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BUG: KASAN: null-ptr-deref in drop_buffers+0x65/0x4f0
Read of size 4 at addr 0000000000000060 by task syz.6.7234/1646

CPU: 0 UID: 0 PID: 1646 Comm: syz.6.7234 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150
 kasan_report+0x117/0x150
 kasan_check_range+0x264/0x2c0
 drop_buffers+0x65/0x4f0
 try_to_free_buffers+0x209/0x300
 shrink_folio_list+0x2226/0x5290
 evict_folios+0x4795/0x5880
 try_to_shrink_lruvec+0xb62/0xfa0
 shrink_lruvec+0x509/0x2b60
 shrink_node+0xa41/0x3a90
 do_try_to_free_pages+0x6a2/0x1980
 try_to_free_mem_cgroup_pages+0x2dd/0x820
 try_charge_memcg+0x827/0x1560
 __mem_cgroup_charge+0xab/0x1e0
 filemap_add_folio+0x152/0x530
 page_cache_ra_unbounded+0x49c/0xa50
 page_cache_ra_order+0xaf2/0xeb0
 f2fs_readdir+0x4c0/0xaf0
 iterate_dir+0x399/0x570
 __se_sys_getdents64+0xf1/0x280
 do_syscall_64+0x14d/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5793f9cdd9
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:00007f5794da6028 EFLAGS: 00000246 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 00007f5794215fa0 RCX: 00007f5793f9cdd9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000005
RBP: 00007f5794032d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5794216038 R14: 00007f5794215fa0 R15: 00007ffd7b6f8f38
 </TASK>
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