Hi, I haven't yet succeeded to reproduce the issue with the attached program. How reproducible is it in your environment? (Does it take a long time to reproduce ?) Regards, Ryusuke Konishi On Mon, Mar 22, 2021 at 6:05 PM butt3rflyh4ck <butterflyhuangxx@xxxxxxxxx> wrote: > > Hi, guy, I reported a bug found by syzkaller fuzzer with custom > modifications and reproduced in 5.12.0-rc3+ too. > > There are use-after-free crashes in nilfs_mdt_destroy in fs/nilfs2/mdt.c. > > and there is a latest crash logs as follows: > > ================================================================== > BUG: KASAN: use-after-free in nilfs_mdt_destroy+0x6f/0x80 fs/nilfs2/mdt.c:485 > Read of size 8 at addr ffff8880478f0098 by task syz-executor325/8480 > > CPU: 1 PID: 8480 Comm: syz-executor325 Not tainted 5.12.0-rc3+ #42 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS > 1.13.0-1ubuntu1 04/01/2014 > Call Trace: > __dump_stack lib/dump_stack.c:79 [inline] > dump_stack+0xfa/0x151 lib/dump_stack.c:120 > print_address_description.constprop.0.cold+0x82/0x32c mm/kasan/report.c:232 > __kasan_report mm/kasan/report.c:399 [inline] > kasan_report.cold+0x7c/0xd8 mm/kasan/report.c:416 > nilfs_mdt_destroy+0x6f/0x80 fs/nilfs2/mdt.c:485 > nilfs_free_inode+0x3e/0x60 fs/nilfs2/super.c:167 > i_callback+0x3f/0x70 fs/inode.c:223 > alloc_inode+0x13e/0x1e0 fs/inode.c:248 > iget5_locked fs/inode.c:1148 [inline] > iget5_locked+0x57/0xd0 fs/inode.c:1141 > nilfs_iget_locked fs/nilfs2/inode.c:570 [inline] > nilfs_iget+0xb2/0x870 fs/nilfs2/inode.c:579 > nilfs_lookup fs/nilfs2/namei.c:63 [inline] > nilfs_lookup+0xfd/0x130 fs/nilfs2/namei.c:54 > __lookup_slow+0x255/0x490 fs/namei.c:1626 > lookup_slow fs/namei.c:1643 [inline] > walk_component+0x418/0x6a0 fs/namei.c:1939 > link_path_walk.part.0+0x6b6/0xc10 fs/namei.c:2266 > link_path_walk fs/namei.c:2190 [inline] > path_lookupat.isra.0+0x8d/0x530 fs/namei.c:2419 > filename_lookup+0x1a3/0x3e0 fs/namei.c:2453 > user_path_at include/linux/namei.h:60 [inline] > vfs_statx+0x13c/0x370 fs/stat.c:195 > do_statx+0xd9/0x160 fs/stat.c:590 > __do_sys_statx fs/stat.c:613 [inline] > __se_sys_statx fs/stat.c:608 [inline] > __x64_sys_statx+0xba/0x150 fs/stat.c:608 > do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 > entry_SYSCALL_64_after_hwframe+0x44/0xae > RIP: 0033:0x4505ad > Code: 02 b8 ff ff ff ff c3 66 0f 1f 44 00 00 f3 0f 1e fa 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 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48 > RSP: 002b:00007fff7db857c8 EFLAGS: 00000246 ORIG_RAX: 000000000000014c > RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00000000004505ad > RDX: 0000000000000000 RSI: 0000000020000040 RDI: 0000000000000006 > RBP: 0000000000000004 R08: 0000000000000000 R09: 00000000004a4099 > R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff7db857ec > R13: 00007fff7db85810 R14: 00007fff7db857f0 R15: 0000000000000010 > > Allocated by task 8426: > kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 > kasan_set_track mm/kasan/common.c:46 [inline] > set_alloc_info mm/kasan/common.c:427 [inline] > ____kasan_kmalloc mm/kasan/common.c:506 [inline] > ____kasan_kmalloc mm/kasan/common.c:465 [inline] > __kasan_kmalloc+0x99/0xc0 mm/kasan/common.c:515 > kasan_kmalloc include/linux/kasan.h:233 [inline] > __kmalloc+0x1c7/0x3d0 mm/slub.c:4055 > kmalloc include/linux/slab.h:559 [inline] > kzalloc include/linux/slab.h:684 [inline] > nilfs_mdt_init+0x2c/0x1e0 fs/nilfs2/mdt.c:448 > nilfs_dat_read+0x11b/0x2c0 fs/nilfs2/dat.c:489 > nilfs_load_super_root fs/nilfs2/the_nilfs.c:120 [inline] > load_nilfs+0x327/0x11c0 fs/nilfs2/the_nilfs.c:269 > nilfs_fill_super fs/nilfs2/super.c:1058 [inline] > nilfs_mount+0xab0/0xfe0 fs/nilfs2/super.c:1316 > legacy_get_tree+0x105/0x220 fs/fs_context.c:592 > vfs_get_tree+0x89/0x2f0 fs/super.c:1497 > do_new_mount fs/namespace.c:2903 [inline] > path_mount+0x123b/0x1cc0 fs/namespace.c:3233 > do_mount+0xf3/0x110 fs/namespace.c:3246 > __do_sys_mount fs/namespace.c:3454 [inline] > __se_sys_mount fs/namespace.c:3431 [inline] > __x64_sys_mount+0x18f/0x230 fs/namespace.c:3431 > do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 > entry_SYSCALL_64_after_hwframe+0x44/0xae > > Last potentially related work creation: > kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 > kasan_record_aux_stack+0xe5/0x110 mm/kasan/generic.c:345 > __call_rcu kernel/rcu/tree.c:3039 [inline] > call_rcu+0xb1/0x700 kernel/rcu/tree.c:3114 > netlink_release+0xd41/0x1c20 net/netlink/af_netlink.c:810 > __sock_release+0xcd/0x280 net/socket.c:599 > sock_close+0x18/0x20 net/socket.c:1258 > __fput+0x288/0x920 fs/file_table.c:280 > task_work_run+0xe0/0x1a0 kernel/task_work.c:140 > tracehook_notify_resume include/linux/tracehook.h:189 [inline] > exit_to_user_mode_loop kernel/entry/common.c:174 [inline] > exit_to_user_mode_prepare+0x25c/0x270 kernel/entry/common.c:208 > __syscall_exit_to_user_mode_work kernel/entry/common.c:290 [inline] > syscall_exit_to_user_mode+0x19/0x50 kernel/entry/common.c:301 > entry_SYSCALL_64_after_hwframe+0x44/0xae > > Second to last potentially related work creation: > kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 > kasan_record_aux_stack+0xe5/0x110 mm/kasan/generic.c:345 > insert_work+0x4a/0x3a0 kernel/workqueue.c:1331 > __queue_work+0x4d4/0x1120 kernel/workqueue.c:1497 > queue_work_on+0xae/0xc0 kernel/workqueue.c:1524 > kref_put include/linux/kref.h:65 [inline] > tty_kref_put drivers/tty/tty_io.c:1589 [inline] > release_tty+0x4e9/0x610 drivers/tty/tty_io.c:1626 > tty_release_struct+0x37/0x50 drivers/tty/tty_io.c:1725 > tty_release+0xbd2/0x1140 drivers/tty/tty_io.c:1885 > __fput+0x288/0x920 fs/file_table.c:280 > task_work_run+0xe0/0x1a0 kernel/task_work.c:140 > tracehook_notify_resume include/linux/tracehook.h:189 [inline] > exit_to_user_mode_loop kernel/entry/common.c:174 [inline] > exit_to_user_mode_prepare+0x25c/0x270 kernel/entry/common.c:208 > __syscall_exit_to_user_mode_work kernel/entry/common.c:290 [inline] > syscall_exit_to_user_mode+0x19/0x50 kernel/entry/common.c:301 > entry_SYSCALL_64_after_hwframe+0x44/0xae > > The buggy address belongs to the object at ffff8880478f0000 > which belongs to the cache kmalloc-2k of size 2048 > The buggy address is located 152 bytes inside of > 2048-byte region [ffff8880478f0000, ffff8880478f0800) > The buggy address belongs to the page: > page:0000000003e87868 refcount:1 mapcount:0 mapping:0000000000000000 > index:0xffff8880478f0000 pfn:0x478f0 > head:0000000003e87868 order:3 compound_mapcount:0 compound_pincount:0 > flags: 0x4fff00000010200(slab|head) > raw: 04fff00000010200 ffffea00011e0600 0000000200000002 ffff88800fc42000 > raw: ffff8880478f0000 0000000080080007 00000001ffffffff 0000000000000000 > page dumped because: kasan: bad access detected > > Memory state around the buggy address: > ffff8880478eff80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > ffff8880478f0000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > >ffff8880478f0080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ^ > ffff8880478f0100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff8880478f0180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ================================================================== > > the attachment is reproduce. > > Regards, > butt3rflyh4ck.
