VoIP Developer

Job Title: Senior Linux Kernel Engineer

Experience: 5–10 Years

Location: Bangalore / Chennai

Domain: Enterprise Linux / Kernel Development

Job Summary

We are seeking a highly skilled Senior Linux Kernel Engineer with deep expertise in kernel development, debugging, and performance optimization. The role involves working on enterprise-grade Linux distributions, kernel lifecycle management, security patching, and low-level hardware integration.

Key Responsibilities

1. Kernel Lifecycle & Maintenance

• Lead kernel upgrade strategies (e.g., LTS migrations such as 5.15 → 6.x) while ensuring stability and compatibility.
• Perform patch porting across kernel versions, resolving API and dependency conflicts.
• Track and mitigate security vulnerabilities by monitoring CVEs and upstream sources (e.g., LKML).
• Backport critical fixes to production kernels without impacting system stability.

2. Debugging & System Stability

• Act as an escalation point for kernel panics and system crashes.
• Perform post-mortem analysis using kdump, crash, and gdb.
• Debug early boot issues (UEFI, initramfs, kernel initialization).
• Conduct performance analysis using eBPF, ftrace, and perf to optimize system behavior.

3. Driver Development & Hardware Integration

• Design, develop, and maintain device drivers (network, storage, GPU, or character devices).
• Work closely with hardware through DMA, interrupts (MSI-X), and register-level programming.
• Maintain out-of-tree drivers using DKMS or similar frameworks.
• Ensure compatibility of drivers across kernel updates.

Required Technical Skills

• Programming: Strong expertise in C (mandatory) and C++
• Kernel Internals: Deep understanding of:
• Virtual File System (VFS)
• Memory Management (MMU, Paging)
• Process Scheduler
• Linux Networking Stack
• Debugging Tools:
• kdump, crash, gdb
• kprobes, trace-cmd, ftrace
• perf, valgrind
• Hardware debugging tools (JTAG, Serial Console)
• Build Systems:
• Kbuild, Makefiles
• Kernel packaging (RPM/Debian)
• Security:
• Experience with CVE patching and backporting
• Knowledge of SELinux/AppArmor
• Kernel hardening (FIPS, KSPP)

Preferred Skills

• Experience contributing to open-source kernel projects
• Familiarity with Linux Kernel Mailing List (LKML) workflows
• Exposure to enterprise Linux distributions (RHEL, Ubuntu, SUSE)
• Experience with performance tuning and system optimization at scale

1. Core Programming (C Language)

• Must have strong hands-on experience in C programming
• Comfortable with pointers, memory management, and low-level concepts

2. Kernel Internals Expertise

• Should have worked in at least one subsystem:
• VFS / File Systems
• Memory Management
• Scheduler / Networking

3. Debugging & Crash Analysis

• Experience handling kernel panics
• Hands-on with vmcore analysis tools

4. Security & Patching

• Understanding of CVE fixes and backporting

5. Driver Development

• Experience in writing or maintaining device drivers

6. Performance & Advanced Debugging

• Exposure to eBPF, ftrace, perf

7. Hardware-Level Understanding

• Knowledge of DMA, interrupts, hardware interaction

Soft Skills

• Strong analytical and problem-solving abilities
• Excellent communication skills
• Ability to work independently and in collaborative environments
• Quick learner with adaptability to new technologies

✅ Mandatory Skills

• Strong programming experience in C++ (C++11/14/17)
• Hands-on experience with Kubernetes (K8s)Application-level understanding
• Experience with StatefulSets & DaemonSets
• Good understanding of Linux systems
• Experience in multithreading and concurrency
• Strong problem-solving and debugging skills

⭐ Good to Have

• Experience in Microservices architecture
• Knowledge of Docker / containerization
• Basic knowledge of Python (for scripting/automation)
• Exposure to Distributed Systems
• Familiarity with CI/CD pipelines
• Experience with cloud platforms (AWS / Azure / GCP)

About the job

As a Senior SIP Engineer, you must take complete ownership of supporting all VoIP infrastructure, debugging issues related to specific servers or software, or remote clients such as SIP devices (both virtual such as soft-phone or WebRTC client, and physical such as a desk phone or an on-premise PBX), and providing fixes.

• Support customers during EST timezone during critical releases or emergency incidents 5+ yrs of supporting global VoIP services and/or applications on cloud-based servers.
• Expertise in SIP call flow analysis and debugging Expertise in setup and maintaining SIP-based monitoring, debugging, and alerting services
• Experience scripting call flow, dialplan, and custom routing with FreeSwitch using LUA and XML
• Experience in debugging Kamailio and Freeswitch-based applications is a must Good problem-solving and analytical skills Excellent written and verbal communication
• Experience working with open-source projects
• Exposure to SIP Carrier Integration
• Advanced Experience with cloud media infrastructure (load balancers, gateways, SBCs, STUN, TURN)
• Advanced Knowledge of all modern VoIP protocols/platforms including (SIP, RTP stack & SDP, RTCP, TCP, UDP, SIP, HTTPS, SSL/TLS)

• Write a significant amount of code for new and existing databases and related systems
• Scale and own these backend systems and databases
• Ship high-quality code and architecture
• Mentor engineers on the team, developing their skills and helping advance their careers
• Work with the founders to flesh out the future of the product
• Help shape the future of our engineering organization

Requirements

• A passion for working on deeply technical projects and wanting to work on distributed systems, concurrency & parallelism, replication protocols, file systems & correctness
• You have been building applications for 5+ years with C/C++ or Rust and have significant backend, database, or systems-level programming experience
• You have a BS/MS/Ph.D. in a scientific field or equivalent experience
• You want to work in a fast-paced, high-growth startup environment that respects its engineers and customers
• You are comfortable working with a 100% distributed engineering team, collaborating on GitHub, Slack, Zoom, etc. in the open and as a self-starter

Bonus points:

• Experience working on databases or other storage systems internals
• Experience with Apache Arrow, Apache Parquet
• Know how columnar databases work
• Know how to convert an algorithm to use SIMD instructions
• Good knowledge of Linux internals
• You’ve contributed to open-source libraries and actively participate in the development community (blogging, giving talks, meetups, tweeting, etc.)

• Develop new features and improve existing code in C++, specializing in the iOS/Android platforms.
• Has experience with working on huge codebases and comfortable writing and debugging multi-threaded & asynchronous code in Android and the native C++ libraries.
• Understands the resource constraints of mobile devices and implements accordingly robust and efficient solutions with respect to CPU, memory and battery life.
• Be customer-focused and unafraid to challenge the status quo

• Work as part of a dedicated, high-energy team to develop code that spans multiple products.

• Maintain exceptional development standards, especially related to performance, robustness, and testing.

• Support other development teams, build robust relationships and effectively articulate complex ideas.

• Proactively learn new languages, libraries, and platforms as needed. Adapt quickly to changing requirements.

• Activity planning and estimations
• Participate in the design and architecture of the overall product and lead the same for your features.
• Study upcoming technologies, analyze and propose how they can be incorporated to improve the existing product.
• Create high & low-level design artifacts.
• Code Reviews
• Mentoring Android developers in the team
• Develop document solutions for close to a million Acrobat Android users 
• We are looking for you if your answer to the following questions is YES

• Are you interested to be part of a highly collaborative team developing next-generation document solutions?
• Have you developed mobile applications having complex UI and high performance?
• Do you like to solve problems and possess an aptitude for analytical troubleshooting?