Re: [Crash-utility] [PATCH v2] ppc64: do page traversal if vmemmap_list not populated

Hi, Aditya Thank you for the update. On Mon, Sep 25, 2023 at 5:28 PM Aditya Gupta <adityag(a)linux.ibm.com&gt; wrote: > Currently 'crash-tool' fails on vmcore collected on upstream kernel on > PowerPC64 with the error: > > crash: invalid kernel virtual address: 0 type: "first list entry > > Presently the address translation for vmemmap addresses is done using > the vmemmap_list. But with the below commit in Linux, vmemmap_list can > be empty, in case of Radix MMU on PowerPC64 > > 368a0590d954: (powerpc/book3s64/vmemmap: switch radix to use a > different vmemmap handling function) > > In case vmemmap_list is empty, then it's head is NULL, which crash tries > to access and fails due to accessing NULL. > > Instead of depending on 'vmemmap_list' for address translation for > vmemmap addresses, do a kernel pagetable walk to get the physical > address associated with given virtual address > > Tested-by: Sachin Sant <sachinp(a)linux.ibm.com&gt; > Reviewed-by: Hari Bathini <hbathini(a)linux.ibm.com&gt; > Signed-off-by: Aditya Gupta <adityag(a)linux.ibm.com&gt; > > --- > > Testing > ======= > > Git tree with patch applied: > https://github.com/adi-g15-ibm/crash/tree/bugzilla-203296-list-v2 > > This can be tested with '/proc/vmcore' as the vmcore, since makedumpfile > also fails in absence of 'vmemmap_list' in upstream linux > > The fix for makedumpfile will also been sent to upstream > > Changelog > ========= > > V2 > + handle the case of 'vmemmap_list' symbol missing according to reviews > > The v2 looks good to me, so: Ack.