From: Omar Polo <op@omarpolo.com>
Subject: Re: crash in 'got log' (no reliable way to reproduce)
To: Mikhail <mp39590@gmail.com>
Cc: gameoftrees@openbsd.org
Date: Sat, 01 Apr 2023 13:45:03 +0200

On 2023/04/01 13:04:53 +0300, Mikhail <mp39590@gmail.com> wrote:
> core:/sys$ got log -p  dev/pci/if_iwx.c  | less
> /updatechan
> n
> n
> (i suspect next pressings should be done quickly)
> <ctrl-c>
> q
> 
> Core is here: https://people.freebsd.org/~misha/got.core

Haven't tried to reproduce with this recipe, but looking at the
stacktrace it seems that blob is NULL and got_object_blob_close
doesn't like it.

> Reading symbols from got...
> [New process 31956]
> Core was generated by `got'.
> Program terminated with signal SIGSEGV, Segmentation fault.
> #0  0x0000030e9bd80ec5 in got_object_blob_close (blob=0x0) at /home/misha/work/got/got/../lib/object.c:360
> 360             free(blob->read_buf);
> gef➤  bt
> #0  0x0000030e9bd80ec5 in got_object_blob_close (blob=0x0) at /home/misha/work/got/got/../lib/object.c:360
> #1  0x0000030e9bd6427a in diff_blobs (blob_id1=0x3116c2de400, blob_id2=0x3116c2decc0, path=0x310f0af3480 "//sys/dev/pci/if_iwx.c", diff_context=0x3, ignore_whitespace=0x0, force_text_diff=0x0, dsa=0x0,
>     repo=0x310bb102460, outfile=0x31158fac818 <__sF+152>) at /home/misha/work/got/got/got.c:3711

So I guess the issue is here.  We should guard
got_object_blob_close(blob2) like with do with blob1.

diff /home/op/w/got
commit - e9e0377f452e9d3f600011e0714cc6c779f10bab
path + /home/op/w/got
blob - a51a450a06ab2800d2fe4a200fc31cc59364dac6
file + got/got.c
--- got/got.c
+++ got/got.c
@@ -3707,9 +3707,10 @@ done:
 	if (blob1)
 		got_object_blob_close(blob1);
 	if (fd2 != -1 && close(fd2) == -1 && err == NULL)
 		err = got_error_from_errno("close");
-	got_object_blob_close(blob2);
+	if (blob2)
+		got_object_blob_close(blob2);
 	if (f1 && fclose(f1) == EOF && err == NULL)
 		err = got_error_from_errno("fclose");
 	if (f2 && fclose(f2) == EOF && err == NULL)
 		err = got_error_from_errno("fclose");