Re: git: 62d47d73b7eb - main - tcp: stop timers and clean scoreboard in tcp_close()

In message <202402100934.41A9Y11l044213@gitrepo.freebsd.org>, Richard 
Scheffene
gger writes:
> The branch main has been updated by rscheff:
>
> URL: https://cgit.FreeBSD.org/src/commit/?id=62d47d73b7eb01f3b0a37541df5e7aaa
> 36f54335
>
> commit 62d47d73b7eb01f3b0a37541df5e7aaa36f54335
> Author:     Richard Scheffenegger <rscheff@FreeBSD.org>
> AuthorDate: 2024-02-10 09:28:42 +0000
> Commit:     Richard Scheffenegger <rscheff@FreeBSD.org>
> CommitDate: 2024-02-10 09:30:00 +0000
>
>     tcp: stop timers and clean scoreboard in tcp_close()
>     
>     Stop timers when in tcp_close() instead of doing that in tcp_discardcb().
>     A connection in CLOSED state shall not need any timers. Assert that no
>     timer is rescheduled after that in tcp_timer_activate() and verfiy that
>     this is also the expected state in tcp_discardcb().
>     
>     PR:                     276761
>     Reviewed By:            glebius, tuexen, #transport
>     Sponsored by:           NetApp, Inc.
>     Differential Revision:  https://reviews.freebsd.org/D43792
> ---
>  sys/netinet/tcp_subr.c  | 4 ++--
>  sys/netinet/tcp_timer.c | 1 +
>  2 files changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/sys/netinet/tcp_subr.c b/sys/netinet/tcp_subr.c
> index 6043a3d458e5..90e1496a822c 100644
> --- a/sys/netinet/tcp_subr.c
> +++ b/sys/netinet/tcp_subr.c
> @@ -2383,10 +2383,9 @@ tcp_discardcb(struct tcpcb *tp)
>  #endif
>  
>  	INP_WLOCK_ASSERT(inp);
> +	MPASS(!callout_active(&tp->t_callout));
>  	MPASS(TAILQ_EMPTY(&tp->snd_holes));
>  
> -	tcp_timer_stop(tp);
> -
>  	/* free the reassembly queue, if any */
>  	tcp_reass_flush(tp);
>  
> @@ -2522,6 +2521,7 @@ tcp_close(struct tcpcb *tp)
>  		tcp_fastopen_decrement_counter(tp->t_tfo_pending);
>  		tp->t_tfo_pending = NULL;
>  	}
> +	tcp_timer_stop(tp);
>  	if (tp->t_fb->tfb_tcp_timer_stop_all != NULL)
>  		tp->t_fb->tfb_tcp_timer_stop_all(tp);
>  	in_pcbdrop(inp);
> diff --git a/sys/netinet/tcp_timer.c b/sys/netinet/tcp_timer.c
> index f0eb3bad33cf..ed50659abf8e 100644
> --- a/sys/netinet/tcp_timer.c
> +++ b/sys/netinet/tcp_timer.c
> @@ -907,6 +907,7 @@ tcp_timer_activate(struct tcpcb *tp, tt_which which, u_in
> t delta)
>  #endif
>  
>  	INP_WLOCK_ASSERT(inp);
> +	MPASS(tp->t_state > TCPS_CLOSED);
>  
>  	if (delta > 0) {
>  		what = TT_STARTING;
>

Every machine in my farm is getting kernel page faults as of this revision.

#0  __curthread () at /opt/src/git-src/sys/amd64/include/pcpu_aux.h:57
#1  doadump (textdump=textdump@entry=1) at /opt/src/git-src/sys/kern/kern_sh
utdown.c:403
#2  0xffffffff806c68b9 in kern_reboot (howto=260) at 
/opt/src/git-src/sys/kern/kern_shutdown.c:521
#3  0xffffffff806c6dc2 in vpanic (fmt=0xffffffff80ae244b "%s", 
ap=ap@entry=0xfffffe008304abc0) at /opt/src/git-src/sys/kern/kern_shutdown.c
:973
#4  0xffffffff806c6c13 in panic (fmt=<unavailable>) at 
/opt/src/git-src/sys/kern/kern_shutdown.c:889
#5  0xffffffff80a5b18f in trap_fatal (frame=0xfffffe008304acb0, eva=72) at 
/opt/src/git-src/sys/amd64/amd64/trap.c:950
#6  0xffffffff80a5b1df in trap_pfault (frame=0xfffffe008304acb0, 
usermode=false, signo=<optimized out>, ucode=<optimized out>) at 
/opt/src/git-src/sys/amd64/amd64/trap.c:758
#7  <signal handler called>
#8  0xffffffff8084dd72 in cc_cong_signal (tp=0xfffff8008d207540, th=0x0, 
type=2) at /opt/src/git-src/sys/netinet/tcp_input.c:465
#9  0xffffffff8086ba4f in tcp_timer_rexmt (tp=0xfffff8008d207540) at 
/opt/src/git-src/sys/netinet/tcp_timer.c:803
#10 0xffffffff8086b1fe in tcp_timer_enter (xtp=0xfffff8008d207540) at 
/opt/src/git-src/sys/netinet/tcp_timer.c:880
#11 0xffffffff806e603e in softclock_call_cc (c=0xfffff8008d2076d8, 
cc=cc@entry=0xffffffff820b10c0, direct=direct@entry=0) at 
/opt/src/git-src/sys/kern/kern_timeout.c:714
#12 0xffffffff806e77b8 in softclock_thread (arg=arg@entry=0xffffffff820b10c0
) at /opt/src/git-src/sys/kern/kern_timeout.c:846
#13 0xffffffff8067f05f in fork_exit (callout=0xffffffff806e76c0 
<softclock_thread>, arg=0xffffffff820b10c0, frame=0xfffffe008304af40) at 
/opt/src/git-src/sys/kern/kern_fork.c:1157
#14 <signal handler called>
#15 0x21ffa5a87b4e3f70 in ?? ()


When rebooting one of my machines, the others panic as above. This is 100% 
reproducible when one of the machines in my basement are rebooted.


-- 
Cheers,
Cy Schubert <Cy.Schubert@cschubert.com>
FreeBSD UNIX:  <cy@FreeBSD.org>   Web:  https://FreeBSD.org
NTP:           <cy@nwtime.org>    Web:  https://nwtime.org

			e^(i*pi)+1=0