How the devil can gettid() return 1?
Every once in a while google-chrome goes into a 100% cpu loop. I got curious and examined the thread that was running at 100% and strace says this over and over again till I interrupt it:
gettid() = 1 gettid() = 1 gettid() = 1 gettid() = 1
^Cstrace: Process 18863 detached
<detached ...>
Clearly Process 18863 isn't the init process, how can it have a tid of 1?
This is on a fedora 24 box with a 4.6 kernel:
Linux tomh 4.6.4-301.fc24.x86_64 #1 SMP Tue Jul 12 11:50:00 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux
Just curious...
Quoted 8 lines · Tom Horsley
Every once in a while google-chrome goes into a 100% cpu loop. I got curious and examined the thread that was running at 100% and strace says this over and over again till I interrupt it:
gettid() = 1 gettid() = 1 gettid() = 1 gettid() = 1
Quoted 5 lines
^Cstrace: Process 18863 detached
<detached ...>Clearly Process 18863 isn't the init process, how can it have a tid of 1?
If you call clone() with CLONE_NEWPID then the new process will run in a new PID namespace (with new pids/tids starting at 1). The new process still has a pid in the old (containing) namespace, here presumably 18863. Chrome is probably using namespaces to isolate itself from the rest of the system.
You can read more about CLONE_NEWPID in 'man 2 clone'.
Vegard