Re: epoll gives broken results when interrupted with a signal

[Ben Mansell]

On Wed, 29 Oct 2003, Davide Libenzi wrote:

> Can you try the patch below and show me a dmesg when this happen?

Ok, patch applied. (I changed DEBUG_EPOLL to 10 however, otherwise
nothing would be printed). Now, epoll appears to behave perfectly and I
can't re-create the problem :(
Maybe it is a race of some kind and the printks change the behaviour?
The bug still occured the first time I tried the patch with DEBUG_EPOLL
1.

> Also, it shouldn't change a whit, but are you able to try on a x86 UP?

I could set one up if needed; we have a x86 build machine running
2.6.0-test3 here which I can upgrade (epoll seems fine on that btw)

Here's the dmesg output anyway:


[0000010009d462c0] eventpoll: sys_epoll_create(10)
[0000010009d462c0] eventpoll: ep_file_init() ep=000001000475e000
[0000010009d462c0] eventpoll: sys_epoll_create(10) = 4
[0000010009d462c0] eventpoll: close() ep=000001000475e000
[0000010009d462c0] eventpoll: sys_epoll_create(256)
[0000010009d462c0] eventpoll: ep_file_init() ep=000001000475e000
[0000010009d462c0] eventpoll: sys_epoll_create(256) = 4
[0000010009d462c0] eventpoll: sys_epoll_ctl(4, 1, 5, 0000007fbffff070)
[0000010009d462c0] eventpoll: ep_find(00000100059c9580) -> 0000000000000000
[0000010009d462c0] eventpoll: ep_insert(000001000475e000, 00000100059c9580, 5)
[0000010009d462c0] eventpoll: sys_epoll_ctl(4, 1, 5, 0000007fbffff070) = 0
[0000010009d462c0] eventpoll: sys_epoll_ctl(4, 1, 6, 0000007fbffff290)
[0000010009d462c0] eventpoll: ep_find(000001000cc3a980) -> 0000000000000000
[0000010009d462c0] eventpoll: ep_insert(000001000475e000, 000001000cc3a980, 6)
[0000010009d462c0] eventpoll: sys_epoll_ctl(4, 1, 6, 0000007fbffff290) = 0
[0000010009d46b50] eventpoll: sys_epoll_create(1024)
[0000010009d46b50] eventpoll: ep_file_init() ep=000001000ccf2000
[0000010009d46b50] eventpoll: sys_epoll_create(1024) = 3
[0000010009d46b50] eventpoll: sys_epoll_ctl(3, 1, 7, 0000007fbffff1c0)
[0000010009d46b50] eventpoll: ep_find(0000010005e2c180) -> 0000000000000000
[0000010009d46b50] eventpoll: ep_insert(000001000ccf2000, 0000010005e2c180, 7)
[0000010009d46b50] eventpoll: sys_epoll_ctl(3, 1, 7, 0000007fbffff1c0) = 0
[0000010009d46b50] eventpoll: sys_epoll_ctl(3, 3, 7, 000000000070fcc0)
[0000010009d46b50] eventpoll: ep_find(0000010005e2c180) -> 00000100091cde00
[0000010009d46b50] eventpoll: sys_epoll_ctl(3, 3, 7, 000000000070fcc0) = 0
[0000010009d46b50] eventpoll: sys_epoll_wait(3, 000000000073e3b0, 32, 1000)
[0000010009d462c0] eventpoll: poll_callback(0000010005e2c180) epi=00000100091cde00 ep=000001000ccf2000
[0000010009d46b50] eventpoll: polling file=0000010005e2c180 ep=000001000ccf2000 epi=00000100091cde00
[0000010009d46b50] eventpoll: pollres file=0000010005e2c180 ep=000001000ccf2000 epi=00000100091cde00 events=1
[0000010009d46b50] eventpoll: sys_epoll_wait(3, 000000000073e3b0, 32, 1000) = 1
[0000010009d46b50] eventpoll: sys_epoll_wait(3, 000000000073e3b0, 32, 1000)
[0000010009d46b50] eventpoll: polling file=0000010005e2c180 ep=000001000ccf2000 epi=00000100091cde00
[0000010009d462c0] eventpoll: poll_callback(0000010005e2c180) epi=00000100091cde00 ep=000001000ccf2000
[0000010009d462c0] eventpoll: sys_epoll_ctl(4, 3, 6, 000000000070fcc0)
[0000010009d462c0] eventpoll: ep_find(000001000cc3a980) -> 00000100091cdec0
[0000010009d462c0] eventpoll: sys_epoll_ctl(4, 3, 6, 000000000070fcc0) = 0
[0000010009d462c0] eventpoll: sys_epoll_ctl(4, 3, 5, 000000000070fcc0)
[0000010009d462c0] eventpoll: ep_find(00000100059c9580) -> 00000100091cd980
[0000010009d462c0] eventpoll: sys_epoll_ctl(4, 3, 5, 000000000070fcc0) = 0
[0000010009d462c0] eventpoll: sys_epoll_wait(4, 0000000000734510, 32, 0)
[0000010009d462c0] eventpoll: sys_epoll_wait(4, 0000000000734510, 32, 0) = 0
[0000010009d462c0] eventpoll: poll_callback(0000010005e2c180) epi=00000100091cde00 ep=000001000ccf2000
[0000010009d46b50] eventpoll: polling file=0000010005e2c180 ep=000001000ccf2000 epi=00000100091cde00
[0000010009d46b50] eventpoll: pollres file=0000010005e2c180 ep=000001000ccf2000 epi=00000100091cde00 events=1
[0000010009d46b50] eventpoll: sys_epoll_wait(3, 000000000073e3b0, 32, 1000) = 1
[0000010009d46b50] eventpoll: sys_epoll_wait(3, 000000000073e3b0, 32, 1000)
[0000010009d46b50] eventpoll: polling file=0000010005e2c180 ep=000001000ccf2000 epi=00000100091cde00
[0000010009d462c0] eventpoll: poll_callback(0000010005e2c180) epi=00000100091cde00 ep=000001000ccf2000
[0000010009d46b50] eventpoll: polling file=0000010005e2c180 ep=000001000ccf2000 epi=00000100091cde00
[0000010009d462c0] eventpoll: poll_callback(0000010005e2c180) epi=00000100091cde00 ep=000001000ccf2000
[0000010009d46b50] eventpoll: polling file=0000010005e2c180 ep=000001000ccf2000 epi=00000100091cde00
[0000010009d46b50] eventpoll: pollres file=0000010005e2c180 ep=000001000ccf2000 epi=00000100091cde00 events=1
[0000010009d46b50] eventpoll: sys_epoll_wait(3, 000000000073e3b0, 32, 1000) = 1
[0000010009d46b50] eventpoll: sys_epoll_wait(3, 000000000073e3b0, 32, 1000)
[0000010009d46b50] eventpoll: polling file=0000010005e2c180 ep=000001000ccf2000 epi=00000100091cde00
[0000010009d462c0] eventpoll: poll_callback(0000010005e2c180) epi=00000100091cde00 ep=000001000ccf2000
[0000010009d462c0] eventpoll: poll_callback(0000010005e2c180) epi=00000100091cde00 ep=000001000ccf2000
[0000010009d462c0] eventpoll: poll_callback(0000010005e2c180) epi=00000100091cde00 ep=000001000ccf2000
[0000010009d46b50] eventpoll: polling file=0000010005e2c180 ep=000001000ccf2000 epi=00000100091cde00
[0000010009d46b50] eventpoll: pollres file=0000010005e2c180 ep=000001000ccf2000 epi=00000100091cde00 events=1
[0000010009d46b50] eventpoll: sys_epoll_wait(3, 000000000073e3b0, 32, 1000) = 1
[0000010009d46b50] eventpoll: sys_epoll_ctl(3, 1, 4, 0000007fbfffe9a0)
[0000010009d46b50] eventpoll: ep_find(000001000eb6a080) -> 0000000000000000
[0000010009d46b50] eventpoll: ep_insert(000001000ccf2000, 000001000eb6a080, 4)
[0000010009d46b50] eventpoll: sys_epoll_ctl(3, 1, 4, 0000007fbfffe9a0) = 0
[0000010009d46b50] eventpoll: sys_epoll_ctl(3, 3, 4, 000000000070fcc0)
[0000010009d46b50] eventpoll: ep_find(000001000eb6a080) -> 00000100091cdd40
[0000010009d46b50] eventpoll: sys_epoll_ctl(3, 3, 4, 000000000070fcc0) = 0
[0000010009d46b50] eventpoll: sys_epoll_wait(3, 000000000073e3b0, 32, 1000)
[0000010009d46b50] eventpoll: polling file=0000010005e2c180 ep=000001000ccf2000 epi=00000100091cde00
[0000010009d462c0] eventpoll: poll_callback(0000010005e2c180) epi=00000100091cde00 ep=000001000ccf2000
[0000010009d462c0] eventpoll: sys_epoll_wait(4, 0000000000734510, 32, 3000)
[0000010009d46b50] eventpoll: polling file=0000010005e2c180 ep=000001000ccf2000 epi=00000100091cde00
[0000010009d462c0] eventpoll: sys_epoll_wait(4, 0000000000734510, 32, 3000) = -4
[0000010009d462c0] eventpoll: sys_epoll_wait(4, 0000000000734510, 32, 2000)
[0000010009d46b50] eventpoll: sys_epoll_wait(3, 000000000073e3b0, 32, 1000) = 0
[0000010009d46b50] eventpoll: sys_epoll_wait(3, 000000000073e3b0, 32, 1000)
[0000010009d462c0] eventpoll: sys_epoll_wait(4, 0000000000734510, 32, 2000) = -4
[0000010009d462c0] eventpoll: sys_epoll_wait(4, 0000000000734510, 32, 1000)
[0000010009d46b50] eventpoll: sys_epoll_wait(3, 000000000073e3b0, 32, 1000) = 0
[0000010009d46b50] eventpoll: sys_epoll_wait(3, 000000000073e3b0, 32, 1000)
[0000010009d462c0] eventpoll: sys_epoll_wait(4, 0000000000734510, 32, 1000) = -4
[0000010009d462c0] eventpoll: poll_callback(000001000eb6a080) epi=00000100091cdd40 ep=000001000ccf2000
[0000010009d462c0] eventpoll: poll_callback(000001000eb6a080) epi=00000100091cdd40 ep=000001000ccf2000
[0000010009d462c0] eventpoll: poll_callback(00000100059c9580) epi=00000100091cd980 ep=000001000475e000
[0000010009d462c0] eventpoll: poll_callback(00000100059c9580) epi=00000100091cd980 ep=000001000475e000
[0000010009d462c0] eventpoll: eventpoll_release_file(00000100059c9580)
[0000010009d462c0] eventpoll: remove ep=000001000475e000 epi=00000100091cd980
[0000010009d462c0] eventpoll: ep_unlink(000001000475e000, 00000100059c9580) = 0
[0000010009d462c0] eventpoll: ep_remove(000001000475e000, 00000100059c9580) = 0
[0000010009d462c0] eventpoll: eventpoll_release_file(000001000cc3a980)
[0000010009d462c0] eventpoll: remove ep=000001000475e000 epi=00000100091cdec0
[0000010009d462c0] eventpoll: ep_unlink(000001000475e000, 000001000cc3a980) = 0
[0000010009d462c0] eventpoll: ep_remove(000001000475e000, 000001000cc3a980) = 0
[0000010009d462c0] eventpoll: close() ep=000001000475e000
[0000010009d462c0] eventpoll: poll_callback(0000010005e2c180) epi=00000100091cde00 ep=000001000ccf2000
[0000010009d46b50] eventpoll: polling file=0000010005e2c180 ep=000001000ccf2000 epi=00000100091cde00
[0000010009d46b50] eventpoll: pollres file=0000010005e2c180 ep=000001000ccf2000 epi=00000100091cde00 events=17
[0000010009d46b50] eventpoll: polling file=000001000eb6a080 ep=000001000ccf2000 epi=00000100091cdd40
[0000010009d46b50] eventpoll: pollres file=000001000eb6a080 ep=000001000ccf2000 epi=00000100091cdd40 events=16
[0000010009d46b50] eventpoll: sys_epoll_wait(3, 000000000073e3b0, 32, 1000) = 2
[0000010009d46b50] eventpoll: eventpoll_release_file(0000010005e2c180)
[0000010009d46b50] eventpoll: remove ep=000001000ccf2000 epi=00000100091cde00
[0000010009d46b50] eventpoll: ep_unlink(000001000ccf2000, 0000010005e2c180) = 0
[0000010009d46b50] eventpoll: ep_remove(000001000ccf2000, 0000010005e2c180) = 0
[0000010009d46b50] eventpoll: eventpoll_release_file(000001000eb6a080)
[0000010009d46b50] eventpoll: remove ep=000001000ccf2000 epi=00000100091cdd40
[0000010009d46b50] eventpoll: ep_unlink(000001000ccf2000, 000001000eb6a080) = 0
[0000010009d46b50] eventpoll: ep_remove(000001000ccf2000, 000001000eb6a080) = 0
[0000010009d46b50] eventpoll: close() ep=000001000ccf2000



-- 
Ben Mansell, <ben@xxxxxxxx>                       Zeus Technology Ltd
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