================================================================== BUG: KASAN: slab-out-of-bounds in __fb_pad_aligned_buffer include/linux/fb.h:654 [inline] BUG: KASAN: slab-out-of-bounds in bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:96 [inline] BUG: KASAN: slab-out-of-bounds in bit_putcs+0x103a/0x1bf0 drivers/video/fbdev/core/bitblit.c:185 Read of size 1 at addr ffff8880977e2120 by task syz-executor.1/1877 CPU: 0 PID: 1877 Comm: syz-executor.1 Not tainted 5.9.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1d6/0x29e lib/dump_stack.c:118 print_address_description+0x66/0x620 mm/kasan/report.c:383 __kasan_report mm/kasan/report.c:513 [inline] kasan_report+0x132/0x1d0 mm/kasan/report.c:530 __fb_pad_aligned_buffer include/linux/fb.h:654 [inline] bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:96 [inline] bit_putcs+0x103a/0x1bf0 drivers/video/fbdev/core/bitblit.c:185 fbcon_putcs+0x790/0xaf0 drivers/video/fbdev/core/fbcon.c:1362 do_update_region+0x462/0x620 drivers/tty/vt/vt.c:675 redraw_screen+0xa25/0x1420 drivers/tty/vt/vt.c:1034 fbcon_modechanged+0x8d5/0xd90 drivers/video/fbdev/core/fbcon.c:3022 do_fb_ioctl+0x5df/0x6e0 drivers/video/fbdev/core/fbmem.c:1106 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl+0xfb/0x170 fs/ioctl.c:739 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45d5f9 Code: 5d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 2b b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f87d6552c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000000e280 RCX: 000000000045d5f9 RDX: 00000000200001c0 RSI: 0000000000004601 RDI: 0000000000000003 RBP: 000000000118cf80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cf4c R13: 00007ffff430306f R14: 00007f87d65539c0 R15: 000000000118cf4c Allocated by task 15911: kasan_save_stack mm/kasan/common.c:48 [inline] kasan_set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc+0x100/0x130 mm/kasan/common.c:461 __do_kmalloc mm/slab.c:3655 [inline] __kmalloc+0x205/0x300 mm/slab.c:3664 kmalloc include/linux/slab.h:559 [inline] fbcon_set_font+0x2c4/0x970 drivers/video/fbdev/core/fbcon.c:2694 con_font_set drivers/tty/vt/vt.c:4663 [inline] con_font_op+0xebc/0x1630 drivers/tty/vt/vt.c:4728 vt_io_ioctl drivers/tty/vt/vt_ioctl.c:506 [inline] vt_ioctl+0xd7f/0x3d70 drivers/tty/vt/vt_ioctl.c:856 tty_ioctl+0xee4/0x15c0 drivers/tty/tty_io.c:2656 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl+0xfb/0x170 fs/ioctl.c:739 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Last call_rcu(): kasan_save_stack+0x27/0x50 mm/kasan/common.c:48 kasan_record_aux_stack+0x7b/0xb0 mm/kasan/generic.c:346 __call_rcu kernel/rcu/tree.c:2894 [inline] call_rcu+0x141/0x830 kernel/rcu/tree.c:2968 perf_event_exit_task_context kernel/events/core.c:12335 [inline] perf_event_exit_task+0x1f1c/0x2270 kernel/events/core.c:12364 do_exit+0x603/0x1f20 kernel/exit.c:815 do_group_exit+0x161/0x2d0 kernel/exit.c:903 get_signal+0x13bb/0x1d50 kernel/signal.c:2757 arch_do_signal+0x33/0x610 arch/x86/kernel/signal.c:811 exit_to_user_mode_loop kernel/entry/common.c:159 [inline] exit_to_user_mode_prepare+0x8d/0x1e0 kernel/entry/common.c:190 syscall_exit_to_user_mode+0x82/0x1d0 kernel/entry/common.c:265 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The buggy address belongs to the object at ffff8880977e2000 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 288 bytes inside of 512-byte region [ffff8880977e2000, ffff8880977e2200) The buggy address belongs to the page: page:00000000c92e6694 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff8880977e2c00 pfn:0x977e2 flags: 0xfffe0000000200(slab) raw: 00fffe0000000200 ffffea000217c9c8 ffffea0002255f08 ffff8880aa440600 raw: ffff8880977e2c00 ffff8880977e2000 0000000100000003 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880977e2000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8880977e2080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff8880977e2100: 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff8880977e2180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880977e2200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================