Messages in this thread | ![/](/images/icornerl.gif) | | From | Andy Lutomirski <> | Date | Wed, 18 Mar 2015 11:06:00 -0700 | Subject | Re: [PATCH v3 1/2] x86_64,signal: Fix SS handling for signals delivered to 64-bit programs |
| |
On Wed, Mar 18, 2015 at 10:48 AM, Oleg Nesterov <oleg@redhat.com> wrote: > On 03/18, Andrey Wagin wrote: >> >> This commit breaks CRIU. I don't have any details yet. I'm going to >> investigate this issue and provide more details tomorrow. >> >> [root@avagin-fc19-cr criu]# setsid sleep 1000 & >> [1] 1225 >> [root@avagin-fc19-cr criu]# ps -C sleep >> PID TTY TIME CMD >> 1226 ? 00:00:00 sleep >> [root@avagin-fc19-cr criu]# ./criu dump -t 1226 -D dump --shell-job >> [root@avagin-fc19-cr criu]# ./criu restore -D dump --shell-job >> Error (parasite-syscall.c:923): Task is in unexpected state: b7f (SIGSEGV) > > This is funny. Because currenty I am looking into criu sources for quite > different reason (and I HATE this reason ;) > > Shot in a dark afer a quick grep: restore_gpregs() should initialize ->ss? > > perhaps something like below... obviously uncompiled/untested. > > And my grep can't find the definition of UserX86RegsEntry in crtools... > Perhaps the change below needs CPREG1(ss, anothername). > > Seriously, where is UserX86RegsEntry? > > Oleg. > > > --- a/arch/x86/crtools.c > +++ b/arch/x86/crtools.c > @@ -475,6 +475,7 @@ int restore_gpregs(struct rt_sigframe *f, UserX86RegsEntry *r) > CPREG2(rip, ip); > CPREG2(eflags, flags); > CPREG1(cs); > + CPREG1(ss); > CPREG1(gs); > CPREG1(fs);
Huh? Is CRIU actually trying to build an entire sigcontext from scratch here? I don't see how this can reliably work across kernel versions or CPU versions.
Also, what's up with CPREG1(gs) and CPREG1(fs)? I assume that's redundant, because that hasn't worked for many years, but CRIU works, so there must be correct code somewhere to restore those regs.
--Andy
| ![\](/images/icornerr.gif) |