What is the “canary thread†and why is it starving?
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The following occasionally appears in /var/log/syslog:
rtkit-daemon[1145]: The canary thread is apparently starving. Taking action.
rtkit-daemon[1145]: Demoting known real-time threads.
rtkit-daemon[1145]: Successfully demoted thread 1431 of process 1368 (n/a).
rtkit-daemon[1145]: Successfully demoted thread 1430 of process 1368 (n/a).
rtkit-daemon[1145]: Successfully demoted thread 1368 of process 1368 (n/a).
rtkit-daemon[1145]: Demoted 3 threads.
What's going on here?
11.04 log
asked Dec 11 '11 at 19:43
ændrük
40.5k59188336
add a comment |Â
up vote
11
down vote
favorite
The following occasionally appears in /var/log/syslog:
rtkit-daemon[1145]: The canary thread is apparently starving. Taking action.
rtkit-daemon[1145]: Demoting known real-time threads.
rtkit-daemon[1145]: Successfully demoted thread 1431 of process 1368 (n/a).
rtkit-daemon[1145]: Successfully demoted thread 1430 of process 1368 (n/a).
rtkit-daemon[1145]: Successfully demoted thread 1368 of process 1368 (n/a).
rtkit-daemon[1145]: Demoted 3 threads.
What's going on here?
11.04 log
asked Dec 11 '11 at 19:43
ændrük
40.5k59188336
Any errors in kern.log concerning ACPI? If so: enter BIOS and check ifACPI power save optionsis set toExtended. Change it toNormal.
– Rinzwind
Dec 11 '11 at 19:59
add a comment |Â
up vote
11
down vote
favorite
up vote
11
down vote
favorite
The following occasionally appears in /var/log/syslog:
rtkit-daemon[1145]: The canary thread is apparently starving. Taking action.
rtkit-daemon[1145]: Demoting known real-time threads.
rtkit-daemon[1145]: Successfully demoted thread 1431 of process 1368 (n/a).
rtkit-daemon[1145]: Successfully demoted thread 1430 of process 1368 (n/a).
rtkit-daemon[1145]: Successfully demoted thread 1368 of process 1368 (n/a).
rtkit-daemon[1145]: Demoted 3 threads.
What's going on here?
11.04 log
asked Dec 11 '11 at 19:43
ændrük
40.5k59188336
The following occasionally appears in /var/log/syslog:
rtkit-daemon[1145]: The canary thread is apparently starving. Taking action.
rtkit-daemon[1145]: Demoting known real-time threads.
rtkit-daemon[1145]: Successfully demoted thread 1431 of process 1368 (n/a).
rtkit-daemon[1145]: Successfully demoted thread 1430 of process 1368 (n/a).
rtkit-daemon[1145]: Successfully demoted thread 1368 of process 1368 (n/a).
rtkit-daemon[1145]: Demoted 3 threads.
What's going on here?
11.04 log
asked Dec 11 '11 at 19:43
ændrük
40.5k59188336
edited Dec 11 '11 at 22:34
asked Dec 11 '11 at 19:43
ændrük
40.5k59188336
asked Dec 11 '11 at 19:43
ændrük
40.5k59188336
asked Dec 11 '11 at 19:43
ændrük
40.5k59188336
40.5k59188336
Any errors in kern.log concerning ACPI? If so: enter BIOS and check ifACPI power save optionsis set toExtended. Change it toNormal.
– Rinzwind
Dec 11 '11 at 19:59
add a comment |Â
Any errors in kern.log concerning ACPI? If so: enter BIOS and check ifACPI power save optionsis set toExtended. Change it toNormal.
– Rinzwind
Dec 11 '11 at 19:59
Any errors in kern.log concerning ACPI? If so: enter BIOS and check if
ACPI power save options is set to Extended. Change it to Normal.– Rinzwind
Dec 11 '11 at 19:59
Any errors in kern.log concerning ACPI? If so: enter BIOS and check if
ACPI power save options is set to Extended. Change it to Normal.– Rinzwind
Dec 11 '11 at 19:59
add a comment |Â
2 Answers
2
active
oldest
votes
up vote
21
down vote
accepted
The term "canary" as used here comes from coal mining originally. Coal miners used canaries to detect dangerous gases (if the canary they carried with them died, they knew they had to get out of the shaft/mine ASAP). As a result the term "canary" is now often used for anything that you use to get an (early) warning about a dangerous situation.
In this case it seems like 'rtkit' starts a "normal" thread to test if the threads that get "real time" priorities are "starving" other threads (& processes), where "starving" means that they get too little processor time. This is a safety measure to make sure that processes/threads that have access to real time priorities don't use up so much CPU time that other tasks get none anymore.
So apparently some thread(s) that got real-time priorities from rtkit is/are misbehaving, and trying to monopolize the CPU, rtkit detects this with its "canary thread", and thus rtkit takes away the real-time priorities.
answered Dec 11 '11 at 20:06
JanC
16.3k13446
add a comment |Â
up vote
-3
down vote
It is a buffer overflow
Wikipedia buffer overflow canaries
I can not tell from the logs you posted where the problem is, can you check or pastebin log entries above an below those messages ? What is process 1368 ?
sudo ps -p 1368
answered Dec 11 '11 at 20:00
Panther
74.8k10149256
2
This is not about buffer overflows, but the use of the word "canary" there is also derived from the use of coal miner's canaries.
– JanC
Dec 11 '11 at 20:08
add a comment |Â
2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
21
down vote
accepted
The term "canary" as used here comes from coal mining originally. Coal miners used canaries to detect dangerous gases (if the canary they carried with them died, they knew they had to get out of the shaft/mine ASAP). As a result the term "canary" is now often used for anything that you use to get an (early) warning about a dangerous situation.
In this case it seems like 'rtkit' starts a "normal" thread to test if the threads that get "real time" priorities are "starving" other threads (& processes), where "starving" means that they get too little processor time. This is a safety measure to make sure that processes/threads that have access to real time priorities don't use up so much CPU time that other tasks get none anymore.
So apparently some thread(s) that got real-time priorities from rtkit is/are misbehaving, and trying to monopolize the CPU, rtkit detects this with its "canary thread", and thus rtkit takes away the real-time priorities.
answered Dec 11 '11 at 20:06
JanC
16.3k13446
add a comment |Â
up vote
21
down vote
accepted
The term "canary" as used here comes from coal mining originally. Coal miners used canaries to detect dangerous gases (if the canary they carried with them died, they knew they had to get out of the shaft/mine ASAP). As a result the term "canary" is now often used for anything that you use to get an (early) warning about a dangerous situation.
In this case it seems like 'rtkit' starts a "normal" thread to test if the threads that get "real time" priorities are "starving" other threads (& processes), where "starving" means that they get too little processor time. This is a safety measure to make sure that processes/threads that have access to real time priorities don't use up so much CPU time that other tasks get none anymore.
So apparently some thread(s) that got real-time priorities from rtkit is/are misbehaving, and trying to monopolize the CPU, rtkit detects this with its "canary thread", and thus rtkit takes away the real-time priorities.
answered Dec 11 '11 at 20:06
JanC
16.3k13446
add a comment |Â
up vote
21
down vote
accepted
up vote
21
down vote
accepted
The term "canary" as used here comes from coal mining originally. Coal miners used canaries to detect dangerous gases (if the canary they carried with them died, they knew they had to get out of the shaft/mine ASAP). As a result the term "canary" is now often used for anything that you use to get an (early) warning about a dangerous situation.
In this case it seems like 'rtkit' starts a "normal" thread to test if the threads that get "real time" priorities are "starving" other threads (& processes), where "starving" means that they get too little processor time. This is a safety measure to make sure that processes/threads that have access to real time priorities don't use up so much CPU time that other tasks get none anymore.
So apparently some thread(s) that got real-time priorities from rtkit is/are misbehaving, and trying to monopolize the CPU, rtkit detects this with its "canary thread", and thus rtkit takes away the real-time priorities.
answered Dec 11 '11 at 20:06
JanC
16.3k13446
The term "canary" as used here comes from coal mining originally. Coal miners used canaries to detect dangerous gases (if the canary they carried with them died, they knew they had to get out of the shaft/mine ASAP). As a result the term "canary" is now often used for anything that you use to get an (early) warning about a dangerous situation.
In this case it seems like 'rtkit' starts a "normal" thread to test if the threads that get "real time" priorities are "starving" other threads (& processes), where "starving" means that they get too little processor time. This is a safety measure to make sure that processes/threads that have access to real time priorities don't use up so much CPU time that other tasks get none anymore.
So apparently some thread(s) that got real-time priorities from rtkit is/are misbehaving, and trying to monopolize the CPU, rtkit detects this with its "canary thread", and thus rtkit takes away the real-time priorities.
answered Dec 11 '11 at 20:06
JanC
16.3k13446
edited Dec 11 '11 at 20:15
answered Dec 11 '11 at 20:06
JanC
16.3k13446
answered Dec 11 '11 at 20:06
JanC
16.3k13446
answered Dec 11 '11 at 20:06
JanC
16.3k13446
16.3k13446
add a comment |Â
add a comment |Â
up vote
-3
down vote
It is a buffer overflow
Wikipedia buffer overflow canaries
I can not tell from the logs you posted where the problem is, can you check or pastebin log entries above an below those messages ? What is process 1368 ?
sudo ps -p 1368
answered Dec 11 '11 at 20:00
Panther
74.8k10149256
2
This is not about buffer overflows, but the use of the word "canary" there is also derived from the use of coal miner's canaries.
– JanC
Dec 11 '11 at 20:08
add a comment |Â
up vote
-3
down vote
It is a buffer overflow
Wikipedia buffer overflow canaries
I can not tell from the logs you posted where the problem is, can you check or pastebin log entries above an below those messages ? What is process 1368 ?
sudo ps -p 1368
answered Dec 11 '11 at 20:00
Panther
74.8k10149256
2
This is not about buffer overflows, but the use of the word "canary" there is also derived from the use of coal miner's canaries.
– JanC
Dec 11 '11 at 20:08
add a comment |Â
up vote
-3
down vote
up vote
-3
down vote
It is a buffer overflow
Wikipedia buffer overflow canaries
I can not tell from the logs you posted where the problem is, can you check or pastebin log entries above an below those messages ? What is process 1368 ?
sudo ps -p 1368
answered Dec 11 '11 at 20:00
Panther
74.8k10149256
It is a buffer overflow
Wikipedia buffer overflow canaries
I can not tell from the logs you posted where the problem is, can you check or pastebin log entries above an below those messages ? What is process 1368 ?
sudo ps -p 1368
answered Dec 11 '11 at 20:00
Panther
74.8k10149256
answered Dec 11 '11 at 20:00
Panther
74.8k10149256
answered Dec 11 '11 at 20:00
Panther
74.8k10149256
answered Dec 11 '11 at 20:00
Panther
74.8k10149256
74.8k10149256
2
This is not about buffer overflows, but the use of the word "canary" there is also derived from the use of coal miner's canaries.
– JanC
Dec 11 '11 at 20:08
add a comment |Â
2
This is not about buffer overflows, but the use of the word "canary" there is also derived from the use of coal miner's canaries.
– JanC
Dec 11 '11 at 20:08
2
2
This is not about buffer overflows, but the use of the word "canary" there is also derived from the use of coal miner's canaries.
– JanC
Dec 11 '11 at 20:08
This is not about buffer overflows, but the use of the word "canary" there is also derived from the use of coal miner's canaries.
– JanC
Dec 11 '11 at 20:08
add a comment |Â
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Any errors in kern.log concerning ACPI? If so: enter BIOS and check if
ACPI power save optionsis set toExtended. Change it toNormal.– Rinzwind
Dec 11 '11 at 19:59