Your patch is not correct, it will leave row_buffer unitialized if it fails and the program will crash afterwards anyway. Please handle correctly the failure case

Created attachment 41782 [details] [review]
patch to call setjmp before jpeg_create_decompress()

Thanks.  The attached patch makes sure to initialize row_buffer even if jpeg_create_decompress() fails.  Though DCTStream still keeps uninitialized cinfo after failure, I think that it is safe since each jpeg_*() checks the state internally.

There's still something that needs improvement, i did

diff --git a/poppler/DCTStream.cc b/poppler/DCTStream.cc
index 212a8bd..34db5bf 100644
--- a/poppler/DCTStream.cc
+++ b/poppler/DCTStream.cc
@@ -91,8 +91,10 @@ void DCTStream::init()
   limit = NULL;
   
   cinfo.err = &jerr;
-  jpeg_create_decompress(&cinfo);
-  cinfo.src = (jpeg_source_mgr *)&src;
+  if (false && !setjmp(src.setjmp_buffer)) {
+    jpeg_create_decompress(&cinfo);
+    cinfo.src = (jpeg_source_mgr *)&src;
+  }
   row_buffer = NULL;
 }
 

To simulate a "failure" of jpeg_create_decompress and then ran pdftoppm over a file that uses that code and still crashes. Could you try to find what is the problem?

Created attachment 41798 [details] [review]
patch to call setjmp before jpeg_create_decompress()

Right, sorry for bothering you.

I'm attaching a new patch, which I tested with:
- edit /usr/include/jpeglib.h to change JPEG_LIB_VERSION (80 -> 81 here)
- rebuild poppler
- run cpp/tests/poppler-render -o foo.png ~/pdf-embedding-jpeg.pdf

Actually the previous patches crash poppler-render :-(

Created attachment 41799 [details] [review]
patch to call setjmp before jpeg_create_decompress()

Sorry again, the previous patch breaks the normal case...
This patch should work with both cases.

Created attachment 41802 [details] [review]
patch to call setjmp before jpeg_create_decompress()

Moved setjmp_buffer from str_src_mgr to a wrapper struct of jpeg_error_mgr so as to catch failures after cinfo->src is cleared in jpeg_create_decompress().

Commited, thanks.