Noralf Trønnes
951df98024
UBSAN complains about invalid value for bool:
[ 101.165172] [drm] Initialized gud 1.0.0 20200422 for 2-3.2:1.0 on minor 1
[ 101.213360] gud 2-3.2:1.0: [drm] fb1: guddrmfb frame buffer device
[ 101.213426] usbcore: registered new interface driver gud
[ 101.989431] ================================================================================
[ 101.989441] UBSAN: invalid-load in linux/include/linux/iosys-map.h:253:9
[ 101.989447] load of value 121 is not a valid value for type '_Bool'
[ 101.989451] CPU: 1 PID: 455 Comm: kworker/1:6 Not tainted 5.18.0-rc5-gud-5.18-rc5 #3
[ 101.989456] Hardware name: Hewlett-Packard HP EliteBook 820 G1/1991, BIOS L71 Ver. 01.44 04/12/2018
[ 101.989459] Workqueue: events_long gud_flush_work [gud]
[ 101.989471] Call Trace:
[ 101.989474] <TASK>
[ 101.989479] dump_stack_lvl+0x49/0x5f
[ 101.989488] dump_stack+0x10/0x12
[ 101.989493] ubsan_epilogue+0x9/0x3b
[ 101.989498] __ubsan_handle_load_invalid_value.cold+0x44/0x49
[ 101.989504] dma_buf_vmap.cold+0x38/0x3d
[ 101.989511] ? find_busiest_group+0x48/0x300
[ 101.989520] drm_gem_shmem_vmap+0x76/0x1b0 [drm_shmem_helper]
[ 101.989528] drm_gem_shmem_object_vmap+0x9/0xb [drm_shmem_helper]
[ 101.989535] drm_gem_vmap+0x26/0x60 [drm]
[ 101.989594] drm_gem_fb_vmap+0x47/0x150 [drm_kms_helper]
[ 101.989630] gud_prep_flush+0xc1/0x710 [gud]
[ 101.989639] ? _raw_spin_lock+0x17/0x40
[ 101.989648] gud_flush_work+0x1e0/0x430 [gud]
[ 101.989653] ? __switch_to+0x11d/0x470
[ 101.989664] process_one_work+0x21f/0x3f0
[ 101.989673] worker_thread+0x200/0x3e0
[ 101.989679] ? rescuer_thread+0x390/0x390
[ 101.989684] kthread+0xfd/0x130
[ 101.989690] ? kthread_complete_and_exit+0x20/0x20
[ 101.989696] ret_from_fork+0x22/0x30
[ 101.989706] </TASK>
[ 101.989708] ================================================================================
The source of this warning is in iosys_map_clear() called from
dma_buf_vmap(). It conditionally sets values based on map->is_iomem. The
iosys_map variables are allocated uninitialized on the stack leading to
->is_iomem having all kinds of values and not only 0/1.
Fix this by zeroing the iosys_map variables.
Fixes: 40e1a70b4a ("drm: Add GUD USB Display driver")
Cc: <stable@vger.kernel.org> # v5.18+
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20221122-gud-shadow-plane-v2-1-435037990a83@tronnes.org
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.