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SubjectRe: [PATCH v2 000/101] fbdev: Fix memory leak in option parsing
From
Geert, Helge?  Do you have further comments?  There's not really much 
for a v3 yet.

Best regards
Thomas

Am 09.03.23 um 17:00 schrieb Thomas Zimmermann:
> Introduce struct option_iter and helpers to parse command-line
> options with comma-separated key-value pairs. Then convert fbdev
> drivers to the new interface. Fixes a memory leak in the parsing of
> the video= option.
>
> Before commit 73ce73c30ba9 ("fbdev: Transfer video= option strings to
> caller; clarify ownership"), a call to fb_get_options() either
> returned an internal string or a duplicated string; hence ownership of
> the string's memory buffer was not well defined, but depended on how
> users specified the video= option on the kernel command line. For
> global settings, the caller owned the returned memory and for per-driver
> settings, fb_get_options() owned the memory. As calling drivers were
> unable to detect the case, they had no option but to leak the the memory.
>
> Commit 73ce73c30ba9 ("fbdev: Transfer video= option strings to caller;
> clarify ownership") changed semantics to caller-owned strings. Drivers
> still leaked the memory, but at least ownership was clear.
>
> This patchset fixes the memory leak and changes string ownership back
> to fb_get_options(). Patch 1 introduces struct option_iter and a few
> helpers. The interface takes an option string, such as video=, in the
> common form value1,key2:value2,value3 etc and returns the individual
> comma-separated pairs. Various modules use this pattern, so the code
> is located under lib/.
>
> Patches 2 to 100 go through fbdev drivers and convert them to the new
> interface. This often requires a number of cleanups. A driver would
> typically refer to the option string's video mode. Such strings are now
> copied to driver-allocated memory so that drivers don't refer directly
> to the option string's memory. The option iterator then replaces manual
> parsing loops based on strsep(","). All driver-allocated memory is
> released by removing the device or unloading the module.
>
> Patch 101 finally changes the ownership of the option string to be
> internal to fb_get_option(); thereby fixing the memory leak. The option
> iterator holds its own copy of the string and is not affected by the
> change.
>
> Most fbdev drivers only support to parse option strings if they are
> built-in. I assume that's because of the original fuzzy semantics of
> fb_get_options(). A later patchset could change the driver to respect
> video= settings in any configuration.
>
> v2:
> * use kstrdup()/kfree() for video strings (Geert, Timur)
> * fix iterator docs (Randy)
> * update iterator interface
>
> Thomas Zimmermann (101):
> lib: Add option iterator
> fbdev/68328fb: Remove trailing whitespaces
> fbdev/68328fb: Remove unused option string
> fbdev/acornfb: Only init fb_info once
> fbdev/acornfb: Parse option string with struct option_iter
> fbdev/amifb: Duplicate video-mode option string
> fbdev/amifb: Parse option string with struct option_iter
> fbdev/arkfb: Duplicate video-mode option string
> fbdev/atafb: Duplicate video-mode option string
> fbdev/atafb: Parse option string with struct option_iter
> fbdev/aty: Duplicate video-mode option string
> fbdev/aty: Parse option string with struct option_iter
> fbdev/au1100fb: Parse option string with struct option_iter
> fbdev/au1200fb: Parse option string with struct option_iter
> fbdev/cirrusfb: Duplicate video-mode option string
> fbdev/cirrusfb: Parse option string with struct option_iter
> fbdev/controlfb: Remove trailing whitespaces
> fbdev/controlfb: Parse option string with struct option_iter
> fbdev/cyber2000fb: Parse option string with struct option_iter
> fbdev/efifb: Parse option string with struct option_iter
> fbdev/fm2fb: Parse option string with struct option_iter
> fbdev/fsl-diu-fb: Duplicate video-mode option string
> fbdev/fsl-diu-fb: Parse option string with struct option_iter
> fbdev/gbefb: Duplicate video-mode option string
> fbdev/gbefb: Parse option string with struct option_iter
> fbdev/geode: Duplicate video-mode option string
> fbdev/geode: Parse option string with struct option_iter
> fbdev/grvga: Duplicate video-mode option string
> fbdev/grvga: Parse option string with struct option_iter
> fbdev/gxt4500: Duplicate video-mode option string
> fbdev/hyperv_fb: Duplicate video-mode option string
> fbdev/i740fb: Duplicate video-mode option string
> fbdev/i740fb: Parse option string with struct option_iter
> fbdev/i810: Duplicate video-mode option string
> fbdev/i810: Parse option string with struct option_iter
> fbdev/imsttfb: Parse option string with struct option_iter
> fbdev/intelfb: Duplicate video-mode option string
> fbdev/intelfb: Parse option string with struct option_iter
> fbdev/imxfb: Duplicate video-mode option string
> fbdev/imxfb: Parse option string with struct option_iter
> fbdev/kyrofb: Duplicate video-mode option string
> fbdev/kyrofb: Parse option string with struct option_iter
> fbdev/macfb: Remove trailing whitespaces
> fbdev/macfb: Parse option string with struct option_iter
> fbdev/matroxfb: Parse option string with struct option_iter
> fbdev/mx3fb: Duplicate video-mode option string
> fbdev/mx3fb: Parse option string with struct option_iter
> fbdev/neofb: Duplicate video-mode option string
> fbdev/neofb: Parse option string with struct option_iter
> fbdev/nvidiafb: Duplicate video-mode option string
> fbdev/nvidiafb: Parse option string with struct option_iter
> fbdev/ocfb: Duplicate video-mode option string
> fbdev/ocfb: Parse option string with struct option_iter
> fbdev/omapfb: Parse option string with struct option_iter
> fbdev/platinumfb: Remove trailing whitespaces
> fbdev/platinumfb: Parse option string with struct option_iter
> fbdev/pm2fb: Duplicate video-mode option string
> fbdev/pm2fb: Parse option string with struct option_iter
> fbdev/pm3fb: Duplicate video-mode option string
> fbdev/pm3fb: Parse option string with struct option_iter
> fbdev/ps3fb: Duplicate video-mode option string
> fbdev/ps3fb: Parse option string with struct option_iter
> fbdev/pvr2fb: Duplicate video-mode option string
> fbdev/pvr2fb: Parse option string with struct option_iter
> fbdev/pxafb: Parse option string with struct option_iter
> fbdev/rivafb: Duplicate video-mode option string
> fbdev/rivafb: Parse option string with struct option_iter
> fbdev/s3fb: Duplicate video-mode option string
> fbdev/s3fb: Parse option string with struct option_iter
> fbdev/savagefb: Duplicate video-mode option string
> fbdev/savagefb: Parse option string with struct option_iter
> fbdev/sisfb: Constify mode string
> fbdev/sisfb: Parse option string with struct option_iter
> fbdev/skeletonfb: Parse option string with struct option_iter
> fbdev/sm712fb: Duplicate video-mode option string
> fbdev/sstfb: Duplicate video-mode option string
> fbdev/sstfb: Parse option string with struct option_iter
> fbdev/stifb: Remove trailing whitespaces
> fbdev/stifb: Constify option string
> fbdev/tdfxfb: Duplicate video-mode option string
> fbdev/tdfxfb: Parse option string with struct option_iter
> fbdev/tgafb: Duplicate video-mode option string
> fbdev/tgafb: Parse option string with struct option_iter
> fbdev/tmiofb: Remove unused option string
> fbdev/tridentfb: Duplicate video-mode option string
> fbdev/tridentfb: Parse option string with struct option_iter
> fbdev/uvesafb: Duplicate video-mode option string
> fbdev/uvesafb: Parse option string with struct option_iter
> fbdev/valkyriefb: Remove trailing whitespaces
> fbdev/valkyriefb: Parse option string with struct option_iter
> fbdev/vermilion: Remove unused option string
> fbdev/vesafb: Parse option string with struct option_iter
> fbdev/vfb: Remove trailing whitespaces
> fbdev/vfb: Duplicate video-mode option string
> fbdev/vfb: Parse option string with struct option_iter
> fbdev/viafb: Parse option string with struct option_iter
> fbdev/vt8623fb: Duplicate video-mode option string
> staging/sm750fb: Release g_settings in module-exit function
> staging/sm750fb: Duplicate video-mode option string
> staging/sm750fb: Parse option string with struct option_iter
> fbdev: Constify option strings
>
> Documentation/core-api/kernel-api.rst | 9 ++
> drivers/staging/sm750fb/sm750.c | 63 ++++----
> drivers/video/fbdev/68328fb.c | 24 +--
> drivers/video/fbdev/acornfb.c | 23 ++-
> drivers/video/fbdev/amifb.c | 23 +--
> drivers/video/fbdev/arkfb.c | 10 +-
> drivers/video/fbdev/atafb.c | 21 +--
> drivers/video/fbdev/aty/aty128fb.c | 22 ++-
> drivers/video/fbdev/aty/atyfb_base.c | 23 ++-
> drivers/video/fbdev/aty/radeon_base.c | 26 +--
> drivers/video/fbdev/au1100fb.c | 13 +-
> drivers/video/fbdev/au1200fb.c | 15 +-
> drivers/video/fbdev/cirrusfb.c | 30 ++--
> drivers/video/fbdev/controlfb.c | 47 +++---
> drivers/video/fbdev/core/fb_cmdline.c | 13 +-
> drivers/video/fbdev/core/modedb.c | 8 +-
> drivers/video/fbdev/cyber2000fb.c | 17 +-
> drivers/video/fbdev/efifb.c | 44 ++---
> drivers/video/fbdev/ep93xx-fb.c | 2 +-
> drivers/video/fbdev/fm2fb.c | 14 +-
> drivers/video/fbdev/fsl-diu-fb.c | 24 +--
> drivers/video/fbdev/gbefb.c | 23 +--
> drivers/video/fbdev/geode/gx1fb_core.c | 16 +-
> drivers/video/fbdev/geode/gxfb_core.c | 23 +--
> drivers/video/fbdev/geode/lxfb_core.c | 25 +--
> drivers/video/fbdev/grvga.c | 18 ++-
> drivers/video/fbdev/gxt4500.c | 13 +-
> drivers/video/fbdev/hyperv_fb.c | 18 ++-
> drivers/video/fbdev/i740fb.c | 26 +--
> drivers/video/fbdev/i810/i810_main.c | 26 ++-
> drivers/video/fbdev/imsttfb.c | 16 +-
> drivers/video/fbdev/imxfb.c | 21 +--
> drivers/video/fbdev/intelfb/intelfbdrv.c | 23 ++-
> drivers/video/fbdev/kyro/fbdev.c | 21 ++-
> drivers/video/fbdev/macfb.c | 26 +--
> drivers/video/fbdev/matrox/matroxfb_base.c | 19 +--
> drivers/video/fbdev/mx3fb.c | 23 ++-
> drivers/video/fbdev/neofb.c | 26 +--
> drivers/video/fbdev/nvidia/nvidia.c | 26 ++-
> drivers/video/fbdev/ocfb.c | 21 ++-
> drivers/video/fbdev/omap/omapfb_main.c | 15 +-
> drivers/video/fbdev/platinumfb.c | 44 ++---
> drivers/video/fbdev/pm2fb.c | 25 +--
> drivers/video/fbdev/pm3fb.c | 27 ++--
> drivers/video/fbdev/ps3fb.c | 28 ++--
> drivers/video/fbdev/pvr2fb.c | 32 ++--
> drivers/video/fbdev/pxafb.c | 18 ++-
> drivers/video/fbdev/riva/fbdev.c | 26 ++-
> drivers/video/fbdev/s3fb.c | 27 ++--
> drivers/video/fbdev/savage/savagefb_driver.c | 20 ++-
> drivers/video/fbdev/sis/sis_main.c | 24 +--
> drivers/video/fbdev/skeletonfb.c | 17 +-
> drivers/video/fbdev/sm712fb.c | 12 +-
> drivers/video/fbdev/sstfb.c | 25 +--
> drivers/video/fbdev/stifb.c | 162 +++++++++----------
> drivers/video/fbdev/tdfxfb.c | 21 ++-
> drivers/video/fbdev/tgafb.c | 30 ++--
> drivers/video/fbdev/tmiofb.c | 24 +--
> drivers/video/fbdev/tridentfb.c | 27 ++--
> drivers/video/fbdev/uvesafb.c | 21 ++-
> drivers/video/fbdev/valkyriefb.c | 30 ++--
> drivers/video/fbdev/vermilion/vermilion.c | 7 +-
> drivers/video/fbdev/vesafb.c | 16 +-
> drivers/video/fbdev/vfb.c | 35 ++--
> drivers/video/fbdev/via/viafbdev.c | 15 +-
> drivers/video/fbdev/vt8623fb.c | 11 +-
> include/linux/cmdline.h | 36 +++++
> include/linux/fb.h | 2 +-
> lib/Makefile | 2 +-
> lib/cmdline_iter.c | 109 +++++++++++++
> 70 files changed, 1087 insertions(+), 682 deletions(-)
> create mode 100644 include/linux/cmdline.h
> create mode 100644 lib/cmdline_iter.c
>

--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev
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