Board-level Linux integration, U-Boot, device trees, kernel drivers and peripheral bring-up. Separate power and hardware checks from software adaptation, and define a recoverable boot path.
When process or thread creation fails, inspect task-count limits and their hierarchy before blaming free-memory capacity. Linux’s cgroup PID controller counts kernel tasks, including threads. A service with only a few process IDs can still consume its allowance through worker pools and helper activity. This guide uses upstream Linux v6.12 cgroup v2 behavior and Linux…
Correlate service stalls with cgroup CPU-bandwidth enforcement before assuming that the whole machine is overloaded. A group can exhaust its permitted CPU time while other processors are idle. Additional application threads can consume that shared allowance sooner without increasing the amount available during the period. This guide uses upstream Linux v6.12 cgroup v2 interfaces and…
Review the synchronization property each driver path relies on before treating PREEMPT_RT as a configuration-only migration. On the RT kernel, a familiar spinlock or interrupt suffix can have different execution-context behavior. Code that accidentally relied on non-preemptibility may need a deliberate locking or per-CPU ownership change. This guide uses upstream Linux v6.12. It proposes a…
Trace the exact requested firmware name through the selected loader API and the storage available at that moment. Finding a similarly named blob after boot does not prove that the driver could load it during initialization. A direct-load warning may also be an intermediate event before another permitted mechanism succeeds. This procedure uses upstream Linux…
Resolve the faulting instruction to the exact binary, then compare that instruction path’s requirements with the features exposed to userspace on the replacement board. Two processors sharing an architecture name do not necessarily support every instruction emitted by the same build. A successful boot or application startup can leave an incompatible library path untested. The…
Obtain the running process’s base page size, use it in mapping arithmetic and qualify every binary that assumes a particular layout. A source constant of 4096 can work for years and fail when an otherwise similar image uses a different page size. The failure can occur in file offsets, protection boundaries, allocator assumptions or binary…
Identify the attempted syscall and the exact returned error before changing a seccomp policy. A library can interpret “not implemented” as permission to use an older path while treating “not permitted” as a final failure. An unchanged application can therefore behave differently after its libc changes syscall strategy. This guide pins Linux seccomp semantics to…
Give production applications a documented interface whose semantics are maintained, and keep debug-only files out of the application’s required startup path. Moving a filename from debugfs to sysfs is not enough. The contract must define what a value means, who may change it, how errors appear and what survives an upgrade. This article uses upstream…
Keep the request number, payload layout and compat dispatch path consistent, then send the same semantic test vectors from native and 32-bit applications. Fixed-width fields help, but they do not by themselves prove that a private driver ioctl works across different application ABIs. This guide uses upstream Linux v6.12 ioctl rules. A compile-only x86 fixture…
An allocation failure means that a particular request could not be satisfied under its constraints, not simply that the machine had no free RAM. Decode the request’s context, order, eligible memory and reclaim permissions before proposing a capacity increase. Those constraints explain why a small atomic allocation and a large sleepable allocation can fail for…