[ 43.510442] audit: type=1800 audit(1555981414.673:29): pid=7629 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 [ 43.532154] audit: type=1800 audit(1555981414.673:30): pid=7629 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 periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. Starting mcstransd: [....] 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 '10.128.0.22' (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 syzkaller login: [ 675.329840] kauditd_printk_skb: 5 callbacks suppressed [ 675.329858] audit: type=1400 audit(1555982046.493:36): avc: denied { map } for pid=7817 comm="syz-executor636" path="/root/syz-executor636004708" dev="sda1" ino=1426 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 [ 675.446071] ================================================================== [ 675.453762] BUG: KASAN: use-after-free in __vb2_perform_fileio+0x105d/0x1140 [ 675.461058] Read of size 4 at addr ffff888093f2ec5c by task syz-executor636/7855 [ 675.468774] [ 675.470418] CPU: 0 PID: 7855 Comm: syz-executor636 Not tainted 4.19.36 #4 [ 675.477358] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 675.486729] Call Trace: [ 675.489438] dump_stack+0x172/0x1f0 [ 675.493478] ? __vb2_perform_fileio+0x105d/0x1140 [ 675.498336] print_address_description.cold+0x7c/0x20d [ 675.503644] ? __vb2_perform_fileio+0x105d/0x1140 [ 675.508509] kasan_report.cold+0x8c/0x2ba [ 675.512689] __asan_report_load4_noabort+0x14/0x20 [ 675.517643] __vb2_perform_fileio+0x105d/0x1140 [ 675.522519] ? vb2_thread_start+0x370/0x370 [ 675.527060] ? kasan_check_read+0x11/0x20 [ 675.541024] ? do_raw_spin_unlock+0x57/0x270 [ 675.545459] vb2_read+0x3b/0x50 [ 675.548768] vb2_fop_read+0x212/0x410 [ 675.552691] ? vb2_fop_write+0x410/0x410 [ 675.556858] v4l2_read+0x1ce/0x230 [ 675.560444] __vfs_read+0x116/0x800 [ 675.564098] ? v4l2_write+0x230/0x230 [ 675.567927] ? vfs_copy_file_range+0xba0/0xba0 [ 675.572838] ? __sanitizer_cov_trace_const_cmp1+0x1a/0x20 [ 675.578405] ? __inode_security_revalidate+0xda/0x120 [ 675.583803] ? avc_policy_seqno+0xd/0x70 [ 675.588058] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 675.593100] ? security_file_permission+0x1ce/0x230 [ 675.598168] ? security_file_permission+0x8f/0x230 [ 675.603207] ? rw_verify_area+0x118/0x360 [ 675.607395] vfs_read+0x194/0x3d0 [ 675.610871] ksys_read+0xea/0x1f0 [ 675.614435] ? kernel_write+0x120/0x120 [ 675.618432] ? do_syscall_64+0x26/0x610 [ 675.622426] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 675.627808] ? do_syscall_64+0x26/0x610 [ 675.631818] __x64_sys_read+0x73/0xb0 [ 675.635638] do_syscall_64+0x103/0x610 [ 675.639568] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 675.644947] RIP: 0033:0x444ef9 [ 675.648367] Code: e8 ac 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 0b cd fb ff c3 66 2e 0f 1f 84 00 00 00 00 [ 675.667855] RSP: 002b:00007fff695871f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 [ 675.675590] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000444ef9 [ 675.682875] RDX: 0000000000000008 RSI: 0000000020000000 RDI: 0000000000000003 [ 675.690327] RBP: 00000000000a4e2e R08: 0000000000000004 R09: 00000000004002e0 [ 675.697612] R10: 000000000000000f R11: 0000000000000246 R12: 0000000000402090 [ 675.704901] R13: 0000000000402120 R14: 0000000000000000 R15: 0000000000000000 [ 675.712208] [ 675.713844] Allocated by task 7854: [ 675.717496] save_stack+0x45/0xd0 [ 675.720960] kasan_kmalloc+0xce/0xf0 [ 675.724779] kmem_cache_alloc_trace+0x152/0x760 [ 675.729553] __vb2_init_fileio+0x1cb/0xbe0 [ 675.733797] __vb2_perform_fileio+0xbff/0x1140 [ 675.738382] vb2_read+0x3b/0x50 [ 675.741666] vb2_fop_read+0x212/0x410 [ 675.745474] v4l2_read+0x1ce/0x230 [ 675.749016] __vfs_read+0x116/0x800 [ 675.752643] vfs_read+0x194/0x3d0 [ 675.756099] ksys_read+0xea/0x1f0 [ 675.759560] __x64_sys_read+0x73/0xb0 [ 675.763371] do_syscall_64+0x103/0x610 [ 675.767267] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 675.772479] [ 675.774106] Freed by task 7854: [ 675.777389] save_stack+0x45/0xd0 [ 675.780843] __kasan_slab_free+0x102/0x150 [ 675.785086] kasan_slab_free+0xe/0x10 [ 675.788887] kfree+0xcf/0x230 [ 675.791996] __vb2_cleanup_fileio+0x100/0x170 [ 675.796496] vb2_core_queue_release+0x20/0x80 [ 675.801127] _vb2_fop_release+0x1cf/0x2a0 [ 675.805277] vb2_fop_release+0x75/0xc0 [ 675.809178] vivid_fop_release+0x18e/0x430 [ 675.813417] v4l2_release+0xfb/0x1a0 [ 675.817136] __fput+0x2df/0x8b0 [ 675.820420] ____fput+0x16/0x20 [ 675.823713] task_work_run+0x14a/0x1c0 [ 675.827614] do_exit+0x933/0x2fa0 [ 675.831328] do_group_exit+0x135/0x370 [ 675.835227] __x64_sys_exit_group+0x44/0x50 [ 675.839557] do_syscall_64+0x103/0x610 [ 675.843449] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 675.848639] [ 675.850286] The buggy address belongs to the object at ffff888093f2e940 [ 675.850286] which belongs to the cache kmalloc-1024 of size 1024 [ 675.863330] The buggy address is located 796 bytes inside of [ 675.863330] 1024-byte region [ffff888093f2e940, ffff888093f2ed40) [ 675.875312] The buggy address belongs to the page: [ 675.880263] page:ffffea00024fcb80 count:1 mapcount:0 mapping:ffff88812c3f0ac0 index:0x0 compound_mapcount: 0 [ 675.890337] flags: 0x1fffc0000008100(slab|head) [ 675.895121] raw: 01fffc0000008100 ffffea000266f208 ffff88812c3f1848 ffff88812c3f0ac0 [ 675.903111] raw: 0000000000000000 ffff888093f2e040 0000000100000007 0000000000000000 [ 675.911358] page dumped because: kasan: bad access detected [ 675.917075] [ 675.918707] Memory state around the buggy address: [ 675.923661] ffff888093f2eb00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 675.931040] ffff888093f2eb80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 675.938415] >ffff888093f2ec00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 675.945783] ^ [ 675.952026] ffff888093f2ec80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 675.959399] ffff888093f2ed00: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc [ 675.966777] ================================================================== [ 675.974237] Disabling lock debugging due to kernel taint [ 675.980155] Kernel panic - not syncing: panic_on_warn set ... [ 675.980155] [ 675.987563] CPU: 0 PID: 7855 Comm: syz-executor636 Tainted: G B 4.19.36 #4 [ 675.995887] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 676.005341] Call Trace: [ 676.007958] dump_stack+0x172/0x1f0 [ 676.011596] ? __vb2_perform_fileio+0x105d/0x1140 [ 676.016447] panic+0x263/0x51d [ 676.019663] ? __warn_printk+0xf3/0xf3 [ 676.023696] ? __vb2_perform_fileio+0x105d/0x1140 [ 676.028630] ? preempt_schedule+0x4b/0x60 [ 676.032788] ? ___preempt_schedule+0x16/0x18 [ 676.037212] ? trace_hardirqs_on+0x5e/0x230 [ 676.041542] ? __vb2_perform_fileio+0x105d/0x1140 [ 676.046389] kasan_end_report+0x47/0x4f [ 676.050379] kasan_report.cold+0xa9/0x2ba [ 676.054540] __asan_report_load4_noabort+0x14/0x20 [ 676.059477] __vb2_perform_fileio+0x105d/0x1140 [ 676.064161] ? vb2_thread_start+0x370/0x370 [ 676.068587] ? kasan_check_read+0x11/0x20 [ 676.073341] ? do_raw_spin_unlock+0x57/0x270 [ 676.077875] vb2_read+0x3b/0x50 [ 676.081272] vb2_fop_read+0x212/0x410 [ 676.085200] ? vb2_fop_write+0x410/0x410 [ 676.089267] v4l2_read+0x1ce/0x230 [ 676.092994] __vfs_read+0x116/0x800 [ 676.096801] ? v4l2_write+0x230/0x230 [ 676.100613] ? vfs_copy_file_range+0xba0/0xba0 [ 676.105297] ? __sanitizer_cov_trace_const_cmp1+0x1a/0x20 [ 676.110848] ? __inode_security_revalidate+0xda/0x120 [ 676.116049] ? avc_policy_seqno+0xd/0x70 [ 676.120256] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 676.125317] ? security_file_permission+0x1ce/0x230 [ 676.130455] ? security_file_permission+0x8f/0x230 [ 676.135519] ? rw_verify_area+0x118/0x360 [ 676.139797] vfs_read+0x194/0x3d0 [ 676.143266] ksys_read+0xea/0x1f0 [ 676.146740] ? kernel_write+0x120/0x120 [ 676.150752] ? do_syscall_64+0x26/0x610 [ 676.154827] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 676.160306] ? do_syscall_64+0x26/0x610 [ 676.164728] __x64_sys_read+0x73/0xb0 [ 676.168552] do_syscall_64+0x103/0x610 [ 676.172454] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 676.177666] RIP: 0033:0x444ef9 [ 676.180863] Code: e8 ac 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 0b cd fb ff c3 66 2e 0f 1f 84 00 00 00 00 [ 676.199829] RSP: 002b:00007fff695871f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 [ 676.207555] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000444ef9 [ 676.214948] RDX: 0000000000000008 RSI: 0000000020000000 RDI: 0000000000000003 [ 676.222228] RBP: 00000000000a4e2e R08: 0000000000000004 R09: 00000000004002e0 [ 676.229600] R10: 000000000000000f R11: 0000000000000246 R12: 0000000000402090 [ 676.236885] R13: 0000000000402120 R14: 0000000000000000 R15: 0000000000000000 [ 676.245309] Kernel Offset: disabled [ 676.248958] Rebooting in 86400 seconds..