===================================================== BUG: KMSAN: kernel-infoleak in kmsan_copy_to_user+0x9c/0xb0 mm/kmsan/kmsan_hooks.c:249 CPU: 1 PID: 18438 Comm: syz-executor.1 Not tainted 5.12.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x24c/0x2e0 lib/dump_stack.c:120 kmsan_report+0xfb/0x1e0 mm/kmsan/kmsan_report.c:121 kmsan_internal_check_memory+0x48c/0x520 mm/kmsan/kmsan.c:437 kmsan_copy_to_user+0x9c/0xb0 mm/kmsan/kmsan_hooks.c:249 instrument_copy_to_user include/linux/instrumented.h:121 [inline] _copy_to_user+0x1ac/0x270 lib/usercopy.c:33 copy_to_user include/linux/uaccess.h:209 [inline] fb_cmap_to_user+0x40a/0x990 drivers/video/fbdev/core/fbcmap.c:208 do_fb_ioctl+0xc53/0x1090 drivers/video/fbdev/core/fbmem.c:1136 fb_ioctl+0x1e4/0x210 drivers/video/fbdev/core/fbmem.c:1185 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl+0x311/0x4d0 fs/ioctl.c:739 __x64_sys_ioctl+0x4a/0x70 fs/ioctl.c:739 do_syscall_64+0x9f/0x140 arch/x86/entry/common.c:48 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x4665d9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f3c1c002188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665d9 RDX: 0000000020000140 RSI: 0000000000004604 RDI: 0000000000000003 RBP: 00000000004bfcb9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf80 R13: 0000000000a9fb1f R14: 00007f3c1c002300 R15: 0000000000022000 Uninit was created at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:121 [inline] kmsan_internal_poison_shadow+0x5c/0xf0 mm/kmsan/kmsan.c:104 kmsan_slab_alloc+0x8e/0xe0 mm/kmsan/kmsan_hooks.c:76 slab_alloc_node mm/slub.c:2922 [inline] slab_alloc mm/slub.c:2931 [inline] __kmalloc+0x387/0x550 mm/slub.c:4068 kmalloc include/linux/slab.h:559 [inline] fb_alloc_cmap_gfp+0x39b/0xa70 drivers/video/fbdev/core/fbcmap.c:104 fb_alloc_cmap+0x95/0xb0 drivers/video/fbdev/core/fbcmap.c:135 drm_fb_helper_alloc_fbi+0x106/0x3f0 drivers/gpu/drm/drm_fb_helper.c:563 drm_fb_helper_generic_probe+0x4f3/0xc70 drivers/gpu/drm/drm_fb_helper.c:2330 drm_fb_helper_single_fb_probe drivers/gpu/drm/drm_fb_helper.c:1668 [inline] __drm_fb_helper_initial_config_and_unlock+0x1cac/0x26c0 drivers/gpu/drm/drm_fb_helper.c:1826 drm_fb_helper_initial_config drivers/gpu/drm/drm_fb_helper.c:1921 [inline] drm_fbdev_client_hotplug+0xbb8/0xd70 drivers/gpu/drm/drm_fb_helper.c:2423 drm_fbdev_generic_setup+0x39d/0xa00 drivers/gpu/drm/drm_fb_helper.c:2510 vkms_create drivers/gpu/drm/vkms/vkms_drv.c:178 [inline] vkms_init+0x9d6/0xc43 drivers/gpu/drm/vkms/vkms_drv.c:202 do_one_initcall+0x362/0x8d0 init/main.c:1229 do_initcall_level+0x1e7/0x35a init/main.c:1302 do_initcalls+0x127/0x1cb init/main.c:1318 do_basic_setup+0x33/0x36 init/main.c:1338 kernel_init_freeable+0x287/0x3cc init/main.c:1540 kernel_init+0x1f/0x840 init/main.c:1427 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 Bytes 32-511 of 512 are uninitialized Memory access of size 512 starts at ffff88810497d200 =====================================================