[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 19.246317] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 24.402332] random: sshd: uninitialized urandom read (32 bytes read) [ 24.696375] random: sshd: uninitialized urandom read (32 bytes read) [ 25.576078] random: sshd: uninitialized urandom read (32 bytes read) [ 25.742400] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.2' (ECDSA) to the list of known hosts. [ 31.175584] random: sshd: uninitialized urandom read (32 bytes read) executing program [ 31.279011] IPVS: ftp: loaded support on port[0] = 21 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 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 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 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 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 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 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 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 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 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 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 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 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 executing program executing program [ 45.681206] ================================================================== [ 45.688660] BUG: KASAN: use-after-free in p9_poll_workfn+0x660/0x6d0 [ 45.695133] Read of size 4 at addr ffff8801d3c538c4 by task kworker/0:1/25 [ 45.702118] [ 45.703736] CPU: 0 PID: 25 Comm: kworker/0:1 Not tainted 4.18.0-rc6+ #160 [ 45.710650] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 45.719988] Workqueue: events p9_poll_workfn [ 45.724374] Call Trace: [ 45.726944] dump_stack+0x1c9/0x2b4 [ 45.730562] ? dump_stack_print_info.cold.2+0x52/0x52 [ 45.735748] ? printk+0xa7/0xcf [ 45.739006] ? kmsg_dump_rewind_nolock+0xe4/0xe4 [ 45.743748] ? p9_poll_workfn+0x660/0x6d0 [ 45.747884] print_address_description+0x6c/0x20b [ 45.752713] ? p9_poll_workfn+0x660/0x6d0 [ 45.756842] kasan_report.cold.7+0x242/0x2fe [ 45.761240] __asan_report_load4_noabort+0x14/0x20 [ 45.766157] p9_poll_workfn+0x660/0x6d0 [ 45.770115] ? p9_read_work+0x1060/0x1060 [ 45.774244] ? graph_lock+0x170/0x170 [ 45.778023] ? lock_acquire+0x1e4/0x540 [ 45.781986] ? process_one_work+0xb9b/0x1ba0 [ 45.786377] ? kasan_check_read+0x11/0x20 [ 45.790505] ? __lock_is_held+0xb5/0x140 [ 45.794551] process_one_work+0xc73/0x1ba0 [ 45.798813] ? trace_hardirqs_on+0x10/0x10 [ 45.803034] ? pwq_dec_nr_in_flight+0x4a0/0x4a0 [ 45.807685] ? lock_repin_lock+0x430/0x430 [ 45.811914] ? __sched_text_start+0x8/0x8 [ 45.816047] ? graph_lock+0x170/0x170 [ 45.819828] ? lock_downgrade+0x8f0/0x8f0 [ 45.823971] ? kasan_check_read+0x11/0x20 [ 45.828108] ? do_raw_spin_unlock+0xa7/0x2f0 [ 45.832507] ? lock_acquire+0x1e4/0x540 [ 45.836458] ? worker_thread+0x3dc/0x13c0 [ 45.840591] ? lock_downgrade+0x8f0/0x8f0 [ 45.844721] ? lock_release+0xa30/0xa30 [ 45.848681] ? kasan_check_read+0x11/0x20 [ 45.852809] ? do_raw_spin_unlock+0xa7/0x2f0 [ 45.857197] ? do_raw_spin_trylock+0x1c0/0x1c0 [ 45.861761] ? kasan_check_write+0x14/0x20 [ 45.865976] ? do_raw_spin_lock+0xc1/0x200 [ 45.870192] worker_thread+0x189/0x13c0 [ 45.874153] ? process_one_work+0x1ba0/0x1ba0 [ 45.878631] ? graph_lock+0x170/0x170 [ 45.882411] ? graph_lock+0x170/0x170 [ 45.886189] ? find_held_lock+0x36/0x1c0 [ 45.890234] ? find_held_lock+0x36/0x1c0 [ 45.894282] ? kasan_check_read+0x11/0x20 [ 45.898421] ? do_raw_spin_unlock+0xa7/0x2f0 [ 45.902812] ? _raw_spin_unlock_irqrestore+0x74/0xc0 [ 45.907903] ? __kthread_parkme+0x58/0x1b0 [ 45.912118] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 45.917128] ? trace_hardirqs_on+0xd/0x10 [ 45.921261] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 45.926777] ? __kthread_parkme+0x106/0x1b0 [ 45.931078] kthread+0x345/0x410 [ 45.934423] ? process_one_work+0x1ba0/0x1ba0 [ 45.938896] ? kthread_bind+0x40/0x40 [ 45.942680] ret_from_fork+0x3a/0x50 [ 45.946484] [ 45.948091] Allocated by task 5330: [ 45.951702] save_stack+0x43/0xd0 [ 45.955133] kasan_kmalloc+0xc4/0xe0 [ 45.958826] kmem_cache_alloc_trace+0x152/0x780 [ 45.963478] p9_fd_create+0x1a7/0x3f0 [ 45.967437] p9_client_create+0x8ed/0x1770 [ 45.971651] v9fs_session_init+0x21a/0x1a80 [ 45.975959] v9fs_mount+0x7c/0x900 [ 45.979482] mount_fs+0xae/0x328 [ 45.982831] vfs_kern_mount.part.34+0xdc/0x4e0 [ 45.987391] do_mount+0x581/0x30e0 [ 45.990909] ksys_mount+0x12d/0x140 [ 45.994513] __x64_sys_mount+0xbe/0x150 [ 45.998471] do_syscall_64+0x1b9/0x820 [ 46.002361] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 46.007522] [ 46.009126] Freed by task 5330: [ 46.012399] save_stack+0x43/0xd0 [ 46.015833] __kasan_slab_free+0x11a/0x170 [ 46.020048] kasan_slab_free+0xe/0x10 [ 46.023843] kfree+0xd9/0x260 [ 46.026925] p9_fd_close+0x416/0x5b0 [ 46.030617] p9_client_create+0xa9a/0x1770 [ 46.034831] v9fs_session_init+0x21a/0x1a80 [ 46.039216] v9fs_mount+0x7c/0x900 [ 46.042732] mount_fs+0xae/0x328 [ 46.046077] vfs_kern_mount.part.34+0xdc/0x4e0 [ 46.050639] do_mount+0x581/0x30e0 [ 46.054158] ksys_mount+0x12d/0x140 [ 46.057771] __x64_sys_mount+0xbe/0x150 [ 46.061734] do_syscall_64+0x1b9/0x820 [ 46.065605] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 46.070770] [ 46.072384] The buggy address belongs to the object at ffff8801d3c53840 [ 46.072384] which belongs to the cache kmalloc-512 of size 512 [ 46.085023] The buggy address is located 132 bytes inside of [ 46.085023] 512-byte region [ffff8801d3c53840, ffff8801d3c53a40) [ 46.097325] The buggy address belongs to the page: [ 46.102234] page:ffffea00074f14c0 count:1 mapcount:0 mapping:ffff8801da800940 index:0x0 [ 46.110354] flags: 0x2fffc0000000100(slab) [ 46.114570] raw: 02fffc0000000100 ffffea00074f1488 ffffea00074f1548 ffff8801da800940 [ 46.122431] raw: 0000000000000000 ffff8801d3c530c0 0000000100000006 0000000000000000 [ 46.130289] page dumped because