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

[Tycho Andersen]

Hi Kir,

On Sun, Oct 18, 2015 at 02:30:13PM -0700, Kir Kolyshkin wrote:
> 
> 
> 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.

Interesting that it still gave 4.1 instead of something in 4.3-rc.
Anyway, thanks for pointing this out.

Tycho

> 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;
>