Bug 89952 - Memory Leak in CairoFreeTypeFont::create
Summary: Memory Leak in CairoFreeTypeFont::create
Status: RESOLVED FIXED
Alias: None
Product: poppler
Classification: Unclassified
Component: cairo backend (show other bugs)
Version: unspecified
Hardware: All All
: medium minor
Assignee: poppler-bugs
QA Contact:
URL:
Whiteboard:
Keywords:
: 89951 (view as bug list)
Depends on:
Blocks:
 
Reported: 2015-04-08 07:00 UTC by Jason Crain
Modified: 2015-04-13 12:20 UTC (History)
0 users

See Also:
i915 platform:
i915 features:


Attachments
PDF with duplicate TrueType fonts (2.35 KB, application/pdf)
2015-04-08 07:00 UTC, Jason Crain
Details
Free font data when we find duplicate (737 bytes, patch)
2015-04-08 07:05 UTC, Jason Crain
Details | Splinter Review
Fix memory leak in CairoFreeTypeFont::create (2.05 KB, patch)
2015-04-09 04:00 UTC, Jason Crain
Details | Splinter Review

Description Jason Crain 2015-04-08 07:00:27 UTC
Created attachment 114946 [details]
PDF with duplicate TrueType fonts

Attached PDF has a duplicated font which causes a memory leak.  Output of valgrind --tool=memcheck --leak-check=full --show-leak-kinds=definite pdftocairo -png pdf/CairoDoubleTrueType.pdf a :

==10368== 4,096 bytes in 1 blocks are definitely lost in loss record 129 of 137
==10368==    at 0x4C28C20: malloc (vg_replace_malloc.c:296)
==10368==    by 0x50553B8: gmalloc(unsigned long, bool) (gmem.cc:110)
==10368==    by 0x5055425: gmalloc (gmem.cc:120)
==10368==    by 0x4F45C04: Stream::toUnsignedChars(int*, int, int) (Stream.h:147)
==10368==    by 0x4FA5036: GfxFont::readEmbFontFile(XRef*, int*) (GfxFont.cc:908)
==10368==    by 0x41A3F1: CairoFreeTypeFont::create(GfxFont*, XRef*, FT_LibraryRec_*, bool) (CairoFontEngine.cc:433)
==10368==    by 0x41B5CE: CairoFontEngine::getFont(GfxFont*, PDFDoc*, bool, XRef*) (CairoFontEngine.cc:818)
==10368==    by 0x40E2F3: CairoOutputDev::updateFont(GfxState*) (CairoOutputDev.cc:631)
==10368==    by 0x4F99E20: Gfx::opShowText(Object*, int) (Gfx.cc:3803)
==10368==    by 0x4F89F6B: Gfx::execOp(Object*, Object*, int) (Gfx.cc:904)
==10368==    by 0x4F8989C: Gfx::go(bool) (Gfx.cc:763)
==10368==    by 0x4F896D0: Gfx::display(Object*, bool) (Gfx.cc:729)
Comment 1 Jason Crain 2015-04-08 07:05:23 UTC
Created attachment 114947 [details] [review]
Free font data when we find duplicate

Attached patch frees the font data when _ft_new_face detects a duplicate.
Comment 2 Carlos Garcia Campos 2015-04-08 17:02:01 UTC
Comment on attachment 114947 [details] [review]
Free font data when we find duplicate

Review of attachment 114947 [details] [review]:
-----------------------------------------------------------------

The commit message is a bit confusing, this only happens when _ft_new_face is called with font_data + font_data_len (embedded fonts). I wonder if we should release that data in more cases, because _ft_done_face is assuming the data is mmaped. So, for example, when FT_New_Memory_Face fails, we should also free the data? Should we check in _ft_done_face if data->fd is -1 to do the unmap ro gfree? I'm confused, because _ft_done_face should fail for embedded fonts, or it's simply never called due to the cairo cache being always alive.
Comment 3 Carlos Garcia Campos 2015-04-08 17:05:27 UTC
Ok, I'm seeing patch in bug #89951 now, it does what I suggested indeed. I think we should still free the bytes also when FT_New_Memory_Face fails. I think all these are pretty much the same thing, we are leaking the data of embedded fonts, so we could probably merge both bugs into a single one with a single patch.
Comment 4 Jason Crain 2015-04-09 03:28:34 UTC
*** Bug 89951 has been marked as a duplicate of this bug. ***
Comment 5 Jason Crain 2015-04-09 04:00:49 UTC
Created attachment 114973 [details] [review]
Fix memory leak in CairoFreeTypeFont::create

I was hoping it would be less confusing as separate patches. :)

I've squashed the patches.  This frees things in three places:

- In _ft_done_face, free the embedded font data.
- In _ft_new_face, free the embedded font data if it's found to be a duplicate.
- In CairoFreeTypeFont::create, free the embedded font data and codeToGID array if font creation fails.
Comment 6 Carlos Garcia Campos 2015-04-10 11:10:54 UTC
(In reply to Jason Crain from comment #5)
> Created attachment 114973 [details] [review] [review]
> Fix memory leak in CairoFreeTypeFont::create
> 
> I was hoping it would be less confusing as separate patches. :)

And confused me :-P

> I've squashed the patches.  This frees things in three places:
> 
> - In _ft_done_face, free the embedded font data.
> - In _ft_new_face, free the embedded font data if it's found to be a
> duplicate.

You should also free the bytes in _ft_new_face when FT_New_Memory_Face fails, no?

> - In CairoFreeTypeFont::create, free the embedded font data and codeToGID
> array if font creation fails.

Good catch! This one is probably more unrelated and could be in a separate patch, but I'm fine with a single patch too.
Comment 7 Jason Crain 2015-04-13 00:23:33 UTC
(In reply to Carlos Garcia Campos from comment #6)
> You should also free the bytes in _ft_new_face when FT_New_Memory_Face
> fails, no?

It should be fine because when FT_New_Memory_Face fails, _ft_new_face will return false, and CairoFreeTypeFont::create will free it in the err2 label.
Comment 8 Carlos Garcia Campos 2015-04-13 12:20:49 UTC
(In reply to Jason Crain from comment #7)
> (In reply to Carlos Garcia Campos from comment #6)
> > You should also free the bytes in _ft_new_face when FT_New_Memory_Face
> > fails, no?
> 
> It should be fine because when FT_New_Memory_Face fails, _ft_new_face will
> return false, and CairoFreeTypeFont::create will free it in the err2 label.

Ah, I missed the gfree(font_data) in err2: label part. Pushed to git master now, thanks!


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