[ 41.278973] audit: type=1800 audit(1555552448.293:29): pid=7659 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:kernel_t:s0 op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2447 res=0 [ 41.299894] audit: type=1800 audit(1555552448.293:30): pid=7659 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:kernel_t:s0 op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2490 res=0 Starting mcstransd: [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting file context maintaining daemon: restorecond[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.0.91' (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 syzkaller login: [ 49.791066] kauditd_printk_skb: 5 callbacks suppressed [ 49.791083] audit: type=1400 audit(1555552456.803:36): avc: denied { map } for pid=7846 comm="syz-executor275" path="/root/syz-executor275683528" dev="sda1" ino=16483 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 50.449737] ================================================================== [ 50.457301] BUG: KASAN: use-after-free in __vb2_perform_fileio+0x105d/0x1140 [ 50.464497] Read of size 4 at addr ffff8880868eec5c by task syz-executor275/8370 [ 50.472208] [ 50.473916] CPU: 1 PID: 8370 Comm: syz-executor275 Not tainted 4.19.35 #3 [ 50.480838] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 50.490211] Call Trace: [ 50.492794] dump_stack+0x172/0x1f0 [ 50.496421] ? __vb2_perform_fileio+0x105d/0x1140 [ 50.501268] print_address_description.cold+0x7c/0x20d [ 50.506556] ? __vb2_perform_fileio+0x105d/0x1140 [ 50.511410] kasan_report.cold+0x8c/0x2ba [ 50.515572] __asan_report_load4_noabort+0x14/0x20 [ 50.520517] __vb2_perform_fileio+0x105d/0x1140 [ 50.525212] ? vb2_thread_start+0x370/0x370 [ 50.529565] ? mark_held_locks+0x100/0x100 [ 50.533801] vb2_read+0x3b/0x50 [ 50.537070] vb2_fop_read+0x212/0x410 [ 50.540925] ? vb2_fop_write+0x410/0x410 [ 50.545013] v4l2_read+0x1ce/0x230 [ 50.548562] __vfs_read+0x116/0x800 [ 50.552223] ? v4l2_write+0x230/0x230 [ 50.556041] ? vfs_copy_file_range+0xba0/0xba0 [ 50.560636] ? __sanitizer_cov_trace_const_cmp1+0x1a/0x20 [ 50.566804] ? __inode_security_revalidate+0xda/0x120 [ 50.572090] ? avc_policy_seqno+0xd/0x70 [ 50.576221] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 50.581432] ? security_file_permission+0x1ce/0x230 [ 50.586451] ? security_file_permission+0x8f/0x230 [ 50.591384] ? rw_verify_area+0x118/0x360 [ 50.595566] vfs_read+0x194/0x3d0 [ 50.599018] ksys_read+0xea/0x1f0 [ 50.602486] ? kernel_write+0x120/0x120 [ 50.606454] ? do_syscall_64+0x26/0x610 [ 50.610506] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 50.615876] ? do_syscall_64+0x26/0x610 [ 50.619856] __x64_sys_read+0x73/0xb0 [ 50.623858] do_syscall_64+0x103/0x610 [ 50.627934] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 50.633220] RIP: 0033:0x44a649 [ 50.636403] Code: e8 0c e8 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b cb fb ff c3 66 2e 0f 1f 84 00 00 00 00 [ 50.655392] RSP: 002b:00007f52332cbd98 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 [ 50.663223] RAX: ffffffffffffffda RBX: 00000000006dbc28 RCX: 000000000044a649 [ 50.670586] RDX: 000000000000004b RSI: 0000000020000280 RDI: 0000000000000003 [ 50.677951] RBP: 00000000006dbc20 R08: 0000000000000000 R09: 0000000000000000 [ 50.685225] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dbc2c [ 50.695714] R13: 371866fd49719180 R14: 000001f132010000 R15: 00000000000007d6 [ 50.703191] [ 50.704825] Allocated by task 8363: [ 50.708460] save_stack+0x45/0xd0 [ 50.711921] kasan_kmalloc+0xce/0xf0 [ 50.715660] kmem_cache_alloc_trace+0x152/0x760 [ 50.720650] __vb2_init_fileio+0x1cb/0xbe0 [ 50.724899] __vb2_perform_fileio+0xbff/0x1140 [ 50.729515] vb2_read+0x3b/0x50 [ 50.732795] vb2_fop_read+0x212/0x410 [ 50.736584] v4l2_read+0x1ce/0x230 [ 50.740111] __vfs_read+0x116/0x800 [ 50.743738] vfs_read+0x194/0x3d0 [ 50.747205] ksys_read+0xea/0x1f0 [ 50.750654] __x64_sys_read+0x73/0xb0 [ 50.754443] do_syscall_64+0x103/0x610 [ 50.758326] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 50.763622] [ 50.766372] Freed by task 8365: [ 50.769893] save_stack+0x45/0xd0 [ 50.773348] __kasan_slab_free+0x102/0x150 [ 50.777709] kasan_slab_free+0xe/0x10 [ 50.781825] kfree+0xcf/0x230 [ 50.785296] __vb2_cleanup_fileio+0x100/0x170 [ 50.790589] vb2_core_queue_release+0x20/0x80 [ 50.795088] _vb2_fop_release+0x1cf/0x2a0 [ 50.799270] vb2_fop_release+0x75/0xc0 [ 50.803152] vivid_fop_release+0x18e/0x430 [ 50.807386] v4l2_release+0xfb/0x1a0 [ 50.811106] __fput+0x2df/0x8b0 [ 50.814380] ____fput+0x16/0x20 [ 50.817655] task_work_run+0x14a/0x1c0 [ 50.821560] do_exit+0x933/0x2fa0 [ 50.825001] do_group_exit+0x135/0x370 [ 50.828963] get_signal+0x399/0x1d50 [ 50.832675] do_signal+0x95/0x1950 [ 50.836221] exit_to_usermode_loop+0x244/0x2c0 [ 50.840808] do_syscall_64+0x52d/0x610 [ 50.844691] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 50.849958] [ 50.851606] The buggy address belongs to the object at ffff8880868ee940 [ 50.851606] which belongs to the cache kmalloc-1024 of size 1024 [ 50.864443] The buggy address is located 796 bytes inside of [ 50.864443] 1024-byte region [ffff8880868ee940, ffff8880868eed40) [ 50.876420] The buggy address belongs to the page: [ 50.881841] page:ffffea00021a3b80 count:1 mapcount:0 mapping:ffff88812c3f0ac0 index:0x0 compound_mapcount: 0 [ 50.892291] flags: 0x1fffc0000008100(slab|head) [ 50.897086] raw: 01fffc0000008100 ffffea0002518608 ffff88812c3f1848 ffff88812c3f0ac0 [ 50.904959] raw: 0000000000000000 ffff8880868ee040 0000000100000007 0000000000000000 [ 50.912830] page dumped because: kasan: bad access detected [ 50.918558] [ 50.920180] Memory state around the buggy address: [ 50.925108] ffff8880868eeb00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 50.932578] ffff8880868eeb80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 50.939947] >ffff8880868eec00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 50.947295] ^ [ 50.953619] ffff8880868eec80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 50.961341] ffff8880868eed00: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc [ 50.968877] ================================================================== [ 50.976328] Disabling lock debugging due to kernel taint [ 50.986384] Kernel panic - not syncing: panic_on_warn set ... [ 50.986384] [ 50.993793] CPU: 1 PID: 8370 Comm: syz-executor275 Tainted: G B 4.19.35 #3 [ 51.002288] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 51.011809] Call Trace: [ 51.014397] dump_stack+0x172/0x1f0 [ 51.018019] ? __vb2_perform_fileio+0x105d/0x1140 [ 51.023897] panic+0x263/0x51d [ 51.027608] ? __warn_printk+0xf3/0xf3 [ 51.031831] ? __vb2_perform_fileio+0x105d/0x1140 [ 51.036662] ? preempt_schedule+0x4b/0x60 [ 51.040802] ? ___preempt_schedule+0x16/0x18 [ 51.045204] ? trace_hardirqs_on+0x5e/0x230 [ 51.049518] ? __vb2_perform_fileio+0x105d/0x1140 [ 51.054378] kasan_end_report+0x47/0x4f [ 51.058348] kasan_report.cold+0xa9/0x2ba [ 51.062508] __asan_report_load4_noabort+0x14/0x20 [ 51.067551] __vb2_perform_fileio+0x105d/0x1140 [ 51.072314] ? vb2_thread_start+0x370/0x370 [ 51.076643] ? mark_held_locks+0x100/0x100 [ 51.080877] vb2_read+0x3b/0x50 [ 51.084145] vb2_fop_read+0x212/0x410 [ 51.087950] ? vb2_fop_write+0x410/0x410 [ 51.092121] v4l2_read+0x1ce/0x230 [ 51.095663] __vfs_read+0x116/0x800 [ 51.099277] ? v4l2_write+0x230/0x230 [ 51.103176] ? vfs_copy_file_range+0xba0/0xba0 [ 51.107746] ? __sanitizer_cov_trace_const_cmp1+0x1a/0x20 [ 51.113268] ? __inode_security_revalidate+0xda/0x120 [ 51.118446] ? avc_policy_seqno+0xd/0x70 [ 51.122746] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 51.127757] ? security_file_permission+0x1ce/0x230 [ 51.132764] ? security_file_permission+0x8f/0x230 [ 51.137682] ? rw_verify_area+0x118/0x360 [ 51.141825] vfs_read+0x194/0x3d0 [ 51.145303] ksys_read+0xea/0x1f0 [ 51.150960] ? kernel_write+0x120/0x120 [ 51.155990] ? do_syscall_64+0x26/0x610 [ 51.160072] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 51.165519] ? do_syscall_64+0x26/0x610 [ 51.169581] __x64_sys_read+0x73/0xb0 [ 51.173375] do_syscall_64+0x103/0x610 [ 51.177252] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 51.182452] RIP: 0033:0x44a649 [ 51.185636] Code: e8 0c e8 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b cb fb ff c3 66 2e 0f 1f 84 00 00 00 00 [ 51.204804] RSP: 002b:00007f52332cbd98 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 [ 51.212532] RAX: ffffffffffffffda RBX: 00000000006dbc28 RCX: 000000000044a649 [ 51.219819] RDX: 000000000000004b RSI: 0000000020000280 RDI: 0000000000000003 [ 51.227076] RBP: 00000000006dbc20 R08: 0000000000000000 R09: 0000000000000000 [ 51.234341] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dbc2c [ 51.241616] R13: 371866fd49719180 R14: 000001f132010000 R15: 00000000000007d6 [ 51.249608] Kernel Offset: disabled [ 51.253251] Rebooting in 86400 seconds..