[ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... Starting Load/Save RF Kill Switch Status... [ OK ] Started Load/Save RF Kill Switch Status. [ OK ] Started Update UTMP about System Runlevel Changes. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.10.61' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program syzkaller login: [ 28.367937] ================================================================== [ 28.367965] BUG: KASAN: slab-out-of-bounds in soft_cursor+0x442/0xa50 [ 28.367970] Read of size 15 at addr ffff8880b4533c70 by task kworker/1:3/4645 [ 28.367972] [ 28.367980] CPU: 1 PID: 4645 Comm: kworker/1:3 Not tainted 4.14.232-syzkaller #0 [ 28.367984] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 28.367991] Workqueue: events_power_efficient fb_flashcursor [ 28.367996] Call Trace: [ 28.368007] dump_stack+0x1b2/0x281 [ 28.368020] print_address_description.cold+0x54/0x1d3 [ 28.368029] kasan_report_error.cold+0x8a/0x191 [ 28.368035] ? soft_cursor+0x442/0xa50 [ 28.368042] kasan_report+0x6f/0x80 [ 28.368050] ? soft_cursor+0x442/0xa50 [ 28.368057] memcpy+0x20/0x50 [ 28.368064] soft_cursor+0x442/0xa50 [ 28.368075] ? trace_hardirqs_on_caller+0x3a8/0x580 [ 28.368083] bit_cursor+0xf7a/0x1580 [ 28.368095] ? bit_update_start+0x1f0/0x1f0 [ 28.368125] ? fb_get_color_depth+0x100/0x200 [ 28.368133] ? get_color+0x1be/0x3a0 [ 28.368140] ? __down_trylock_console_sem+0x11f/0x1e0 [ 28.368147] ? bit_update_start+0x1f0/0x1f0 [ 28.368153] fb_flashcursor+0x356/0x3f0 [ 28.368163] process_one_work+0x793/0x14a0 [ 28.368175] ? work_busy+0x320/0x320 [ 28.368181] ? worker_thread+0x158/0xff0 [ 28.368191] ? _raw_spin_unlock_irq+0x24/0x80 [ 28.368200] worker_thread+0x5cc/0xff0 [ 28.368214] ? rescuer_thread+0xc80/0xc80 [ 28.368222] kthread+0x30d/0x420 [ 28.368228] ? kthread_create_on_node+0xd0/0xd0 [ 28.368236] ret_from_fork+0x24/0x30 [ 28.368246] [ 28.368250] Allocated by task 7955: [ 28.368255] kasan_kmalloc+0xeb/0x160 [ 28.368262] __kmalloc+0x15a/0x400 [ 28.368267] fbcon_set_font+0x2fb/0x7c0 [ 28.368274] con_font_op+0x9e8/0xdb0 [ 28.368281] vt_ioctl+0xd5d/0x1d50 [ 28.368287] tty_ioctl+0x50f/0x13c0 [ 28.368292] do_vfs_ioctl+0x75a/0xff0 [ 28.368297] SyS_ioctl+0x7f/0xb0 [ 28.368303] do_syscall_64+0x1d5/0x640 [ 28.368308] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 28.368310] [ 28.368312] Freed by task 6216: [ 28.368317] kasan_slab_free+0xc3/0x1a0 [ 28.368322] kfree+0xc9/0x250 [ 28.368328] skb_release_data+0x5f6/0x820 [ 28.368332] consume_skb+0xe0/0x380 [ 28.368337] skb_free_datagram+0x16/0xe0 [ 28.368345] netlink_recvmsg+0x5c1/0xda0 [ 28.368350] sock_recvmsg+0xc0/0x100 [ 28.368355] ___sys_recvmsg+0x20b/0x4d0 [ 28.368359] __sys_recvmsg+0xa0/0x120 [ 28.368364] SyS_recvmsg+0x27/0x40 [ 28.368368] do_syscall_64+0x1d5/0x640 [ 28.368374] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 28.368376] [ 28.368381] The buggy address belongs to the object at ffff8880b4533a80 [ 28.368381] which belongs to the cache kmalloc-512 of size 512 [ 28.368386] The buggy address is located 496 bytes inside of [ 28.368386] 512-byte region [ffff8880b4533a80, ffff8880b4533c80) [ 28.368388] The buggy address belongs to the page: [ 28.368393] page:ffffea0002d14cc0 count:1 mapcount:0 mapping:ffff8880b4533080 index:0x0 [ 28.368400] flags: 0xfff00000000100(slab) [ 28.368409] raw: 00fff00000000100 ffff8880b4533080 0000000000000000 0000000100000006 [ 28.368416] raw: ffffea0002d29820 ffffea0002595720 ffff88813fe80940 0000000000000000 [ 28.368419] page dumped because: kasan: bad access detected [ 28.368421] [ 28.368424] Memory state around the buggy address: [ 28.368429] ffff8880b4533b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 28.368434] ffff8880b4533b80: 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 28.368439] >ffff8880b4533c00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 28.368442] ^ [ 28.368447] ffff8880b4533c80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 28.368451] ffff8880b4533d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 28.368454] ================================================================== [ 28.368456] Disabling lock debugging due to kernel taint [ 28.368459] Kernel panic - not syncing: panic_on_warn set ... [ 28.368459] [ 28.368465] CPU: 1 PID: 4645 Comm: kworker/1:3 Tainted: G B 4.14.232-syzkaller #0 [ 28.368469] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 28.368475] Workqueue: events_power_efficient fb_flashcursor [ 28.368478] Call Trace: [ 28.368486] dump_stack+0x1b2/0x281 [ 28.368493] panic+0x1f9/0x42d [ 28.368498] ? add_taint.cold+0x16/0x16 [ 28.368504] ? lock_downgrade+0x740/0x740 [ 28.368512] kasan_end_report+0x43/0x49 [ 28.368518] kasan_report_error.cold+0xa7/0x191 [ 28.368523] ? soft_cursor+0x442/0xa50 [ 28.368528] kasan_report+0x6f/0x80 [ 28.368534] ? soft_cursor+0x442/0xa50 [ 28.368539] memcpy+0x20/0x50 [ 28.368545] soft_cursor+0x442/0xa50 [ 28.368552] ? trace_hardirqs_on_caller+0x3a8/0x580 [ 28.368558] bit_cursor+0xf7a/0x1580 [ 28.368566] ? bit_update_start+0x1f0/0x1f0 [ 28.368575] ? fb_get_color_depth+0x100/0x200 [ 28.368580] ? get_color+0x1be/0x3a0 [ 28.368586] ? __down_trylock_console_sem+0x11f/0x1e0 [ 28.368591] ? bit_update_start+0x1f0/0x1f0 [ 28.368596] fb_flashcursor+0x356/0x3f0 [ 28.368602] process_one_work+0x793/0x14a0 [ 28.368610] ? work_busy+0x320/0x320 [ 28.368615] ? worker_thread+0x158/0xff0 [ 28.368621] ? _raw_spin_unlock_irq+0x24/0x80 [ 28.368627] worker_thread+0x5cc/0xff0 [ 28.368636] ? rescuer_thread+0xc80/0xc80 [ 28.368641] kthread+0x30d/0x420 [ 28.368646] ? kthread_create_on_node+0xd0/0xd0 [ 28.368651] ret_from_fork+0x24/0x30 [ 28.369427] Kernel Offset: disabled [ 28.891985] Rebooting in 86400 seconds..