BUG: kernel NULL pointer dereference, address: 0000000000000008
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 5a4b8067 P4D 5a4b8067 PUD 6f33a067 PMD 0 
Oops: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 2998 Comm: kworker/0:2 Not tainted 5.11.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events free_ipc
RIP: 0010:kasan_record_aux_stack+0x77/0xb0 mm/kasan/generic.c:341
Code: 48 f7 fe 8b 47 24 49 89 f0 48 29 d3 8d 70 ff 41 0f af f0 48 01 ce 48 39 f3 48 0f 46 f3 e8 81 e9 ff ff bf 00 08 00 00 48 89 c3 <8b> 40 08 89 43 0c e8 1e e6 ff ff 89 43 08 5b c3 48 8b 50 08 48 c7
RSP: 0018:ffffc900098b7ae8 EFLAGS: 00010046
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff888088400000
RDX: 0000000000000078 RSI: ffff888088400000 RDI: 0000000000000800
RBP: ffffffff837aae30 R08: 0000000000400000 R09: ffffffff8ebe48c7
R10: ffffffff8132a9c0 R11: 0000000000000000 R12: 0000000000035b40
R13: ffff888088400088 R14: ffffc900098b7c08 R15: 0000000000000200
FS:  0000000000000000(0000) GS:ffff8880b9e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000008 CR3: 0000000034f6a000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 __call_rcu kernel/rcu/tree.c:2965 [inline]
 call_rcu+0xbb/0x700 kernel/rcu/tree.c:3038
 ipc_rcu_putref+0x83/0xb0 ipc/util.c:505
 freeary+0x137f/0x1b10 ipc/sem.c:1188
 free_ipcs+0x98/0x1c0 ipc/namespace.c:112
 sem_exit_ns+0x1b/0x40 ipc/sem.c:260
 free_ipc_ns ipc/namespace.c:124 [inline]
 free_ipc+0xf8/0x200 ipc/namespace.c:141
 process_one_work+0x98d/0x15f0 kernel/workqueue.c:2275
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2421
 kthread+0x3b1/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
Modules linked in:
CR2: 0000000000000008
---[ end trace 1978e6e112798ad7 ]---
RIP: 0010:kasan_record_aux_stack+0x77/0xb0 mm/kasan/generic.c:341
Code: 48 f7 fe 8b 47 24 49 89 f0 48 29 d3 8d 70 ff 41 0f af f0 48 01 ce 48 39 f3 48 0f 46 f3 e8 81 e9 ff ff bf 00 08 00 00 48 89 c3 <8b> 40 08 89 43 0c e8 1e e6 ff ff 89 43 08 5b c3 48 8b 50 08 48 c7
RSP: 0018:ffffc900098b7ae8 EFLAGS: 00010046
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff888088400000
RDX: 0000000000000078 RSI: ffff888088400000 RDI: 0000000000000800
RBP: ffffffff837aae30 R08: 0000000000400000 R09: ffffffff8ebe48c7
R10: ffffffff8132a9c0 R11: 0000000000000000 R12: 0000000000035b40
R13: ffff888088400088 R14: ffffc900098b7c08 R15: 0000000000000200
FS:  0000000000000000(0000) GS:ffff8880b9e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000008 CR3: 0000000034f6a000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400