Linux
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- What is a kernel panic?
- The Linux kernel gets into a situation where it doesn't know what to do next. When this happens, the kernel gives as much information as it can about what caused the problem, depending on what caused the panic.
- What are the two kinds of kernel panic?
- 1. Hard Panic - also known as Aieee! 2. Soft Panic - also known as Oops
- What can cause a kernel panic?
- Only modules that are located within the kernel space can directly cause kernel to panic. Dynamically loaded modules (ismod) or built-in components (memory map, etc.).
- What are symptoms of a hard kernel panic?
- 1. Machine is completely locked up and unusable. 2. Num Lock / Caps Lock / Scroll Lock keys usually blink. 3. If in console mode, dump is displayed on monitor (including the phrase "Aieee!") 4. Similar to Windows Blue Screen
- What are causes of hard kernel panics?
- The most common cause of a hard kernel panic is when a driver crashes within an interrupt handler, usually because it tried to access a null pointer within the interrupt handler. When this happens, the driver cannot handle any new interrupts and eventual
- What information should be collected for a hard kernel panic?
- 1. /var/log/messages - sometimes the entire kernel panic stack trace will be logged there 2. Application / Library logs (RTF, cheetah, etc.) - may show what was happening before the panic 3. Other information about what happened prior to the panic, or h
- What are symptoms of a soft kernel panic?
- 1. Much less severe than a hard panic. 2. Usually results in a segmentation fault. 3. Can see the oops message - search /var/log/messages for string 'Oops'. 4. Machine still somewhat usable (but should be rebooted after information is collected)
- What are causes of a soft kernel panic?
- Almost anything that causes a module to crash when it is not within an interrupt handler can cause a soft panic. In this case, the driver itself will crash, but will not cause catastrophic system failure since it was not locked in an interrupt handler.