================================================================== BUG: KASAN: slab-out-of-bounds in vsscanf+0x2666/0x2ef0 lib/vsprintf.c:3321 Read of size 1 at addr ffff8880929b8ad6 by task syz-executor.4/25257 CPU: 1 PID: 25257 Comm: syz-executor.4 Not tainted 5.7.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1e9/0x30e lib/dump_stack.c:118 print_address_description+0x74/0x5c0 mm/kasan/report.c:382 __kasan_report+0x103/0x1a0 mm/kasan/report.c:511 kasan_report+0x4d/0x80 mm/kasan/common.c:625 Allocated by task 25257: save_stack mm/kasan/common.c:49 [inline] set_track mm/kasan/common.c:57 [inline] __kasan_kmalloc+0x114/0x160 mm/kasan/common.c:495 __do_kmalloc mm/slab.c:3656 [inline] __kmalloc_track_caller+0x249/0x320 mm/slab.c:3671 memdup_user_nul+0x26/0xf0 mm/util.c:259 smk_set_cipso+0xff/0x6a0 security/smack/smackfs.c:859 __vfs_write+0xa7/0x710 fs/read_write.c:495 vfs_write+0x274/0x580 fs/read_write.c:559 ksys_write+0x11b/0x220 fs/read_write.c:612 do_syscall_64+0xf3/0x1b0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 Freed by task 24986: save_stack mm/kasan/common.c:49 [inline] set_track mm/kasan/common.c:57 [inline] kasan_set_free_info mm/kasan/common.c:317 [inline] __kasan_slab_free+0x125/0x190 mm/kasan/common.c:456 __cache_free mm/slab.c:3426 [inline] kfree+0x10a/0x220 mm/slab.c:3757 smk_fetch security/smack/smack_lsm.c:302 [inline] smack_d_instantiate+0xae2/0xd90 security/smack/smack_lsm.c:3451 security_d_instantiate+0xa5/0x100 security/security.c:1925 d_instantiate_new+0x61/0x110 fs/dcache.c:1973 ext4_add_nondir+0x1f6/0x260 fs/ext4/namei.c:2582 ext4_symlink+0x8ba/0xef0 fs/ext4/namei.c:3364 vfs_symlink+0x36f/0x520 fs/namei.c:3937 do_symlinkat+0x18b/0x420 fs/namei.c:3964 do_syscall_64+0xf3/0x1b0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 The buggy address belongs to the object at ffff8880929b8a00 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 214 bytes inside of 256-byte region [ffff8880929b8a00, ffff8880929b8b00) The buggy address belongs to the page: page:ffffea00024a6e00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 flags: 0xfffe0000000200(slab) raw: 00fffe0000000200 ffffea00028b08c8 ffffea0002805448 ffff8880aa4008c0 raw: 0000000000000000 ffff8880929b8000 0000000100000008 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880929b8980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880929b8a00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff8880929b8a80: 00 00 00 00 00 00 00 00 00 00 06 fc fc fc fc fc ^ ffff8880929b8b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880929b8b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================