--- title: Using syzkaller, part 4: Driver fuzzing | daily.dev description: Part 4 of a series on Syzkaller explores how to extend the fuzzer to target specific Linux kernel drivers, using the V4L2 vim2m virtual driver as a case study.... canonical: https://daily.dev/posts/using-syzkaller-part-4-driver-fuzzing-aqht6ei2i twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Using syzkaller, part 4: Driver fuzzing | daily.dev og:description: Part 4 of a series on Syzkaller explores how to extend the fuzzer to target specific Linux kernel drivers, using the V4L2 vim2m virtual driver as a case study.... og:url: https://daily.dev/posts/using-syzkaller-part-4-driver-fuzzing-aqht6ei2i og:image: https://api.daily.dev/og/posts/AqhT6Ei2I.png og:image:alt: Using syzkaller, part 4: Driver fuzzing og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Using syzkaller, part 4: Driver fuzzing **[Collabora Blog](https://daily.dev/sources/collabora)** · 9 min read · 0 upvotes · 0 comments ## Summary Part 4 of a series on Syzkaller explores how to extend the fuzzer to target specific Linux kernel drivers, using the V4L2 vim2m virtual driver as a case study. The post explains limitations of purely random fuzzing for complex driver APIs like V4L2's Request API, then walks through practical solutions: splitting monolithic syscall descriptions into driver-specific files, using syzlang resources to encode ordering constraints between syscalls, leveraging udev rules to create stable device symlinks (e.g., /dev/vim2m), and writing pseudo-syscalls for controlled C code execution. Contributed changes are already merged into Syzkaller and have enabled fuzzing of previously unreachable V4L2 code paths. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### How do I make syzkaller focus on a specific Linux kernel driver instead of fuzzing all syscalls randomly? Narrow the fuzzer's scope by writing driver-specific syscall descriptions in syzlang, enabling only those syscalls in the config (e.g., 'openat$vim2m' and 'ioctl'), and using udev rules to create a stable symlink like /dev/vim2m pointing to the correct /dev/videoX device. Syzlang resources encode producer/consumer relationships between syscalls, giving the fuzzer implicit ordering guidance without hard-coding sequences. _Developers targeting specific drivers with syzkaller track description patterns and merged examples on daily.dev._ ### What are pseudo-syscalls in syzkaller and when should I use them? Pseudo-syscalls are literal C functions embedded in the syzkaller executor that let you perform static, non-fuzzed operations as part of generated test programs. They are useful for setting up a controlled test environment before fuzzing begins — for example, initializing driver state or issuing a fixed sequence of ioctls that must happen in a specific order. Adding static code to the executor is discouraged but documented. _Engineers writing syzkaller pseudo-syscalls for driver setup find related kernel testing discussions on daily.dev._ ## Similar posts on daily.dev - [Linux Kernel Introducing New Taint Due To Fuzzing Bots Yielding Impractical Bug Reports](https://daily.dev/posts/linux-kernel-introducing-new-taint-due-to-fuzzing-bots-yielding-impractical-bug-reports-xgx8vvj7q) · Phoronix · 0 upvotes · 0 comments - [Linux Fu: Fake Webcams Have Many Uses](https://daily.dev/posts/linux-fu-fake-webcams-have-many-uses-bbsynkgs3) · Hackaday · 1 upvotes · 0 comments - [Igniting the GPU: From Kernel Plumbing to 3D Rendering on RISC-V](https://daily.dev/posts/igniting-the-gpu-from-kernel-plumbing-to-3d-rendering-on-risc-v-n3d4nu797) · Hacker News · 1 upvotes · 0 comments - [Flatpak Exploring GPU Virtualization To Ease Driver Challenges](https://daily.dev/posts/flatpak-exploring-gpu-virtualization-to-ease-driver-challenges-0irfkmyja) · Phoronix · 1 upvotes · 0 comments --- Tags: [#linux](https://daily.dev/tags/linux) [View this post on daily.dev](https://daily.dev/posts/using-syzkaller-part-4-driver-fuzzing-aqht6ei2i) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Using syzkaller, part 4: Driver fuzzing","url":"https://daily.dev/posts/using-syzkaller-part-4-driver-fuzzing-aqht6ei2i","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/using-syzkaller-part-4-driver-fuzzing-aqht6ei2i"},"datePublished":"2026-08-11T08:55:00.624Z","dateModified":"2026-08-11T09:20:38.658Z","description":"Part 4 of a series on Syzkaller explores how to extend the fuzzer to target specific Linux kernel drivers, using the V4L2 vim2m virtual driver as a case study....","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/5370ca52d596b53ce865038989a66b09?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/5370ca52d596b53ce865038989a66b09?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"Collabora Blog","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"Collabora Blog","logo":"https://media.daily.dev/image/upload/s--ZGZ0FjqS--/f_auto,q_auto/v1786438306/logos/collabora?_a=BAMAMicg0","url":"https://daily.dev/sources/collabora"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/using-syzkaller-part-4-driver-fuzzing-aqht6ei2i","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"linux","timeRequired":"PT9M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Collabora Blog","item":"https://daily.dev/sources/collabora"},{"@type":"ListItem","position":3,"name":"Using syzkaller, part 4: Driver fuzzing"}]} {"@context":"https://schema.org","@type":"FAQPage","@id":"https://daily.dev/posts/using-syzkaller-part-4-driver-fuzzing-aqht6ei2i#faq","mainEntity":[{"@type":"Question","name":"How do I make syzkaller focus on a specific Linux kernel driver instead of fuzzing all syscalls randomly?","acceptedAnswer":{"@type":"Answer","text":"Narrow the fuzzer's scope by writing driver-specific syscall descriptions in syzlang, enabling only those syscalls in the config (e.g., 'openat$vim2m' and 'ioctl'), and using udev rules to create a stable symlink like /dev/vim2m pointing to the correct /dev/videoX device. 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