random: sshd: uninitialized urandom read (32 bytes read) random: sshd: uninitialized urandom read (32 bytes read) kauditd_printk_skb: 10 callbacks suppressed audit: type=1400 audit(1571481878.347:36): avc: denied { map } for pid=6857 comm="syz-executor638" path="/root/syz-executor638862518" dev="sda1" ino=16484 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1 ================================================================== BUG: KASAN: use-after-free in __read_once_size include/linux/compiler.h:183 [inline] BUG: KASAN: use-after-free in compound_head include/linux/page-flags.h:147 [inline] BUG: KASAN: use-after-free in get_page include/linux/mm.h:833 [inline] BUG: KASAN: use-after-free in submit_page_section fs/direct-io.c:890 [inline] BUG: KASAN: use-after-free in do_direct_IO fs/direct-io.c:1097 [inline] BUG: KASAN: use-after-free in do_blockdev_direct_IO+0x70c1/0x7fd0 fs/direct-io.c:1336 Read of size 8 at addr ffff8880a5940f08 by task syz-executor638/6857 CPU: 0 PID: 6857 Comm: syz-executor638 Not tainted 4.14.150 #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+0x138/0x197 lib/dump_stack.c:53 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 __read_once_size include/linux/compiler.h:183 [inline] compound_head include/linux/page-flags.h:147 [inline] get_page include/linux/mm.h:833 [inline] submit_page_section fs/direct-io.c:890 [inline] do_direct_IO fs/direct-io.c:1097 [inline] do_blockdev_direct_IO+0x70c1/0x7fd0 fs/direct-io.c:1336 __blockdev_direct_IO+0xa1/0xca fs/direct-io.c:1422 ext4_direct_IO_write fs/ext4/inode.c:3703 [inline] ext4_direct_IO+0x70d/0x1890 fs/ext4/inode.c:3833 generic_file_direct_write+0x1e7/0x430 mm/filemap.c:2949 __generic_file_write_iter+0x2bc/0x5b0 mm/filemap.c:3128 ext4_file_write_iter+0x2ac/0xe90 fs/ext4/file.c:268 call_write_iter include/linux/fs.h:1777 [inline] do_iter_readv_writev+0x418/0x670 fs/read_write.c:675 do_iter_write fs/read_write.c:954 [inline] do_iter_write+0x154/0x540 fs/read_write.c:935 vfs_iter_write+0x77/0xb0 fs/read_write.c:967 iter_file_splice_write+0x572/0xad0 fs/splice.c:749 do_splice_from fs/splice.c:851 [inline] do_splice fs/splice.c:1147 [inline] SYSC_splice fs/splice.c:1402 [inline] SyS_splice+0xd92/0x1430 fs/splice.c:1382 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x440309 RSP: 002b:00007ffe6bef4568 EFLAGS: 00000246 ORIG_RAX: 0000000000000113 RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440309 RDX: 0000000000000007 RSI: 0000000000000000 RDI: 0000000000000004 RBP: 00000000006ca018 R08: 00000000ffffffff R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401b90 R13: 0000000000401c20 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 6835: 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_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 getname_kernel+0x53/0x350 fs/namei.c:218 open_exec+0x18/0x70 fs/exec.c:877 load_elf_binary+0x77c/0x4d60 fs/binfmt_elf.c:767 search_binary_handler fs/exec.c:1638 [inline] search_binary_handler+0x149/0x6f0 fs/exec.c:1616 exec_binprm fs/exec.c:1680 [inline] do_execveat_common.isra.0+0x1000/0x1dd0 fs/exec.c:1802 do_execve fs/exec.c:1847 [inline] SYSC_execve fs/exec.c:1928 [inline] SyS_execve+0x39/0x50 fs/exec.c:1923 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 Freed by task 6835: 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 __cache_free mm/slab.c:3496 [inline] kmem_cache_free+0x83/0x2b0 mm/slab.c:3758 putname+0xdb/0x120 fs/namei.c:259 open_exec+0x42/0x70 fs/exec.c:882 load_elf_binary+0x77c/0x4d60 fs/binfmt_elf.c:767 search_binary_handler fs/exec.c:1638 [inline] search_binary_handler+0x149/0x6f0 fs/exec.c:1616 exec_binprm fs/exec.c:1680 [inline] do_execveat_common.isra.0+0x1000/0x1dd0 fs/exec.c:1802 do_execve fs/exec.c:1847 [inline] SYSC_execve fs/exec.c:1928 [inline] SyS_execve+0x39/0x50 fs/exec.c:1923 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 ffff8880a59404c0 which belongs to the cache names_cache of size 4096 The buggy address is located 2632 bytes inside of 4096-byte region [ffff8880a59404c0, ffff8880a59414c0) The buggy address belongs to the page: page:ffffea0002965000 count:1 mapcount:0 mapping:ffff8880a59404c0 index:0x0 compound_mapcount: 0 flags: 0x1fffc0000008100(slab|head) raw: 01fffc0000008100 ffff8880a59404c0 0000000000000000 0000000100000001 raw: ffffea000298b620 ffffea0001f73320 ffff8880aa9e0cc0 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880a5940e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a5940e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880a5940f00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880a5940f80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a5941000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================