On Thu, Sep 21, 2023 at 11:36:10AM +0800, lijiang wrote:
> On Wed, Sep 20, 2023 at 7:17 PM Aditya Gupta <adityag@xxxxxxxxxxxxx> wrote:
>
> > Hello lijiang,
> >
> > On Wed, Sep 20, 2023 at 10:21:18AM +0800, lijiang wrote:
> > > On Tue, Sep 19, 2023 at 2:23 PM Aditya Gupta <adityag@xxxxxxxxxxxxx>
> > wrote:
> > >
> > > > Hello lijiang,
> > > >
> > > > On Mon, Sep 18, 2023 at 07:34:04PM +0800, lijiang wrote:
> > > > > Hi, Aditya
> > > > > Thank you for the patch.
> > > > >
> > > > > ...
> > > > >
> > > > > Test kernel commit: ce9ecca0238b ("Linux 6.6-rc2")
> > > > >
> > > > > # ./crash /home/linux/vmlinux
> > > >
> > > > Thanks for testing it.
> > > >
> > > > This issue occurs only in case of Radix MMU.
> > > >
> > > > Overall, these are all the requirements:
> > > > 1. Upstream linux (master branch) (your commit will also work,
> > > > ce9ecca0238b)
> > > > 2. 'CONFIG_PPC_BOOK3S_64' should be 'y' in kernel config (this should
> > be
> > > > there
> > > > in default configs)
> > > >
> > >
> > > # grep "CONFIG_PPC_BOOK3S_64" /home/linux/.config
> > > CONFIG_PPC_BOOK3S_64=y
> > >
> > > 3. Check in dmesg of the crashed kernel, if it prints 'hash-mmu' or
> > > > 'radix-mmu'. It should be 'radix-mmu'.
> > > >
> > > >
> > > # dmesg|grep mmu
> > > [ 0.000000] hash-mmu: Page sizes from device-tree:
> > > [ 0.000000] hash-mmu: base_shift=12: shift=12, sllp=0x0000,
> > > avpnm=0x00000000, tlbiel=1, penc=0
> > > [ 0.000000] hash-mmu: base_shift=12: shift=16, sllp=0x0000,
> > > avpnm=0x00000000, tlbiel=1, penc=7
> > > [ 0.000000] hash-mmu: base_shift=12: shift=24, sllp=0x0000,
> > > avpnm=0x00000000, tlbiel=1, penc=56
> > > [ 0.000000] hash-mmu: base_shift=16: shift=16, sllp=0x0110,
> > > avpnm=0x00000000, tlbiel=1, penc=1
> > > [ 0.000000] hash-mmu: base_shift=16: shift=24, sllp=0x0110,
> > > avpnm=0x00000000, tlbiel=1, penc=8
> > > [ 0.000000] hash-mmu: base_shift=24: shift=24, sllp=0x0100,
> > > avpnm=0x00000001, tlbiel=0, penc=0
> > > [ 0.000000] hash-mmu: base_shift=34: shift=34, sllp=0x0120,
> > > avpnm=0x000007ff, tlbiel=0, penc=3
> > > [ 0.000000] hash-mmu: Initializing hash mmu with SLB
> > > [ 0.000000] mmu_features = 0xfc006e01
> > > [ 0.000000] hash-mmu: ppc64_pft_size = 0x1b
> > > [ 0.000000] hash-mmu: htab_hash_mask = 0xfffff
> > >
> >
> > This seems to using Hash MMU, hence the error doesn't come up.
> > Since vmemmap_list is NOT empty in case of Hash MMU, so crash works as
> > expected.
> >
> >
> Thank you for the explanation, Aditya.
>
>
> > Can you try it on a system with Radix MMU ? (Rainier/Denali systems might
> > have
> > that by default)
> >
> >
> I'm afraid I don't have such machines with Radix MMU. Looks like I can not
> test it, let's reback to the discussion of patches.
>
Sure, thanks for trying.
Thanks
- Aditya Gupta
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