[CRIU] [PATCH 1/4] check: seccomp suspend is now in mainline

[Kir Kolyshkin]

On 10/15/2015 03:28 PM, Tycho Andersen wrote:
> As of
> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=13c4a9011
> PTRACE_O_SUSPEND_SECCOMP is in the mainline kernel, so we should check for
> it in --ms.

Well, it was actually only merged in
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=b793c00
so the first kernel it's included is v4.3-rc1. As 4.3 is not yet released,
I'd say hold this patch for a few months.

In the mean time, I found out a horrible horrible thing -- apparently we 
can't
rely on "git describe --tags" to tell us when a patch was included. For 
example,
this patch adding PTRACE_O_SUSPEND_SECCOMP is commit 13c4a90, and

[kir at kir-tpad linux]$ git describe --tags 13c4a901
v4.1-rc1-43-g13c4a90

I guess this is the reason why https://criu.org/Upstream_kernel_commits
[incorrectly] lists (listed -- I just fixed it) it to be included into 
4.1-rc2.
In fact, it was only included into v4.3-rc1, as shown above.

This is because git describe looks back in history from the given commit
to the previous, i.e. earlier tag. In order to make sure since when the 
patch
is included, we need to look the other direction. The problem, of course, is
there is no single way.

It took me quite some time to figure out how to do this, ended up with this:

$ git log --topo-order --oneline | awk '($2 == "(tag:") {tag=$3} 
/^13c4a90/ {print tag; exit}'

And once it worked, I found out "git describe --contains" which does 
exactly what I need:

[kir at kir-tpad linux]$ git describe --contains 13c4a90
v4.3-rc1~56^2~11^2~1

So, long story short, this is what should be used to figure out which 
tagged version
contains a given commit. I wrote a short script and fixed a few other 
mistakes in
https://criu.org/Upstream_kernel_commits

>
> Signed-off-by: Tycho Andersen <tycho.andersen at canonical.com>
> ---
>   cr-check.c | 5 -----
>   1 file changed, 5 deletions(-)
>
> diff --git a/cr-check.c b/cr-check.c
> index 4842d9d..21bd508 100644
> --- a/cr-check.c
> +++ b/cr-check.c
> @@ -589,11 +589,6 @@ static int check_ptrace_suspend_seccomp(void)
>   	pid_t pid;
>   	int ret = 0;
>   
> -	if (opts.check_ms_kernel) {
> -		pr_warn("Skipping PTRACE_O_SUSPEND_SECCOMP check\n");
> -		return 0;
> -	}
> -
>   	pid = fork_and_ptrace_attach();
>   	if (pid < 0)
>   		return -1;