u/Ill-Department-8585

▲ 1 r/kernel

Syzkaller Issue

Hi all,

I’m running syzkaller for kernel fuzzing on a very constrained VM (1 GB RAM) and hitting a recurring issue after some iterations:

- Syzkaller starts fine

- My script automatically starts the next iteration after one finishes

- After running for a while, I start getting:

- “fork not possible”

- “cannot allocate memory”

- Eventually fuzzing stalls

Current setup:

- procs=1

- low-memory VM (1GB)

- repeated automated iterations

- considering target_reboot and swap, not fully tuned yet

My suspicion is one of:

  1. syz-executor processes accumulating
  2. kernel slab/kmalloc growth from fuzzing
  3. fork failing due to Linux overcommit / no swap
  4. my iteration loop not cleaning up enough between runs

Questions:

- Has anyone run syzkaller reliably on very low memory?

- What tuning helped most? (swap, drop_caches, target_reboot, overcommit settings, smaller corpus, disabling coverage, etc.)

- Is periodic reboot normal for long-running syzkaller on small VMs?

- Any way to detect whether this is executor leakage vs kernel memory pressure?

I’ve seen fork failures can happen under memory pressure on Linux :contentReference[oaicite:1]{index=1}, but wondering what syzkaller-specific fixes people use.

Would appreciate configs, scripts, or debugging ideas.

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u/Ill-Department-8585 — 7 days ago