BUG: using smp_processor_id() in preemptible [00000000] code: syz.0.904/6682
caller is debug_smp_processor_id+0x20/0x24 lib/smp_processor_id.c:58
CPU: 1 UID: 0 PID: 6682 Comm: syz.0.904 Not tainted syzkaller #0 PREEMPT 
Hardware name: ARM-Versatile Express
Call trace: 
[<80201998>] (dump_backtrace) from [<80201a8c>] (show_stack+0x18/0x1c arch/arm/kernel/traps.c:257)
 r7:60000013 r6:60000013 r5:82332a10 r4:00000000
[<80201a74>] (show_stack) from [<8021e580>] (__dump_stack lib/dump_stack.c:94 [inline])
[<80201a74>] (show_stack) from [<8021e580>] (dump_stack_lvl+0x5c/0x70 lib/dump_stack.c:120)
[<8021e524>] (dump_stack_lvl) from [<8021e5ac>] (dump_stack+0x18/0x1c lib/dump_stack.c:129)
 r7:00000001 r6:82341988 r5:81b58220 r4:83febd40
[<8021e594>] (dump_stack) from [<81b581fc>] (check_preemption_disabled+0xfc/0x100 lib/smp_processor_id.c:47)
[<81b58100>] (check_preemption_disabled) from [<81b58220>] (debug_smp_processor_id+0x20/0x24 lib/smp_processor_id.c:58)
 r7:828d00f0 r6:83febd40 r5:a42bfbd8 r4:861664c4
[<81b58200>] (debug_smp_processor_id) from [<8045dfd0>] (bpf_mem_cache_free_rcu+0x1c/0x38 kernel/bpf/memalloc.c:954)
[<8045dfb4>] (bpf_mem_cache_free_rcu) from [<8042ddd8>] (rhtab_delete_elem+0x2d8/0x934 kernel/bpf/hashtab.c:2969)
 r5:84f7ea00 r4:861664c4
[<8042db00>] (rhtab_delete_elem) from [<8042e8fc>] (__rhtab_map_lookup_and_delete_batch+0x468/0x95c kernel/bpf/hashtab.c:3349)
 r10:83362000 r9:00000001 r8:00000000 r7:00000000 r6:00000000 r5:00000001
 r4:84f7ea00
[<8042e494>] (__rhtab_map_lookup_and_delete_batch) from [<8042ee04>] (rhtab_map_lookup_and_delete_batch+0x14/0x18 kernel/bpf/hashtab.c:3390)
 r10:863e0081 r9:20000700 r8:00000019 r7:863e0080 r6:84f7ea00 r5:e01bde98
 r4:84f7eab0
[<8042edf0>] (rhtab_map_lookup_and_delete_batch) from [<803e14e4>] (bpf_map_do_batch+0x120/0x208 kernel/bpf/syscall.c:5834)
[<803e13c4>] (bpf_map_do_batch) from [<803ea8e8>] (__sys_bpf+0xf14/0x219c kernel/bpf/syscall.c:6483)
 r10:83febd40 r9:00000038 r8:00000000 r7:00000038 r6:00000019 r5:e01bde40
 r4:00000000 r3:00000335
[<803e99d4>] (__sys_bpf) from [<803ec180>] (__do_sys_bpf kernel/bpf/syscall.c:6537 [inline])
[<803e99d4>] (__sys_bpf) from [<803ec180>] (sys_bpf+0x50/0x6c kernel/bpf/syscall.c:6534)
 r10:00000182 r9:83febd40 r8:8020029c r7:00000182 r6:00356310 r5:00000000
 r4:00000000
[<803ec130>] (sys_bpf) from [<80200060>] (ret_fast_syscall+0x0/0x1c arch/arm/mm/proc-v7.S:67)
Exception stack(0xe01bdfa8 to 0xe01bdff0)
dfa0:                   00000000 00000000 00000019 20000700 00000038 00000000
dfc0: 00000000 00000000 00356310 00000182 003562d8 00000000 00000001 76fd00dc
dfe0: 76fcfe88 76fcfe78 00018ebc 00130820