On 2/22/21 11:40 AM, Natanael Copa wrote:
On Fri, 19 Feb 2021 19:50:13 +0100
Natanael Copa <[email protected]> wrote:
On Fri, 19 Feb 2021 19:38:53 +0100
Natanael Copa <[email protected]> wrote:
Hi,
I tried to update the kernel for alpine 3.12-stable branch from 5.4.84
to 5.4.99. The 3rd part kernel module drbd 9.0.22-2 failed to build so
I updated it to 9.0.27-1. This passed on the x86_64 machine I tested
built it on so I pushed it.
But it failed on 32 bit arm builders:
...
In file included from ./include/linux/module.h:27,
from
/home/buildozer/aports/main/drbd-lts/src/drbd-9.0.27-1/drbd/drbd_req.h:16,
from
/home/buildozer/aports/main/drbd-lts/src/drbd-9.0.27-1/drbd/drbd_state.c:22:
./arch/arm/include/asm/module.h:59: warning: "MODULE_ARCH_VERMAGIC" redefined
59 | #define MODULE_ARCH_VERMAGIC \
|
In file included from
/home/buildozer/aports/main/drbd-lts/src/drbd-9.0.27-1/drbd/drbd_state.c:19:
./include/linux/vermagic.h:28: note: this is the location of the previous
definition
28 | #define MODULE_ARCH_VERMAGIC ""
|
GEN
/home/buildozer/aports/main/drbd-lts/src/drbd-9.0.27-1/drbd/drbd_buildtag.c
CC [M]
/home/buildozer/aports/main/drbd-lts/src/drbd-9.0.27-1/drbd/drbd_buildtag.o
LD [M] /home/buildozer/aports/main/drbd-lts/src/drbd-9.0.27-1/drbd/drbd.o
Building modules, stage 2.
MODPOST 2 modules
ERROR: "__aeabi_ldivmod"
[/home/buildozer/aports/main/drbd-lts/src/drbd-9.0.27-1/drbd/drbd.ko] undefined!
ERROR: "__aeabi_uldivmod"
[/home/buildozer/aports/main/drbd-lts/src/drbd-9.0.27-1/drbd/drbd.ko] undefined!
make[3]: *** [scripts/Makefile.modpost:94: __modpost] Error 1
make[2]: *** [Makefile:1639: modules] Error 2
make[1]: *** [Makefile:132: kbuild] Error 2
make[1]: Leaving directory
'/home/buildozer/aports/main/drbd-lts/src/drbd-9.0.27-1/drbd'
make: *** [Makefile:131: module] Error 2
ERROR: drbd-lts: build failed
And on 32 bit x86:
GEN
/home/buildozer/aports/main/drbd-lts/src/drbd-9.0.27-1/drbd/drbd_buildtag.c
CC [M]
/home/buildozer/aports/main/drbd-lts/src/drbd-9.0.27-1/drbd/drbd_buildtag.o
LD [M] /home/buildozer/aports/main/drbd-lts/src/drbd-9.0.27-1/drbd/drbd.o
Building modules, stage 2.
MODPOST 2 modules
ERROR: "__udivdi3"
[/home/buildozer/aports/main/drbd-lts/src/drbd-9.0.27-1/drbd/drbd.ko] undefined!
ERROR: "__divdi3"
[/home/buildozer/aports/main/drbd-lts/src/drbd-9.0.27-1/drbd/drbd.ko] undefined!
make[3]: *** [scripts/Makefile.modpost:94: __modpost] Error 1
make[2]: *** [Makefile:1639: modules] Error 2
make[1]: *** [Makefile:132: kbuild] Error 2
make[1]: Leaving directory
'/home/buildozer/aports/main/drbd-lts/src/drbd-9.0.27-1/drbd'
make: *** [Makefile:131: module] Error 2
ERROR: drbd-lts: build failed
I read that this can happen if do_div() is not used and libgcc is not
linked in (which I assume we shouldnt on kernel). I tried to look at
the git log if I could find anything evident but couldn't find anything.
So I tried to find older version. Turns out that the lastest version
that compiles with 5.4 kernel is 9.0.25-2, but it only compiles with
5.4.84 kernel and not the 5.4.99.
Does anyone have a clue how to solve this? If not, I guess I have to
try git bisect it.
I found the commit that introduces the issue using objdump and git log:
commit 8dc8ede32de4410e99148b39d0f960e975eeddea
Author: Joel Colledge <[email protected]>
Date: Wed Nov 11 18:11:26 2020 +0100
drbd: fix slow sync when sync requests are answered quickly
It is the DIV_ROUND_UP in that commit that introduces this.
This change fixes it:
diff --git a/drbd/drbd_sender.c b/drbd/drbd_sender.c
index 30e301fb..34030870 100644
--- a/drbd/drbd_sender.c
+++ b/drbd/drbd_sender.c
@@ -687,7 +687,7 @@ static int drbd_resync_delay(struct drbd_peer_device
*peer_device)
* that the rate limiting prevents any new requests
* from being made. Wait just long enough so that we
* can request some data next time. */
- delay = DIV_ROUND_UP(HZ * BM_SECT_PER_BIT,
pdc->c_max_rate * 2);
+ delay = DIV_ROUND_UP((unsigned long)(HZ * BM_SECT_PER_BIT
/ 2), pdc->c_max_rate);
}
} else {
/* Fixed resync rate. Use the standard delay. */
As I understand, it is the compiler that converts the HZ *
BM_SECT_PER_BIT to 64 bit type which triggers the error.
As I understand the source BM_SECT_PER_BIT = 1 << (12-9) = 8, so it
should be safe to move the `* 2` on the right side to a `/ 2` on the
left, which results in HZ * 4 / pdc->c_max_rate.
HZ is to my understand seldomly (never?) set to anything above 1000?
And 1000 * 4 fits just fine in an unsigned long, so I think the above diff
should be safe.
-nc
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Hi Natanael,
thanks for the proposed fix! Your logic seems right to me.
I have committed it to the drbd repository, along with one other similar
fix. See
https://github.com/LINBIT/drbd/commit/4194a136b08c1f204707bdb0695fc05c0b2997e9
Are you able to test the latest git HEAD (drbd-9.0 branch) on your
infrastructure to verify that this is fixed for you?
Thanks again,
Christoph
--
Christoph Böhmwalder
LINBIT | Keeping the Digital World Running
DRBD HA — Disaster Recovery — Software defined Storage
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