Dear Sir or Madame, A while ago I have described my problem with Homebrew at the following GitHub channel (https://github.com/Homebrew/homebrew-core/issues/2970). In the meanwhile, I believe that I my problem with Homebrew is based on an issues with my Git. I have found the attached Git Crash reports on my Mac and because I am not familiar with reading/analysing Crash Reports, it would be great if someone could give me some feedback on it. If you have any question, please do not hesitate to contact me. Thanks a lot in advance and best regards, Jonas
Heiko VoigtRe: Homebrew and Git
Hi,
On Sun, Sep 18, 2016 at 05:50:28PM +0200, Jonas Thiel wrote:
Show 10 quoted lines
> A while ago I have described my problem with Homebrew at the following > GitHub channel > (https://github.com/Homebrew/homebrew-core/issues/2970). In the > meanwhile, I believe that I my problem with Homebrew is based on an > issues with my Git. I have found the attached Git Crash reports on my > Mac and because I am not familiar with reading/analysing Crash > Reports, it would be great if someone could give me some feedback on > it. > > If you have any question, please do not hesitate to contact me.
From your crash reports I see that git is apparently crashing in a strchr() call from within ident_default_email() which is a function that tries to assemble a name and email to put into your commits.
Can you post us the output of
hostname -f
and
whoami
?
Since it seems you are using an Apple git can you also give us the output of
git version
Since it seems that Apple is compiling its own git (and not publishing the changes they made conveniently via git). Have you tried installing a vanilla git via homebrew and seeing whether that also produces the issue?
In your bugreport you are talking about modifications you do to your system after which the issue occurred. I would suggest to exactly find out which step lead to git crashing (if it actually is the issue). First to identify an issue we need something that is reproduceable.
Cheers Heiko
Heiko VoigtRe: Re: Homebrew and Git
On Tue, Sep 20, 2016 at 01:02:28PM +0200, Heiko Voigt wrote:
Show 17 quoted lines
> Hi, > > On Sun, Sep 18, 2016 at 05:50:28PM +0200, Jonas Thiel wrote: > > A while ago I have described my problem with Homebrew at the following > > GitHub channel > > (https://github.com/Homebrew/homebrew-core/issues/2970). In the > > meanwhile, I believe that I my problem with Homebrew is based on an > > issues with my Git. I have found the attached Git Crash reports on my > > Mac and because I am not familiar with reading/analysing Crash > > Reports, it would be great if someone could give me some feedback on > > it. > > > > If you have any question, please do not hesitate to contact me. > > From your crash reports I see that git is apparently crashing in a > strchr() call from within ident_default_email() which is a function that > tries to assemble a name and email to put into your commits.
BTW, here is the callstack inlined from the crashreport:
bsystem_platform.dylib 0x00007fff840db41c _platform_strchr$VARIANT$Haswell + 28 1 git 0x000000010ba1d3f4 ident_default_email + 801 2 git 0x000000010ba1d68f fmt_ident + 66 3 git 0x000000010ba4b495 files_log_ref_write + 175 4 git 0x000000010ba4b0a6 commit_ref_update + 106 5 git 0x000000010ba4c3a8 ref_transaction_commit + 468 6 git 0x000000010b994dd8 s_update_ref + 271 7 git 0x000000010b994556 fetch_refs + 1969 8 git 0x000000010b9935f2 fetch_one + 1913 9 git 0x000000010b992bc4 cmd_fetch + 549 10 git 0x000000010b9666c4 handle_builtin + 478 11 git 0x000000010b96602f main + 376 12 libdyld.dylib 0x00007fff834ef5ad start + 1
Maybe someone else has an idea what might be causing this...
Cheers Heiko
John KeepingRe: Re: Homebrew and Git
On Tue, Sep 20, 2016 at 01:07:00PM +0200, Heiko Voigt wrote:
Show 36 quoted lines
> On Tue, Sep 20, 2016 at 01:02:28PM +0200, Heiko Voigt wrote: > > Hi, > > > > On Sun, Sep 18, 2016 at 05:50:28PM +0200, Jonas Thiel wrote: > > > A while ago I have described my problem with Homebrew at the following > > > GitHub channel > > > (https://github.com/Homebrew/homebrew-core/issues/2970). In the > > > meanwhile, I believe that I my problem with Homebrew is based on an > > > issues with my Git. I have found the attached Git Crash reports on my > > > Mac and because I am not familiar with reading/analysing Crash > > > Reports, it would be great if someone could give me some feedback on > > > it. > > > > > > If you have any question, please do not hesitate to contact me. > > > > From your crash reports I see that git is apparently crashing in a > > strchr() call from within ident_default_email() which is a function that > > tries to assemble a name and email to put into your commits. > > BTW, here is the callstack inlined from the crashreport: > > bsystem_platform.dylib 0x00007fff840db41c _platform_strchr$VARIANT$Haswell + 28 > 1 git 0x000000010ba1d3f4 ident_default_email + 801 > 2 git 0x000000010ba1d68f fmt_ident + 66 > 3 git 0x000000010ba4b495 files_log_ref_write + 175 > 4 git 0x000000010ba4b0a6 commit_ref_update + 106 > 5 git 0x000000010ba4c3a8 ref_transaction_commit + 468 > 6 git 0x000000010b994dd8 s_update_ref + 271 > 7 git 0x000000010b994556 fetch_refs + 1969 > 8 git 0x000000010b9935f2 fetch_one + 1913 > 9 git 0x000000010b992bc4 cmd_fetch + 549 > 10 git 0x000000010b9666c4 handle_builtin + 478 > 11 git 0x000000010b96602f main + 376 > 12 libdyld.dylib 0x00007fff834ef5ad start + 1 > > Maybe someone else has an idea what might be causing this...
The only strchr I can see that could be called here is in canonical_name(), where it's called with addrinfo::ai_canonname.
Searching for OS X and ai_canonname, leads me straight back to this list, although 7 years ago! I think ident.c needs a fix similar to commit 3e8a00a (daemon.c: fix segfault on OS X, 2009-04-27); from the commit message there:
On OS X (and maybe other unices), getaddrinfo(3) returns NULL in the ai_canonname field if it's called with an IP address for the hostname.
Jeff KingRe: Re: Homebrew and Git
On Tue, Sep 20, 2016 at 08:15:55PM +0100, John Keeping wrote:
Show 20 quoted lines
> > BTW, here is the callstack inlined from the crashreport: > > > > bsystem_platform.dylib 0x00007fff840db41c _platform_strchr$VARIANT$Haswell + 28 > > 1 git 0x000000010ba1d3f4 ident_default_email + 801 > > 2 git 0x000000010ba1d68f fmt_ident + 66 > > 3 git 0x000000010ba4b495 files_log_ref_write + 175 > > 4 git 0x000000010ba4b0a6 commit_ref_update + 106 > > 5 git 0x000000010ba4c3a8 ref_transaction_commit + 468 > > 6 git 0x000000010b994dd8 s_update_ref + 271 > > 7 git 0x000000010b994556 fetch_refs + 1969 > > 8 git 0x000000010b9935f2 fetch_one + 1913 > > 9 git 0x000000010b992bc4 cmd_fetch + 549 > > 10 git 0x000000010b9666c4 handle_builtin + 478 > > 11 git 0x000000010b96602f main + 376 > > 12 libdyld.dylib 0x00007fff834ef5ad start + 1 > > > > Maybe someone else has an idea what might be causing this... > > The only strchr I can see that could be called here is in > canonical_name(), where it's called with addrinfo::ai_canonname.
There's one in add_domainname(), too, but it can never be NULL (we could walk off the end of the buffer, but only if gethostname() lies to us about its result code, which seems unlikely). So I agree it's probably the call in canonical_name().
Show 8 quoted lines
> Searching for OS X and ai_canonname, leads me straight back to this > list, although 7 years ago! I think ident.c needs a fix similar to > commit 3e8a00a (daemon.c: fix segfault on OS X, 2009-04-27); from the > commit message there: > > On OS X (and maybe other unices), getaddrinfo(3) returns NULL > in the ai_canonname field if it's called with an IP address for > the hostname.
Interesting. We are already prepared for failure from getaddrinfo() here, so probably:
diff --git a/ident.c b/ident.c index e20a772..d17b5bd 100644 --- a/ident.c +++ b/ident.c @@ -101,7 +101,7 @@ static int canonical_name(const char *host, struct strbuf *out) memset (&hints, '\0', sizeof (hints)); hints.ai_flags = AI_CANONNAME; if (!getaddrinfo(host, NULL, &hints, &ai)) { - if (ai && strchr(ai->ai_canonname, '.')) { + if (ai && ai->ai_canonname && strchr(ai->ai_canonname, '.')) { strbuf_addstr(out, ai->ai_canonname); status = 0; } would be sufficient. Jonas, can you see if that patch helps? -Peff
Aw: Re: Re: Homebrew and Git
Sorry for my late reply. Thanks for your support -- I really appreciate that.
@Jeff: Unfortunately, I do not know how to implement the patch you provided. Can you explain how to do that?
Thanks and best regards, Jonas
Show 64 quoted lines
> Gesendet: Mittwoch, 21. September 2016 um 10:48 Uhr
> Von: "Jeff King" <peff@peff.net>
> An: "John Keeping" <john@keeping.me.uk>
> Cc: "Heiko Voigt" <hvoigt@hvoigt.net>, "Jonas Thiel" <jonas.lierschied@gmx.de>, git@vger.kernel.org
> Betreff: Re: Re: Homebrew and Git
>
> On Tue, Sep 20, 2016 at 08:15:55PM +0100, John Keeping wrote:
>
> > > BTW, here is the callstack inlined from the crashreport:
> > >
> > > bsystem_platform.dylib 0x00007fff840db41c _platform_strchr$VARIANT$Haswell + 28
> > > 1 git 0x000000010ba1d3f4 ident_default_email + 801
> > > 2 git 0x000000010ba1d68f fmt_ident + 66
> > > 3 git 0x000000010ba4b495 files_log_ref_write + 175
> > > 4 git 0x000000010ba4b0a6 commit_ref_update + 106
> > > 5 git 0x000000010ba4c3a8 ref_transaction_commit + 468
> > > 6 git 0x000000010b994dd8 s_update_ref + 271
> > > 7 git 0x000000010b994556 fetch_refs + 1969
> > > 8 git 0x000000010b9935f2 fetch_one + 1913
> > > 9 git 0x000000010b992bc4 cmd_fetch + 549
> > > 10 git 0x000000010b9666c4 handle_builtin + 478
> > > 11 git 0x000000010b96602f main + 376
> > > 12 libdyld.dylib 0x00007fff834ef5ad start + 1
> > >
> > > Maybe someone else has an idea what might be causing this...
> >
> > The only strchr I can see that could be called here is in
> > canonical_name(), where it's called with addrinfo::ai_canonname.
>
> There's one in add_domainname(), too, but it can never be NULL (we could
> walk off the end of the buffer, but only if gethostname() lies to us
> about its result code, which seems unlikely). So I agree it's probably
> the call in canonical_name().
>
> > Searching for OS X and ai_canonname, leads me straight back to this
> > list, although 7 years ago! I think ident.c needs a fix similar to
> > commit 3e8a00a (daemon.c: fix segfault on OS X, 2009-04-27); from the
> > commit message there:
> >
> > On OS X (and maybe other unices), getaddrinfo(3) returns NULL
> > in the ai_canonname field if it's called with an IP address for
> > the hostname.
>
> Interesting. We are already prepared for failure from getaddrinfo()
> here, so probably:
>
> diff --git a/ident.c b/ident.c
> index e20a772..d17b5bd 100644
> --- a/ident.c
> +++ b/ident.c
> @@ -101,7 +101,7 @@ static int canonical_name(const char *host, struct strbuf *out)
> memset (&hints, '\0', sizeof (hints));
> hints.ai_flags = AI_CANONNAME;
> if (!getaddrinfo(host, NULL, &hints, &ai)) {
> - if (ai && strchr(ai->ai_canonname, '.')) {
> + if (ai && ai->ai_canonname && strchr(ai->ai_canonname, '.')) {
> strbuf_addstr(out, ai->ai_canonname);
> status = 0;
> }
>
> would be sufficient. Jonas, can you see if that patch helps?
>
> -Peff
> 
Stefan BellerRe: Re: Re: Homebrew and Git
On Thu, Sep 22, 2016 at 2:23 AM, Jonas Thiel <jonas.lierschied@gmx.de> wrote:
> Sorry for my late reply. Thanks for your support -- I really appreciate that. > > @Jeff: Unfortunately, I do not know how to implement the patch you provided. Can you explain how to do that?
I think this should do:
git clone https://github.com/git/git
cd git
# get the email
wget http://public-inbox.org/git/20160921084841.phq7cfbagi5k7ku4@sigill.intra.peff.net/raw
# apply patch:
git am raw
make
make installShow 68 quoted lines
>
> Thanks and best regards,
> Jonas
>
>> Gesendet: Mittwoch, 21. September 2016 um 10:48 Uhr
>> Von: "Jeff King" <peff@peff.net>
>> An: "John Keeping" <john@keeping.me.uk>
>> Cc: "Heiko Voigt" <hvoigt@hvoigt.net>, "Jonas Thiel" <jonas.lierschied@gmx.de>, git@vger.kernel.org
>> Betreff: Re: Re: Homebrew and Git
>>
>> On Tue, Sep 20, 2016 at 08:15:55PM +0100, John Keeping wrote:
>>
>> > > BTW, here is the callstack inlined from the crashreport:
>> > >
>> > > bsystem_platform.dylib 0x00007fff840db41c _platform_strchr$VARIANT$Haswell + 28
>> > > 1 git 0x000000010ba1d3f4 ident_default_email + 801
>> > > 2 git 0x000000010ba1d68f fmt_ident + 66
>> > > 3 git 0x000000010ba4b495 files_log_ref_write + 175
>> > > 4 git 0x000000010ba4b0a6 commit_ref_update + 106
>> > > 5 git 0x000000010ba4c3a8 ref_transaction_commit + 468
>> > > 6 git 0x000000010b994dd8 s_update_ref + 271
>> > > 7 git 0x000000010b994556 fetch_refs + 1969
>> > > 8 git 0x000000010b9935f2 fetch_one + 1913
>> > > 9 git 0x000000010b992bc4 cmd_fetch + 549
>> > > 10 git 0x000000010b9666c4 handle_builtin + 478
>> > > 11 git 0x000000010b96602f main + 376
>> > > 12 libdyld.dylib 0x00007fff834ef5ad start + 1
>> > >
>> > > Maybe someone else has an idea what might be causing this...
>> >
>> > The only strchr I can see that could be called here is in
>> > canonical_name(), where it's called with addrinfo::ai_canonname.
>>
>> There's one in add_domainname(), too, but it can never be NULL (we could
>> walk off the end of the buffer, but only if gethostname() lies to us
>> about its result code, which seems unlikely). So I agree it's probably
>> the call in canonical_name().
>>
>> > Searching for OS X and ai_canonname, leads me straight back to this
>> > list, although 7 years ago! I think ident.c needs a fix similar to
>> > commit 3e8a00a (daemon.c: fix segfault on OS X, 2009-04-27); from the
>> > commit message there:
>> >
>> > On OS X (and maybe other unices), getaddrinfo(3) returns NULL
>> > in the ai_canonname field if it's called with an IP address for
>> > the hostname.
>>
>> Interesting. We are already prepared for failure from getaddrinfo()
>> here, so probably:
>>
>> diff --git a/ident.c b/ident.c
>> index e20a772..d17b5bd 100644
>> --- a/ident.c
>> +++ b/ident.c
>> @@ -101,7 +101,7 @@ static int canonical_name(const char *host, struct strbuf *out)
>> memset (&hints, '\0', sizeof (hints));
>> hints.ai_flags = AI_CANONNAME;
>> if (!getaddrinfo(host, NULL, &hints, &ai)) {
>> - if (ai && strchr(ai->ai_canonname, '.')) {
>> + if (ai && ai->ai_canonname && strchr(ai->ai_canonname, '.')) {
>> strbuf_addstr(out, ai->ai_canonname);
>> status = 0;
>> }
>>
>> would be sufficient. Jonas, can you see if that patch helps?
>>
>> -Peff
>>Jeff KingRe: Re: Re: Homebrew and Git
On Thu, Sep 22, 2016 at 08:57:45AM -0700, Stefan Beller wrote:
Show 13 quoted lines
> On Thu, Sep 22, 2016 at 2:23 AM, Jonas Thiel <jonas.lierschied@gmx.de> wrote: > > Sorry for my late reply. Thanks for your support -- I really appreciate that. > > > > @Jeff: Unfortunately, I do not know how to implement the patch you provided. Can you explain how to do that? > > I think this should do: > > git clone https://github.com/git/git > cd git > # get the email > wget http://public-inbox.org/git/20160921084841.phq7cfbagi5k7ku4@sigill.intra.peff.net/raw > # apply patch: > git am raw
I publish my topic branches via git, too, so it may be easier to replace these steps with:
git clone -b jk/ident-canonname https://github.com/peff/git cd git
> make > make install
After installing, you probably want to do:
PATH=/path/to/git/bin-wrappers:$PATH
to run the new git (and make sure that any git sub-commands that are run come from the built version, not the rest of the system).
I have access to an OS X system, but if I understand the bug correctly, reproducing it may involve re-setting the system hostname, which is not something I'll be able to do. But I'll give it a shot.
-Peff
Jeff King[PATCH] ident: handle NULL ai_canonname
On Fri, Sep 23, 2016 at 12:07:30AM -0400, Jeff King wrote:
> I have access to an OS X system, but if I understand the bug correctly, > reproducing it may involve re-setting the system hostname, which is not > something I'll be able to do. But I'll give it a shot.
Actually, it turned out to be pretty simple to reproduce (after reading 3e8a00a that John found, anyway; hooray for detailed commit messages). We just have to fake the output of gethostname(), but that is easily done since we can modify git's source. :)
So I was able to reproduce the bug, and indeed, the patch I posted fixes it. Here it is with a commit message.
Jonas, I'd be curious to know what the output of "hostname" is on your system.
-- >8 -- Subject: [PATCH] ident: handle NULL ai_canonname
We call getaddrinfo() to try to convert a short hostname into a fully-qualified one (to use it as an email domain). If there isn't a canonical name, getaddrinfo() will generally return either a NULL addrinfo list, or one in which ai->ai_canonname is a copy of the original name.
However, if the result of gethostname() looks like an IP address, then getaddrinfo() behaves differently on some systems. On OS X, it will return a "struct addrinfo" with a NULL ai_canonname, and we segfault feeding it to strchr().
This is hard to test reliably because it involves not only a system where we we have to fallback to gethostname() to come up with an ident, but also where the hostname is a number with no dots. But I was able to replicate the bug by faking a hostname, like:
diff --git a/ident.c b/ident.c
index e20a772..b790d28 100644
--- a/ident.c
+++ b/ident.c
@@ -128,6 +128,7 @@ static void add_domainname(struct strbuf *out, int *is_bogus)
*is_bogus = 1;
return;
}
+ xsnprintf(buf, sizeof(buf), "1");
if (strchr(buf, '.'))
strbuf_addstr(out, buf);
else if (canonical_name(buf, out) < 0) {and running "git var GIT_AUTHOR_IDENT" on an OS X system.
Before this patch it segfaults, and after we correctly complain of the bogus "user@1.(none)" address (though this bogus address would be suitable for non-object uses like writing reflogs).
Reported-by: Jonas Thiel <jonas.lierschied@gmx.de> Diagnosed-by: John Keeping <john@keeping.me.uk> Signed-off-by: Jeff King <peff@peff.net> --- ident.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/ident.c b/ident.c index e20a772..d17b5bd 100644 --- a/ident.c +++ b/ident.c @@ -101,7 +101,7 @@ static int canonical_name(const char *host, struct strbuf *out) memset (&hints, '\0', sizeof (hints)); hints.ai_flags = AI_CANONNAME; if (!getaddrinfo(host, NULL, &hints, &ai)) { - if (ai && strchr(ai->ai_canonname, '.')) { + if (ai && ai->ai_canonname && strchr(ai->ai_canonname, '.')) { strbuf_addstr(out, ai->ai_canonname); status = 0; }
-- 2.10.0.482.gae5a597
Aw: Re: Homebrew and Git
Hi Heiko,
thanks for your reply on my issue.
Here are the following outputs you asked for:
git version git version 2.7.4 (Apple Git-66)
hostname -f 0x6A6E73
whoami jns
I have tried the Homebrew version of git, but no change in case of the issue.
I just customized my system with the Mathias Bynens dotfiles (https://github.com/mathiasbynens/dotfiles) as well as with drduhs OS X Security Guide (https://github.com/drduh/OS-X-Security-and-Privacy-Guide). Because I reinstall my Mac on a regularly basis, wherefore I can say that one year ago these tweaks have not caused any issue.
Thanks a lot. I really appreciate your help.
Cheers, Jonas
Show 51 quoted lines
> Gesendet: Dienstag, 20. September 2016 um 13:02 Uhr > Von: "Heiko Voigt" <hvoigt@hvoigt.net> > An: "Jonas Thiel" <jonas.lierschied@gmx.de> > Cc: git@vger.kernel.org > Betreff: Re: Homebrew and Git > > Hi, > > On Sun, Sep 18, 2016 at 05:50:28PM +0200, Jonas Thiel wrote: > > A while ago I have described my problem with Homebrew at the following > > GitHub channel > > (https://github.com/Homebrew/homebrew-core/issues/2970). In the > > meanwhile, I believe that I my problem with Homebrew is based on an > > issues with my Git. I have found the attached Git Crash reports on my > > Mac and because I am not familiar with reading/analysing Crash > > Reports, it would be great if someone could give me some feedback on > > it. > > > > If you have any question, please do not hesitate to contact me. > > From your crash reports I see that git is apparently crashing in a > strchr() call from within ident_default_email() which is a function that > tries to assemble a name and email to put into your commits. > > Can you post us the output of > > hostname -f > > and > > whoami > > ? > > Since it seems you are using an Apple git can you also give us the > output of > > git version > > Since it seems that Apple is compiling its own git (and not publishing > the changes they made conveniently via git). Have you tried > installing a vanilla git via homebrew and seeing whether that also > produces the issue? > > In your bugreport you are talking about modifications you do to your > system after which the issue occurred. I would suggest to exactly find > out which step lead to git crashing (if it actually is the issue). First > to identify an issue we need something that is reproduceable. > > Cheers Heiko >