Both (java and jstack) are started using the same user. It happens on some systems and if it happens it does with all java versions I checked (java 7 & java 8). On systems where ptrace_scope is available it is set to 0.
Best regards, Piotr On Thu, Nov 21, 2013 at 2:14 PM, Alan Bateman <alan.bate...@oracle.com>wrote: > On 21/11/2013 13:06, Piotr Bzdyl wrote: > >> Hello, >> >> I wasn't sure which OpenJDK mailing list I should choose for my question. >> As I have issues with jstack SA related group seemed the best place. >> >> I have the following issue: >> >> On console one (let's call it pts/1) I start a sample java app (let's say >> its pid is 1234). On another console (pts/2) I execute: >> >> jstack 1234 >> >> As a result pts/2 displays: >> 1234: Unable to open socket file: target process not responding or >> HotSpot VM not loaded >> The -F option can be used when the target process is not responding >> >> And on pts/1 I see the thread dump printed. I would rather expect that >> the thread dump will be displayed on pts/2 and nothing will be printed to >> pts/1. I tried to use different versions of OpenJDK but the result was >> always the same. >> >> Could you provide me any hints what might be wrong? >> >> Best regards, >> Piotr >> > Are pts/1 and pts/2 the same user? Alternatively, any special options to > the target VM that disables the attach mechanism? > > In any case, I suspect the reason that pts/1 is print the stack trace is > that the mechanism to start the attach mechanism in the target VM requires > signalling the target VM with SIGQUIT, the same signal that is used to get > a VM to do a thread dump to its own stdout. > > -Alan >
