On Sat, Mar 25, 2023 at 3:23 AM Akemi Yagi via rocky rocky@lists.resf.org wrote:
On Fri, Mar 24, 2023 at 8:49 PM 박영준 via rocky rocky@lists.resf.org wrote:
I debug the rocky 8.7 kernel. (4.18.0-425.3.1.el8.x86_64 and 4.18.0-425.13.1.el8.x86_64) for our company module issue.
And I have a question . why pv_mmu_ops notify_page_enc_status_changed field is moved to reserved1 field on (4.18.0-425.13.1.el8.x86_64)? I think pv_mmu_ops structure reserved filed may exist for compatibility. By moving field to reserved, size reduced. (I think notify_page_enc_status_changed location dummy field needed or must not change the location)
Is there any reson I don't know ?
Rocky kernels are rebuilt from the source code of RHEL kernels without modifications (except debranding). Therefore you need to ask Red Hat. However here is what I guess has happened.
In the GA kernel of RHEL 8.7 (4.18.0-425.3.1.el8), there was a kABI breakage. This caused failure of kmod packages built against this kernel. Turns out the breakage was in pv_mmu_ops structure and it was fixed in kernel-4.18.0-425.10.1.el8_7 [1]. That likely lead to what you have encountered.
Akemi
Here's some additional info. I was curious to see how the kABI breakage was fixed. Below is a diff in the source code between kernel-425.3.1 and 425.13.1.
Akemi
===================================================== $ diff -uNpr paravirt_types.h.425.3.1 paravirt_types.h.425.13.1 --- paravirt_types.h.425.3.1 2022-09-30 07:54:26.000000000 -0700 +++ paravirt_types.h.425.13.1 2023-02-02 08:42:46.000000000 -0800 @@ -205,8 +205,6 @@ struct pv_irq_ops { struct pv_mmu_ops { unsigned long (*read_cr2)(void);
- void (*notify_page_enc_status_changed)(unsigned long pfn, int npages, bool enc); - void (*write_cr2)(unsigned long);
unsigned long (*read_cr3)(void); @@ -306,7 +304,8 @@ struct pv_mmu_ops { void (*set_fixmap)(unsigned /* enum fixed_addresses */ idx, phys_addr_t phys, pgprot_t flags);
- RH_KABI_RESERVE(1) + RH_KABI_USE(1, void (*notify_page_enc_status_changed)(unsigned long pfn, + int npages, bool enc)) RH_KABI_RESERVE(2) RH_KABI_RESERVE(3) RH_KABI_RESERVE(4)