Bug 264907

Summary:	WPE / cog potential memory leak
Product:	WebKit	Reporter:	Marek Vasut <marex+webkit>
Component:	WPE WebKit	Assignee:	Nobody <webkit-unassigned>
Status:	RESOLVED INVALID
Severity:	Normal	CC:	bugs-noreply, mcatanzaro, philn
Priority:	P2
Version:	WebKit Nightly Build
Hardware:	Other
OS:	Linux

Description Marek Vasut 2023-11-15 16:31:04 PST

When viewing JS/CSS example https://codepen.io/anon/embed/rNMprwo ( first example from https://css-tricks.com/how-to-play-and-pause-css-animations-with-css-custom-properties/ ) using WPE/cog on i.MX8M with Weston 12.0.y , the WPE process grows by some 1 MiB every minute. Eventually, the system would run out of memory and the WPE process is stopped using OOM .

Invocation is ' $ cog https://codepen.io/anon/embed/rNMprwo '

This happens with both WPE 2.40.5 from meta-webkit as well as recent e99d13b4e5e1 ("[WGSL] Add validation to integer modulo https://bugs.webkit.org/show_bug.cgi?id=264603 rdar://118239748") .

I am not able to reproduce it with matching desktop WebkitGTK builds.

Currently I am looking for a way to narrow the leak down, is there some tool for that purpose that would be part of Webkit ?

Comment 1 Marek Vasut 2023-11-15 16:32:52 PST

Furthermore, mesa 23.2.1 (etnaviv driver, so gles2), Linux 6.1.62 (mainline + a couple of DT patches).

Comment 2 Philippe Normand 2023-11-16 00:02:41 PST

> Currently I am looking for a way to narrow the leak down, is there some tool for that purpose that would be part of Webkit ?

I'm not aware of specific tooling for this. Would be nice to have though!

Comment 3 Michael Catanzaro 2023-11-16 05:41:10 PST

I understand people generally try to debug such issues using sysprof, or maybe massif.

(That said, I don't think I've ever successfully debugged an issue like this ever, so....)

Comment 4 Marek Vasut 2023-11-18 21:53:46 PST

This turned out to be a memory leak in Cairo 1.16.y , fixed in 1.18.y , see https://gitlab.freedesktop.org/cairo/cairo/-/issues/805 and similar fixes in the Cairo git tree. Thanks for all the input. Massif helped narrow it down in the end. Resolved .

For future reference:
$ valgrind --tool=massif --depth=8 --trace-children=yes cog http://link
...
$ ms_print massif.out.20
    --------------------------------------------------------------------------------
    Command:            /usr/libexec/wpe-webkit-1.1/WPEWebProcess 10 24
    Massif arguments:   --depth=8
    ms_print arguments: massif.out.20
    --------------------------------------------------------------------------------
    
        MB
    121.2^                                                                       #
         |                                                                    @@@#
         |                                                                 :@@@@@#
         |                                                            @@@:::@@@@@#
         |                                                         :::@@ :::@@@@@#
         |                                                     @:@@:: @@ :::@@@@@#
         |                                                 :@@:@:@ :: @@ :::@@@@@#
         |                                            @@@@::@ :@:@ :: @@ :::@@@@@#
         |                                         :::@@ @::@ :@:@ :: @@ :::@@@@@#
         |                                     :::::::@@ @::@ :@:@ :: @@ :::@@@@@#
         |                                 ::::: : :::@@ @::@ :@:@ :: @@ :::@@@@@#
         |                            @::::: ::: : :::@@ @::@ :@:@ :: @@ :::@@@@@#
         |                         :::@: ::: ::: : :::@@ @::@ :@:@ :: @@ :::@@@@@#
         |                    @:::::: @: ::: ::: : :::@@ @::@ :@:@ :: @@ :::@@@@@#
         |                 @::@::: :: @: ::: ::: : :::@@ @::@ :@:@ :: @@ :::@@@@@#
         |             @@@:@: @::: :: @: ::: ::: : :::@@ @::@ :@:@ :: @@ :::@@@@@#
         |         @@::@@ :@: @::: :: @: ::: ::: : :::@@ @::@ :@:@ :: @@ :::@@@@@#
         |    :::::@ : @@ :@: @::: :: @: ::: ::: : :::@@ @::@ :@:@ :: @@ :::@@@@@#
         | :::: :::@ : @@ :@: @::: :: @: ::: ::: : :::@@ @::@ :@:@ :: @@ :::@@@@@#
         | : :: :::@ : @@ :@: @::: :: @: ::: ::: : :::@@ @::@ :@:@ :: @@ :::@@@@@#
       0 +----------------------------------------------------------------------->Ti
         0                                                                   1.022
...
    74.04% (21,015,725B) (heap allocation functions) malloc/new/new[], --alloc-fns, etc.
    ->31.00% (8,799,962B) 0x9F5CDFD: strdup (strdup.c:42)
    | ->20.62% (5,851,900B) 0xA0CA5C3: _cairo_font_options_init_copy (cairo-font-options.c:90)
    | | ->10.31% (2,925,825B) 0xA105792: _cairo_scaled_font_init_key (cairo-scaled-font.c:665)
    | | | ->10.31% (2,925,825B) 0xA105792: cairo_scaled_font_create (cairo-scaled-font.c:1064)
...