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 _______________________________________________ Star us on GITHUB: https://github.com/LINBIT drbd-user mailing list [email protected] https://lists.linbit.com/mailman/listinfo/drbd-user
