================================================================== BUG: KASAN: vmalloc-out-of-bounds in fb_write_offset drivers/video/fbdev/core/sysmem.h:30 [inline] BUG: KASAN: vmalloc-out-of-bounds in fb_bitmap_2ppw drivers/video/fbdev/core/fb_imageblit.h:364 [inline] BUG: KASAN: vmalloc-out-of-bounds in fb_bitmap_imageblit drivers/video/fbdev/core/fb_imageblit.h:462 [inline] BUG: KASAN: vmalloc-out-of-bounds in fb_imageblit drivers/video/fbdev/core/fb_imageblit.h:492 [inline] BUG: KASAN: vmalloc-out-of-bounds in sys_imageblit+0x19fb/0x1d60 drivers/video/fbdev/core/sysimgblt.c:24 Write of size 8 at addr ffffc90003f3b800 by task syz.2.32/6065 CPU: 1 UID: 0 PID: 6065 Comm: syz.2.32 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x156/0x4c9 mm/kasan/report.c:482 kasan_report+0xdf/0x1e0 mm/kasan/report.c:595 fb_write_offset drivers/video/fbdev/core/sysmem.h:30 [inline] fb_bitmap_2ppw drivers/video/fbdev/core/fb_imageblit.h:364 [inline] fb_bitmap_imageblit drivers/video/fbdev/core/fb_imageblit.h:462 [inline] fb_imageblit drivers/video/fbdev/core/fb_imageblit.h:492 [inline] sys_imageblit+0x19fb/0x1d60 drivers/video/fbdev/core/sysimgblt.c:24 drm_fbdev_shmem_defio_imageblit+0x20/0x130 drivers/gpu/drm/drm_fbdev_shmem.c:39 soft_cursor+0x524/0xa10 drivers/video/fbdev/core/softcursor.c:74 bit_cursor+0xe58/0x16f0 drivers/video/fbdev/core/bitblit.c:395 fbcon_cursor+0x43c/0x5e0 drivers/video/fbdev/core/fbcon.c:1379 set_cursor drivers/tty/vt/vt.c:862 [inline] set_cursor+0x1db/0x250 drivers/tty/vt/vt.c:853 con_flush_chars drivers/tty/vt/vt.c:3636 [inline] con_write+0x89/0xb0 drivers/tty/vt/vt.c:3567 process_output_block drivers/tty/n_tty.c:557 [inline] n_tty_write+0x44f/0x12d0 drivers/tty/n_tty.c:2366 iterate_tty_write drivers/tty/tty_io.c:1006 [inline] file_tty_write.isra.0+0x4d2/0x890 drivers/tty/tty_io.c:1081 tty_write drivers/tty/tty_io.c:1102 [inline] redirected_tty_write drivers/tty/tty_io.c:1125 [inline] redirected_tty_write+0xd4/0x120 drivers/tty/tty_io.c:1105 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x6ac/0x1070 fs/read_write.c:688 ksys_write+0x12a/0x250 fs/read_write.c:740 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f818cb9c819 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f818db29028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f818ce15fa0 RCX: 00007f818cb9c819 RDX: 000000000000fdef RSI: 0000200000000000 RDI: 0000000000000003 RBP: 00007f818cc32c91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f818ce16038 R14: 00007f818ce15fa0 R15: 00007ffc8a8b7e58 The buggy address belongs to a 3-page vmalloc region starting at 0xffffc90003f39000 allocated at n_tty_open+0x1a/0x170 drivers/tty/n_tty.c:1890 The buggy address belongs to the physical page: page: refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888033976e80 pfn:0x33976 flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000000 0000000000000000 dead000000000122 0000000000000000 raw: ffff888033976e80 0000000000000000 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0x2dc2(GFP_KERNEL|__GFP_HIGHMEM|__GFP_ZERO|__GFP_NOWARN), pid 6061, tgid 6058 (syz.1.30), ts 89746580489, free_ts 89746524370 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x153/0x170 mm/page_alloc.c:1889 prep_new_page mm/page_alloc.c:1897 [inline] get_page_from_freelist+0x111d/0x3140 mm/page_alloc.c:3962 __alloc_frozen_pages_noprof+0x27c/0x2ba0 mm/page_alloc.c:5250 __alloc_pages_noprof mm/page_alloc.c:5284 [inline] alloc_pages_bulk_noprof+0x782/0x1490 mm/page_alloc.c:5204 alloc_pages_bulk_mempolicy_noprof+0x255/0x1270 mm/mempolicy.c:2798 vm_area_alloc_pages mm/vmalloc.c:3706 [inline] __vmalloc_area_node mm/vmalloc.c:3876 [inline] __vmalloc_node_range_noprof+0x54b/0x1530 mm/vmalloc.c:4064 __vmalloc_node_noprof+0xad/0xf0 mm/vmalloc.c:4124 n_tty_open+0x1a/0x170 drivers/tty/n_tty.c:1890 tty_ldisc_open+0xa2/0x120 drivers/tty/tty_ldisc.c:432 tty_ldisc_setup+0x40/0xf0 drivers/tty/tty_ldisc.c:745 tty_init_dev.part.0+0x1b5/0x470 drivers/tty/tty_io.c:1431 tty_init_dev include/linux/err.h:78 [inline] tty_open_by_driver drivers/tty/tty_io.c:2073 [inline] tty_open+0xa63/0xfa0 drivers/tty/tty_io.c:2120 chrdev_open+0x234/0x6a0 fs/char_dev.c:411 do_dentry_open+0x6d8/0x1660 fs/open.c:949 vfs_open+0x82/0x3f0 fs/open.c:1081 do_open fs/namei.c:4677 [inline] path_openat+0x208c/0x31a0 fs/namei.c:4836 page last free pid 6061 tgid 6058 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1433 [inline] __free_frozen_pages+0x7e1/0x10d0 mm/page_alloc.c:2978 __kasan_populate_vmalloc_do mm/kasan/shadow.c:393 [inline] __kasan_populate_vmalloc+0x1ea/0x210 mm/kasan/shadow.c:424 kasan_populate_vmalloc include/linux/kasan.h:580 [inline] alloc_vmap_area+0x95d/0x2bd0 mm/vmalloc.c:2129 __get_vm_area_node+0x1ca/0x330 mm/vmalloc.c:3232 __vmalloc_node_range_noprof+0x213/0x1530 mm/vmalloc.c:4024 __vmalloc_node_noprof+0xad/0xf0 mm/vmalloc.c:4124 n_tty_open+0x1a/0x170 drivers/tty/n_tty.c:1890 tty_ldisc_open+0xa2/0x120 drivers/tty/tty_ldisc.c:432 tty_ldisc_setup+0x40/0xf0 drivers/tty/tty_ldisc.c:745 tty_init_dev.part.0+0x1b5/0x470 drivers/tty/tty_io.c:1431 tty_init_dev include/linux/err.h:78 [inline] tty_open_by_driver drivers/tty/tty_io.c:2073 [inline] tty_open+0xa63/0xfa0 drivers/tty/tty_io.c:2120 chrdev_open+0x234/0x6a0 fs/char_dev.c:411 do_dentry_open+0x6d8/0x1660 fs/open.c:949 vfs_open+0x82/0x3f0 fs/open.c:1081 do_open fs/namei.c:4677 [inline] path_openat+0x208c/0x31a0 fs/namei.c:4836 do_file_open+0x20e/0x430 fs/namei.c:4865 Memory state around the buggy address: ffffc90003f3b700: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ffffc90003f3b780: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 >ffffc90003f3b800: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ^ ffffc90003f3b880: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ffffc90003f3b900: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ==================================================================