================================================================== BUG: KASAN: slab-out-of-bounds in soft_cursor+0x458/0xa10 drivers/video/fbdev/core/softcursor.c:70 Read of size 16 at addr ffff888046855600 by task syz.1.334/7113 CPU: 1 UID: 0 PID: 7113 Comm: syz.1.334 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 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+0x13d/0x4b0 mm/kasan/report.c:482 kasan_report+0xdf/0x1c0 mm/kasan/report.c:595 check_region_inline mm/kasan/generic.c:186 [inline] kasan_check_range+0x10f/0x1e0 mm/kasan/generic.c:200 __asan_memcpy+0x23/0x60 mm/kasan/shadow.c:105 soft_cursor+0x458/0xa10 drivers/video/fbdev/core/softcursor.c:70 cw_cursor+0xd70/0x15b0 drivers/video/fbdev/core/fbcon_cw.c:324 fbcon_cursor+0x43c/0x5e0 drivers/video/fbdev/core/fbcon.c:1427 hide_cursor+0x87/0x230 drivers/tty/vt/vt.c:883 redraw_screen+0x5d4/0x760 drivers/tty/vt/vt.c:985 vc_do_resize+0xc3d/0xeb0 drivers/tty/vt/vt.c:1309 vc_resize include/linux/vt_kern.h:49 [inline] fbcon_do_set_font+0x443/0x8c0 drivers/video/fbdev/core/fbcon.c:2435 fbcon_set_def_font+0x188/0x2b0 drivers/video/fbdev/core/fbcon.c:2538 con_font_default drivers/tty/vt/vt.c:5016 [inline] con_font_op+0x541/0x1040 drivers/tty/vt/vt.c:5037 vt_k_ioctl drivers/tty/vt/vt_ioctl.c:474 [inline] vt_ioctl+0xe00/0x3150 drivers/tty/vt/vt_ioctl.c:745 tty_ioctl+0x26a/0x1640 drivers/tty/tty_io.c:2765 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f953a99e0d9 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:00007f953b7c9028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f953ac25fa0 RCX: 00007f953a99e0d9 RDX: 00002000000005c0 RSI: 0000000000004b72 RDI: 0000000000000009 RBP: 00007f953aa35024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f953ac26038 R14: 00007f953ac25fa0 R15: 00007fff192b72a8 Allocated by task 6640: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5337 [inline] __kmalloc_noprof+0x324/0x820 mm/slub.c:5362 _kmalloc_noprof include/linux/slab.h:992 [inline] _kmalloc_array_noprof include/linux/slab.h:1208 [inline] font_data_rotate+0x353/0x3b0 lib/fonts/font_rotate.c:231 fbcon_rotate_font+0x2bf/0x510 drivers/video/fbdev/core/fbcon_rotate.c:33 fbcon_modechanged+0x218/0x7f0 drivers/video/fbdev/core/fbcon.c:2664 fbcon_rotate drivers/video/fbdev/core/fbcon.c:230 [inline] rotate_store+0x261/0x300 drivers/video/fbdev/core/fbcon.c:3196 dev_attr_store+0x58/0x80 drivers/base/core.c:2509 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:145 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:345 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x6af/0x1050 fs/read_write.c:687 ksys_write+0x12a/0x250 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888046855400 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 0 bytes to the right of allocated 512-byte region [ffff888046855400, ffff888046855600) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888046854400 pfn:0x46854 head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000240(workingset|head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000240 ffff88801c042c80 ffffea00011a2110 ffffea0000f04710 raw: ffff888046854400 0000000800100006 00000000f5000000 0000000000000000 head: 00fff00000000240 ffff88801c042c80 ffffea00011a2110 ffffea0000f04710 head: ffff888046854400 0000000800100006 00000000f5000000 0000000000000000 head: 00fff00000000002 ffffffffffffff01 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000004 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 6301, tgid 6301 (syz-executor), ts 67189837292 set_page_owner include/linux/page_owner.h:33 [inline] post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1871 prep_new_page mm/page_alloc.c:1879 [inline] get_page_from_freelist+0x110d/0x35b0 mm/page_alloc.c:3943 __alloc_frozen_pages_noprof+0x2eb/0x3300 mm/page_alloc.c:5436 alloc_slab_page mm/slub.c:3267 [inline] allocate_slab mm/slub.c:3382 [inline] new_slab+0xa5/0x640 mm/slub.c:3428 refill_objects+0xe3/0x410 mm/slub.c:7305 refill_sheaf mm/slub.c:2805 [inline] __pcs_replace_empty_main+0x372/0x680 mm/slub.c:4677 alloc_from_pcs mm/slub.c:4775 [inline] slab_alloc_node mm/slub.c:4907 [inline] __do_kmalloc_node mm/slub.c:5336 [inline] __kmalloc_noprof+0x66b/0x820 mm/slub.c:5362 _kmalloc_noprof include/linux/slab.h:992 [inline] _kzalloc_noprof include/linux/slab.h:1309 [inline] fib6_info_alloc+0x40/0x160 net/ipv6/ip6_fib.c:155 ip6_route_info_create+0x14c/0xad0 net/ipv6/route.c:3833 addrconf_f6i_alloc+0x2d9/0x670 net/ipv6/route.c:4714 fixup_permanent_addr net/ipv6/addrconf.c:3612 [inline] addrconf_permanent_addr net/ipv6/addrconf.c:3663 [inline] addrconf_notify+0x13c6/0x1ba0 net/ipv6/addrconf.c:3730 notifier_call_chain+0x99/0x3f0 kernel/notifier.c:85 call_netdevice_notifiers_info+0xbe/0x110 net/core/dev.c:2275 call_netdevice_notifiers_extack net/core/dev.c:2313 [inline] call_netdevice_notifiers net/core/dev.c:2327 [inline] __dev_notify_flags+0x22c/0x4b0 net/core/dev.c:9853 netif_change_flags+0x108/0x160 net/core/dev.c:9882 do_setlink.isra.0+0x1ac4/0x3e60 net/core/rtnetlink.c:3266 page last free pid 5731 tgid 5731 ts 50377277737 stack trace: reset_page_owner include/linux/page_owner.h:26 [inline] __free_pages_prepare mm/page_alloc.c:1418 [inline] __free_frozen_pages+0x79f/0x10f0 mm/page_alloc.c:2962 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x47/0xf0 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x1a0/0x1f0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:350 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4586 [inline] slab_alloc_node mm/slub.c:4919 [inline] kmem_cache_alloc_noprof+0x26b/0x6a0 mm/slub.c:4933 proc_reg_open+0x23f/0x5f0 fs/proc/inode.c:502 do_dentry_open+0x6ab/0x14d0 fs/open.c:996 vfs_open+0x82/0x3f0 fs/open.c:1101 do_open fs/namei.c:4837 [inline] path_openat+0x19fa/0x2440 fs/namei.c:5000 do_file_open+0x20e/0x430 fs/namei.c:5029 do_sys_openat2+0x10f/0x1e0 fs/open.c:1417 do_sys_open fs/open.c:1423 [inline] __do_sys_openat fs/open.c:1439 [inline] __se_sys_openat fs/open.c:1434 [inline] __x64_sys_openat+0x12d/0x210 fs/open.c:1434 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff888046855500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff888046855580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff888046855600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff888046855680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888046855700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================