问题
Attaching strace shows a lot of these messages:
poll([{fd=5, events=POLLIN}, {fd=6, events=POLLIN}, {fd=7, events=POLLIN}, {fd=8, events=POLLIN}, {fd=9, events=POLLIN}, {fd=10, events=POLLIN}], 6, 0) = 0 (Timeout)
poll([{fd=5, events=POLLIN}, {fd=6, events=POLLIN}, {fd=7, events=POLLIN}, {fd=8, events=POLLIN}, {fd=9, events=POLLIN}, {fd=10, events=POLLIN}], 6, 0) = 0 (Timeout)
poll([{fd=5, events=POLLIN}, {fd=6, events=POLLIN}, {fd=7, events=POLLIN}, {fd=8, events=POLLIN}, {fd=9, events=POLLIN}, {fd=10, events=POLLIN}], 6, 0) = 0 (Timeout)
poll([{fd=5, events=POLLIN}, {fd=6, events=POLLIN}, {fd=7, events=POLLIN}, {fd=8, events=POLLIN}, {fd=9, events=POLLIN}, {fd=10, events=POLLIN}], 6, 0) = 0 (Timeout)
How can I find what file the program is trying to access that causes poll system call to timeout?
strace generates a lot of messages which make it hard to debug
回答1:
How can I find what file the program is trying to access that causes poll system call to timeout?
Invoke:
lsof -p <pid>
And see what the file descriptors in question refer to.
You can also take a look into proc filesystem on Linux:
ls -l /proc/<pid>/fd
回答2:
ls -l /proc//fd/ -> You will get the corresponding node Id. ss -p | grep -> you will get the socket file path the fd belongs to.
来源：https://stackoverflow.com/questions/13018981/poll-system-call-timeout