Hello,
On Mon, Mar 13, 2023 at 09:32:16PM +0100, Andrea Righi wrote:
> On Wed, Jan 11, 2023 at 04:11:51PM +0000, Gary Guo wrote:
> > Currently modversion uses a fixed size array of size (64 - sizeof(long))
> > to store symbol names, thus placing a hard limit on length of symbols.
> > Rust symbols (which encodes crate and module names) can be quite a bit
> > longer. The length limit in kallsyms is increased to 512 for this reason.
> >
> > It's a waste of space to simply expand the fixed array size to 512 in
> > modversion info entries. I therefore make it variably sized, with offset
> > to the next entry indicated by the initial "next" field.
> >
> > In addition to supporting longer-than-56/60 byte symbols, this patch also
> > reduce the size for short symbols by getting rid of excessive 0 paddings.
> > There are still some zero paddings to ensure "next" and "crc" fields are
> > properly aligned.
> >
> > This patch does have a tiny drawback that it makes ".mod.c" files generated
> > a bit less easy to read, as code like
> >
> > "\x08\x00\x00\x00\x78\x56\x34\x12"
> > "symbol\0\0"
> >
> > is generated as opposed to
> >
> > { 0x12345678, "symbol" },
> >
> > because the structure is now variable-length. But hopefully nobody reads
> > the generated file :)
> >
> > Link: b8a94bfb3395 ("kallsyms: increase maximum kernel symbol length to 512")
> > Link: https://github.com/Rust-for-Linux/linux/pull/379
> >
> > Signed-off-by: Gary Guo <gary@xxxxxxxxxxx>
>
> Is there any newer version of this patch?
>
> I'm doing some tests with it, but I'm getting boot failures on ppc64
> with this applied (at boot kernel is spitting out lots of oops'es and
> unfortunately it's really hard to copy paste or just read them from the
> console).
Are you using the ELF ABI v1 or v2?
v1 may have some additional issues when it comes to these symbol tables.
Thanks
Michal
