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SubjectRe: [PATCH modules 0/2] Fix handling of exit unwinding sections (on ARM)
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On Mon, 2019-06-03 at 12:57 +0200, Matthias Schiffer wrote:
> For some time (050d18d1c651 "ARM: 8650/1: module: handle negative
> R_ARM_PREL31 addends correctly", v4.11+), building a kernel without
> CONFIG_MODULE_UNLOAD would lead to module loads failing on ARM
> systems with
> certain memory layouts, with messages like:
>
> imx_sdma: section 16 reloc 0 sym '': relocation 42 out of range
> (0x7f015260 -> 0xc0f5a5e8)
>
> (0x7f015260 is in the module load area, 0xc0f5a5e8 a regular vmalloc
> address; relocation 42 is R_ARM_PREL31)
>
> This is caused by relocatiosn in the .ARM.extab.exit.text and
> .ARM.exidx.exit.text sections referencing the .exit.text section. As
> the
> module loader will omit loading .exit.text without
> CONFIG_MODULE_UNLOAD,
> there will be relocations from loaded to unloaded sections; the
> resulting
> huge offsets trigger the sanity checks added in 050d18d1c651.
>
> IA64 might be affected by a similar issue - sections with names like
> .IA_64.unwind.exit.text and .IA_64.unwind_info.exit.text appear in
> the ld
> script - but I don't know much about that arch.
>
> Also, I'm not sure if this is stable-worthy - just enabling
> CONFIG_MODULE_UNLOAD should be a viable workaround on affected
> kernels.
>
>
> Kind regards,
> Matthias


Hi,
any comments on these patches? If not, who is going to take them in
their tree?

Note that I'll be out of office for the next week, and I won't be able
to read my mail during this period.


Kind regards,
Matthias




>
>
> Matthias Schiffer (2):
> module: allow arch overrides for .exit section names
> ARM: module: recognize unwind exit sections
>
> arch/arm/include/asm/module.h | 11 +++++++++++
> include/linux/moduleloader.h | 8 ++++++++
> kernel/module.c | 2 +-
> 3 files changed, 20 insertions(+), 1 deletion(-)
>

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