1749924 - Mozilla Firefox hangs (100% CPU usage on one single core)

Status: VERIFIED DUPLICATE of bug 1749910

(Core :: Networking, defect)

Description

[daniel]

User Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/92.0.4515.107 Safari/537.36

Steps to reproduce:

start firefox

Actual results:

no website loads at all, Firefox seems to hang, 100% CPU usage on one single core

Expected results:

Firefox should work

Comment 1

[daniel]

Me (Ubuntu) and another user (Mac OS) observe the same problem (see the screenshot).
It happenes since today. Yesterday everything worked as normal.

The process which consumes 100% of one core is the "new-window" process.

A lsof -p <pid> prints some information.
And there I see some Amazon EC2 URL (not sure if this is relevant):

GeckoMain 22281 druf  110rw     REG              253,2  26214400 14680218 /home/druf/.mozilla/firefox/323esygk.default-release/places.sqlite
GeckoMain 22281 druf  111u     unix 0x0000000000000000       0t0   135495 type=STREAM
GeckoMain 22281 druf  112r     FIFO               0,12       0t0   141639 pipe
GeckoMain 22281 druf  113r     FIFO               0,12       0t0   144793 pipe
GeckoMain 22281 druf  115r      REG              253,2    318436  6701202 /usr/lib/firefox/browser/features/[e-mail]
GeckoMain 22281 druf  116u      REG              253,2     46950 14680308 /home/druf/.cache/mozilla/firefox/323esygk.default-release/cache2/entries/9950EA48FDC3A285DDC53B211DEFE42634E26830
GeckoMain 22281 druf  117u     sock                0,9       0t0   142557 protocol: TCP
GeckoMain 22281 druf  118r      REG              253,2     16544  6701138 /usr/lib/firefox/browser/features/[e-mail]
GeckoMain 22281 druf  119u     IPv4             142560       0t0      TCP druf01:60930->ec2-44-233-180-72.us-west-2.compute.amazonaws.com:https (ESTABLISHED)
GeckoMain 22281 druf  120u     sock                0,9       0t0   142558 protocol: TCP
GeckoMain 22281 druf  121u     sock                0,9       0t0   142559 protocol: TCP
GeckoMain 22281 druf  124u     unix 0x0000000000000000       0t0   143431 type=STREAM
GeckoMain 22281 druf  127u     unix 0x0000000000000000       0t0   141252 type=STREAM
GeckoMain 22281 druf  130u      REG              253,2   4096000 14681621 /home/druf/.mozilla/firefox/323esygk.default-release/places.sqlite-wal
GeckoMain 22281 druf  131rw     REG              253,2  26476544 14680221 /home/druf/.mozilla/firefox/323esygk.default-release/favicons.sqlite
GeckoMain 22281 druf  132u      REG              253,2   2197096 14699901 /home/druf/.mozilla/firefox/323esygk.default-release/favicons.sqlite-wal
GeckoMain 22281 druf  133uw     REG              253,2    917504 14680580 /home/druf/.mozilla/firefox/323esygk.default-release/formhistory.sqlite
GeckoMain 22281 druf  134u     unix 0x0000000000000000       0t0   140175 type=SEQPACKET
GeckoMain 22281 druf  136u     unix 0x0000000000000000       0t0   138594 type=STREAM
GeckoMain 22281 druf  137r     FIFO               0,12       0t0   136910 pipe
GeckoMain 22281 druf  155u     unix 0x0000000000000000       0t0   141247 type=SEQPACKET
GeckoMain 22281 druf  157u     unix 0x0000000000000000       0t0   135540 type=STREAM
GeckoMain 22281 druf  158r     FIFO               0,12       0t0   135542 pipe

When you try to open ec2-44-233-180-72.us-west-2.compute.amazonaws.com in a browser or call it with curl or ping, it will never close the connection or send data.

Why is there some EC2 URL and is this relevant?

⋊> /p/22281 curl ec2-44-233-180-72.us-west-2.compute.amazonaws.com                                                                                                                                  09:52:27
^C⏎                                                                                                                                                                                                         ⋊> /p/22281 time curl ec2-44-233-180-72.us-west-2.compute.amazonaws.com                                                                                                                             10:00:42
^C
________________________________________________________
Executed in    2,69 secs      fish           external
   usr time    3,72 millis  267,00 micros    3,46 millis
   sys time    3,50 millis   46,00 micros    3,46 millis

⋊> /p/22281 curl --verbose ec2-44-233-180-72.us-west-2.compute.amazonaws.com                                                                                                                        10:00:48
* Rebuilt URL to: ec2-44-233-180-72.us-west-2.compute.amazonaws.com/
*   Trying 44.233.180.72...
* TCP_NODELAY set
^C⏎                                                                                                                                                                                                         ⋊> /p/22281 curl 44.233.180.72                                                                                                                                                                      10:01:09
^C⏎                                                                                                                                                                                                         ⋊> /p/22281 ping 44.233.180.72                                                                                                                                                                      10:01:17
PING 44.233.180.72 (44.233.180.72) 56(84) bytes of data.
^[[A^C
--- 44.233.180.72 ping statistics ---
519 packets transmitted, 0 received, 100% packet loss, time 530419ms

Comment 2

[daniel]

Attachment: htop-cpu-usage.png

CPU usage directly after start of Firefox 95

Comment 3

[BugBot [:suhaib / :marco/ :calixte]]

The Bugbug bot thinks this bug should belong to the 'Core::Performance' component, and is moving the bug to that component. Please revert this change in case you think the bot is wrong.