On Wed, Jun 09, 2021 at 10:30:23PM +0200, Arnd Bergmann wrote: > On Wed, Jun 9, 2021 at 9:15 PM Guenter Roeck <linux@xxxxxxxxxxxx> wrote: > > On Wed, Jun 09, 2021 at 08:16:11AM -0700, Guenter Roeck wrote: > > > > I suppose we could improve the situation if scripts/link-vmlinux.sh was able > > > > to do that automatically, and compare the kallsyms output .S file between > > > > steps 1 and 2. > > > > > > Comparing the .S files doesn't result in useful data; turns out there are > > > always irrelevant differences. We'll try to run a diff on the output of > > > "objdump --syms". Hopefully that will generate something useful. > > > > > > > Turns out it wasn't that useful. > > > > chromeos-kernel-5_10-5.10.42-r406: Symbol file differences: > > chromeos-kernel-5_10-5.10.42-r406: 7c7 > > chromeos-kernel-5_10-5.10.42-r406: < 00000000000325c8 g .rodata 0000000000000000 kallsyms_relative_base > > chromeos-kernel-5_10-5.10.42-r406: --- > > chromeos-kernel-5_10-5.10.42-r406: > 00000000000325c0 g .rodata 0000000000000000 kallsyms_relative_base > > chromeos-kernel-5_10-5.10.42-r406: 9,13c9,13 > > chromeos-kernel-5_10-5.10.42-r406: < 00000000000325d0 g .rodata 0000000000000000 kallsyms_num_syms > > chromeos-kernel-5_10-5.10.42-r406: < 00000000000325d8 g .rodata 0000000000000000 kallsyms_names > > chromeos-kernel-5_10-5.10.42-r406: < 00000000000cd7f0 g .rodata 0000000000000000 kallsyms_markers > > chromeos-kernel-5_10-5.10.42-r406: < 00000000000cdb18 g .rodata 0000000000000000 kallsyms_token_table > > chromeos-kernel-5_10-5.10.42-r406: < 00000000000cde78 g .rodata 0000000000000000 kallsyms_token_index > > chromeos-kernel-5_10-5.10.42-r406: --- > > chromeos-kernel-5_10-5.10.42-r406: > 00000000000325c8 g .rodata 0000000000000000 kallsyms_num_syms > > chromeos-kernel-5_10-5.10.42-r406: > 00000000000325d0 g .rodata 0000000000000000 kallsyms_names > > chromeos-kernel-5_10-5.10.42-r406: > 00000000000cd7d8 g .rodata 0000000000000000 kallsyms_markers > > chromeos-kernel-5_10-5.10.42-r406: > 00000000000cdb00 g .rodata 0000000000000000 kallsyms_token_table > > chromeos-kernel-5_10-5.10.42-r406: > 00000000000cde60 g .rodata 0000000000000000 kallsyms_token_index > > > > I thought I'd see the added symbols, but it looks like the only difference > > between the two files is the addresses. > > > > What am I missing ? > > I probably misremembered the part about 'objdump --syms' and there was > something more to it. > > Maybe this was the last version before converging? It looks like the '<' version > has one extra symbol ompared to the '>' version. The diff has no context, but I It is the difference between step 1 and 2. Why would diff on objdump not show the additional symbol ? Is it possible that the symbol is not added to the object file ? > assume the first symbol that has a different size is 'kallsyms_offsets', which > is generated by kallsyms. I'll give it another try and run diff -u. > > I see that link-vmlinux.sh already compares the System.map files, using > "cmp -s System.map .tmp_System.map", which is roughly the same as the > objdump --syms diff you got, so comparing these files probably doesn't > help either. However, comparing the .tmp_System.map file with the previous > version might reveal the problem. This might need another step to filter out > the address and only compare the symbol names. I'll do that as well. Thanks! Guenter
