This is a note to let you know that I've just added the patch titled
drm/gud: Fix UBSAN warning
to the 6.2-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-gud-fix-ubsan-warning.patch
and it can be found in the queue-6.2 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 951df98024f7272f85df5044eca7374f5b5b24ef Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Noralf=20Tr=C3=B8nnes?= <noralf@xxxxxxxxxxx>
Date: Wed, 30 Nov 2022 20:26:49 +0100
Subject: drm/gud: Fix UBSAN warning
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
From: Noralf Trønnes <noralf@xxxxxxxxxxx>
commit 951df98024f7272f85df5044eca7374f5b5b24ef upstream.
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: 40e1a70b4aed ("drm: Add GUD USB Display driver")
Cc: <stable@xxxxxxxxxxxxxxx> # v5.18+
Reviewed-by: Javier Martinez Canillas <javierm@xxxxxxxxxx>
Reviewed-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
Signed-off-by: Noralf Trønnes <noralf@xxxxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20221122-gud-shadow-plane-v2-1-435037990a83@xxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/gud/gud_pipe.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/gpu/drm/gud/gud_pipe.c
+++ b/drivers/gpu/drm/gud/gud_pipe.c
@@ -157,8 +157,8 @@ static int gud_prep_flush(struct gud_dev
{
struct dma_buf_attachment *import_attach = fb->obj[0]->import_attach;
u8 compression = gdrm->compression;
- struct iosys_map map[DRM_FORMAT_MAX_PLANES];
- struct iosys_map map_data[DRM_FORMAT_MAX_PLANES];
+ struct iosys_map map[DRM_FORMAT_MAX_PLANES] = { };
+ struct iosys_map map_data[DRM_FORMAT_MAX_PLANES] = { };
struct iosys_map dst;
void *vaddr, *buf;
size_t pitch, len;
Patches currently in stable-queue which might be from noralf@xxxxxxxxxxx are
queue-6.2/drm-gud-fix-ubsan-warning.patch
