* Andy Lutomirski <[email protected]> wrote: > On Nov 23, 2016 10:16 AM, "Dmitry Safonov" <[email protected]> wrote: > > > > From commit 90954e7b9407 ("x86/coredump: Use pr_reg size, rather that > > TIF_IA32 flag") elf coredump file is constructed according to register > > set size - and that's good: if binary crashes with 32-bit code selector, > > generate 32-bit ELF core, otherwise - 64-bit core. > > That was made for restoring 32-bit applications on x86_64: we want > > 32-bit application after restore to generate 32-bit ELF dump on crash. > > All was quite good and recently I started reworking 32-bit applications > > dumping part of CRIU: now it has two parasites (32 and 64) for seizing > > compat/native tasks, after rework it'll have one parasite, working in > > 64-bit mode, to which 32-bit prologue long-jumps during infection. > > > > And while it has worked for my work machine, in VM with > > !CONFIG_X86_X32_ABI during reworking I faced that segfault in 32-bit > > binary, that has long-jumped to 64-bit mode results in dereference > > of garbage: > > Can you point to the actual line that's crashing? I'm wondering if we > have code that should be made more robust.
Agreed. Note that because it fixes a crash this fix is now upstream: Commit-ID: 7b2dd3682896bcf1abbbbe870885728db2832a3c Gitweb: http://git.kernel.org/tip/7b2dd3682896bcf1abbbbe870885728db2832a3c Author: Dmitry Safonov <[email protected]> AuthorDate: Wed, 23 Nov 2016 21:13:30 +0300 Committer: Ingo Molnar <[email protected]> CommitDate: Thu, 24 Nov 2016 06:01:05 +0100 x86/coredump: Always use user_regs_struct for compat_elf_gregset_t Thanks, Ingo
