After rebuild and some re-runs, I finally hit another use-after-free. Unfortunately there is not as much information here. Note that before kasan was enabled I also did see a kernel crash inside the same __fscache_acquire_cookie RIP called from nfs_fscache_init_inode (actual call chain is __fscache_acquire_cookie -> fscache_hash_cookie -> fscache_compare_cookie Looks like the bad address, "BUG: kernel NULL pointer dereference, address: 0000000000000070" refers to RBX: 0000000000000004 since FAULTING ADDRESS is 0x6c + 0x4 == 0x70 So far I'm not able to decode this much further unfortunately I think due to kasan assembly. crash> dis -lr __fscache_acquire_cookie+0x437 | tail --lines=20 0xffffffffc0f33de4 <__fscache_acquire_cookie+0x3f4>: jne 0xffffffffc0f33e0e <__fscache_acquire_cookie+0x41e> 0xffffffffc0f33de6 <__fscache_acquire_cookie+0x3f6>: jmpq 0xffffffffc0f33f35 <__fscache_acquire_cookie+0x545> /mnt/build/kernel/fs/fscache/cookie.c: 299 0xffffffffc0f33deb <__fscache_acquire_cookie+0x3fb>: mov %r15,%rax 0xffffffffc0f33dee <__fscache_acquire_cookie+0x3fe>: sub %rdx,%rax 0xffffffffc0f33df1 <__fscache_acquire_cookie+0x401>: test %rax,%rax 0xffffffffc0f33df4 <__fscache_acquire_cookie+0x404>: je 0xffffffffc0f33e8f <__fscache_acquire_cookie+0x49f> /mnt/build/kernel/fs/fscache/cookie.c: 400 0xffffffffc0f33dfa <__fscache_acquire_cookie+0x40a>: mov %rbx,%rdi 0xffffffffc0f33dfd <__fscache_acquire_cookie+0x40d>: callq 0xffffffff834c4390 <__asan_load8> 0xffffffffc0f33e02 <__fscache_acquire_cookie+0x412>: mov (%rbx),%rbx 0xffffffffc0f33e05 <__fscache_acquire_cookie+0x415>: test %rbx,%rbx 0xffffffffc0f33e08 <__fscache_acquire_cookie+0x418>: je 0xffffffffc0f33f35 <__fscache_acquire_cookie+0x545> /mnt/build/kernel/fs/fscache/cookie.c: 401 0xffffffffc0f33e0e <__fscache_acquire_cookie+0x41e>: mov %rbp,%rdi 0xffffffffc0f33e11 <__fscache_acquire_cookie+0x421>: callq 0xffffffff834c4250 <__asan_load4> 0xffffffffc0f33e16 <__fscache_acquire_cookie+0x426>: mov 0x94(%r12),%r15d 0xffffffffc0f33e1e <__fscache_acquire_cookie+0x42e>: lea 0x6c(%rbx),%rdi 0xffffffffc0f33e22 <__fscache_acquire_cookie+0x432>: callq 0xffffffff834c4250 <__asan_load4> 0xffffffffc0f33e27 <__fscache_acquire_cookie+0x437>: mov 0x6c(%rbx),%edx <---------- FAULTING ADDRESS is 0x6c + 0x4 == 0x70 crash> crash> mod -s fscache MODULE NAME BASE SIZE OBJECT FILE ffffffffc0f52bc0 fscache ffffffffc0f30000 450560 /lib/modules/5.16.0-rc4-fscache-rewrite-82abe23a0865-kasan+/kernel/fs/fscache/fscache.ko crash> struct -o fscache_cookie -x struct fscache_cookie { [0x0] refcount_t ref; [0x4] atomic_t n_active; [0x8] atomic_t n_accesses; [0xc] unsigned int debug_id; [0x10] unsigned int inval_counter; [0x14] spinlock_t lock; [0x18] struct fscache_volume *volume; [0x20] void *cache_priv; [0x28] struct hlist_bl_node hash_link; [0x38] struct list_head proc_link; [0x48] struct list_head commit_link; [0x58] struct work_struct work; [0x78] loff_t object_size; [0x80] unsigned long unused_at; [0x88] unsigned long flags; [0x90] enum fscache_cookie_state state; [0x91] u8 advice; [0x92] u8 key_len; [0x93] u8 aux_len; [0x94] u32 key_hash; union { [0x98] void *key; [0x98] u8 inline_key[16]; }; union { [0xa8] void *aux; [0xa8] u8 inline_aux[8]; }; } SIZE: 0xb0 # eu-addr2line -e fs/fscache/fscache.ko __fscache_acquire_cookie+0x437 fs/fscache/cookie.c:296:22 291 static long fscache_compare_cookie(const struct fscache_cookie *a, 292 const struct fscache_cookie *b) 293 { 294 const void *ka, *kb; 295 296 if (a->key_hash != b->key_hash) 297 return (long)a->key_hash - (long)b->key_hash; 389 static bool fscache_hash_cookie(struct fscache_cookie *candidate) 390 { 391 struct fscache_cookie *cursor, *wait_for = NULL; 392 struct hlist_bl_head *h; 393 struct hlist_bl_node *p; 394 unsigned int bucket; 395 396 bucket = candidate->key_hash & (ARRAY_SIZE(fscache_cookie_hash) - 1); 397 h = &fscache_cookie_hash[bucket]; 398 399 hlist_bl_lock(h); 400 hlist_bl_for_each_entry(cursor, p, h, hash_link) { 401 if (fscache_compare_cookie(candidate, cursor) == 0) { 402 if (!test_bit(FSCACHE_COOKIE_RELINQUISHED, &cursor->flags)) 403 goto collision; 404 wait_for = fscache_get_cookie(cursor, 405 fscache_cookie_get_hash_collision); 406 break; 407 } 408 } 437 struct fscache_cookie *__fscache_acquire_cookie( 438 struct fscache_volume *volume, 439 u8 advice, 440 const void *index_key, size_t index_key_len, 441 const void *aux_data, size_t aux_data_len, 442 loff_t object_size) 443 { 444 struct fscache_cookie *cookie; 445 446 _enter("V=%x", volume->debug_id); 447 448 if (!index_key || !index_key_len || index_key_len > 255 || aux_data_len > 255) 449 return NULL; 450 if (!aux_data || !aux_data_len) { 451 aux_data = NULL; 452 aux_data_len = 0; 453 } 454 455 fscache_stat(&fscache_n_acquires); 456 457 cookie = fscache_alloc_cookie(volume, advice, 458 index_key, index_key_len, 459 aux_data, aux_data_len, 460 object_size); 461 if (!cookie) { 462 fscache_stat(&fscache_n_acquires_oom); 463 return NULL; 464 } 465 466 if (!fscache_hash_cookie(cookie)) { 467 fscache_see_cookie(cookie, fscache_cookie_discard); 468 fscache_free_cookie(cookie); 469 return NULL; 470 } 471 472 trace_fscache_acquire(cookie); 473 fscache_stat(&fscache_n_acquires_ok); 474 _leave(" = c=%08x", cookie->debug_id); 475 return cookie; 476 } 477 EXPORT_SYMBOL(__fscache_acquire_cookie); Fedora 34 (Thirty Four) Kernel 5.16.0-rc4-fscache-rewrite-82abe23a0865-kasan+ on an x86_64 (ttyS0) dwysocha-f33-node1 login: [ 116.240815] Key type dns_resolver registered [ 117.080094] NFS: Registering the id_resolver key type [ 117.080998] Key type id_resolver registered [ 117.081643] Key type id_legacy registered [ 117.883587] run fstests generic/001 at 2021-12-10 16:46:13 [ 166.930231] run fstests generic/002 at 2021-12-10 16:47:02 [ 170.010369] run fstests generic/003 at 2021-12-10 16:47:05 [ 171.409436] run fstests generic/004 at 2021-12-10 16:47:06 [ 172.898169] run fstests generic/005 at 2021-12-10 16:47:08 [ 175.357500] run fstests generic/006 at 2021-12-10 16:47:10 [ 242.079183] run fstests generic/007 at 2021-12-10 16:48:17 [ 279.459361] hrtimer: interrupt took 2998911 ns [ 465.511517] run fstests generic/008 at 2021-12-10 16:52:00 [ 466.972933] run fstests generic/009 at 2021-12-10 16:52:02 [ 468.431876] run fstests generic/010 at 2021-12-10 16:52:03 [ 469.777769] run fstests generic/011 at 2021-12-10 16:52:05 [ 513.637667] run fstests generic/012 at 2021-12-10 16:52:48 [ 515.183967] run fstests generic/013 at 2021-12-10 16:52:50 [ 532.679299] CacheFiles: cachefiles: Inode already in use: Infs,3.0,2,,917aa8c0,11b6fbb0c280227,,,c0,80000,80000,bb8,ea60,7530,ea60,1 [ 542.768838] run fstests generic/014 at 2021-12-10 16:53:17 [ 608.708004] run fstests generic/015 at 2021-12-10 16:54:23 [ 610.067994] run fstests generic/016 at 2021-12-10 16:54:25 [ 611.577736] run fstests generic/017 at 2021-12-10 16:54:26 [ 613.059498] run fstests generic/018 at 2021-12-10 16:54:28 [ 615.072617] run fstests generic/020 at 2021-12-10 16:54:30 [ 616.634443] run fstests generic/021 at 2021-12-10 16:54:31 [ 618.247911] run fstests generic/022 at 2021-12-10 16:54:33 [ 619.751842] run fstests generic/023 at 2021-12-10 16:54:34 [ 624.933556] run fstests generic/024 at 2021-12-10 16:54:40 [ 626.426606] run fstests generic/025 at 2021-12-10 16:54:41 [ 627.936932] run fstests generic/026 at 2021-12-10 16:54:43 [ 629.655207] run fstests generic/027 at 2021-12-10 16:54:44 [ 631.116553] run fstests generic/028 at 2021-12-10 16:54:46 [ 637.674524] run fstests generic/029 at 2021-12-10 16:54:52 [ 641.175538] run fstests generic/030 at 2021-12-10 16:54:56 [ 645.253008] run fstests generic/031 at 2021-12-10 16:55:00 [ 646.721333] run fstests generic/032 at 2021-12-10 16:55:01 [ 648.242824] run fstests generic/033 at 2021-12-10 16:55:03 [ 649.790584] run fstests generic/034 at 2021-12-10 16:55:05 [ 651.252185] run fstests generic/035 at 2021-12-10 16:55:06 [ 652.844684] run fstests generic/036 at 2021-12-10 16:55:08 [ 664.426043] run fstests generic/037 at 2021-12-10 16:55:19 [ 665.807165] run fstests generic/038 at 2021-12-10 16:55:21 [ 667.165004] run fstests generic/039 at 2021-12-10 16:55:22 [ 668.602477] run fstests generic/040 at 2021-12-10 16:55:23 [ 670.010817] run fstests generic/041 at 2021-12-10 16:55:25 [ 671.359989] run fstests generic/043 at 2021-12-10 16:55:26 [ 673.201808] run fstests generic/044 at 2021-12-10 16:55:28 [ 675.092145] run fstests generic/045 at 2021-12-10 16:55:30 [ 677.136490] run fstests generic/046 at 2021-12-10 16:55:32 [ 679.115816] run fstests generic/047 at 2021-12-10 16:55:34 [ 681.169568] run fstests generic/048 at 2021-12-10 16:55:36 [ 683.257478] run fstests generic/049 at 2021-12-10 16:55:38 [ 685.372013] run fstests generic/050 at 2021-12-10 16:55:40 [ 687.444304] run fstests generic/051 at 2021-12-10 16:55:42 [ 689.583228] run fstests generic/052 at 2021-12-10 16:55:44 [ 691.517190] run fstests generic/053 at 2021-12-10 16:55:46 [ 694.986012] run fstests generic/054 at 2021-12-10 16:55:50 [ 696.902722] run fstests generic/055 at 2021-12-10 16:55:52 [ 699.031353] run fstests generic/056 at 2021-12-10 16:55:54 [ 700.677167] run fstests generic/057 at 2021-12-10 16:55:55 [ 702.205106] run fstests generic/058 at 2021-12-10 16:55:57 [ 703.609498] run fstests generic/059 at 2021-12-10 16:55:58 [ 704.950963] run fstests generic/060 at 2021-12-10 16:56:00 [ 706.358202] run fstests generic/061 at 2021-12-10 16:56:01 [ 707.769142] run fstests generic/062 at 2021-12-10 16:56:03 [ 709.173821] run fstests generic/063 at 2021-12-10 16:56:04 [ 710.500507] run fstests generic/064 at 2021-12-10 16:56:05 [ 711.892195] run fstests generic/065 at 2021-12-10 16:56:07 [ 713.396597] run fstests generic/066 at 2021-12-10 16:56:08 [ 714.855525] run fstests generic/067 at 2021-12-10 16:56:10 [ 716.297302] run fstests generic/068 at 2021-12-10 16:56:11 [ 717.667039] run fstests generic/069 at 2021-12-10 16:56:12 [ 732.553128] run fstests generic/070 at 2021-12-10 16:56:27 [ 734.024395] run fstests generic/071 at 2021-12-10 16:56:29 [ 735.423585] run fstests generic/072 at 2021-12-10 16:56:30 [ 736.855479] run fstests generic/073 at 2021-12-10 16:56:32 [ 738.258477] run fstests generic/074 at 2021-12-10 16:56:33 [ 993.158606] run fstests generic/075 at 2021-12-10 17:00:48 [ 1018.989222] run fstests generic/076 at 2021-12-10 17:01:14 [ 1020.338886] run fstests generic/077 at 2021-12-10 17:01:15 [ 1023.279252] run fstests generic/078 at 2021-12-10 17:01:18 [ 1024.710569] run fstests generic/079 at 2021-12-10 17:01:19 [ 1026.039652] run fstests generic/080 at 2021-12-10 17:01:21 [ 1029.559264] run fstests generic/081 at 2021-12-10 17:01:24 [ 1030.893468] run fstests generic/082 at 2021-12-10 17:01:26 [ 1032.200867] run fstests generic/083 at 2021-12-10 17:01:27 [ 1033.541158] run fstests generic/084 at 2021-12-10 17:01:28 [ 1040.703757] run fstests generic/085 at 2021-12-10 17:01:35 [ 1042.241096] run fstests generic/086 at 2021-12-10 17:01:37 [ 1043.773658] run fstests generic/087 at 2021-12-10 17:01:39 [ 1045.782729] run fstests generic/088 at 2021-12-10 17:01:41 [ 1047.354347] run fstests generic/089 at 2021-12-10 17:01:42 [ 1048.524600] ================================================================== [ 1048.525846] BUG: KASAN: use-after-free in __fscache_acquire_cookie+0x437/0x9b0 [fscache] [ 1048.527153] Read of size 4 at addr ffff888118baf264 by task rm/25988 [ 1048.528174] [ 1048.528460] CPU: 5 PID: 25988 Comm: rm Kdump: loaded Not tainted 5.16.0-rc4-fscache-rewrite-82abe23a0865-kasan+ #1 [ 1048.530048] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-4.fc34 04/01/2014 [ 1048.531379] Call Trace: [ 1048.531805] <TASK> [ 1048.532172] dump_stack_lvl+0x48/0x5e [ 1048.532782] print_address_description.constprop.0+0x1f/0x140 [ 1048.533731] ? __fscache_acquire_cookie+0x437/0x9b0 [fscache] [ 1048.534693] kasan_report.cold+0x7f/0x11b [ 1048.535363] ? __fscache_acquire_cookie+0x437/0x9b0 [fscache] [ 1048.536321] __fscache_acquire_cookie+0x437/0x9b0 [fscache] [ 1048.537249] nfs_fscache_init_inode+0x20b/0x270 [nfs] [ 1048.538210] ? nfs_fscache_release_super_cookie+0x90/0x90 [nfs] [ 1048.539266] ? _raw_spin_unlock+0x16/0x30 [ 1048.539941] ? map_id_range_down+0x13f/0x160 [ 1048.540657] ? nfs_drop_inode+0x70/0x70 [nfs] [ 1048.541441] ? nfs_setsecurity+0x26/0xd0 [nfs] [ 1048.542246] nfs_fhget+0x757/0xcd0 [nfs] [ 1048.542967] ? nfs_setattr+0x390/0x390 [nfs] [ 1048.543732] nfs_readdir_page_filler+0xd0c/0x10c0 [nfs] [ 1048.544634] ? kasan_quarantine_put+0x32/0x1d0 [ 1048.545343] ? nfs_unlink+0x4e0/0x4e0 [nfs] [ 1048.546093] ? nfs3_proc_get_root+0x90/0x90 [nfsv3] [ 1048.546890] ? policy_node+0x4c/0x70 [ 1048.547483] nfs_readdir_xdr_to_array+0x74c/0xa30 [nfs] [ 1048.548391] ? nfs_readdir_page_filler+0x10c0/0x10c0 [nfs] [ 1048.549329] ? nfs_readdir_page_get_locked+0x14d/0x190 [nfs] [ 1048.550310] nfs_readdir+0x53d/0x15b0 [nfs] [ 1048.551064] ? preempt_count_sub+0x14/0xc0 [ 1048.551741] ? _raw_spin_unlock+0x16/0x30 [ 1048.552392] ? nfs_readdir_xdr_to_array+0xa30/0xa30 [nfs] [ 1048.553919] ? fsnotify_perm.part.0+0xa0/0x250 [ 1048.554650] iterate_dir+0x101/0x2d0 [ 1048.555255] __x64_sys_getdents64+0xdc/0x190 [ 1048.555965] ? filldir+0x270/0x270 [ 1048.556539] ? up_read+0x15/0x80 [ 1048.557096] ? __ia32_sys_getdents+0x190/0x190 [ 1048.557812] do_syscall_64+0x3b/0x90 [ 1048.558400] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 1048.559206] RIP: 0033:0x7f7cfd846937 [ 1048.559800] Code: 00 00 0f 05 eb b7 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 f3 0f 1e fa b8 ff ff ff 7f 48 39 c2 48 0f 47 d0 b8 d9 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 8b 15 11 a5 0f 00 f7 d8 64 89 02 48 [ 1048.562662] RSP: 002b:00007ffd605b7518 EFLAGS: 00000293 ORIG_RAX: 00000000000000d9 [ 1048.563869] RAX: ffffffffffffffda RBX: 00007f7cfd6fa010 RCX: 00007f7cfd846937 [ 1048.564978] RDX: 0000000000080000 RSI: 00007f7cfd6fa040 RDI: 0000000000000003 [ 1048.566108] RBP: 00007f7cfd6fa040 R08: 0000000000000030 R09: 0000000000000000 [ 1048.567199] R10: 0000000000000022 R11: 0000000000000293 R12: ffffffffffffff88 [ 1048.568303] R13: 00007f7cfd6fa014 R14: 0000000000000000 R15: 00005621b20be5a0 [ 1048.569406] </TASK> [ 1048.569770] [ 1048.570039] The buggy address belongs to the page: [ 1048.570780] page:00000000ef916ee4 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x118baf [ 1048.572203] flags: 0x17ffffc0000000(node=0|zone=2|lastcpupid=0x1fffff) [ 1048.573198] raw: 0017ffffc0000000 0000000000000000 dead000000000122 0000000000000000 [ 1048.574391] raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000 [ 1048.575601] page dumped because: kasan: bad access detected [ 1048.576469] [ 1048.576742] Memory state around the buggy address: [ 1048.577504] ffff888118baf100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [ 1048.578640] ffff888118baf180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [ 1048.579742] >ffff888118baf200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [ 1048.580854] ^ [ 1048.581836] ffff888118baf280: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [ 1048.582955] ffff888118baf300: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [ 1048.584073] ================================================================== [ 1048.585204] Disabling lock debugging due to kernel taint [ 1048.586068] BUG: kernel NULL pointer dereference, address: 0000000000000070 [ 1048.587147] #PF: supervisor read access in kernel mode [ 1048.587968] #PF: error_code(0x0000) - not-present page [ 1048.588771] PGD 0 P4D 0 [ 1048.589203] Oops: 0000 [#1] PREEMPT SMP KASAN PTI [ 1048.589938] CPU: 5 PID: 25988 Comm: rm Kdump: loaded Tainted: G B 5.16.0-rc4-fscache-rewrite-82abe23a0865-kasan+ #1 [ 1048.591695] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-4.fc34 04/01/2014 [ 1048.593004] RIP: 0010:__fscache_acquire_cookie+0x437/0x9b0 [fscache] [ 1048.594013] Code: e8 8e 05 59 c2 48 8b 1b 48 85 db 0f 84 27 01 00 00 48 89 ef e8 3a 04 59 c2 45 8b bc 24 94 00 00 00 48 8d 7b 6c e8 29 04 59 c2 <8b> 53 6c 44 89 f8 48 29 d0 41 39 d7 75 bc 4c 89 f7 e8 53 05 59 c2 [ 1048.596817] RSP: 0018:ffff888105377740 EFLAGS: 00010282 [ 1048.597644] RAX: 0000000000000000 RBX: 0000000000000004 RCX: ffffffffc0f33e27 [ 1048.598767] RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000070 [ 1048.599868] RBP: ffff888104124ae4 R08: ffffffffc0f33e27 R09: ffffffff864f5c67 [ 1048.600946] R10: fffffbfff0c9eb8c R11: 0000000000000001 R12: ffff888104124a50 [ 1048.603185] R13: ffffffffc0f6ead8 R14: ffff888104124a68 R15: 00000000fa13375b [ 1048.608592] FS: 00007f7cfd77b740(0000) GS:ffff888225a80000(0000) knlGS:0000000000000000 [ 1048.612951] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1048.614019] CR2: 0000000000000070 CR3: 000000011c01c005 CR4: 0000000000770ee0 [ 1048.615325] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 1048.616702] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 1048.618138] PKRU: 55555554 [ 1048.618628] Call Trace: [ 1048.619087] <TASK> [ 1048.619523] nfs_fscache_init_inode+0x20b/0x270 [nfs] [ 1048.620456] ? nfs_fscache_release_super_cookie+0x90/0x90 [nfs] [ 1048.621415] ? _raw_spin_unlock+0x16/0x30 [ 1048.622056] ? map_id_range_down+0x13f/0x160 [ 1048.622740] ? nfs_drop_inode+0x70/0x70 [nfs] [ 1048.623500] ? nfs_setsecurity+0x26/0xd0 [nfs] [ 1048.624266] nfs_fhget+0x757/0xcd0 [nfs] [ 1048.624971] ? nfs_setattr+0x390/0x390 [nfs] [ 1048.625720] nfs_readdir_page_filler+0xd0c/0x10c0 [nfs] [ 1048.626623] ? kasan_quarantine_put+0x32/0x1d0 [ 1048.627328] ? nfs_unlink+0x4e0/0x4e0 [nfs] [ 1048.628066] ? nfs3_proc_get_root+0x90/0x90 [nfsv3] [ 1048.628866] ? policy_node+0x4c/0x70 [ 1048.629458] nfs_readdir_xdr_to_array+0x74c/0xa30 [nfs] [ 1048.630350] ? nfs_readdir_page_filler+0x10c0/0x10c0 [nfs] [ 1048.631285] ? nfs_readdir_page_get_locked+0x14d/0x190 [nfs] [ 1048.632234] nfs_readdir+0x53d/0x15b0 [nfs] [ 1048.632971] ? preempt_count_sub+0x14/0xc0 [ 1048.633634] ? _raw_spin_unlock+0x16/0x30 [ 1048.634281] ? nfs_readdir_xdr_to_array+0xa30/0xa30 [nfs] [ 1048.635185] ? down_read+0x180/0x180 [ 1048.635776] ? fsnotify_perm.part.0+0xa0/0x250 [ 1048.636492] iterate_dir+0x101/0x2d0 [ 1048.637079] __x64_sys_getdents64+0xdc/0x190 [ 1048.637766] ? filldir+0x270/0x270 [ 1048.638327] ? up_read+0x15/0x80 [ 1048.638867] ? __ia32_sys_getdents+0x190/0x190 [ 1048.639571] do_syscall_64+0x3b/0x90 [ 1048.640155] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 1048.640946] RIP: 0033:0x7f7cfd846937 [ 1048.641537] Code: 00 00 0f 05 eb b7 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 f3 0f 1e fa b8 ff ff ff 7f 48 39 c2 48 0f 47 d0 b8 d9 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 8b 15 11 a5 0f 00 f7 d8 64 89 02 48 [ 1048.644359] RSP: 002b:00007ffd605b7518 EFLAGS: 00000293 ORIG_RAX: 00000000000000d9 [ 1048.645549] RAX: ffffffffffffffda RBX: 00007f7cfd6fa010 RCX: 00007f7cfd846937 [ 1048.646628] RDX: 0000000000080000 RSI: 00007f7cfd6fa040 RDI: 0000000000000003 [ 1048.647744] RBP: 00007f7cfd6fa040 R08: 0000000000000030 R09: 0000000000000000 [ 1048.648864] R10: 0000000000000022 R11: 0000000000000293 R12: ffffffffffffff88 [ 1048.649961] R13: 00007f7cfd6fa014 R14: 0000000000000000 R15: 00005621b20be5a0 [ 1048.651065] </TASK> [ 1048.651446] Modules linked in: rpcsec_gss_krb5 nfsv4 dns_resolver nfsv3 nfs rfkill cachefiles fscache netfs intel_rapl_msr intel_rapl_common isst_if_common kvm_intel iTCO_wdt intel_pmc_bxt kvm iTCO_vendor_support nfsd joydev i2c_i801 irqbypass virtio_balloon lpc_ich i2c_smbus nfs_acl lockd auth_rpcgss grace drm sunrpc fuse zram ip_tables xfs crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel virtio_console serio_raw virtio_net net_failover virtio_blk failover qemu_fw_cfg [ 1048.657895] CR2: 0000000000000070 [ 1048.658450] ---[ end trace b69def88bec5c486 ]--- [ 1048.659182] RIP: 0010:__fscache_acquire_cookie+0x437/0x9b0 [fscache] [ 1048.660179] Code: e8 8e 05 59 c2 48 8b 1b 48 85 db 0f 84 27 01 00 00 48 89 ef e8 3a 04 59 c2 45 8b bc 24 94 00 00 00 48 8d 7b 6c e8 29 04 59 c2 <8b> 53 6c 44 89 f8 48 29 d0 41 39 d7 75 bc 4c 89 f7 e8 53 05 59 c2 [ 1048.662998] RSP: 0018:ffff888105377740 EFLAGS: 00010282 [ 1048.663828] RAX: 0000000000000000 RBX: 0000000000000004 RCX: ffffffffc0f33e27 [ 1048.664934] RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000070 [ 1048.666054] RBP: ffff888104124ae4 R08: ffffffffc0f33e27 R09: ffffffff864f5c67 [ 1048.667154] R10: fffffbfff0c9eb8c R11: 0000000000000001 R12: ffff888104124a50 [ 1048.668257] R13: ffffffffc0f6ead8 R14: ffff888104124a68 R15: 00000000fa13375b [ 1048.669356] FS: 00007f7cfd77b740(0000) GS:ffff888225a80000(0000) knlGS:0000000000000000 [ 1048.670607] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1048.671507] CR2: 0000000000000070 CR3: 000000011c01c005 CR4: 0000000000770ee0 [ 1048.672609] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 1048.673718] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 1048.674822] PKRU: 55555554 [ 1048.675277] note: rm[25988] exited with preempt_count 1 [ 1048.769127] BUG: Dentry 00000000f445c28a{i=0,n=00000454} still in use (1) [unmount of nfs 0:43] [ 1048.771134] ------------[ cut here ]------------ [ 1048.771904] WARNING: CPU: 5 PID: 25997 at fs/dcache.c:1651 umount_check.cold+0x6b/0x77 [ 1048.773164] Modules linked in: rpcsec_gss_krb5 nfsv4 dns_resolver nfsv3 nfs rfkill cachefiles fscache netfs intel_rapl_msr intel_rapl_common isst_if_common kvm_intel iTCO_wdt intel_pmc_bxt kvm iTCO_vendor_support nfsd joydev i2c_i801 irqbypass virtio_balloon lpc_ich i2c_smbus nfs_acl lockd auth_rpcgss grace drm sunrpc fuse zram i p_tables xfs crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel virtio_console serio_raw virtio_net net_failover virtio_blk failover qemu_fw_cfg [ 1048.779629] CPU: 5 PID: 25997 Comm: umount.nfs Kdump: loaded Tainted: G B D 5.16.0-rc4-fscache-rewrite-82abe23a0865-kasan+ #1 [ 1048.781546] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-4.fc34 04/01/2014 [ 1048.782875] RIP: 0010:umount_check.cold+0x6b/0x77 [ 1048.783632] Code: 31 49 8d 7c 24 40 e8 2c 3c 1a ff 49 8b 54 24 40 41 55 4d 89 f1 41 89 d8 48 89 e9 48 89 ee 48 c7 c7 e0 f6 94 84 e8 89 35 ff ff <0f> 0b 58 e9 23 42 22 ff 31 d2 eb da 49 8d 7c 24 28 49 c7 c7 d8 ff [ 1048.786486] RSP: 0018:ffff88810b827d70 EFLAGS: 00010282 [ 1048.787346] RAX: 0000000000000054 RBX: 0000000000000001 RCX: 0000000000000000 [ 1048.788491] RDX: 0000000000000003 RSI: ffffffff84a9ba80 RDI: ffffed1021704fa5 [ 1048.789630] RBP: ffff88815632f900 R08: 0000000000000054 R09: ffff888225abc8c7 [ 1048.790762] R10: ffffed1044b57918 R11: 0000000000000001 R12: 0000000000000000 [ 1048.791900] R13: ffff888131c303c8 R14: ffffffffc1345e60 R15: ffff88815632f990 [ 1048.793033] FS: 00007f3b1b4f9540(0000) GS:ffff888225a80000(0000) knlGS:0000000000000000 [ 1048.794310] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1048.795240] CR2: 00007f3b1bcef670 CR3: 000000012d47a006 CR4: 0000000000770ee0 [ 1048.796382] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 1048.797508] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 1048.798618] PKRU: 55555554 [ 1048.799093] Call Trace: [ 1048.799511] <TASK> [ 1048.799896] d_walk+0xf2/0x2f0 [ 1048.800407] ? shrink_lock_dentry.part.0+0x130/0x130 [ 1048.801213] shrink_dcache_for_umount+0xf8/0x180 [ 1048.801983] generic_shutdown_super+0x3c/0x1d0 [ 1048.802718] nfs_kill_super+0x35/0x60 [nfs] [ 1048.803486] deactivate_locked_super+0x5d/0xd0 [ 1048.804213] cleanup_mnt+0x1f4/0x260 [ 1048.804819] task_work_run+0x8b/0xc0 [ 1048.805417] exit_to_user_mode_prepare+0x229/0x230 [ 1048.806389] syscall_exit_to_user_mode+0x18/0x40 [ 1048.807148] do_syscall_64+0x48/0x90 [ 1048.807749] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 1048.808590] RIP: 0033:0x7f3b1bbb938b [ 1048.809189] Code: 2a 0c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 90 f3 0f 1e fa 31 f6 e9 05 00 00 00 0f 1f 44 00 00 f3 0f 1e fa b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 05 c3 0f 1f 40 00 48 8b 15 b9 2a 0c 00 f7 d8 [ 1048.812032] RSP: 002b:00007ffddff3db58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [ 1048.813216] RAX: 0000000000000000 RBX: 0000562c6bcc4660 RCX: 00007f3b1bbb938b [ 1048.814364] RDX: 0000562c6bcc4b50 RSI: 0000000000000000 RDI: 0000562c6bcc3d70 [ 1048.815484] RBP: 0000562c6bcc32c0 R08: 0000000000000000 R09: 00000000000000ca [ 1048.816586] R10: 0000000000000008 R11: 0000000000000246 R12: 0000000000000000 [ 1048.817714] R13: 0000562c6bcc3d70 R14: 0000562c6bcc33d0 R15: 0000562c6bcc3410 [ 1048.818839] </TASK> [ 1048.819221] ---[ end trace b69def88bec5c487 ]--- [ 1048.846355] VFS: Busy inodes after unmount of 0:43. Self-destruct in 5 seconds. Have a nice day... [ 1049.162920] run fstests generic/090 at 2021-12-10 17:01:44 [ 1050.821567] run fstests generic/091 at 2021-12-10 17:01:46