What is a panic full on an iPhone?
Updated 2026-10-14
A panic full is a log file (panic-full-….ips) that iOS writes every time the kernel panics and forces a restart. One isolated panic is usually harmless. Repeated panics with the same signature almost always point to hardware: a silent sensor, a faulty flex, the battery or the logic board.
What exactly is a panic full?
A panic full is the report iOS writes when its kernel hits an error it cannot recover from. The kernel stops everything, saves a snapshot of the state of the system, then restarts the iPhone. That snapshot is stored as a text file named panic-full-YYYY-MM-DD-HHMMSS.ips in the device's analytics data.
For a technician, the file is the closest thing to a black box. It says which subsystem gave up, which process or sensor was involved, which iOS version was running and which model the log came from. It does not say "replace this part", but it narrows the search a lot.
In repair shops, "panic full" has become shorthand both for the file and for the symptom it documents: an iPhone that restarts by itself, often in a loop. The file is what you need; the symptom is what the customer describes.
Is one panic full a sign of a broken iPhone?
Not necessarily. One isolated panic in a month can come from:
- an iOS bug, especially just after a major update;
- an app that pushes a driver into a bad state;
- a jailbreak or research tool;
- a one-off event (a drop, extreme heat, a charger glitch).
What matters is repetition. If you open the analytics data and find a dozen panic-full files from the same day, with the same signature, the cause is very likely physical. A sensor that has stopped answering will not start answering again after a restart, so the panic comes back, again and again.
A useful rule of thumb in the shop:
| What you see | Most likely reading |
|---|---|
| 1 panic, then nothing for weeks | Software or a one-off event |
| Several panics, different signatures | Software first (update, restore), then re-check |
| Many panics, same signature | Hardware: follow the signature |
| Restarts every ~3 minutes, same code | A mandatory sensor is missing: see iPhone Restarts Every 3 Minutes: Why and How to Fix |
What does a panic full contain?
A panic-full file has two parts: a short JSON header (with fields such as bug_type, os_version and the model identifier), followed by the body with the panicString. The panic string is the key line. It starts with panic(cpu …) and carries the actual message, for example a "SMC PANIC" with a sensor array value, a list of missing sensors, or a watchdog timeout naming a process.
We explain field by field how to read it in How to Read an iPhone Panic Log (Panic Full Guide).
What are the main panic families?
Most hardware-related panics fall into a small number of families. Recognising the family is the first step, because it tells you where to look.
SMC "sensor array" (silent sensor)
The system management controller, built into the SoC, periodically waits for a response from each mandatory sensor. If one stops responding, it forces a restart. The log shows a line like sensor array 0 - 4 is 0, 4194304: the number is a bitmask that identifies the missing sensor(s). On recent iPhones this is the most common cause of a regular restart loop, and the meaning of each bit depends on the model.
Missing sensor(s)
On other generations, the same idea appears as a watchdog panic: thermalmonitord stops receiving readings from a sensor and the log lists it by name, for example Missing sensor(s): mic2 or prs0. Each name maps to a part: mic1 and prs0 usually live on the charging port flex, mic2 on the power button flex, TG0B and TG0V on the battery side.
Watchdog timeout
userspace watchdog timeout: no successful checkins from wifid means a system process did not check in with the watchdog in time (≈180 s). Depending on the process, it is often software (logd, SpringBoard on early iOS 16), sometimes hardware.
AOP (Always-On Processor)
The AOP is the part of the SoC that stays powered all the time. Its panics are often linked to the power button flex, the front camera / sensors assembly, the charging port flex (which carries loudspeaker signals) or the Taptic Engine.
NAND and storage
Panics mentioning ANS2, nvme or older h2fmi messages point to the storage chip or its lines. They are logic board work, usually with a programmer, and they call for an immediate backup.
SEP (Secure Enclave)
Secure Enclave panics point to the logic board (the SEP link or its ROM) or to corrupted firmware after an iOS downgrade. Device-specific data is involved, so they are not a simple part swap.
Other families
The database also covers i2c bus errors (a specific device on a specific bus, often a display or a camera flex), display coprocessor errors, Wi-Fi / baseband messages and pure kernel software panics. You can browse them all in the codes hub or the table.
Why is a panic full useful for a repair shop?
Because it turns a symptom that looks the same on every phone ("it keeps restarting") into a specific lead. Two iPhones with the same restart loop can have completely different causes: one a torn charging port flex, the other a back glass with a non-genuine wireless coil. Without the log, you swap parts until it stops. With the log, you test the most likely part first.
It also protects you from bad conclusions. Some codes are disputed between sources, and some values that look identical mean different things on two models. A good reading always combines the signature, the model and the history of logs from the same device.
How do I check a panic full?
- Get the file from the iPhone or from a computer: see How to Get the Panic Full Log From an iPhone.
- Open it and find the
panicString, or drop it into the tool. - Read the family, the code and the model together.
- Test the likely part with a known-good part before ordering anything.
The analyzer does steps 2 and 3 for you: it extracts the signature, matches it against 111 sourced rules and shows the likely part in 3D, with the test to run first and the repair pitfalls. It gives a probable part, not a certainty. Always confirm with a known-good part.
Can a panic full be "removed" or "fixed"?
The file is only a record. You fix the panic by fixing its cause: restoring iOS if it is software, or repairing the part the signature points to if it is hardware. Once the cause is gone, no new panic-full files appear. That is also how you confirm a repair: use the phone for a day and check that the analytics data stays clean.