Re: Regression in git-subtree.sh, introduced in 2.20.1, after 315a84f9aa0e2e629b0680068646b0032518ebed

From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Dec 9, 2019, 15:26 UTC
Message-ID: <nycvar.QRO.7.76.6.1912091615200.31080@tvgsbejvaqbjf.bet>
In-Reply-To: <1676A670-C8B7-482B-B330-B03B35CB6B5E@msys.ch>

Hi,

On Mon, 9 Dec 2019, Marc Balmer wrote:

> I am not familiar with the source code, so I can not send in that
> revert.  I can, however, say that I am grateful to whomever does it ;)

I am against reverting the change without knowing the root cause.

The recent reporter only compared Git for Windows v2.19.0 vs v2.20.1, which is _quite_ a big difference.

For what I know, the problem might be a change in the MSYS2 runtime that is mistaken by some malware for malicious code (we did introduce some code to emulate Ctrl+C in MinTTY which injects a remote thread and executes ExitProcess() there, which might very well be construed as an attack, even if it is actually very much desired behavior).

These segmentation faults in `git subtree` on Windows have traditionally been _all_ because of overzealous anti-malware.

So first, a much more fine-grained analysis would be required, e.g. comparing v2.20.1 against v2.20.0, then copying _just_ the `git-subtree` file from a working into a non-working version (or vice versa; I would highly recommend using the portable versions for such side-by side comparison).

Ciao, Johannes

Show 128 quoted lines

>
> - Marc
>
>
> > Am 09.12.2019 um 15:18 schrieb Strain, Roger L. <roger.strain@swri.org>:
> >
> > As I said, I'm using a custom script here. I don't know if anybody else
> > benefited from the change and hasn't said anything, but I won't object
> > to someone submitting that revert.
> >
> > --
> > Roger
> >
> > -----Original Message-----
> > From: Marc Balmer <marc@msys.ch>
> > To: "Strain, Roger L." <roger.strain@swri.org>
> > Cc: ns@nadavsinai.com <ns@nadavsinai.com>, git@vger.kernel.org <
> > git@vger.kernel.org>, Johannes.Schindelin@gmx.de <
> > Johannes.Schindelin@gmx.de>, gitster@pobox.com <gitster@pobox.com>,
> > pclouds@gmail.com <pclouds@gmail.com>
> > Subject: Re: Regression in git-subtree.sh, introduced in 2.20.1, after
> > 315a84f9aa0e2e629b0680068646b0032518ebed
> > Date: Mon, 09 Dec 2019 15:13:47 +0100
> >
> > Roger,
> >
> > I am all for reverting it. if that does not cause any other regressions
> > or headaches (or both...)
> >
> > - Marc
> >
> >
> >
> > Am 09.12.2019 um 15:11 schrieb Strain, Roger L. <roger.strain@swri.org>
> > :
> >
> > I haven't been able to find anything relating to the issue, but I also
> > haven't had a repo that exposes the problem to test more thoroughly
> > against. If this happens to be a public repo somewhere, I'd be more
> > than happy to take a second look.
> >
> > That being said, if the community feels it would be better to revert
> > the changes that were introduced, I won't object. I've had to further
> > customize the script for our internal use, and those changes aren't
> > something that would be useful for the public at large. (A few changes
> > relate to the presence/absence of a specific file, which I certainly
> > wouldn't expect anyone else to have.) Short story is we're going to
> > have to use a custom script going forward, so keeping or reverting the
> > changes here make no difference to us. I still feel that the changes
> > which were made make the script more correct, but clearly there's some
> > undiagnosed logic error somewhere.
> >
> > Honestly, I'm surprised we didn't see this particular issue show up on
> > our own repo; it's ridiculously large and complex. At least if it had,
> > I'd be able to troubleshoot it more reliably.
> >
> > --
> > Roger Strain
> >
> > -----Original Message-----
> > From: Nadav SInai <ns@nadavsinai.com>
> > To: roger.strain@swri.org
> > Cc: Johannes.Schindelin@gmx.de, git@vger.kernel.org, gitster@pobox.com,
> > marc@msys.ch, pclouds@gmail.com
> > Subject: RE: Regression in git-subtree.sh, introduced in 2.20.1, after
> > 315a84f9aa0e2e629b0680068646b0032518ebed
> > Date: Sun, 08 Dec 2019 12:30:48 +0200
> >
> > [EXTERNAL EMAIL]
> >
> > Hi, I'm curious if any of you had any luck in preventing that
> > seg-fault in git-subtree script
> > I'm encountering it myself using git 2.24.0.windows.2., seg-fault is
> > in the same while loop (currently on line 757)
> > When I tried your suggestion of adding the ($parents) ($rev) to the
> > progress print I see that the last commit have only one revision
> > printed
> > like this:
> >
> > 259/290 (523) [271] (843dd34090d36dfabd6a2e3e8459a4887427313b)
> > (a69ee056f66acf66c63f89f55d26c0cc17036623)
> > 259/290 (525) [273] (f5eea1a3cbe1e16acba53e8a9fe07b6525a8b97c)
> > (843dd34090d36dfabd6a2e3e8459a4887427313b)
> > 259/290 (527) [275] (82303752a428cf1d789ac9f156008adb2798b7b5)
> > (f5eea1a3cbe1e16acba53e8a9fe07b6525a8b97c)
> > 259/290 (528) [276]
> > (7187897883c9fb4d33d4c87a02b876f8603728ff05f0945ae2ce9f98a35135)
> > 259/290 (529) [277]
> > (a00a3665343439a426671958dd90ed0407a22cad9ac9f156008adb2798b7b5)
> > 259/290 (530) [278]
> > (90beb94ebd331c457d79d05341453f5829a50bfcd4c87a02b876f8603728ff)
> > 259/290 (531) [279]
> > (9582e0acbed1910173564e250f350b5cc4291a7f671958dd90ed0407a22cad)
> > 259/290 (532) [280]
> > (f183930d6fabd3dccdddc5ec35d754ad28caf3b879d05341453f5829a50bfc)
> > 259/290 (533) [281]
> > (c9309f3a38c41f7991d9e78ddb47f7e85b8521eb564e250f350b5cc4291a7f)
> > 259/290 (534) [282]
> > (3bcf08f63a0e2b93ecc376bd679a16c80e99e7b1ddc5ec35d754ad28caf3b8)
> > 259/290 (535) [283]
> > (134621bb55a0470cdf6519ce08d6909af43ce0e5d9e78ddb47f7e85b8521eb)
> > 259/290 (536) [284]
> > (edb3471fbba29748f9784d29b3cee1dee2df4b37c376bd679a16c80e99e7b1)
> > 259/290 (537) [285]
> > (dd947a095df07a32dfd56666a395a7c42b25ca116519ce08d6909af43ce0e5)
> > 259/290 (538) [286]
> > (a639e09d2cbe1ea1149c080c1c95b8b018340ae2784d29b3cee1dee2df4b37)
> > C:/Program Files/Git/mingw64/libexec/git-core\git-subtree: line 757:
> > 8853 Done                    eval "$grl"
> >     8854 Segmentation fault      (core dumped) | while read rev
> > parents; do
> >   process_split_commit "$rev" "$parents" 0;
> > done
> >
> > I downgraded git to 2.19.0-windows.1 and it works now.
> >
> >
> > I'm thankful for your insights
> > Nadav Sinai
> > Web Tech lead
> > Philips-Algotec
> >
> >
> >
> >
> >
>
>