audit: type=1400 audit(1574267237.775:54): avc: denied { map } for pid=7384 comm="syz-executor.5" path="/dev/sg0" dev="devtmpfs" ino=15409 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=system_u:object_r:scsi_generic_device_t:s0 tclass=chr_file permissive=1 FAT-fs (loop3): error, invalid access to FAT (entry 0x00000f00) ================================================================== BUG: KASAN: use-after-free in ext4_data_block_valid+0x293/0x2e0 fs/ext4/block_validity.c:211 Read of size 8 at addr ffff888215c275c8 by task modprobe/7403 CPU: 0 PID: 7403 Comm: modprobe Not tainted 4.14.154 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x142/0x197 lib/dump_stack.c:58 print_address_description.cold+0x7c/0x1dc mm/kasan/report.c:252 kasan_report_error mm/kasan/report.c:351 [inline] kasan_report mm/kasan/report.c:409 [inline] kasan_report.cold+0xa9/0x2af mm/kasan/report.c:393 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:430 ext4_data_block_valid+0x293/0x2e0 fs/ext4/block_validity.c:211 __check_block_validity.constprop.0+0xc1/0x200 fs/ext4/inode.c:401 ext4_map_blocks+0xe74/0x17c0 fs/ext4/inode.c:591 ext4_getblk+0x346/0x450 fs/ext4/inode.c:971 FAT-fs (loop3): Filesystem has been set read-only ext4_bread_batch+0x6f/0x370 fs/ext4/inode.c:1041 ext4_find_entry+0x466/0xd70 fs/ext4/namei.c:1441 ext4_lookup fs/ext4/namei.c:1583 [inline] ext4_lookup+0x111/0x550 fs/ext4/namei.c:1559 lookup_slow+0x226/0x440 fs/namei.c:1695 sctp: failed to load transform for md5: -2 walk_component+0x698/0x1d00 fs/namei.c:1824 lookup_last fs/namei.c:2292 [inline] path_lookupat.isra.0+0x1bb/0x7b0 fs/namei.c:2342 FAT-fs (loop3): error, invalid access to FAT (entry 0x00000500) filename_lookup+0x18e/0x380 fs/namei.c:2376 kobject: '254:384' (ffff888049915350): kobject_uevent_env user_path_at_empty+0x43/0x50 fs/namei.c:2630 user_path_at include/linux/namei.h:57 [inline] SYSC_faccessat fs/open.c:403 [inline] SyS_faccessat fs/open.c:353 [inline] SYSC_access fs/open.c:450 [inline] SyS_access+0x222/0x6b0 fs/open.c:448 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 FAT-fs (loop3): error, invalid access to FAT (entry 0x00000500) entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x7ff4100ad267 kobject: '254:384' (ffff888049915350): fill_kobj_path: path = '/devices/virtual/bdi/254:384' RSP: 002b:00007ffccc270608 EFLAGS: 00000246 ORIG_RAX: 0000000000000015 RAX: ffffffffffffffda RBX: 000055fd5cd2e5c1 RCX: 00007ff4100ad267 RDX: 00000000000033ef RSI: 0000000000000000 RDI: 00007ff4100b12e6 RBP: 00007ff4102b0000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 00007ff4102b81c8 R13: 00007ff4102b0718 R14: 00000000000033ef R15: 00007ff4102b8570 Allocated by task 1: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 save_stack+0x45/0xd0 mm/kasan/kasan.c:447 kobject: 'loop3' (ffff8880a4a50960): kobject_uevent_env set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc mm/kasan/kasan.c:551 [inline] kasan_kmalloc+0xce/0xf0 mm/kasan/kasan.c:529 kasan_slab_alloc+0xf/0x20 mm/kasan/kasan.c:489 kmem_cache_alloc+0x12e/0x780 mm/slab.c:3552 add_system_zone+0x2b3/0x610 fs/ext4/block_validity.c:85 ext4_setup_system_zone+0x303/0x480 fs/ext4/block_validity.c:169 ext4_fill_super+0x71a0/0xb470 fs/ext4/super.c:4358 mount_bdev+0x2be/0x370 fs/super.c:1134 ext4_mount+0x35/0x40 fs/ext4/super.c:5860 mount_fs+0x97/0x2a1 fs/super.c:1237 vfs_kern_mount.part.0+0x5e/0x3d0 fs/namespace.c:1046 vfs_kern_mount fs/namespace.c:1036 [inline] do_new_mount fs/namespace.c:2549 [inline] do_mount+0x417/0x27d0 fs/namespace.c:2879 SYSC_mount fs/namespace.c:3095 [inline] SyS_mount+0xab/0x120 fs/namespace.c:3072 do_mount_root+0x35/0x1b8 init/do_mounts.c:366 mount_block_root+0x301/0x544 init/do_mounts.c:395 kobject: 'loop3' (ffff8880a4a50960): fill_kobj_path: path = '/devices/virtual/block/loop3' mount_root+0x1dd/0x210 init/do_mounts.c:540 prepare_namespace+0x1de/0x21d init/do_mounts.c:599 kernel_init_freeable+0x514/0x532 init/main.c:1092 kernel_init+0x12/0x162 init/main.c:999 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Freed by task 7395: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 save_stack+0x45/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_slab_free+0x75/0xc0 mm/kasan/kasan.c:524 kobject: 'md_d6' (ffff88804b2c42a0): kobject_add_internal: parent: 'block', set: 'devices' __cache_free mm/slab.c:3496 [inline] kmem_cache_free+0x83/0x2b0 mm/slab.c:3758 ext4_release_system_zone+0x6f/0xf0 fs/ext4/block_validity.c:187 ext4_setup_system_zone+0x3c3/0x480 fs/ext4/block_validity.c:151 ext4_remount+0xf32/0x1f80 fs/ext4/super.c:5309 do_remount_sb+0x15e/0x560 fs/super.c:868 do_remount fs/namespace.c:2370 [inline] do_mount+0x13c9/0x27d0 fs/namespace.c:2870 SYSC_mount fs/namespace.c:3095 [inline] SyS_mount+0xab/0x120 fs/namespace.c:3072 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 The buggy address belongs to the object at ffff888215c275b0 which belongs to the cache ext4_system_zone of size 40 The buggy address is located 24 bytes inside of 40-byte region [ffff888215c275b0, ffff888215c275d8) The buggy address belongs to the page: page:ffffea00085709c0 count:1 mapcount:0 mapping:ffff888215c27000 index:0xffff888215c27fb9 flags: 0x6fffc0000000100(slab) raw: 06fffc0000000100 ffff888215c27000 ffff888215c27fb9 000000010000001b raw: ffff888219fef138 ffff888219fef138 ffff8880a6919d80 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888215c27480: fb fc fc fb fb fb fb fb fc fc fb fb fb fb fb fc ffff888215c27500: fc fb fb fb fb fb fc fc fb fb fb fb fb fc fc fb >ffff888215c27580: fb fb fb fb fc fc fb fb fb fb fb fc fc fc fc fc ^ ffff888215c27600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888215c27680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ================================================================== EXT4-fs (sda1): re-mounted. Opts: noblock_validity,data_err=ignore,sb=0x000000000000c0d5,lazytime, kobject: 'md_d6' (ffff88804b2c42a0): kobject_uevent_env