Tor Browser: Unsolved DNS of a website or HS result in 100% CPU usage
I've been observing this behavior for a while. Tor browser taking 100% CPU for few seconds if it DNS resolver fails for a website and HS is not reachable.
[Sasi@NoNameForHost ~]# pstack 19469 Thread 1 (process 19469): #0 0x00007f05b44b071d in poll () at ../sysdeps/unix/syscall-template.S:81 #1 0x00007f05b56ace60 in ?? () from /home/Sasi/tor-browser_en-US/Browser/libnspr4.so legacy/trac#2 (closed) 0x00007f05b0b16346 in ?? () from /home/Sasi/tor-browser_en-US/Browser/libxul.so legacy/trac#3 (closed) 0x00007f05b0b167d4 in ?? () from /home/Sasi/tor-browser_en-US/Browser/libxul.so legacy/trac#4 (closed) 0x00007f05b0b16bb8 in ?? () from /home/Sasi/tor-browser_en-US/Browser/libxul.so legacy/trac#5 (closed) 0x00007f05b0ae4e95 in ?? () from /home/Sasi/tor-browser_en-US/Browser/libxul.so legacy/trac#6 (closed) 0x00007f05b0aa12f2 in ?? () from /home/Sasi/tor-browser_en-US/Browser/libxul.so legacy/trac#7 (closed) 0x00007f05b0c5de74 in ?? () from /home/Sasi/tor-browser_en-US/Browser/libxul.so legacy/trac#8 (closed) 0x00007f05b0c442eb in ?? () from /home/Sasi/tor-browser_en-US/Browser/libxul.so legacy/trac#9 (closed) 0x00007f05b0ae57e1 in ?? () from /home/Sasi/tor-browser_en-US/Browser/libxul.so legacy/trac#10 (closed) 0x00007f05b56aeff8 in ?? () from /home/Sasi/tor-browser_en-US/Browser/libnspr4.so legacy/trac#11 (closed) 0x00007f05b53c6ee5 in start_thread (arg=0x7f05997ff700) at pthread_create.c:309 legacy/trac#12 (closed) 0x00007f05b44bab8d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111 [Sasi@NoNameForHost ~]# pstack 19469 Thread 1 (process 19469): #0 0x00007f05b44b071d in poll () at ../sysdeps/unix/syscall-template.S:81 #1 0x00007f05b56ace60 in ?? () from /home/Sasi/tor-browser_en-US/Browser/libnspr4.so legacy/trac#2 (closed) 0x00007f05b0b16346 in ?? () from /home/Sasi/tor-browser_en-US/Browser/libxul.so legacy/trac#3 (closed) 0x00007f05b0b167d4 in ?? () from /home/Sasi/tor-browser_en-US/Browser/libxul.so legacy/trac#4 (closed) 0x00007f05b0b16bb8 in ?? () from /home/Sasi/tor-browser_en-US/Browser/libxul.so legacy/trac#5 (closed) 0x00007f05b0ae4e95 in ?? () from /home/Sasi/tor-browser_en-US/Browser/libxul.so legacy/trac#6 (closed) 0x00007f05b0aa12f2 in ?? () from /home/Sasi/tor-browser_en-US/Browser/libxul.so legacy/trac#7 (closed) 0x00007f05b0c5de74 in ?? () from /home/Sasi/tor-browser_en-US/Browser/libxul.so legacy/trac#8 (closed) 0x00007f05b0c442eb in ?? () from /home/Sasi/tor-browser_en-US/Browser/libxul.so legacy/trac#9 (closed) 0x00007f05b0ae57e1 in ?? () from /home/Sasi/tor-browser_en-US/Browser/libxul.so legacy/trac#10 (closed) 0x00007f05b56aeff8 in ?? () from /home/Sasi/tor-browser_en-US/Browser/libnspr4.so legacy/trac#11 (closed) 0x00007f05b53c6ee5 in start_thread (arg=0x7f05997ff700) at pthread_create.c:309 legacy/trac#12 (closed) 0x00007f05b44bab8d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111 [Sasi@NoNameForHost ~]# pstack 19469 Thread 1 (process 19469): #0 0x00007f05b53cdb8b in __libc_recv (fd=71, buf=0x7f057a040f20, n=5, flags=-1) at ../sysdeps/unix/sysv/linux/x86_64/recv.c:33 #1 0x00007f05b56abf36 in ?? () from /home/Sasi/tor-browser_en-US/Browser/libnspr4.so legacy/trac#2 (closed) 0x00007f05b0b5cb61 in ?? () from /home/Sasi/tor-browser_en-US/Browser/libxul.so legacy/trac#3 (closed) 0x00007f05b0b5ccec in ?? () from /home/Sasi/tor-browser_en-US/Browser/libxul.so legacy/trac#4 (closed) 0x00007f05b0b5cd47 in ?? () from /home/Sasi/tor-browser_en-US/Browser/libxul.so legacy/trac#5 (closed) 0x00007f05b0b14426 in ?? () from /home/Sasi/tor-browser_en-US/Browser/libxul.so legacy/trac#6 (closed) 0x00007f05b0b16899 in ?? () from /home/Sasi/tor-browser_en-US/Browser/libxul.so legacy/trac#7 (closed) 0x00007f05b0b16bb8 in ?? () from /home/Sasi/tor-browser_en-US/Browser/libxul.so legacy/trac#8 (closed) 0x00007f05b0ae4e95 in ?? () from /home/Sasi/tor-browser_en-US/Browser/libxul.so legacy/trac#9 (closed) 0x00007f05b0aa12f2 in ?? () from /home/Sasi/tor-browser_en-US/Browser/libxul.so legacy/trac#10 (closed) 0x00007f05b0c5de74 in ?? () from /home/Sasi/tor-browser_en-US/Browser/libxul.so legacy/trac#11 (closed) 0x00007f05b0c442eb in ?? () from /home/Sasi/tor-browser_en-US/Browser/libxul.so legacy/trac#12 (closed) 0x00007f05b0ae57e1 in ?? () from /home/Sasi/tor-browser_en-US/Browser/libxul.so legacy/trac#13 (closed) 0x00007f05b56aeff8 in ?? () from /home/Sasi/tor-browser_en-US/Browser/libnspr4.so legacy/trac#14 (closed) 0x00007f05b53c6ee5 in start_thread (arg=0x7f05997ff700) at pthread_create.c:309 legacy/trac#15 (closed) 0x00007f05b44bab8d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111 [root@NoNameForHost Downloads]# pstack 19469 Thread 1 (process 19469): #0 0x00007f05b44b071d in poll () at ../sysdeps/unix/syscall-template.S:81 #1 0x00007f05b56ace60 in ?? () from /home/Sasi/tor-browser_en-US/Browser/libnspr4.so legacy/trac#2 (closed) 0x00007f05b0b16346 in ?? () from /home/Sasi/tor-browser_en-US/Browser/libxul.so legacy/trac#3 (closed) 0x00007f05b0b167d4 in ?? () from /home/Sasi/tor-browser_en-US/Browser/libxul.so legacy/trac#4 (closed) 0x00007f05b0b16bb8 in ?? () from /home/Sasi/tor-browser_en-US/Browser/libxul.so legacy/trac#5 (closed) 0x00007f05b0ae4e95 in ?? () from /home/Sasi/tor-browser_en-US/Browser/libxul.so legacy/trac#6 (closed) 0x00007f05b0aa12f2 in ?? () from /home/Sasi/tor-browser_en-US/Browser/libxul.so legacy/trac#7 (closed) 0x00007f05b0c5de74 in ?? () from /home/Sasi/tor-browser_en-US/Browser/libxul.so legacy/trac#8 (closed) 0x00007f05b0c442eb in ?? () from /home/Sasi/tor-browser_en-US/Browser/libxul.so legacy/trac#9 (closed) 0x00007f05b0ae57e1 in ?? () from /home/Sasi/tor-browser_en-US/Browser/libxul.so legacy/trac#10 (closed) 0x00007f05b56aeff8 in ?? () from /home/Sasi/tor-browser_en-US/Browser/libnspr4.so legacy/trac#11 (closed) 0x00007f05b53c6ee5 in start_thread (arg=0x7f05997ff700) at pthread_create.c:309 legacy/trac#12 (closed) 0x00007f05b44bab8d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111
Trac:
Username: Sasi