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Date:      Thu, 19 Jun 2025 11:26:30 +0000
From:      bugzilla-noreply@freebsd.org
To:        net@FreeBSD.org
Subject:   [Bug 287229] IP reassembly issue in FreeBSD 14.1
Message-ID:  <bug-287229-7501-ihd1B3lyEn@https.bugs.freebsd.org/bugzilla/>
In-Reply-To: <bug-287229-7501@https.bugs.freebsd.org/bugzilla/>
References:  <bug-287229-7501@https.bugs.freebsd.org/bugzilla/>

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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D287229

--- Comment #15 from Lucas Aubard <lucas.aubard@irisa.fr> ---
Sorry for the late reply; I was running more tests based on the information=
 you
provided.

@Timo=20
Thanks for the FreeBSD operating description when processing fragments.=20

I confirm that by commenting vm.kmem_size and vm.kmem_size_max in box
bento/freebsd-14.1, the net.inet.ip.maxfragbucketsize value is now set to 7
after a reboot.=20
I also confirm observing the same reassembly across the runs for all our te=
st
cases.
Thanks a lot for pointing out these kernel parameters.

@Michael=20
Actually, I did not modify nor check the default VM settings since I observ=
ed
this behavior with different FreeBSD boxes.
For example, the official (?) FreeBSD box freebsd/FreeBSD-14.1-STABLE has o=
nly
one parameter specified in /boot/loader.conf: autoboot_delay=3D"-1". I am a=
lso
able to observe a net.inet.ip.maxfragbucketsize value of 1 with this box (t=
hat
has thus not the vm.kmem_size and vm.kmem_size_max specified) in the case I=
 run
multiple VMs in parallel. From @Rodney's comment, I guess the memory
dynamically allocated to the FreeBSD VM is low because multiple VMs are
running, leading to a net.inet.ip.maxfragbucketsize value of 1.=20

With the freebsd/FreeBSD-14.1-STABLE box, by manually allocating memory to =
the
Vagrantfile:
- 512Mb gives net.inet.ip.maxfragbucketsize =3D 1. For 40 test cases tested=
 in
parallel, I observed many reassembly inconsistencies.
- 1024Mb gives net.inet.ip.maxfragbucketsize =3D 3. For 40 test cases teste=
d in
parallel, I observed 1 test case reassembly inconsistency (out of the 10,362
test cases).
- 2048Mb gives net.inet.ip.maxfragbucketsize =3D 7. For 40 test cases teste=
d in
parallel, I did not observe any reassembly inconsistency.
So, I should force the allocated memory to the FreeBSD box to 2048Mb when
running my tests in parallel to avoid observing reassembly inconsistencies.

--=20
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