[CRIU] failure dumping nginx in docker container

[Andrew Vagin]

On Wed, Jun 24, 2015 at 12:34:51PM -0700, Ross Boucher wrote:
> Here's the output same procedure without the restore-sibling option:
> https://gist.githubusercontent.com/boucher/b18593b9da2782d17e95/raw/strace.txt
> 
> It's rather long. I'm not really sure how to read the strace output.

Thank you.

16272 write(1023, "(00.139818)      1: \t\tCreate transport fd /crtools-fd-1-5\n", 58) = 58
16272 socket(PF_LOCAL, SOCK_DGRAM, 0)   = 0
16272 bind(0, {sa_family=AF_LOCAL, sun_path=@"/crtools-fd-1-5"}, 18) = 0
16272 fcntl(5, F_GETFD)                 = -1 EBADF (Bad file descriptor)
16272 dup2(0, 5)                        = 5

16272 write(1023, "(00.142054)      1: Found id pipe:[122747] (fd 8) in inherit fd list\n", 69) = 69
16272 dup(8)                            = 9
16272 write(1023, "(00.142074)      1: File pipe:[122747] will be restored from fd 9 duped from inherit fd 8\n", 90) = 90
16272 fcntl(5, F_GETFD)                 = 0
16272 write(1023, "(00.142095)      1: Error (util.c:131): fd 5 already in use (called at files.c:872)\n", 84) = 84

Looks like we meet both ends of an inhereted pipe.

The same problem can be reproduced by the pipes test with the following
path:

diff --git a/test/pipes/pipe.c b/test/pipes/pipe.c
index cb34703..03efccc 100644
--- a/test/pipes/pipe.c
+++ b/test/pipes/pipe.c
@@ -232,7 +232,7 @@ int main(int argc, char *argv[])
 
                child_pid = getpid();
 
-               close_safe(pipefd[READ_FD]);
+//             close_safe(pipefd[READ_FD]);
                setsid();
                logfd = open_safe(OLD_LOG_FILE, O_WRONLY | O_APPEND | O_CREAT);
                dup2_safe(logfd, 1);

> 
> On Tue, Jun 23, 2015 at 11:39 PM, Pavel Emelyanov <xemul at parallels.com> wrote:
> 
>     On 06/24/2015 01:42 AM, Ross Boucher wrote:
>     > If I run strace on the docker daemon, criu fails to restore with a
>     different error:
>     >
>     > https://gist.github.com/boucher/bef6e944ae700526a979
>     > (I included both the restore log and the strace)
>     >
>     > Without strace, I get the same fd already in use error.
> 
>     Hm... The new error is because criu tries to PTRACE_SEIZE the init to do
>     the
>     --restore-sibling restore and can't do it since strace is already there.
> 
>     Can you (for experiment only) patch out the --restore-sibling option from
>     the
>     code that calls criu? Or (!) call criu restore manually on the existing
>     images
>     with all the options being "correct" by yet again w/o the
>     --restore-sibling?
>    
>     -- Pavel
> 
> 
> 

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