==================================================================
BUG: KASAN: slab-use-after-free in rcu_cblist_dequeue+0xb0/0xe0 kernel/rcu/rcu_segcblist.c:75
Read of size 8 at addr ffff8880513d8dd8 by task syz.8.15707/7738

CPU: 2 UID: 0 PID: 7738 Comm: syz.8.15707 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xcd/0x630 mm/kasan/report.c:482
 kasan_report+0xe0/0x110 mm/kasan/report.c:595
 rcu_cblist_dequeue+0xb0/0xe0 kernel/rcu/rcu_segcblist.c:75
 rcu_do_batch kernel/rcu/tree.c:2593 [inline]
 rcu_core+0x6f6/0x15f0 kernel/rcu/tree.c:2857
 handle_softirqs+0x219/0x950 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x109/0x170 kernel/softirq.c:723
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
 sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1056
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_release+0x183/0x2d0 kernel/locking/lockdep.c:5893
Code: 0f c1 05 78 07 19 12 83 f8 01 0f 85 03 01 00 00 9c 58 f6 c4 02 0f 85 ee 00 00 00 41 f7 c5 00 02 00 00 74 01 fb 48 8b 44 24 10 <65> 48 2b 05 0d c0 18 12 0f 85 32 01 00 00 48 83 c4 18 5b 41 5c 41
RSP: 0018:ffffc90003dc7430 EFLAGS: 00000206
RAX: 6d3c59a4689cd100 RBX: ffffffff8e3c9520 RCX: ffffc90003dc743c
RDX: 0000000000000001 RSI: ffffffff8daa494a RDI: ffffffff8bf2b580
RBP: 0000000000000001 R08: ffffffff911ae744 R09: 0000000082608fbb
R10: 0000000000000002 R11: 000000000000001e R12: ffffffff816c79a4
R13: 0000000000000206 R14: ffff888024e224c0 R15: 0000000000000002
 rcu_lock_release include/linux/rcupdate.h:341 [inline]
 rcu_read_unlock include/linux/rcupdate.h:897 [inline]
 class_rcu_destructor include/linux/rcupdate.h:1195 [inline]
 unwind_next_frame+0x3f9/0x20b0 arch/x86/kernel/unwind_orc.c:495
 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:56
 kasan_save_track+0x14/0x30 mm/kasan/common.c:77
 poison_kmalloc_redzone mm/kasan/common.c:397 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:414
 kasan_kmalloc include/linux/kasan.h:262 [inline]
 __do_kmalloc_node mm/slub.c:5657 [inline]
 __kmalloc_noprof+0x33d/0x910 mm/slub.c:5669
 kmalloc_noprof include/linux/slab.h:961 [inline]
 sock_kmalloc+0x111/0x170 net/core/sock.c:2880
 hash_alloc_result+0xd7/0x150 crypto/algif_hash.c:41
 hash_recvmsg+0x198/0x960 crypto/algif_hash.c:196
 sock_recvmsg_nosec net/socket.c:1078 [inline]
 ____sys_recvmsg+0x5f9/0x6b0 net/socket.c:2810
 ___sys_recvmsg+0x114/0x1a0 net/socket.c:2854
 do_recvmmsg+0x55d/0x750 net/socket.c:2941
 __sys_recvmmsg+0x21c/0x280 net/socket.c:3023
 __do_compat_sys_recvmmsg_time32 net/compat.c:418 [inline]
 __se_compat_sys_recvmmsg_time32 net/compat.c:414 [inline]
 __ia32_compat_sys_recvmmsg_time32+0xc4/0x160 net/compat.c:414
 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
 __do_fast_syscall_32+0xe8/0x680 arch/x86/entry/syscall_32.c:307
 do_fast_syscall_32+0x32/0x80 arch/x86/entry/syscall_32.c:332
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf7fc7579
Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00
RSP: 002b:00000000f54b655c EFLAGS: 00000296 ORIG_RAX: 0000000000000151
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000080003700
RDX: 0000000000000600 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>

Allocated by task 7729:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:56
 kasan_save_track+0x14/0x30 mm/kasan/common.c:77
 unpoison_slab_object mm/kasan/common.c:339 [inline]
 __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:365
 kasan_slab_alloc include/linux/kasan.h:252 [inline]
 slab_post_alloc_hook mm/slub.c:4953 [inline]
 slab_alloc_node mm/slub.c:5263 [inline]
 kmem_cache_alloc_noprof+0x25e/0x770 mm/slub.c:5270
 radix_tree_node_alloc.constprop.0+0x7c/0x350 lib/radix-tree.c:276
 idr_get_free+0x528/0xa30 lib/radix-tree.c:1506
 idr_alloc_u32+0x190/0x2f0 lib/idr.c:46
 idr_alloc_cyclic+0x10b/0x230 lib/idr.c:125
 afs_alloc_cell fs/afs/cell.c:209 [inline]
 afs_lookup_cell+0x11d1/0x1900 fs/afs/cell.c:278
 afs_parse_source fs/afs/super.c:292 [inline]
 afs_parse_param+0x5c4/0x970 fs/afs/super.c:330
 vfs_parse_fs_param+0x20b/0x3c0 fs/fs_context.c:146
 vfs_fsconfig_locked fs/fsopen.c:303 [inline]
 __do_sys_fsconfig+0x930/0xbe0 fs/fsopen.c:473
 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
 __do_fast_syscall_32+0xe8/0x680 arch/x86/entry/syscall_32.c:307
 do_fast_syscall_32+0x32/0x80 arch/x86/entry/syscall_32.c:332
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e

Freed by task 33:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:56
 kasan_save_track+0x14/0x30 mm/kasan/common.c:77
 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:252 [inline]
 __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:284
 kasan_slab_free include/linux/kasan.h:234 [inline]
 slab_free_hook mm/slub.c:2540 [inline]
 slab_free mm/slub.c:6670 [inline]
 kmem_cache_free+0x2d8/0x770 mm/slub.c:6781
 rcu_do_batch kernel/rcu/tree.c:2605 [inline]
 rcu_core+0x79c/0x15f0 kernel/rcu/tree.c:2857
 handle_softirqs+0x219/0x950 kernel/softirq.c:622
 run_ksoftirqd kernel/softirq.c:1063 [inline]
 run_ksoftirqd+0x3a/0x60 kernel/softirq.c:1055
 smpboot_thread_fn+0x3f7/0xae0 kernel/smpboot.c:160
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

Last potentially related work creation:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:56
 kasan_record_aux_stack+0xa7/0xc0 mm/kasan/generic.c:556
 __call_rcu_common.constprop.0+0xa5/0xa10 kernel/rcu/tree.c:3119
 radix_tree_node_free lib/radix-tree.c:310 [inline]
 delete_node+0x1fc/0x8d0 lib/radix-tree.c:573
 __radix_tree_delete+0x193/0x3d0 lib/radix-tree.c:1379
 radix_tree_delete_item+0xea/0x230 lib/radix-tree.c:1430
 afs_cell_destroy+0x1db/0x310 fs/afs/cell.c:580
 rcu_do_batch kernel/rcu/tree.c:2605 [inline]
 rcu_core+0x79c/0x15f0 kernel/rcu/tree.c:2857
 handle_softirqs+0x219/0x950 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x109/0x170 kernel/softirq.c:723
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
 sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1056
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697

The buggy address belongs to the object at ffff8880513d8dc0
 which belongs to the cache radix_tree_node of size 576
The buggy address is located 24 bytes inside of
 freed 576-byte region [ffff8880513d8dc0, ffff8880513d9000)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x513d8
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff888040f04501
anon flags: 0x4fff00000000040(head|node=1|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 04fff00000000040 ffff88801b44cc80 0000000000000000 dead000000000001
raw: 0000000000000000 0000000080170017 00000000f5000000 ffff888040f04501
head: 04fff00000000040 ffff88801b44cc80 0000000000000000 dead000000000001
head: 0000000000000000 0000000080170017 00000000f5000000 ffff888040f04501
head: 04fff00000000002 ffffea000144f601 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000004
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Reclaimable, gfp_mask 0x52810(GFP_NOWAIT|__GFP_RECLAIMABLE|__GFP_NORETRY|__GFP_COMP), pid 5557, tgid 5556 (syz.4.14728), ts 645627099578, free_ts 633604523094
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1af/0x220 mm/page_alloc.c:1846
 prep_new_page mm/page_alloc.c:1854 [inline]
 get_page_from_freelist+0xd0b/0x31a0 mm/page_alloc.c:3915
 __alloc_frozen_pages_noprof+0x25f/0x2430 mm/page_alloc.c:5210
 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2486
 alloc_slab_page mm/slub.c:3075 [inline]
 allocate_slab mm/slub.c:3248 [inline]
 new_slab+0x2c3/0x430 mm/slub.c:3302
 ___slab_alloc+0xe18/0x1c90 mm/slub.c:4656
 __slab_alloc.constprop.0+0x63/0x110 mm/slub.c:4779
 __slab_alloc_node mm/slub.c:4855 [inline]
 slab_alloc_node mm/slub.c:5251 [inline]
 kmem_cache_alloc_lru_noprof+0x451/0x770 mm/slub.c:5282
 xas_alloc+0x34f/0x460 lib/xarray.c:378
 xas_create+0x72b/0x1460 lib/xarray.c:685
 xas_store+0x90/0x1910 lib/xarray.c:795
 shmem_add_to_page_cache+0x7b7/0xa70 mm/shmem.c:922
 shmem_alloc_and_add_folio+0x662/0xc20 mm/shmem.c:1958
 shmem_get_folio_gfp+0x67f/0x1610 mm/shmem.c:2556
 shmem_fault+0x1fe/0xa00 mm/shmem.c:2757
 __do_fault+0x10d/0x490 mm/memory.c:5320
page last free pid 27875 tgid 27875 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1395 [inline]
 __free_frozen_pages+0x7df/0x1170 mm/page_alloc.c:2943
 discard_slab mm/slub.c:3346 [inline]
 __put_partials+0x130/0x170 mm/slub.c:3886
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x4c/0xf0 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x195/0x1e0 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:349
 kasan_slab_alloc include/linux/kasan.h:252 [inline]
 slab_post_alloc_hook mm/slub.c:4953 [inline]
 slab_alloc_node mm/slub.c:5263 [inline]
 kmem_cache_alloc_noprof+0x25e/0x770 mm/slub.c:5270
 getname_flags.part.0+0x4c/0x550 fs/namei.c:146
 getname_flags+0x93/0xf0 include/linux/audit.h:345
 getname include/linux/fs.h:2498 [inline]
 __do_sys_unlinkat fs/namei.c:5468 [inline]
 __se_sys_unlinkat fs/namei.c:5462 [inline]
 __ia32_sys_unlinkat+0xe4/0x130 fs/namei.c:5462
 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
 __do_fast_syscall_32+0xe8/0x680 arch/x86/entry/syscall_32.c:307
 do_fast_syscall_32+0x32/0x80 arch/x86/entry/syscall_32.c:332
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e

Memory state around the buggy address:
 ffff8880513d8c80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8880513d8d00: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
>ffff8880513d8d80: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
                                                    ^
 ffff8880513d8e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880513d8e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess):
   0:	0f c1 05 78 07 19 12 	xadd   %eax,0x12190778(%rip)        # 0x1219077f
   7:	83 f8 01             	cmp    $0x1,%eax
   a:	0f 85 03 01 00 00    	jne    0x113
  10:	9c                   	pushf
  11:	58                   	pop    %rax
  12:	f6 c4 02             	test   $0x2,%ah
  15:	0f 85 ee 00 00 00    	jne    0x109
  1b:	41 f7 c5 00 02 00 00 	test   $0x200,%r13d
  22:	74 01                	je     0x25
  24:	fb                   	sti
  25:	48 8b 44 24 10       	mov    0x10(%rsp),%rax
* 2a:	65 48 2b 05 0d c0 18 	sub    %gs:0x1218c00d(%rip),%rax        # 0x1218c03f <-- trapping instruction
  31:	12
  32:	0f 85 32 01 00 00    	jne    0x16a
  38:	48 83 c4 18          	add    $0x18,%rsp
  3c:	5b                   	pop    %rbx
  3d:	41 5c                	pop    %r12
  3f:	41                   	rex.B