================================================================== BUG: KASAN: use-after-free in __fb_pad_aligned_buffer include/linux/fb.h:663 [inline] BUG: KASAN: use-after-free in bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:96 [inline] BUG: KASAN: use-after-free in bit_putcs+0xa8a/0xc00 drivers/video/fbdev/core/bitblit.c:185 Read of size 1 at addr ffff8880948a3d8a by task syz-executor.2/6935 CPU: 0 PID: 6935 Comm: syz-executor.2 Not tainted 4.14.184-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x1b2/0x283 lib/dump_stack.c:58 print_address_description.cold+0x54/0x1dc mm/kasan/report.c:252 kasan_report_error mm/kasan/report.c:351 [inline] kasan_report mm/kasan/report.c:409 [inline] kasan_report.cold+0xa9/0x2b9 mm/kasan/report.c:393 __fb_pad_aligned_buffer include/linux/fb.h:663 [inline] bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:96 [inline] bit_putcs+0xa8a/0xc00 drivers/video/fbdev/core/bitblit.c:185 fbcon_putcs+0x3bb/0x480 drivers/video/fbdev/core/fbcon.c:1301 do_update_region+0x34b/0x5b0 drivers/tty/vt/vt.c:373 redraw_screen+0x562/0x760 drivers/tty/vt/vt.c:705 vc_do_resize+0xbe0/0xde0 drivers/tty/vt/vt.c:967 vt_ioctl+0x1a64/0x1f20 drivers/tty/vt/vt_ioctl.c:901 tty_ioctl+0x6c9/0x1220 drivers/tty/tty_io.c:2661 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x75a/0xfe0 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x45cb29 RSP: 002b:00007f110974ec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000004f36a0 RCX: 000000000045cb29 RDX: 0000000020000240 RSI: 000000000000560a RDI: 0000000000000003 RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000680 R14: 00000000004c9884 R15: 00007f110974f6d4 Allocated by task 6651: save_stack mm/kasan/kasan.c:447 [inline] set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc.part.0+0x4f/0xd0 mm/kasan/kasan.c:551 kmem_cache_alloc_trace+0x14d/0x3f0 mm/slab.c:3618 kmalloc include/linux/slab.h:488 [inline] kzalloc include/linux/slab.h:661 [inline] alloc_perf_context+0x44/0xe0 kernel/events/core.c:3859 inherit_task_group kernel/events/core.c:11019 [inline] inherit_task_group kernel/events/core.c:10998 [inline] perf_event_init_context kernel/events/core.c:11093 [inline] perf_event_init_task+0x444/0x790 kernel/events/core.c:11145 copy_process.part.0+0x15ca/0x6fa0 kernel/fork.c:1745 copy_process kernel/fork.c:1586 [inline] _do_fork+0x180/0xc80 kernel/fork.c:2070 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb Freed by task 7: save_stack mm/kasan/kasan.c:447 [inline] set_track mm/kasan/kasan.c:459 [inline] kasan_slab_free+0xaf/0x190 mm/kasan/kasan.c:524 __cache_free mm/slab.c:3496 [inline] kfree+0xcb/0x260 mm/slab.c:3815 __rcu_reclaim kernel/rcu/rcu.h:195 [inline] rcu_do_batch kernel/rcu/tree.c:2699 [inline] invoke_rcu_callbacks kernel/rcu/tree.c:2962 [inline] __rcu_process_callbacks kernel/rcu/tree.c:2929 [inline] rcu_process_callbacks+0x78d/0x1180 kernel/rcu/tree.c:2946 __do_softirq+0x254/0x9bf kernel/softirq.c:288 The buggy address belongs to the object at ffff8880948a3d00 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 138 bytes inside of 512-byte region [ffff8880948a3d00, ffff8880948a3f00) The buggy address belongs to the page: page:ffffea00025228c0 count:1 mapcount:0 mapping:ffff8880948a3080 index:0xffff8880948a3080 flags: 0xfffe0000000100(slab) raw: 00fffe0000000100 ffff8880948a3080 ffff8880948a3080 0000000100000004 raw: ffffea0001988ca0 ffffea0002464520 ffff8880aa800940 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880948a3c80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880948a3d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880948a3d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880948a3e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880948a3e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================