What types of Linux kernel development does Joya Systems handle?

We handle kernel module development, character and block device drivers, VFS-layer file system interception, netfilter and eBPF-based networking, block layer filters, and security hooks via LSM. We have delivered production solutions on mainline kernels as well as vendor-patched distributions.

Can you port our Windows driver to Linux?

Yes. We have ported Windows filter drivers, storage miniports, and network drivers to their Linux equivalents. The work involves mapping Windows kernel abstractions — IRPs, filter manager callbacks, NDIS OIDs — to the corresponding Linux subsystems: VFS hooks, the block layer, and the netfilter or socket-buffer path.

Do you work with embedded Linux?

Yes. We write kernel modules and board support packages for embedded targets, including device tree customization, platform driver development, and driver bring-up on ARM and x86 SoCs. We are comfortable working with Yocto, Buildroot, and vendor SDKs.

How does Linux kernel module development differ from user-space development?

Kernel modules run in ring 0 with no memory protection between modules, no standard C library, and no tolerance for unhandled errors — a NULL dereference crashes the machine. Concurrency must be managed with spinlocks, mutexes, RCU, and atomic operations appropriate to the execution context. Memory is allocated from slab caches or vmalloc, not the heap. Debugging requires kprobes, ftrace, or an attached KGDB session rather than a conventional debugger.

What Linux subsystems do you have experience with?

Our experience spans the VFS layer, the block layer (bio/request queues), netfilter (xtables, nftables), eBPF (XDP, TC, LSM), the LSM framework (including SELinux and AppArmor policy integration), SCSI mid-layer and libata, USB gadget and host drivers, the PCI subsystem, and the perf/tracing infrastructure.

Linux Kernel Development & Driver Consulting

Deep kernel expertise, delivered.

Linux kernel development consulting is the practice of writing and debugging code that runs inside the kernel itself — kernel modules, device drivers, file system implementations, networking hooks, and security extensions — rather than in user space. This work sits at the boundary between hardware and software where conventional debugging tools do not reach, execution context rules determine which kernel APIs are legal to call, and a single bad pointer dereference takes down the entire system. Joya Systems has been doing this work for over two decades across Windows, Linux, and macOS, and we bring the same rigorous engineering discipline to every Linux engagement.

Linux Kernel Work We Do

Our Linux kernel engagements span every major subsystem. We are not generalists who occasionally dip into kernel code — this is our primary domain.

Kernel modules and loadable drivers. We design, write, and debug production-grade kernel modules including character devices, block devices, and pseudo-filesystems. We handle module signing, versioning across kernel ABIs, and out-of-tree maintenance strategies.
VFS-layer file system interception. Using the Linux Virtual File System layer we intercept, redirect, or augment file operations transparently to applications. Common use cases include encryption, access auditing, copy-on-write snapshotting, and executable whitelisting — analogous to the Windows minifilter work we do on Windows.
Block layer interception and modification. We insert ourselves into the block I/O path via bio manipulation and request-queue filters to implement transparent encryption, compression, deduplication, and thin provisioning below the file system layer.
Networking: netfilter, eBPF, XDP. We write netfilter modules, nftables extensions, and eBPF programs (XDP, TC classifier, socket filter) for deep packet inspection, traffic shaping, connection tracking modification, and high-performance packet forwarding that bypasses most of the kernel network stack.
LSM security hooks. We work with the Linux Security Module framework to implement custom mandatory access control policies, integrate with SELinux and AppArmor, and build kernel-level security enforcement that cannot be bypassed from user space.
Device drivers for custom hardware. We write PCI, USB, I2C, SPI, and platform drivers for custom and off-the-shelf hardware, including device tree authoring and board support package development for embedded targets.
Application execution modification. Using a combination of LSM hooks, kprobes, and kernel-level process monitoring we have built solutions that intercept process creation, modify execution context, and enforce policy on what binaries may run and under what conditions.

Specific Use Cases

The following are representative problems our customers bring to us. They are technically diverse but share a common thread: they cannot be solved reliably from user space.

Embedded Linux bring-up. Porting a mainline or vendor kernel to new hardware, writing device tree overlays, and bringing up platform drivers for peripherals that have no existing Linux support.
Custom kernel module development. Building loadable modules that extend kernel behavior for a product — storage accelerators, security monitors, hardware abstraction layers — while maintaining compatibility across a range of kernel versions and distributions (RHEL, Ubuntu, Debian, embedded variants).
Windows-to-Linux driver porting. Mapping Windows kernel constructs (IRPs, filter manager callbacks, NDIS data paths) to their Linux equivalents (VFS hooks, bio requests, socket buffer manipulation). We have direct experience with all three sides of this translation problem because we work in all three kernels.
Kernel debugging and crash analysis. Using crash dump analysis, ftrace, kprobes, eBPF-based tracing, and KGDB to diagnose kernel panics, memory corruption, deadlocks, and subtle race conditions in production or staging environments.
Performance instrumentation. Instrumenting the kernel with perf events, BPF programs attached to tracepoints, and custom ftrace hooks to identify bottlenecks in storage I/O paths, network throughput, and scheduling latency without modifying the applications being measured.

Why Specialized Linux Kernel Expertise Matters

Most software engineers are productive in user space. The kernel is a different world. The rules that make user-space code safe — virtual memory isolation, process boundaries, preemptible execution with a safety net — do not apply. In the kernel, every line of code must account for which CPU it is running on, whether it can sleep, whether interrupts are enabled, and whether any other CPU might be modifying the same data structure at that exact moment. Getting this wrong does not produce a crash report you can attach to a bug ticket: it produces a system hang, silent data corruption, or a security vulnerability that is nearly impossible to reproduce deterministically.

The consequences of substandard kernel code also differ from user-space bugs. A deadlock in a kernel module locks the entire machine. A memory leak in a long-running driver eventually exhausts non-pageable memory and triggers an OOM kill or kernel panic. A race condition in a block driver can silently corrupt the filesystem of a production server. These failure modes require engineers who understand kernel memory management, locking hierarchies, interrupt context restrictions, and the specific ABI guarantees (and non-guarantees) of the Linux kernel.

Joya Systems brings this depth. We have debugged kernel panics in storage drivers, found subtle concurrency bugs in networking code, and optimized eBPF programs running in the fast path of high-throughput packet processing. Our engineers read kernel source — not just documentation — and we stay current with the upstream development that affects out-of-tree code.

Cross-Platform Kernel Capability

Many products need to run on more than one operating system. Joya Systems is one of a small number of consulting firms with genuine depth in all three major OS kernels: Windows (WDM, KMDF, minifilter, WFP), Linux (VFS, block layer, netfilter, eBPF), and macOS (IOKit, Kext, Network Kernel Extensions, Endpoint Security). This cross-platform fluency matters when you are porting a product, designing a new one that must ship on multiple platforms, or debugging an interaction between OS-level components that behave differently on each platform.

See our Windows driver development page for details on our Windows kernel work, or our past projects page for a summary of completed engagements across all three platforms. To discuss a Linux kernel project, contact us or review our full list of consulting services.

Frequently Asked Questions

What types of Linux kernel development does Joya Systems handle?: We handle kernel module development, character and block device drivers, VFS-layer file system interception, netfilter and eBPF-based networking, block layer filters, and security hooks via LSM. We have delivered production solutions on mainline kernels as well as vendor-patched distributions such as RHEL, Ubuntu LTS, and embedded variants.
Can you port our Windows driver to Linux?: Yes. We have ported Windows filter drivers, storage miniports, and network drivers to their Linux equivalents. The work involves mapping Windows kernel abstractions — IRPs, filter manager callbacks, NDIS OIDs — to the corresponding Linux subsystems: VFS hooks, the block layer, and the netfilter or socket-buffer path. Having engineers who understand both sides of that mapping in depth is what makes the difference between a clean port and one that is fragile under load.
Do you work with embedded Linux?: Yes. We write kernel modules and board support packages for embedded targets, including device tree customization, platform driver development, and driver bring-up on ARM and x86 SoCs. We are comfortable working with Yocto, Buildroot, and vendor SDKs, and we understand the constraints of cross-compilation, limited debug tooling, and resource-constrained environments.
How does Linux kernel module development differ from user-space development?: Kernel modules run in ring 0 with no memory protection between modules, no standard C library, and no tolerance for unhandled errors — a NULL dereference crashes the machine. Concurrency must be managed with spinlocks, mutexes, RCU, and atomic operations appropriate to the execution context. Memory is allocated from slab caches or vmalloc. Debugging requires kprobes, ftrace, or an attached KGDB session rather than a conventional debugger. The kernel's internal ABI is not stable across versions, so out-of-tree modules require active maintenance.
What Linux subsystems do you have experience with?: Our experience spans the VFS layer, the block layer (bio/request queues), netfilter (xtables, nftables), eBPF (XDP, TC, LSM), the LSM framework (including SELinux and AppArmor policy integration), SCSI mid-layer and libata, USB gadget and host drivers, the PCI subsystem, and the perf/tracing infrastructure.

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