panic | 易学教程

Go: returning from defer

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问题 I want to return an error from a function if it panics (in Go): func getReport(filename string) (rep report, err error) { rep.data = make(map[string]float64) defer func() { if r := recover(); r != nil { fmt.Println("Recovered in f", r) err, _ = r.(error) return nil, err } }() panic("Report format not recognized.") // rest of the getReport function, which can try to out-of-bound-access a slice ... } I appear to have misunderstood the very concept of panic and defer. Can anybody enlighten me?

How to read, understand, analyze and debug a Linux kernel panic?

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问题 Consider the following linux kernel dump stack trace, you can trigger a panic from the kernel source code by calling panic("debugging a linux kernel panic"); : [<001360ac>] (unwind_backtrace+0x0/0xf8) from [<00147b7c>] (warn_slowpath_common+0x50/0x60) [<00147b7c>] (warn_slowpath_common+0x50/0x60) from [<00147c40>] (warn_slowpath_null+0x1c/0x24) [<00147c40>] (warn_slowpath_null+0x1c/0x24) from [<0014de44>] (local_bh_enable_ip+0xa0/0xac) [<0014de44>] (local_bh_enable_ip+0xa0/0xac) from [

How to solve “Kernel panic - not syncing - Attempted to kill init” — without erasing any user data [closed]

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问题 I was trying to update libc in our Ubuntu server but it failed and now when I reboot the server I get a error message: Kernel panic - not syncing - Attempted to kill init! and it just hangs. What is the solution to this problem? The server is used by 10 people so I don't want to reinstall erasing their data. 回答1: if the full message is: kernel panic - not syncing: Attempted to kill inint ! PId: 1, comm: init not tainted 2.6.32.-279-5.2.e16.x86_64 #1 then you should have disabled selinux and

Android: How to get kernel logs after kernel panic?

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I am using an Android Custom ROM on my device, also with a custom boot.img (custom kernel + cmdline + ramdisk). I now want to be able to view the kernel logs immediately after a kernel panic, but unfortunately I can not use a serial console. The good news: There seem to be some sources/modules in the Linux kernel of Android that are written exactly for this purpose. For example, the following lines are activated in my .config file for the kernel: CONFIG_ANDROID_RAM_CONSOLE=y CONFIG_ANDROID_RAM_CONSOLE_ENABLE_VERBOSE=y CONFIG_APANIC=y CONFIG_APANIC_PLABEL="oem_log" My problem is: After I forced

Android/Eclipse PANIC: Could not open

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I'm brand new to Android development and Eclipse so I have just set it all up and I am attempting the Hello World tutorial. Sadly when I try and run the program I get the following error: PANIC: Could not open: C:\Users\Nathan Smith.android/avd/Droid_4.0.3.ini I have heard that you should avoid spaces in these paths. Is the space in the name where the problem is? If so how do I go about changing it? If anyone could help me out with this that would be grand. By the way I also noticed that my SDK path is C:\Users\Asus Laptop\android-sdks\ should I change this to the same user? This was not

How to recover from concurrent map writes?

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问题 How do you recover from a runtime panic on a "concurrent map read and map write"? The usual defer with recover doesn't seem to work. Why is that? I know that you are not supposed to use maps in concurrent contexts, but still: how to recover here? Example: package main import "time" var m = make(map[string]string) func main() { go func() { for { m["x"] = "foo" } }() go func() { for { m["x"] = "foo" } }() time.Sleep(1 * time.Second) } Please add recovery code. :) 回答1: Recovering doesn't work

Android: How to get kernel logs after kernel panic?

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问题 I am using an Android Custom ROM on my device, also with a custom boot.img (custom kernel + cmdline + ramdisk). I now want to be able to view the kernel logs immediately after a kernel panic, but unfortunately I can not use a serial console. The good news: There seem to be some sources/modules in the Linux kernel of Android that are written exactly for this purpose. For example, the following lines are activated in my .config file for the kernel: CONFIG_ANDROID_RAM_CONSOLE=y CONFIG_ANDROID

golang中recover和panic用法

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golang中没有try... catch...，所以当golang中遇到panic时，如果不进行recover，便会导致整个程序挂掉，具体例子如下： package main import ( "fmt" ) func main() { panic("fault") fmt.Println("panic") } 运行结果： panic: fault goroutine 16 [running]:... 程序挂掉，并且报告出错的地方，并打印出掉用的栈解决办理：利用defer延迟处理的recover进行恢复，具体例子如下： package main import ( "fmt" ) func main() { defer func() { fmt.Println("1") }() defer func() { if err := recover(); err != nil { fmt.Println(err) } }() panic("fault") fmt.Println("2") } 运行结果： fault 1 程序首先运行panic，出现故障，此时跳转到包含recover()的defer函数执行，recover捕获panic，此时panic就不继续传递．但是recover之后，程序并不会返回到panic那个点继续执行以后的动作，而是在recover这个点继续执行以后的动作