[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 20.813487] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 25.351405] random: sshd: uninitialized urandom read (32 bytes read) [ 25.643740] random: sshd: uninitialized urandom read (32 bytes read) [ 26.549884] random: sshd: uninitialized urandom read (32 bytes read) [ 26.710282] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.35' (ECDSA) to the list of known hosts. [ 32.200380] random: sshd: uninitialized urandom read (32 bytes read) executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 32.639411] ================================================================== [ 32.646933] BUG: KASAN: use-after-free in kernel_accept+0x2a4/0x310 [ 32.653329] Read of size 8 at addr ffff8801a7ffb1a8 by task kworker/0:46/4718 [ 32.660585] [ 32.662219] CPU: 0 PID: 4718 Comm: kworker/0:46 Not tainted 4.18.0-rc3+ #15 [ 32.669445] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 32.678805] Workqueue: events smc_tcp_listen_work [ 32.683649] Call Trace: [ 32.686234] dump_stack+0x1c9/0x2b4 [ 32.689859] ? dump_stack_print_info.cold.2+0x52/0x52 [ 32.695048] ? printk+0xa7/0xcf [ 32.698320] ? kmsg_dump_rewind_nolock+0xe4/0xe4 [ 32.703068] ? kernel_accept+0x2a4/0x310 [ 32.707123] print_address_description+0x6c/0x20b [ 32.711979] ? kernel_accept+0x2a4/0x310 [ 32.716043] kasan_report.cold.7+0x242/0x2fe [ 32.720455] __asan_report_load8_noabort+0x14/0x20 [ 32.725378] kernel_accept+0x2a4/0x310 [ 32.729260] smc_tcp_listen_work+0x222/0xef0 [ 32.733663] ? smc_link_save_peer_info+0x320/0x320 [ 32.738589] ? __lock_is_held+0xb5/0x140 [ 32.742753] process_one_work+0xc73/0x1ba0 [ 32.746980] ? trace_hardirqs_on+0x10/0x10 [ 32.751224] ? pwq_dec_nr_in_flight+0x4a0/0x4a0 [ 32.755885] ? lock_repin_lock+0x430/0x430 [ 32.760126] ? __sched_text_start+0x8/0x8 [ 32.764265] ? lock_downgrade+0x8f0/0x8f0 [ 32.768416] ? graph_lock+0x170/0x170 [ 32.772207] ? find_held_lock+0x36/0x1c0 [ 32.776279] ? lock_acquire+0x1e4/0x540 [ 32.780246] ? worker_thread+0x3dc/0x13c0 [ 32.784380] ? lock_downgrade+0x8f0/0x8f0 [ 32.788525] ? lock_release+0xa30/0xa30 [ 32.792491] ? kasan_check_read+0x11/0x20 [ 32.796631] ? do_raw_spin_unlock+0xa7/0x2f0 [ 32.801124] ? do_raw_spin_trylock+0x1c0/0x1c0 [ 32.805697] ? kasan_check_write+0x14/0x20 [ 32.809921] ? do_raw_spin_lock+0xc1/0x200 [ 32.814148] worker_thread+0x189/0x13c0 [ 32.818124] ? process_one_work+0x1ba0/0x1ba0 [ 32.822637] ? __sched_text_start+0x8/0x8 [ 32.826778] ? graph_lock+0x170/0x170 [ 32.830573] ? find_held_lock+0x36/0x1c0 [ 32.834633] ? find_held_lock+0x36/0x1c0 [ 32.838693] ? schedule+0xfb/0x450 [ 32.842264] ? __schedule+0x1ed0/0x1ed0 [ 32.846234] ? kasan_check_read+0x11/0x20 [ 32.850371] ? do_raw_spin_unlock+0xa7/0x2f0 [ 32.854780] ? do_raw_spin_trylock+0x1c0/0x1c0 [ 32.859369] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 32.864907] ? __kthread_parkme+0x111/0x1d0 [ 32.869223] ? parse_args.cold.15+0x1b3/0x1b3 [ 32.873711] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 32.878720] ? trace_hardirqs_on+0xd/0x10 [ 32.882874] kthread+0x345/0x410 [ 32.886242] ? process_one_work+0x1ba0/0x1ba0 [ 32.890754] ? kthread_bind+0x40/0x40 [ 32.894727] ret_from_fork+0x3a/0x50 [ 32.898448] [ 32.900067] Allocated by task 4719: [ 32.903689] save_stack+0x43/0xd0 [ 32.907140] kasan_kmalloc+0xc4/0xe0 [ 32.910856] kasan_slab_alloc+0x12/0x20 [ 32.914845] kmem_cache_alloc+0x12e/0x760 [ 32.919091] sock_alloc_inode+0x78/0x320 [ 32.923153] alloc_inode+0x63/0x190 [ 32.926786] new_inode_pseudo+0x71/0x1a0 [ 32.930844] sock_alloc+0x41/0x270 [ 32.934387] __sock_create+0x175/0x940 [ 32.938273] sock_create_kern+0x3b/0x50 [ 32.942246] smc_create+0x141/0x360 [ 32.945867] __sock_create+0x53c/0x940 [ 32.949746] __sys_socket+0x106/0x260 [ 32.953551] __x64_sys_socket+0x73/0xb0 [ 32.957514] do_syscall_64+0x1b9/0x820 [ 32.961661] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 32.966829] [ 32.968440] Freed by task 4719: [ 32.971719] save_stack+0x43/0xd0 [ 32.975171] __kasan_slab_free+0x11a/0x170 [ 32.979410] kasan_slab_free+0xe/0x10 [ 32.983212] kmem_cache_free+0x86/0x2d0 [ 32.987258] sock_destroy_inode+0x56/0x70 [ 32.991393] destroy_inode+0x159/0x200 [ 32.995271] evict+0x5d5/0x990 [ 32.998459] iput+0x635/0xaa0 [ 33.001550] __sock_release+0x1f1/0x260 [ 33.005520] sock_release+0x17/0x20 [ 33.009131] smc_release+0x1a8/0x720 [ 33.012829] __sock_release+0xd7/0x260 [ 33.016703] sock_close+0x19/0x20 [ 33.020157] __fput+0x355/0x8b0 [ 33.023424] ____fput+0x15/0x20 [ 33.026698] task_work_run+0x1ec/0x2a0 [ 33.030588] exit_to_usermode_loop+0x313/0x370 [ 33.035173] do_syscall_64+0x6be/0x820 [ 33.039049] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 33.044217] [ 33.045837] The buggy address belongs to the object at ffff8801a7ffb180 [ 33.045837] which belongs to the cache sock_inode_cache of size 992 [ 33.059702] The buggy address is located 40 bytes inside of [ 33.059702] 992-byte region [ffff8801a7ffb180, ffff8801a7ffb560) [ 33.071471] The buggy address belongs to the page: [ 33.076393] page:ffffea00069ffec0 count:1 mapcount:0 mapping:ffff8801d9476c00 index:0xffff8801a7ffbffd [ 33.086016] flags: 0x2fffc0000000100(slab) [ 33.090259] raw: 02fffc0000000100 ffffea00069ffe88 ffffea00069e06c8 ffff8801d9476c00 [ 33.098139] raw: ffff8801a7ffbffd ffff8801a7ffb180 0000000100000003 0000000000000000 [ 33.106034] page dumped because: kasan: bad access detected [ 33.111726] [ 33.113333] Memory state around the buggy address: [ 33.118245] ffff8801a7ffb080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 33.125596] ffff8801a7ffb100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 33.132954] >ffff8801a7ffb180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb executing program executing program executing program [ 33.140390] ^ [ 33.145065] ffff8801a7ffb200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 33.153628] ffff8801a7ffb280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 33.160980] ================================================================== [ 33.168604] Disabling lock debugging due to kernel taint [ 33.174149] Kernel panic - not syncing: panic_on_warn set ... [ 33.174149] [ 33.181531] CPU: 0 PID: 4718 Comm: kworker/0:46 Tainted: G B 4.18.0-rc3+ #15 executing program executing program executing program executing program executing program executing program [ 33.190028] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 33.199418] Workqueue: events smc_tcp_listen_work [ 33.204267] Call Trace: [ 33.206866] dump_stack+0x1c9/0x2b4 [ 33.210502] ? dump_stack_print_info.cold.2+0x52/0x52 [ 33.215726] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 33.220502] panic+0x238/0x4e7 [ 33.223711] ? add_taint.cold.5+0x16/0x16 [ 33.227885] ? do_raw_spin_unlock+0xa7/0x2f0 [ 33.232321] ? do_raw_spin_unlock+0xa7/0x2f0 [ 33.236744] ? kernel_accept+0x2a4/0x310 [ 33.240818] kasan_end_report+0x47/0x4f [ 33.244807] kasan_report.cold.7+0x76/0x2fe [ 33.249186] __asan_report_load8_noabort+0x14/0x20 [ 33.254133] kernel_accept+0x2a4/0x310 [ 33.258042] smc_tcp_listen_work+0x222/0xef0 [ 33.262475] ? smc_link_save_peer_info+0x320/0x320 [ 33.267479] ? __lock_is_held+0xb5/0x140 [ 33.271558] process_one_work+0xc73/0x1ba0 [ 33.275981] ? trace_hardirqs_on+0x10/0x10 [ 33.280253] ? pwq_dec_nr_in_flight+0x4a0/0x4a0 [ 33.284948] ? lock_repin_lock+0x430/0x430 [ 33.289206] ? __sched_text_start+0x8/0x8 [ 33.293735] ? lock_downgrade+0x8f0/0x8f0 [ 33.297906] ? graph_lock+0x170/0x170 [ 33.301728] ? find_held_lock+0x36/0x1c0 [ 33.305822] ? lock_acquire+0x1e4/0x540 [ 33.309815] ? worker_thread+0x3dc/0x13c0 [ 33.313980] ? lock_downgrade+0x8f0/0x8f0 [ 33.318155] ? lock_release+0xa30/0xa30 [ 33.322162] ? kasan_check_read+0x11/0x20 [ 33.326326] ? do_raw_spin_unlock+0xa7/0x2f0 [ 33.330745] ? do_raw_spin_trylock+0x1c0/0x1c0 [ 33.335344] ? kasan_check_write+0x14/0x20 [ 33.339610] ? do_raw_spin_lock+0xc1/0x200 [ 33.343879] worker_thread+0x189/0x13c0 [ 33.347880] ? process_one_work+0x1ba0/0x1ba0 [ 33.352396] ? __sched_text_start+0x8/0x8 [ 33.356561] ? graph_lock+0x170/0x170 [ 33.360376] ? find_held_lock+0x36/0x1c0 [ 33.364471] ? find_held_lock+0x36/0x1c0 [ 33.368554] ? schedule+0xfb/0x450 [ 33.372106] ? __schedule+0x1ed0/0x1ed0 [ 33.376101] ? kasan_check_read+0x11/0x20 [ 33.380265] ? do_raw_spin_unlock+0xa7/0x2f0 [ 33.384692] ? do_raw_spin_trylock+0x1c0/0x1c0 [ 33.389319] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 33.394885] ? __kthread_parkme+0x111/0x1d0 [ 33.399830] ? parse_args.cold.15+0x1b3/0x1b3 [ 33.404342] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 33.409375] ? trace_hardirqs_on+0xd/0x10 [ 33.413538] kthread+0x345/0x410 [ 33.417181] ? process_one_work+0x1ba0/0x1ba0 [ 33.421686] ? kthread_bind+0x40/0x40 [ 33.425500] ret_from_fork+0x3a/0x50 [ 33.429882] Dumping ftrace buffer: [ 33.433415] (ftrace buffer empty) [ 33.437290] Kernel Offset: disabled [ 33.440904] Rebooting in 86400 seconds..