[Possible Bug] Commit generates GC repack failure

>
> Hi All,
>
> I'm trying to track down what happened this morning. We had a commit that
> caused a background gc to occur. What happened was:
>
> $ git commit -m "history commit ... "
> Auto packing the repository in background for optimum performance.
> See "git help gc" for manual housekeeping.
> warning: The last gc run reported the following. Please correct the root
> cause
> and remove .git/gc.log.
> Automatic cleanup will not be performed until the file is removed.
>
> fatal: open /dev/null failed: Invalid function argument

> fatal: failed to run repack
>
> Obviously the /dev/null open was not right, but I don't know where this is
> in the git code to investigate further. Any pointers on where to look would
> be appreciated. This started happening at  2.20.1 on the NonStop platform.
>
> Cheers,
> Randall
>
> -- Brief whoami:
>  NonStop developer since approximately 211288444200000000
>  UNIX developer since approximately 421664400
> -- In my real life, I talk too much.
>
>
>
>

>
> On Mon, Jan 14, 2019 at 9:51 PM Randall S. Becker
> <rsbecker@nexbridge.com> wrote:
> >
> > Hi All,
> >
> > I'm trying to track down what happened this morning. We had a commit that
> > caused a background gc to occur. What happened was:
> >
> > $ git commit -m "history commit ... "
> > Auto packing the repository in background for optimum performance.
> > See "git help gc" for manual housekeeping.
> > warning: The last gc run reported the following. Please correct the root
> > cause
> > and remove .git/gc.log.
> > Automatic cleanup will not be performed until the file is removed.
> >
> > fatal: open /dev/null failed: Invalid function argument
>
> sanitize_stdfds() in setup.c can attempt to open /dev/null then
> redirect stdout and stderr to it. I think this is part of the
> daemonization that is done in background gc.

> Hi All,
>
> I'm trying to track down what happened this morning. We had a commit that
> caused a background gc to occur. What happened was:
>
> $ git commit -m "history commit ... "
> Auto packing the repository in background for optimum performance.
> See "git help gc" for manual housekeeping.
> warning: The last gc run reported the following. Please correct the root
> cause
> and remove .git/gc.log.
> Automatic cleanup will not be performed until the file is removed.
>
> fatal: open /dev/null failed: Invalid function argument
> fatal: failed to run repack
>
> Obviously the /dev/null open was not right, but I don't know where this is
> in the git code to investigate further. Any pointers on where to look would
> be appreciated. This started happening at  2.20.1 on the NonStop platform.

> On Mon, Jan 14 2019, Randall S. Becker wrote:
> 
> > Hi All,
> >
> > I'm trying to track down what happened this morning. We had a commit
> > that caused a background gc to occur. What happened was:
> >
> > $ git commit -m "history commit ... "
> > Auto packing the repository in background for optimum performance.
> > See "git help gc" for manual housekeeping.
> > warning: The last gc run reported the following. Please correct the
> > root cause and remove .git/gc.log.
> > Automatic cleanup will not be performed until the file is removed.
> >
> > fatal: open /dev/null failed: Invalid function argument
> > fatal: failed to run repack
> >
> > Obviously the /dev/null open was not right, but I don't know where
> > this is in the git code to investigate further. Any pointers on where
> > to look would be appreciated. This started happening at  2.20.1 on the
> NonStop platform.
> 
> We use start_command() when gc does run_command_v_opt() of e.g. git-
> repack. See in that file:
> 
>     null_fd = open("/dev/null", O_RDWR | O_CLOEXEC)
> 
> Maybe that sort of code just fails on NonStop?