loop7: detected capacity change from 0 to 512
EXT4-fs (loop7): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: none.
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BUG: KASAN: null-ptr-deref in drop_buffers+0x65/0x4f0
Read of size 4 at addr 0000000000000060 by task syz.7.854/9832

CPU: 0 UID: 0 PID: 9832 Comm: syz.7.854 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+0x189/0x250
 kasan_report+0x118/0x150
 kasan_check_range+0x2b0/0x2c0
 drop_buffers+0x65/0x4f0
 try_to_free_buffers+0x1e1/0x2d0
 shrink_folio_list+0x20ac/0x4cd0
 evict_folios+0x47f2/0x58b0
 try_to_shrink_lruvec+0x8a3/0xb50
 shrink_one+0x21b/0x7c0
 shrink_node+0x314e/0x3760
 do_try_to_free_pages+0x668/0x1960
 try_to_free_pages+0x8a2/0xdd0
 __alloc_pages_direct_reclaim+0x144/0x300
 __alloc_pages_slowpath+0x5ff/0xce0
 __alloc_frozen_pages_noprof+0x319/0x370
 __folio_alloc_noprof+0x18/0x120
 alloc_charge_folio+0x3c7/0x830
 hpage_collapse_scan_pmd+0x12a3/0x3c60
 madvise_collapse+0x3d1/0xa40
 madvise_vma_behavior+0xec8/0x3af0
 madvise_walk_vmas+0x51c/0xa30
 madvise_do_behavior+0x38e/0x550
 do_madvise+0x1bc/0x270
 __x64_sys_madvise+0xa7/0xc0
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd55bb8ebe9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fd55c961038 EFLAGS: 00000246 ORIG_RAX: 000000000000001c
RAX: ffffffffffffffda RBX: 00007fd55bdb5fa0 RCX: 00007fd55bb8ebe9
RDX: 0000000000000019 RSI: 0000000000600003 RDI: 0000200000000000
RBP: 00007fd55bc11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd55bdb6038 R14: 00007fd55bdb5fa0 R15: 00007fffeee1f388
 </TASK>
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