsec.o \
/usr/src/linux-2.4.26/arch/i386/lib/lib.a /usr/src/linux-2.4.26/lib/lib.a /usr/src/linux-2.4.26/arch/i386/lib/lib.a \
--end-group \
-o vmlinux
fs/fs.o: In function `dput':
fs/fs.o(.text+0x13495): undefined reference to `atomic_dec_and_lock'
make: *** [vmlinux] Error 1

Can someone tell me what's wrong?

i'm not sure. have you tried 2.4.23? i've heard about..

XPediTioN:
I am also trying to update Linux 2.4.26 with the corresponding grsecurity patch. I elected to download the newest Knoppix 3.4 (with Linux 2.4.26) and apply the patch from there. But when I look into the ...usr/src/linux-2.4.26 directory, all I see are "Documentation" and "include" directories? I cant find a Makefile or an image? Any help getting to the place where you are stuck would be greatly appreciated.
Ric :-)