[....] Starting enhanced syslogd: rsyslogd[ 12.798098] audit: type=1400 audit(1514419964.858:4): avc: denied { syslog } for pid=3176 comm="rsyslogd" capability=34 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=capability2 permissive=1 [?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [....] Starting periodic command scheduler: cron[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. Starting mcstransd: [....] Starting file context maintaining daemon: restorecond[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.15.238' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 33.512557] ================================================================== [ 33.519997] BUG: KASAN: double-free or invalid-free in relay_open+0x603/0x860 [ 33.519998] [ 33.520004] CPU: 1 PID: 3335 Comm: syzkaller992317 Not tainted 4.9.72-gcb7518e #114 [ 33.520006] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 33.520019] ffff8801c9b57988 ffffffff81d922b9 ffffea0007200300 ffff8801c800c280 [ 33.520024] ffff8801da001280 ffffffff8137ba63 0000000000000282 ffff8801c9b579c0 [ 33.520028] ffffffff8153bab3 ffff8801c800c280 ffffffff8137ba63 ffff8801da001280 [ 33.520029] Call Trace: [ 33.520036] [] dump_stack+0xc1/0x128 [ 33.520040] [] ? relay_open+0x603/0x860 [ 33.520048] [] print_address_description+0x73/0x280 [ 33.520053] [] ? relay_open+0x603/0x860 [ 33.520057] [] ? relay_open+0x603/0x860 [ 33.520060] [] kasan_report_double_free+0x64/0xa0 [ 33.520064] [] kasan_slab_free+0xa4/0xc0 [ 33.520068] [] kfree+0x103/0x300 [ 33.520071] [] relay_open+0x603/0x860 [ 33.520076] [] do_blk_trace_setup+0x3e9/0x950 [ 33.520079] [] blk_trace_setup+0xe0/0x1a0 [ 33.520083] [] ? do_blk_trace_setup+0x950/0x950 [ 33.520088] [] sg_ioctl+0xbe0/0x2c30 [ 33.520092] [] ? sg_new_write.isra.26+0x940/0x940 [ 33.520098] [] ? lru_cache_add+0xd9/0x1e0 [ 33.520105] [] ? handle_mm_fault+0xb12/0x2530 [ 33.520109] [] ? sg_new_write.isra.26+0x940/0x940 [ 33.520114] [] do_vfs_ioctl+0x1aa/0x1140 [ 33.520117] [] ? ioctl_preallocate+0x220/0x220 [ 33.520124] [] ? selinux_file_ioctl+0x355/0x530 [ 33.520128] [] ? selinux_capable+0x40/0x40 [ 33.520133] [] ? up_read+0x1a/0x40 [ 33.520139] [] ? __do_page_fault+0x3bd/0xd40 [ 33.520143] [] ? security_file_ioctl+0x89/0xb0 [ 33.520146] [] SyS_ioctl+0x8f/0xc0 [ 33.520151] [] entry_SYSCALL_64_fastpath+0x23/0xc6 [ 33.520153] [ 33.520155] Allocated by task 3335: [ 33.520159] save_stack_trace+0x16/0x20 [ 33.520162] save_stack+0x43/0xd0 [ 33.520165] kasan_kmalloc+0xad/0xe0 [ 33.520167] kmem_cache_alloc_trace+0xfb/0x2a0 [ 33.520170] relay_open+0x91/0x860 [ 33.520173] do_blk_trace_setup+0x3e9/0x950 [ 33.520175] blk_trace_setup+0xe0/0x1a0 [ 33.520178] sg_ioctl+0xbe0/0x2c30 [ 33.520180] do_vfs_ioctl+0x1aa/0x1140 [ 33.520183] SyS_ioctl+0x8f/0xc0 [ 33.520186] entry_SYSCALL_64_fastpath+0x23/0xc6 [ 33.520186] [ 33.520188] Freed by task 3335: [ 33.520190] save_stack_trace+0x16/0x20 [ 33.520193] save_stack+0x43/0xd0 [ 33.520196] kasan_slab_free+0x72/0xc0 [ 33.520198] kfree+0x103/0x300 [ 33.520201] relay_destroy_channel+0x16/0x20 [ 33.520204] relay_open+0x5ea/0x860 [ 33.520207] do_blk_trace_setup+0x3e9/0x950 [ 33.520209] blk_trace_setup+0xe0/0x1a0 [ 33.520212] sg_ioctl+0xbe0/0x2c30 [ 33.520214] do_vfs_ioctl+0x1aa/0x1140 [ 33.520217] SyS_ioctl+0x8f/0xc0 [ 33.520219] entry_SYSCALL_64_fastpath+0x23/0xc6 [ 33.520220] [ 33.520223] The buggy address belongs to the object at ffff8801c800c280 [ 33.520223] which belongs to the cache kmalloc-512 of size 512 [ 33.520225] The buggy address is located 0 bytes inside of [ 33.520225] 512-byte region [ffff8801c800c280, ffff8801c800c480) [ 33.520226] The buggy address belongs to the page: [ 33.520231] page:ffffea0007200300 count:1 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 0 [ 33.520234] flags: 0x8000000000004080(slab|head) [ 33.520235] page dumped because: kasan: bad access detected [ 33.520236] [ 33.520237] Memory state around the buggy address: [ 33.520241] ffff8801c800c180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 33.520244] ffff8801c800c200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 33.520246] >ffff8801c800c280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 33.520247] ^ [ 33.520250] ffff8801c800c300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 33.520252] ffff8801c800c380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 33.520253] ================================================================== [ 33.520255] Disabling lock debugging due to kernel taint [ 33.520310] Kernel panic - not syncing: panic_on_warn set ... [ 33.520310] [ 33.520314] CPU: 1 PID: 3335 Comm: syzkaller992317 Tainted: G B 4.9.72-gcb7518e #114 [ 33.520316] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 33.520321] ffff8801c9b578e0 ffffffff81d922b9 ffffffff841955bf ffff8801c9b579b8 [ 33.520326] ffff8801da001200 ffffffff8137ba63 0000000000000282 ffff8801c9b579a8 [ 33.520330] ffffffff8142d741 0000000041b58ab3 ffffffff84189000 ffffffff8142d585 [ 33.520331] Call Trace: [ 33.520335] [] dump_stack+0xc1/0x128 [ 33.520339] [] ? relay_open+0x603/0x860 [ 33.520344] [] panic+0x1bc/0x3a8 [ 33.520349] [] ? percpu_up_read_preempt_enable.constprop.53+0xd7/0xd7 [ 33.520353] [] ? preempt_schedule+0x25/0x30 [ 33.520357] [] ? ___preempt_schedule+0x16/0x18 [ 33.520360] [] ? relay_open+0x603/0x860 [ 33.520364] [] ? relay_open+0x603/0x860 [ 33.520367] [] kasan_end_report+0x50/0x50 [ 33.520371] [] kasan_report_double_free+0x81/0xa0 [ 33.520375] [] kasan_slab_free+0xa4/0xc0 [ 33.520378] [] kfree+0x103/0x300 [ 33.520381] [] relay_open+0x603/0x860 [ 33.520385] [] do_blk_trace_setup+0x3e9/0x950 [ 33.520388] [] blk_trace_setup+0xe0/0x1a0 [ 33.520392] [] ? do_blk_trace_setup+0x950/0x950 [ 33.520395] [] sg_ioctl+0xbe0/0x2c30 [ 33.520399] [] ? sg_new_write.isra.26+0x940/0x940 [ 33.520403] [] ? lru_cache_add+0xd9/0x1e0 [ 33.520407] [] ? handle_mm_fault+0xb12/0x2530 [ 33.520411] [] ? sg_new_write.isra.26+0x940/0x940 [ 33.520414] [] do_vfs_ioctl+0x1aa/0x1140 [ 33.520418] [] ? ioctl_preallocate+0x220/0x220 [ 33.520422] [] ? selinux_file_ioctl+0x355/0x530 [ 33.520426] [] ? selinux_capable+0x40/0x40 [ 33.520429] [] ? up_read+0x1a/0x40 [ 33.520433] [] ? __do_page_fault+0x3bd/0xd40 [ 33.520437] [] ? security_file_ioctl+0x89/0xb0 [ 33.520440] [] SyS_ioctl+0x8f/0xc0 [ 33.520443] [] entry_SYSCALL_64_fastpath+0x23/0xc6 [ 33.527798] Dumping ftrace buffer: [ 33.527801] (ftrace buffer empty) [ 33.527803] Kernel Offset: disabled [ 34.171465] Rebooting in 86400 seconds..