On Tue, Sep 26, 2023 at 02:12:25PM +0800, lijiang wrote: > Hi, Aditya > Thank you for the update. > On Mon, Sep 25, 2023 at 5:28 PM Aditya Gupta <adityag@xxxxxxxxxxxxx> 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@xxxxxxxxxxxxx> > > Reviewed-by: Hari Bathini <hbathini@xxxxxxxxxxxxx> > > Signed-off-by: Aditya Gupta <adityag@xxxxxxxxxxxxx> > > > > --- > > > > 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. Thanks for the ack. - Aditya Gupta > > Thanks > Lianbo > > > > --- > > --- > > ppc64.c | 51 +++++++++++++++++++++++++++++++++++---------------- > > 1 file changed, 35 insertions(+), 16 deletions(-) > > > > diff --git a/ppc64.c b/ppc64.c > > index fc34006f4863..cd98a679c45e 100644 > > --- a/ppc64.c > > +++ b/ppc64.c > > @@ -1280,10 +1280,32 @@ void ppc64_vmemmap_init(void) > > long backing_size, virt_addr_offset, phys_offset, list_offset; > > ulong *vmemmap_list; > > char *vmemmap_buf; > > - struct machine_specific *ms; > > - > > - if (!(kernel_symbol_exists("vmemmap_list")) || > > - !(kernel_symbol_exists("mmu_psize_defs")) || > > + struct machine_specific *ms = machdep->machspec; > > + > > + ld = &list_data; > > + BZERO(ld, sizeof(struct list_data)); > > + > > + /* > > + * vmemmap_list is missing or set to 0 in the kernel would imply > > + * vmemmap region is mapped in the kernel pagetable. So, read > > vmemmap_list > > + * anyway and use the translation method accordingly. > > + */ > > + if (kernel_symbol_exists("vmemmap_list")) > > + readmem(symbol_value("vmemmap_list"), KVADDR, &ld->start, > > + sizeof(void *), "vmemmap_list", > > RETURN_ON_ERROR|QUIET); > > + if (!ld->start) { > > + /* > > + * vmemmap_list is set to 0 or missing. Do kernel > > pagetable walk > > + * for vmemmap address translation. > > + */ > > + ms->vmemmap_list = NULL; > > + ms->vmemmap_cnt = 0; > > + > > + machdep->flags |= VMEMMAP_AWARE; > > + return; > > + } > > + > > + if (!(kernel_symbol_exists("mmu_psize_defs")) || > > !(kernel_symbol_exists("mmu_vmemmap_psize")) || > > !STRUCT_EXISTS("vmemmap_backing") || > > !STRUCT_EXISTS("mmu_psize_def") || > > @@ -1293,8 +1315,6 @@ void ppc64_vmemmap_init(void) > > !MEMBER_EXISTS("vmemmap_backing", "list")) > > return; > > > > - ms = machdep->machspec; > > - > > backing_size = STRUCT_SIZE("vmemmap_backing"); > > virt_addr_offset = MEMBER_OFFSET("vmemmap_backing", "virt_addr"); > > phys_offset = MEMBER_OFFSET("vmemmap_backing", "phys"); > > @@ -1313,14 +1333,8 @@ void ppc64_vmemmap_init(void) > > > > ms->vmemmap_psize = 1 << shift; > > > > - ld = &list_data; > > - BZERO(ld, sizeof(struct list_data)); > > - if (!readmem(symbol_value("vmemmap_list"), > > - KVADDR, &ld->start, sizeof(void *), "vmemmap_list", > > - RETURN_ON_ERROR)) > > - return; > > - ld->end = symbol_value("vmemmap_list"); > > - ld->list_head_offset = list_offset; > > + ld->end = symbol_value("vmemmap_list"); > > + ld->list_head_offset = list_offset; > > > > hq_open(); > > cnt = do_list(ld); > > @@ -1366,7 +1380,7 @@ ppc64_vmemmap_to_phys(ulong kvaddr, physaddr_t > > *paddr, int verbose) > > { > > int i; > > ulong offset; > > - struct machine_specific *ms; > > + struct machine_specific *ms = machdep->machspec; > > > > if (!(machdep->flags & VMEMMAP_AWARE)) { > > /* > > @@ -1386,7 +1400,12 @@ ppc64_vmemmap_to_phys(ulong kvaddr, physaddr_t > > *paddr, int verbose) > > return FALSE; > > } > > > > - ms = machdep->machspec; > > + /** > > + * When vmemmap_list is not populated, kernel does the mapping in > > init_mm > > + * page table, so do a pagetable walk in kernel page table > > + */ > > + if (!ms->vmemmap_list) > > + return ppc64_vtop_level4(kvaddr, (ulong > > *)vt->kernel_pgd[0], paddr, verbose); > > > > for (i = 0; i < ms->vmemmap_cnt; i++) { > > if ((kvaddr >= ms->vmemmap_list[i].virt) && > > -- > > 2.41.0 > > > > -- Crash-utility mailing list Crash-utility@xxxxxxxxxx https://listman.redhat.com/mailman/listinfo/crash-utility Contribution Guidelines: https://github.com/crash-utility/crash/wiki
