Date: Wed, 26 Apr 2023 14:19:18 +0200 From: Jan Martin Mikkelsen <janm@transactionware.com> To: Hans Petter Selasky <hselasky@freebsd.org> Cc: Konstantin Belousov <kostikbel@gmail.com>, Zhenlei Huang <zlei@freebsd.org>, FreeBSD CURRENT <freebsd-current@freebsd.org>, Gleb Smirnoff <glebius@freebsd.org> Subject: Re: Link modules to DYN type Message-ID: <72A678C8-4293-4D50-BCCC-AFE92DB1DA76@transactionware.com> In-Reply-To: <f200bce7-add8-6aff-38cf-2ee15dc35411@freebsd.org> References: <97390FE1-1DF5-43A1-A3F4-2B945D681437@FreeBSD.org> <2bb66cac-c7f1-e45b-693a-8afbda05cfa6@freebsd.org> <ZEkHKJ_BRhV22gf_@kib.kiev.ua> <f200bce7-add8-6aff-38cf-2ee15dc35411@freebsd.org>
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> On 26. Apr 2023, at 13:38, Hans Petter Selasky <hselasky@freebsd.org> =
wrote:
>=20
> On 4/26/23 13:12, Konstantin Belousov wrote:
>> No, in-kernel linker does not behave this way.
>> Modules need to contain explicit reference to all modules they depend =
upon,
>> using the MODULE_DEPEND() macro. Only symbols from the dependencies =
are
>> resolved.
>> All modules get an implicit reference to kernel.
>=20
> Hi Konstantin,
>=20
> Maybe I wasn't so clear. Trying again:
>=20
>> diff --git a/sys/tests/ktest.c b/sys/tests/ktest.c
>> index 495fedf95dde..eb42cf062487 100644
>> --- a/sys/tests/ktest.c
>> +++ b/sys/tests/ktest.c
>> @@ -409,6 +409,12 @@ static moduledata_t ktestmod =3D {
>> 0
>> };
>> +int
>> +printf(const char *fmt, ...)
>> +{
>> + return (0);
>> +}
>> +
>> DECLARE_MODULE(ktestmod, ktestmod, SI_SUB_PSEUDO, SI_ORDER_ANY);
>> MODULE_VERSION(ktestmod, 1);
>> MODULE_DEPEND(ktestmod, netlink, 1, 1, 1);
>=20
> Then kldload ktest.ko . Which printf() function will be used if =
ktest.c calls printf() ?
>=20
> I would expect a warning from the kernel at least =E2=80=A6
Hi,
This looks similar to this:
https://lists.freebsd.org/pipermail/freebsd-stable/2015-July/082751.html
https://lists.freebsd.org/pipermail/freebsd-stable/2015-July/082760.html
The =E2=80=9Cnot knowing=E2=80=9D about how symbols are going to be =
resolved has bothered me for a while.
Regards,
Jan M.
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<html><head><meta http-equiv=3D"content-type" content=3D"text/html; =
charset=3Dutf-8"></head><body style=3D"overflow-wrap: break-word; =
-webkit-nbsp-mode: space; line-break: =
after-white-space;"><br><div><br><blockquote type=3D"cite"><div>On 26. =
Apr 2023, at 13:38, Hans Petter Selasky <hselasky@freebsd.org> =
wrote:</div><br class=3D"Apple-interchange-newline"><div><div>On 4/26/23 =
13:12, Konstantin Belousov wrote:<br><blockquote type=3D"cite">No, =
in-kernel linker does not behave this way.<br>Modules need to contain =
explicit reference to all modules they depend upon,<br>using the =
MODULE_DEPEND() macro. Only symbols from the dependencies =
are<br>resolved.<br>All modules get an implicit reference to =
kernel.<br></blockquote><br>Hi Konstantin,<br><br>Maybe I wasn't so =
clear. Trying again:<br><br><blockquote type=3D"cite">diff --git =
a/sys/tests/ktest.c b/sys/tests/ktest.c<br>index =
495fedf95dde..eb42cf062487 100644<br>--- a/sys/tests/ktest.c<br>+++ =
b/sys/tests/ktest.c<br>@@ -409,6 +409,12 @@ static moduledata_t ktestmod =
=3D {<br> 0<br> };<br> =
+int<br>+printf(const char *fmt, ...)<br>+{<br>+ =
return (0);<br>+}<br>+<br> =
DECLARE_MODULE(ktestmod, ktestmod, SI_SUB_PSEUDO, SI_ORDER_ANY);<br> =
MODULE_VERSION(ktestmod, 1);<br> MODULE_DEPEND(ktestmod, netlink, 1, 1, =
1);<br></blockquote><br>Then kldload ktest.ko . Which printf() function =
will be used if ktest.c calls printf() ?<br><br>I would expect a warning =
from the kernel at least =
=E2=80=A6</div></div></blockquote></div><div><br></div>Hi,<div><br></div><=
div>This looks similar to this:</div><div><br></div><div><a =
href=3D"https://lists.freebsd.org/pipermail/freebsd-stable/2015-July/08275=
1.html">https://lists.freebsd.org/pipermail/freebsd-stable/2015-July/08275=
1.html</a></div><div><br></div><div><a =
href=3D"https://lists.freebsd.org/pipermail/freebsd-stable/2015-July/08276=
0.html">https://lists.freebsd.org/pipermail/freebsd-stable/2015-July/08276=
0.html</a></div><div><br></div><div>The =E2=80=9Cnot knowing=E2=80=9D =
about how symbols are going to be resolved has bothered me for a =
while.</div><div><br><div>Regards,</div></div><div><br></div><div>Jan =
M.</div><div><br></div></body></html>=
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