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Peter Wu authored
After drm_fb_helper_fbdev_setup calls drm_fb_helper_init, "dev->fb_helper" will be initialized (and thus drm_fb_helper_fini will have some effect). After that, drm_fb_helper_initial_config is called which may call the "fb_probe" driver callback. This driver callback may call drm_fb_helper_defio_init (as is done by drm_fb_helper_generic_probe) or set a framebuffer (as is done by bochs) as documented. These are normally cleaned up on exit by drm_fb_helper_fbdev_teardown which also calls drm_fb_helper_fini. If an error occurs after "fb_probe", but before setup is complete, then calling just drm_fb_helper_fini will leak resources. This was triggered by df2052cc ("bochs: convert to drm_fb_helper_fbdev_setup/teardown"): [ 50.008030] bochsdrmfb: enable CONFIG_FB_LITTLE_ENDIAN to support this framebuffer [ 50.009436] bochs-drm 0000:00:02.0: [drm:drm_fb_helper_fbdev_setup] *ERROR* fbdev: Failed to set configuration (ret=-38) [ 50.011456] [drm] Initialized bochs-drm 1.0.0 20130925 for 0000:00:02.0 on minor 2 [ 50.013604] WARNING: CPU: 1 PID: 1 at drivers/gpu/drm/drm_mode_config.c:477 drm_mode_config_cleanup+0x280/0x2a0 [ 50.016175] CPU: 1 PID: 1 Comm: swapper/0 Tainted: G T 4.20.0-rc7 #1 [ 50.017732] EIP: drm_mode_config_cleanup+0x280/0x2a0 ... [ 50.023155] Call Trace: [ 50.023155] ? bochs_kms_fini+0x1e/0x30 [ 50.023155] ? bochs_unload+0x18/0x40 This can be reproduced with QEMU and CONFIG_FB_LITTLE_ENDIAN=n. Link: https://lkml.kernel.org/r/20181221083226.GI23332@shao2-debian Link: https://lkml.kernel.org/r/20181223004315.GA11455@al Fixes: 87412163 ("drm/fb-helper: Add drm_fb_helper_fbdev_setup/teardown()") Reported-by:
kernel test robot <rong.a.chen@intel.com> Cc: Noralf Trønnes <noralf@tronnes.org> Signed-off-by:
Peter Wu <peter@lekensteyn.nl> Reviewed-by:
Noralf Trønnes <noralf@tronnes.org> Signed-off-by:
00eb5b0d
