Re: [REGRESSION] Warning in tcp_fastretrans_alert() of net/ipv4/tcp_input.c

Uhh, sorry, just found the original submission [1]. [1] https://marc.info/?l=linux-netdev=151009763926816=2 10.11.2017 14:15, Oleksandr Natalenko wrote: Hi. I'm running the machine with this patch applied for 7 hours now, and the warning hasn't appeared yet. Typically, it should be there

Re: [REGRESSION] Warning in tcp_fastretrans_alert() of net/ipv4/tcp_input.c

Hi. I'm running the machine with this patch applied for 7 hours now, and the warning hasn't appeared yet. Typically, it should be there within the first hour. I'll keep an eye on it for a longer time, but as of now it looks good. Some explanation on this please? Thanks! 06.11.2017 23:27,

Re: [REGRESSION] Warning in tcp_fastretrans_alert() of net/ipv4/tcp_input.c

On Fri, Oct 27, 2017 at 1:38 PM, Eric Dumazet wrote: > > On Wed, Oct 25, 2017 at 10:37 PM, Yuchung Cheng wrote: > > On Wed, Oct 25, 2017 at 7:07 PM, Alexei Starovoitov > > wrote: > >> > >> On Thu, Sep 28, 2017 at 04:36:58PM

Re: [REGRESSION] Warning in tcp_fastretrans_alert() of net/ipv4/tcp_input.c

On Wed, Oct 25, 2017 at 10:37 PM, Yuchung Cheng wrote: > On Wed, Oct 25, 2017 at 7:07 PM, Alexei Starovoitov > wrote: >> >> On Thu, Sep 28, 2017 at 04:36:58PM -0700, Yuchung Cheng wrote: >> > On Thu, Sep 28, 2017 at 1:14 AM, Oleksandr Natalenko >>

Re: [REGRESSION] Warning in tcp_fastretrans_alert() of net/ipv4/tcp_input.c

On Wed, Oct 25, 2017 at 7:07 PM, Alexei Starovoitov wrote: > > On Thu, Sep 28, 2017 at 04:36:58PM -0700, Yuchung Cheng wrote: > > On Thu, Sep 28, 2017 at 1:14 AM, Oleksandr Natalenko > > wrote: > > > Hi. > > > > > > Won't tell about panic

Re: [REGRESSION] Warning in tcp_fastretrans_alert() of net/ipv4/tcp_input.c

On Thu, Sep 28, 2017 at 04:36:58PM -0700, Yuchung Cheng wrote: > On Thu, Sep 28, 2017 at 1:14 AM, Oleksandr Natalenko > wrote: > > Hi. > > > > Won't tell about panic in tcp_sacktag_walk() since I cannot trigger it > > intentionally, but setting

Re: [REGRESSION] Warning in tcp_fastretrans_alert() of net/ipv4/tcp_input.c

On Thu, Sep 28, 2017 at 1:14 AM, Oleksandr Natalenko wrote: > Hi. > > Won't tell about panic in tcp_sacktag_walk() since I cannot trigger it > intentionally, but setting net.ipv4.tcp_retrans_collapse to 0 *does not* fix > warning in tcp_fastretrans_alert() for me. Hi

Re: [REGRESSION] Warning in tcp_fastretrans_alert() of net/ipv4/tcp_input.c

Hi. Won't tell about panic in tcp_sacktag_walk() since I cannot trigger it intentionally, but setting net.ipv4.tcp_retrans_collapse to 0 *does not* fix warning in tcp_fastretrans_alert() for me. On středa 27. září 2017 2:18:32 CEST Yuchung Cheng wrote: > On Tue, Sep 26, 2017 at 5:12 PM,

Re: [REGRESSION] Warning in tcp_fastretrans_alert() of net/ipv4/tcp_input.c

On Tue, Sep 26, 2017 at 5:12 PM, Yuchung Cheng wrote: > On Tue, Sep 26, 2017 at 6:10 AM, Roman Gushchin wrote: >>> On Wed, Sep 20, 2017 at 6:46 PM, Roman Gushchin wrote: >>> > >>> > > Hello. >>> > > >>> > > Since, IIRC, v4.11, there is some

Re: [REGRESSION] Warning in tcp_fastretrans_alert() of net/ipv4/tcp_input.c

On Tue, Sep 26, 2017 at 6:10 AM, Roman Gushchin wrote: >> On Wed, Sep 20, 2017 at 6:46 PM, Roman Gushchin wrote: >> > >> > > Hello. >> > > >> > > Since, IIRC, v4.11, there is some regression in TCP stack resulting in >> > > the >> > > warning shown below. Most of the

Re: [REGRESSION] Warning in tcp_fastretrans_alert() of net/ipv4/tcp_input.c

> On Wed, Sep 20, 2017 at 6:46 PM, Roman Gushchin wrote: > > > > > Hello. > > > > > > Since, IIRC, v4.11, there is some regression in TCP stack resulting in the > > > warning shown below. Most of the time it is harmless, but rarely it just > > > causes either freeze or (I believe,

Re: [REGRESSION] Warning in tcp_fastretrans_alert() of net/ipv4/tcp_input.c

On Wed, Sep 20, 2017 at 6:46 PM, Roman Gushchin wrote: > > > Hello. > > > > Since, IIRC, v4.11, there is some regression in TCP stack resulting in the > > warning shown below. Most of the time it is harmless, but rarely it just > > causes either freeze or (I believe, this is related

Re: [REGRESSION] Warning in tcp_fastretrans_alert() of net/ipv4/tcp_input.c

> Hello. > > Since, IIRC, v4.11, there is some regression in TCP stack resulting in the > warning shown below. Most of the time it is harmless, but rarely it just > causes either freeze or (I believe, this is related too) panic in > tcp_sacktag_walk() (because sk_buff passed to this function is

Re: [REGRESSION] Warning in tcp_fastretrans_alert() of net/ipv4/tcp_input.c

On Tue, Sep 19, 2017 at 4:04 AM, Oleksandr Natalenko wrote: > Hi. > > 18.09.2017 23:40, Yuchung Cheng wrote: >> >> I assume this kernel does not have the patch that Neal proposed in his >> first reply? > > > Correct. > >> The main warning needs to be triggered by another

Re: [REGRESSION] Warning in tcp_fastretrans_alert() of net/ipv4/tcp_input.c

And 2 more events: === $ dmesg --time-format iso | grep RIP … 2017-09-19T16:52:21,623328+0200 RIP: 0010:tcp_undo_cwnd_reduction+0xbd/0xd0 2017-09-19T16:52:40,455296+0200 RIP: 0010:tcp_fastretrans_alert+0x7c8/0x990 2017-09-19T16:52:41,047378+0200 RIP: 0010:tcp_undo_cwnd_reduction+0xbd/0xd0 …

Re: [REGRESSION] Warning in tcp_fastretrans_alert() of net/ipv4/tcp_input.c

Hi. 18.09.2017 23:40, Yuchung Cheng wrote: I assume this kernel does not have the patch that Neal proposed in his first reply? Correct. The main warning needs to be triggered by another peculiar SACK that kicks the sender into recovery again (after undo). Please let it run longer if

Re: [REGRESSION] Warning in tcp_fastretrans_alert() of net/ipv4/tcp_input.c

On Mon, Sep 18, 2017 at 1:46 PM, Oleksandr Natalenko wrote: > Actually, same warning was just triggered with RACK enabled. But main warning > was not triggered in this case. Thanks. I assume this kernel does not have the patch that Neal proposed in his first reply? The

Re: [REGRESSION] Warning in tcp_fastretrans_alert() of net/ipv4/tcp_input.c

Actually, same warning was just triggered with RACK enabled. But main warning was not triggered in this case. === Sep 18 22:44:32 defiant kernel: [ cut here ] Sep 18 22:44:32 defiant kernel: WARNING: CPU: 1 PID: 702 at net/ipv4/ tcp_input.c:2392

Re: [REGRESSION] Warning in tcp_fastretrans_alert() of net/ipv4/tcp_input.c

OK, with: net.ipv4.tcp_recovery = 0 net.ipv4.tcp_fack = 0 and your patch I got the following warning within 10 min uptime: === Sep 18 22:18:34 defiant kernel: [ cut here ] Sep 18 22:18:34 defiant kernel: WARNING: CPU: 0 PID: 702 at net/ipv4/ tcp_input.c:2392

Re: [REGRESSION] Warning in tcp_fastretrans_alert() of net/ipv4/tcp_input.c

On pondělí 18. září 2017 20:01:42 CEST Yuchung Cheng wrote: > Yes since it is disabled in the upstream by default. Although you can > experiment FACK enabled additionally. OK. > Do we know the crash you first experienced is tied to this issue? No, unfortunately. I wasn't able to re-create it

Re: [REGRESSION] Warning in tcp_fastretrans_alert() of net/ipv4/tcp_input.c

On Mon, Sep 18, 2017 at 10:59 AM, Oleksandr Natalenko wrote: > OK. Should I keep FACK disabled? Yes since it is disabled in the upstream by default. Although you can experiment FACK enabled additionally. Do we know the crash you first experienced is tied to this issue?

Re: [REGRESSION] Warning in tcp_fastretrans_alert() of net/ipv4/tcp_input.c

OK. Should I keep FACK disabled? On pondělí 18. září 2017 19:51:21 CEST Yuchung Cheng wrote: > Can you try this patch to verify my theory with tcp_recovery=0 and 1? thanks > > diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c > index 5af2f04f8859..9253d9ee7d0e 100644 > ---

Re: [REGRESSION] Warning in tcp_fastretrans_alert() of net/ipv4/tcp_input.c

On Mon, Sep 18, 2017 at 10:18 AM, Yuchung Cheng wrote: > On Sun, Sep 17, 2017 at 11:43 AM, Oleksandr Natalenko > wrote: >> Hi. >> >> Just to note that it looks like disabling RACK and re-enabling FACK prevents >> warning from happening: >> >>

Re: [REGRESSION] Warning in tcp_fastretrans_alert() of net/ipv4/tcp_input.c

On Sun, Sep 17, 2017 at 11:43 AM, Oleksandr Natalenko wrote: > Hi. > > Just to note that it looks like disabling RACK and re-enabling FACK prevents > warning from happening: > > net.ipv4.tcp_fack = 1 > net.ipv4.tcp_recovery = 0 > > Hope I get semantics of these tunables

Re: [REGRESSION] Warning in tcp_fastretrans_alert() of net/ipv4/tcp_input.c

Hi. Just to note that it looks like disabling RACK and re-enabling FACK prevents warning from happening: net.ipv4.tcp_fack = 1 net.ipv4.tcp_recovery = 0 Hope I get semantics of these tunables right. On pátek 15. září 2017 21:04:36 CEST Oleksandr Natalenko wrote: > Hello. > > With

Re: [REGRESSION] Warning in tcp_fastretrans_alert() of net/ipv4/tcp_input.c

Hello. With net.ipv4.tcp_fack set to 0 the warning still appears: === » sysctl net.ipv4.tcp_fack net.ipv4.tcp_fack = 0 » LC_TIME=C dmesg -T | grep WARNING [Fri Sep 15 20:40:30 2017] WARNING: CPU: 1 PID: 711 at net/ipv4/tcp_input.c: 2826 tcp_fastretrans_alert+0x7c8/0x990 [Fri Sep 15

Re: [REGRESSION] Warning in tcp_fastretrans_alert() of net/ipv4/tcp_input.c

On Fri, Sep 15, 2017 at 1:03 AM, Oleksandr Natalenko wrote: > Hi. > > I've applied your test patch but it doesn't fix the issue for me since the > warning is still there. > > Were you able to reproduce it? Hi, Thanks for testing that. That is a very useful data point.

Re: [REGRESSION] Warning in tcp_fastretrans_alert() of net/ipv4/tcp_input.c

Hi. I've applied your test patch but it doesn't fix the issue for me since the warning is still there. Were you able to reproduce it? On pondělí 11. září 2017 1:59:02 CEST Neal Cardwell wrote: > Thanks for the detailed report! > > I suspect this is due to the following commit, which happened

Re: [REGRESSION] Warning in tcp_fastretrans_alert() of net/ipv4/tcp_input.c

On Sun, Sep 10, 2017 at 4:53 PM, Oleksandr Natalenko wrote: > Hello. > > Since, IIRC, v4.11, there is some regression in TCP stack resulting in the > warning shown below. Most of the time it is harmless, but rarely it just > causes either freeze or (I believe, this is

[REGRESSION] Warning in tcp_fastretrans_alert() of net/ipv4/tcp_input.c

Hello. Since, IIRC, v4.11, there is some regression in TCP stack resulting in the warning shown below. Most of the time it is harmless, but rarely it just causes either freeze or (I believe, this is related too) panic in tcp_sacktag_walk() (because sk_buff passed to this function is NULL).