How to debug multithreaded process in Linux?

Question

A multi-threaded application freezes and does not respond to any commands. I tried the following things with no luck:

• Attach process to gdb (error: (gdb) attach 6026 Attach to process 6026 ptrace: operation not allowed.)
• gstack (gstack just hangs)

Is there a good way to debug this process?

Answer 1

Thanks for your reply. The problem is at the kernel level. we used echo t> / proc / sysrq-trigger, which registers the stack of the entire running process in / var / log / messages. This stack trace helped analyze the problem.

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Answer 2

, - . , , proc.

cat /proc/6026/status|grep TracerPid