On Wed, Feb 26, 2025 at 09:28:41PM +0800, Xi Ruoyao wrote:
> Since commit 6f2c2f93a190 ("scripts/sorttable: Remove unneeded
> Elf_Rel"), sorttable no longer clears relocs against __ex_table,
> claiming "it was never used." But in fact MIPS relocatable kernel had
> been implicitly depending on this behavior, so after this commit the
> MIPS relocatable kernel has started to spit oops like:
>
> CPU 1 Unable to handle kernel paging request at virtual address 000000fffbbdbff8, epc == ffffffff818f9a6c, ra == ffffffff813ad7d0
> ... ...
> Call Trace:
> [<ffffffff818f9a6c>] __raw_copy_from_user+0x48/0x2fc
> [<ffffffff813ad7d0>] cp_statx+0x1a0/0x1e0
> [<ffffffff813ae528>] do_statx_fd+0xa8/0x118
> [<ffffffff813ae670>] sys_statx+0xd8/0xf8
> [<ffffffff81156cc8>] syscall_common+0x34/0x58
>
> So ignore those relocs on our own to fix the issue.
>
> Fixes: 6f2c2f93a190 ("scripts/sorttable: Remove unneeded Elf_Rel")
> Signed-off-by: Xi Ruoyao <xry111@xxxxxxxxxxx>
> ---
> arch/mips/boot/tools/relocs.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/arch/mips/boot/tools/relocs.c b/arch/mips/boot/tools/relocs.c
> index a88d66c46d7f..9863e1d5c62e 100644
> --- a/arch/mips/boot/tools/relocs.c
> +++ b/arch/mips/boot/tools/relocs.c
> @@ -468,6 +468,8 @@ static void walk_relocs(int (*process)(struct section *sec, Elf_Rel *rel,
> Elf_Sym *sym, const char *symname))
> {
> int i;
> + struct section *extab_sec = sec_lookup("__ex_table");
> + int extab_index = extab_sec ? extab_sec - secs : -1;
>
> /* Walk through the relocations */
> for (i = 0; i < ehdr.e_shnum; i++) {
> @@ -480,6 +482,9 @@ static void walk_relocs(int (*process)(struct section *sec, Elf_Rel *rel,
> if (sec->shdr.sh_type != SHT_REL_TYPE)
> continue;
>
> + if (sec->shdr.sh_info == extab_index)
> + continue;
> +
> sec_symtab = sec->link;
> sec_applies = &secs[sec->shdr.sh_info];
> if (!(sec_applies->shdr.sh_flags & SHF_ALLOC))
> --
> 2.48.1
applied to mips-fixes.
Thomas.
--
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea. [ RFC1925, 2.3 ]
