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BUG: KASAN: slab-use-after-free in ecryptfs_write_tag_70_packet+0x1241/0x12e0 fs/ecryptfs/keystore.c:742
Read of size 4 at addr ffff888043632298 by task syz.0.0/5326

CPU: 0 UID: 0 PID: 5326 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description+0x55/0x1e0 mm/kasan/report.c:378
 print_report+0x58/0x70 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 ecryptfs_write_tag_70_packet+0x1241/0x12e0 fs/ecryptfs/keystore.c:742
 ecryptfs_encrypt_filename fs/ecryptfs/crypto.c:1378 [inline]
 ecryptfs_encrypt_and_encode_filename+0x576/0x1580 fs/ecryptfs/crypto.c:1789
 ecryptfs_lookup+0x20e/0x780 fs/ecryptfs/inode.c:402
 lookup_open+0x9e1/0x1a40 fs/namei.c:4528
 open_last_lookups fs/namei.c:4767 [inline]
 path_openat+0x677/0x1d60 fs/namei.c:4997
 do_file_open+0x23e/0x4a0 fs/namei.c:5029
 do_sys_openat2+0x115/0x200 fs/open.c:1417
 do_sys_open fs/open.c:1423 [inline]
 __do_sys_open fs/open.c:1431 [inline]
 __se_sys_open fs/open.c:1427 [inline]
 __x64_sys_open+0x11e/0x150 fs/open.c:1427
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f861cb9e159
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f861da5ffe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007f861ce25fa0 RCX: 00007f861cb9e159
RDX: 000000000000000a RSI: 0000000000008901 RDI: 0000200000000180
RBP: 00007f861cc3506b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f861ce26038 R14: 00007f861ce25fa0 R15: 00007ffd06786568
 </TASK>

Allocated by task 5326:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:409 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:426
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5414 [inline]
 __kvmalloc_node_noprof+0x50f/0x820 mm/slub.c:7015
 __do_sys_add_key security/keys/keyctl.c:116 [inline]
 __se_sys_add_key+0x289/0x420 security/keys/keyctl.c:74
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 5326:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:264 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:296
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2748 [inline]
 slab_free mm/slub.c:6509 [inline]
 kfree+0x1c5/0x650 mm/slub.c:6802
 __do_sys_add_key security/keys/keyctl.c:147 [inline]
 __se_sys_add_key+0x3a3/0x420 security/keys/keyctl.c:74
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888043632200
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 152 bytes inside of
 freed 256-byte region [ffff888043632200, ffff888043632300)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x43632
flags: 0x4fff00000000000(node=1|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 04fff00000000000 ffff88801b041b40 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000080008 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5288, tgid 5288 (syz-executor), ts 99233786890
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1871
 prep_new_page mm/page_alloc.c:1879 [inline]
 get_page_from_freelist+0x2209/0x2280 mm/page_alloc.c:3943
 __alloc_frozen_pages_noprof+0x217/0x5a0 mm/page_alloc.c:5436
 alloc_slab_page mm/slub.c:3347 [inline]
 allocate_slab+0x7d/0x620 mm/slub.c:3462
 new_slab mm/slub.c:3513 [inline]
 refill_objects+0x2d5/0x350 mm/slub.c:7418
 refill_sheaf mm/slub.c:2885 [inline]
 __pcs_replace_empty_main+0x2c8/0x6c0 mm/slub.c:4774
 alloc_from_pcs mm/slub.c:4850 [inline]
 slab_alloc_node mm/slub.c:4984 [inline]
 __do_kmalloc_node mm/slub.c:5413 [inline]
 __kmalloc_noprof+0x47b/0x720 mm/slub.c:5439
 _kmalloc_noprof include/linux/slab.h:995 [inline]
 _kzalloc_noprof include/linux/slab.h:1312 [inline]
 fib_create_info+0x16fe/0x3170 net/ipv4/fib_semantics.c:1429
 fib_table_insert+0xcb/0x1b10 net/ipv4/fib_trie.c:1212
 fib_magic+0x43b/0x530 net/ipv4/fib_frontend.c:1147
 fib_add_ifaddr+0x139/0x5d0 net/ipv4/fib_frontend.c:1169
 fib_inetaddr_event+0x12e/0x190 net/ipv4/fib_frontend.c:1483
 notifier_call_chain+0x1a5/0x3d0 kernel/notifier.c:85
 blocking_notifier_call_chain+0x6a/0x90 kernel/notifier.c:380
 __inet_insert_ifa+0x9ef/0xbc0 net/ipv4/devinet.c:566
 inet_rtm_newaddr+0x1039/0x19f0 net/ipv4/devinet.c:1001
page last free pid 110 tgid 110 ts 98303634763 stack trace:
 reset_page_owner include/linux/page_owner.h:26 [inline]
 __free_pages_prepare mm/page_alloc.c:1418 [inline]
 __free_frozen_pages+0xc93/0xd90 mm/page_alloc.c:2962
 __slab_free+0x274/0x2c0 mm/slub.c:5823
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:361
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4683 [inline]
 slab_alloc_node mm/slub.c:4996 [inline]
 __kmalloc_cache_noprof+0x29f/0x600 mm/slub.c:5559
 _kmalloc_noprof include/linux/slab.h:991 [inline]
 _kzalloc_noprof include/linux/slab.h:1312 [inline]
 regulatory_hint_core net/wireless/reg.c:3266 [inline]
 restore_regulatory_settings+0x1e19/0x2f70 net/wireless/reg.c:3598
 crda_timeout_work+0x28/0x80 net/wireless/reg.c:531
 process_one_work kernel/workqueue.c:3396 [inline]
 process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3479
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3560
 kthread+0x38b/0x480 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Memory state around the buggy address:
 ffff888043632180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888043632200: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888043632280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff888043632300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888043632380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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