Re: [Crash-utility] [PATCH 0/3] Fix KASLR problem on virsh dump and sadump

----- Original Message ----- > > > ----- Original Message ----- >> Hi Dave, Hatayama-san, >> >> These patch series fix a problem that crash cannot open a dumpfile which is >> captured by "virsh dump --memory-only" or sadump on KASLR enabled kernel. >> >> When KASLR feature is enabled, a kernel is placed on the memory randomly and >> therefore crash cannot open a dumpfile because addresses of kernel symbols in >> vmlinux are different from actual addresses. In the case of kdump, information >> to get actual address is included in the vmcoreinfo, but dumpfile of virsh dump >> or sadump does not have such a information. > > Hello Takao, > > Are you aware that the upstream maintainers of virsh are currently addressing the > issue by gathering and including phys_base in the ELF header and in the makedumpfile > kdump_sub_header? I haven't looked at this patch as of yet, but I worry whether > this will somehow interfere with virsh dump when it is released? The "virsh dump --memory-only" facility will copy all of the VMCOREINFO ELF note from kernel memory into the dumpfile, which since 4.10 includes the *value* of phys_base.

Dave > > I don't know why sadump was never able to store phys_base. But I will > defer to Daisuke as to the sadump changes. > > Dave > > > >> >> These patches calculate kaslr offset and phys_base to solve this problem. >> The >> basic idea is getting register (IDTR and CR3) from dump header, and >> calculate >> kaslr_offset/phys_base using them. >> >> Takao Indoh (3): >> Introduce x86_64_kvtop_pagetable >> Fix a KASLR problem of virsh dump >> Fix a KASLR problem of sadump >> >> defs.h | 11 ++ >> netdump.c | 505 >> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ >> netdump.h | 1 + >> sadump.c | 60 +++++++- >> sadump.h | 4 + >> symbols.c | 38 +++++ >> x86_64.c | 35 ++++- >> 7 files changed, 652 insertions(+), 2 deletions(-) >> >> -- >> 2.9.5 >> >> >> -- >> Crash-utility mailing list >> Crash-utility(a)redhat.com >> https://www.redhat.com/mailman/listinfo/crash-utility >> > > -- > Crash-utility mailing list > Crash-utility(a)redhat.com > https://www.redhat.com/mailman/listinfo/crash-utility > -- Crash-utility mailing list Crash-utility(a)redhat.com https://www.redhat.com/mailman/listinfo/crash-utility