On 2018-09-12 10:18, Vincent Lefevre wrote:
> On 2018-09-11 19:15:25 -0700, Russ Allbery wrote:
>> If you set IGNORE_CC_MISMATCH=1 in the environment before installing the
>> package, does everything build and work correctly?
>
> Yes, everything is fine.
It is probably very fragile. When upgrading from stretch/gcc-6 to
sid/gcc-6 the whole toolchain gets updated, too (binutils ...).
I have (for an older stretch kernel and cannot reboot to the current
one, but that should not matter) for 396.45 two modules - one built in a
mixed sid environment, unloadable, and a working one built in clean
stretch.
# insmod ./sid/lib/modules/4.9.0-6-amd64/nvidia/nvidia-current.ko
insmod: ERROR: could not insert module
./sid/lib/modules/4.9.0-6-amd64/nvidia/nvidia-current.ko: Invalid module format
# dmesg | tail -n 1
[12261789.197235] module: nvidia: Unknown rela relocation: 4
# insmod ./stretch/lib/modules/4.9.0-6-amd64/nvidia/nvidia-current.ko
# dmesg | tail -n 3
[12261835.731804] nvidia-nvlink: Nvlink Core is being initialized, major device
number 245
[12261835.732157] vgaarb: device changed decodes:
PCI:0000:01:00.0,olddecodes=none,decodes=none:owns=io+mem
[12261835.732275] NVRM: loading NVIDIA UNIX x86_64 Kernel Module 396.45 Thu
Jul 12 20:49:29 PDT 2018 (using threaded interrupts)
Looking with diffoscope at the modules I find this interesting
difference:
│ -Relocation section '.rela.text' at offset 0x122def8 contains 138066 entries:
│ +Relocation section '.rela.text' at offset 0x122de38 contains 138066 entries:
│ Offset Info Type Symbol's Value
Symbol's Name + Addend
│ -0000000000000001 00008fdb00000002 R_X86_64_PC32 0000000000000000
__fentry__ - 4
│ +0000000000000001 00008fdb00000004 R_X86_64_PLT32 0000000000000000
__fentry__ - 4
│ 0000000000000015 00008f760000000b R_X86_64_32S 0000000000000000
nv_minor_num_table + 0
│ -0000000000000028 00008fed00000002 R_X86_64_PC32 0000000000000000
__x86_indirect_thunk_rax - 4
│ -0000000000000031 00008fdb00000002 R_X86_64_PC32 0000000000000000
__fentry__ - 4
│ +0000000000000028 00008fed00000004 R_X86_64_PLT32 0000000000000000
__x86_indirect_thunk_rax - 4
│ +0000000000000031 00008fdb00000004 R_X86_64_PLT32 0000000000000000
__fentry__ - 4
│ 0000000000000048 00008f760000000b R_X86_64_32S 0000000000000000
nv_minor_num_table + 0
│ -000000000000006a 0000919e00000002 R_X86_64_PC32 0000000000000000
__x86_indirect_thunk_r9 - 4
│ -0000000000000081 00008fdb00000002 R_X86_64_PC32 0000000000000000
__fentry__ - 4
│ -0000000000000091 00008fdb00000002 R_X86_64_PC32 0000000000000000
__fentry__ - 4
│ +000000000000006a 0000919e00000004 R_X86_64_PLT32 0000000000000000
__x86_indirect_thunk_r9 - 4
│ +0000000000000081 00008fdb00000004 R_X86_64_PLT32 0000000000000000
__fentry__ - 4
│ +0000000000000091 00008fdb00000004 R_X86_64_PLT32 0000000000000000
__fentry__ - 4
...
arch/x86/include/asm/elf.h says:
#define R_X86_64_PC32 2 /* PC relative 32 bit signed */
#define R_X86_64_PLT32 4 /* 32 bit PLT address */
The same behavior I see comparing the modules built for current
driver and stretch kernel in different environments, therefore
I conclude that they won't work if built with the mismatching
toolchain (mismatching gcc may be just an indicator for the
mismatching toolchain, using a gcc6 6.4.0 built in stretch might
actually result in working modules).
---
nvidia-kernel-4.9.0-8-amd64_390.87-1+4.9.110-3+deb9u4_amd64_gcc-6.3.0-18+deb9u1.deb
+++ nvidia-kernel-4.9.0-8-amd64_390.87-1+4.9.110-3+deb9u4_amd64_gcc-6.4.0-20.deb
-Relocation section '.rela.text' at offset 0x253768 contains 701 entries:
+Relocation section '.rela.text' at offset 0x253708 contains 701 entries:
Offset Info Type Symbol's Value
Symbol's Name + Addend
-0000000000000001 000000c200000002 R_X86_64_PC32 0000000000000000
__fentry__ - 4
+0000000000000001 000000c200000004 R_X86_64_PLT32 0000000000000000
__fentry__ - 4
0000000000000008 0000000f0000000b R_X86_64_32S 0000000000000000
.data + 0
-000000000000000d 0000012500000002 R_X86_64_PC32 0000000000000000
nvKmsKapiGetFunctionsTable - 4
-0000000000000016 000000e500000002 R_X86_64_PC32 0000000000000950
nv_drm_probe_devices - 4
+000000000000000d 0000012500000004 R_X86_64_PLT32 0000000000000000
nvKmsKapiGetFunctionsTable - 4
+0000000000000016 000000e500000004 R_X86_64_PLT32 0000000000000950
nv_drm_probe_devices - 4
...
build test environment:
stretch chroot + linux-headers-amd64 module-assistant nvidia-kernel-source
m-a -t -f -l 4.9.0-8-amd64 build nvidia
add sid sources
apt-get install gcc-6/sid
m-a -t -f -l 4.9.0-8-amd64 build nvidia
Andreas
