================================================================== BUG: KASAN: slab-out-of-bounds in fast_imageblit drivers/video/fbdev/core/sysimgblt.c:251 [inline] BUG: KASAN: slab-out-of-bounds in sys_imageblit+0x1cf7/0x23d0 drivers/video/fbdev/core/sysimgblt.c:302 Read of size 1 at addr ffff88801bbca000 by task syz-executor.0/16244 CPU: 0 PID: 16244 Comm: syz-executor.0 Tainted: G W 5.17.0-syzkaller-09727-g34af78c4e616 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1dc/0x2d8 lib/dump_stack.c:106 print_address_description+0x64/0x400 mm/kasan/report.c:247 __kasan_report mm/kasan/report.c:434 [inline] kasan_report+0x19a/0x1f0 mm/kasan/report.c:451 fast_imageblit drivers/video/fbdev/core/sysimgblt.c:251 [inline] sys_imageblit+0x1cf7/0x23d0 drivers/video/fbdev/core/sysimgblt.c:302 drm_fb_helper_sys_imageblit drivers/gpu/drm/drm_fb_helper.c:826 [inline] drm_fbdev_fb_imageblit+0x163/0x300 drivers/gpu/drm/drm_fb_helper.c:2327 soft_cursor+0xace/0xd20 drivers/video/fbdev/core/softcursor.c:74 bit_cursor+0x1848/0x2430 drivers/video/fbdev/core/bitblit.c:377 hide_cursor+0x7e/0x310 drivers/tty/vt/vt.c:907 redraw_screen+0x1d4/0x1280 drivers/tty/vt/vt.c:1012 vc_do_resize+0x1361/0x1930 drivers/tty/vt/vt.c:1342 fbcon_do_set_font+0x9ef/0x10d0 drivers/video/fbdev/core/fbcon.c:2442 fbcon_set_font+0x9f9/0xc80 drivers/video/fbdev/core/fbcon.c:2528 con_font_set drivers/tty/vt/vt.c:4666 [inline] con_font_op+0xbcd/0x1080 drivers/tty/vt/vt.c:4710 vt_k_ioctl drivers/tty/vt/vt_ioctl.c:474 [inline] vt_ioctl+0x183f/0x38a0 drivers/tty/vt/vt_ioctl.c:752 tty_ioctl+0xf6a/0x1830 drivers/tty/tty_io.c:2778 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl+0xfb/0x170 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7fd87b489049 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 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fd87c5a0168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fd87b59bf60 RCX: 00007fd87b489049 RDX: 0000000020000000 RSI: 0000000000004b72 RDI: 0000000000000003 RBP: 00007fd87b4e308d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fff07e256bf R14: 00007fd87c5a0300 R15: 0000000000022000 Allocated by task 1: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track mm/kasan/common.c:45 [inline] set_alloc_info mm/kasan/common.c:436 [inline] ____kasan_kmalloc+0xdc/0x110 mm/kasan/common.c:515 kasan_kmalloc include/linux/kasan.h:249 [inline] kmem_cache_alloc_trace+0x9d/0x330 mm/slub.c:3258 kmalloc include/linux/slab.h:581 [inline] do_register_framebuffer drivers/video/fbdev/core/fbmem.c:1632 [inline] register_framebuffer+0x406/0xa50 drivers/video/fbdev/core/fbmem.c:1892 __drm_fb_helper_initial_config_and_unlock+0x1481/0x1e80 drivers/gpu/drm/drm_fb_helper.c:1899 drm_fb_helper_initial_config drivers/gpu/drm/drm_fb_helper.c:1965 [inline] drm_fbdev_client_hotplug+0x688/0x800 drivers/gpu/drm/drm_fb_helper.c:2477 drm_fbdev_generic_setup+0x191/0x410 drivers/gpu/drm/drm_fb_helper.c:2564 vkms_create drivers/gpu/drm/vkms/vkms_drv.c:208 [inline] vkms_init+0x5b7/0x71a drivers/gpu/drm/vkms/vkms_drv.c:233 do_one_initcall+0xbd/0x2b0 init/main.c:1298 do_initcall_level+0x14a/0x1f5 init/main.c:1371 do_initcalls+0x4b/0x8c init/main.c:1387 kernel_init_freeable+0x43a/0x5c6 init/main.c:1613 kernel_init+0x19/0x2b0 init/main.c:1502 ret_from_fork+0x1f/0x30 The buggy address belongs to the object at ffff88801bbc8000 which belongs to the cache kmalloc-8k of size 8192 The buggy address is located 0 bytes to the right of 8192-byte region [ffff88801bbc8000, ffff88801bbca000) The buggy address belongs to the page: page:ffffea00006ef200 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1bbc8 head:ffffea00006ef200 order:3 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 0000000000000000 dead000000000001 ffff888011442280 raw: 0000000000000000 0000000000020002 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, ts 6173302991, free_ts 0 prep_new_page mm/page_alloc.c:2382 [inline] get_page_from_freelist+0x708/0xa80 mm/page_alloc.c:4123 __alloc_pages+0x255/0x580 mm/page_alloc.c:5349 alloc_page_interleave+0x22/0x1c0 mm/mempolicy.c:2107 alloc_slab_page+0x70/0xf0 mm/slub.c:1799 allocate_slab+0x5d/0x380 mm/slub.c:1944 new_slab mm/slub.c:2004 [inline] ___slab_alloc+0x40e/0xcc0 mm/slub.c:3005 __slab_alloc mm/slub.c:3092 [inline] slab_alloc_node mm/slub.c:3183 [inline] slab_alloc mm/slub.c:3225 [inline] kmem_cache_alloc_trace+0x28c/0x330 mm/slub.c:3256 kmalloc include/linux/slab.h:581 [inline] do_register_framebuffer drivers/video/fbdev/core/fbmem.c:1632 [inline] register_framebuffer+0x406/0xa50 drivers/video/fbdev/core/fbmem.c:1892 __drm_fb_helper_initial_config_and_unlock+0x1481/0x1e80 drivers/gpu/drm/drm_fb_helper.c:1899 drm_fb_helper_initial_config drivers/gpu/drm/drm_fb_helper.c:1965 [inline] drm_fbdev_client_hotplug+0x688/0x800 drivers/gpu/drm/drm_fb_helper.c:2477 drm_fbdev_generic_setup+0x191/0x410 drivers/gpu/drm/drm_fb_helper.c:2564 vkms_create drivers/gpu/drm/vkms/vkms_drv.c:208 [inline] vkms_init+0x5b7/0x71a drivers/gpu/drm/vkms/vkms_drv.c:233 do_one_initcall+0xbd/0x2b0 init/main.c:1298 do_initcall_level+0x14a/0x1f5 init/main.c:1371 do_initcalls+0x4b/0x8c init/main.c:1387 kernel_init_freeable+0x43a/0x5c6 init/main.c:1613 page_owner free stack trace missing Memory state around the buggy address: ffff88801bbc9f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88801bbc9f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff88801bbca000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff88801bbca080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88801bbca100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================