syzbot

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BUG: KASAN: null-ptr-deref in instrument_atomic_read include/linux/instrumented.h:68 [inline]
BUG: KASAN: null-ptr-deref in atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline]
BUG: KASAN: null-ptr-deref in buffer_busy fs/buffer.c:2886 [inline]
BUG: KASAN: null-ptr-deref in drop_buffers+0x65/0x4f0 fs/buffer.c:2898
Read of size 4 at addr 0000000000000060 by task syz.1.6642/25604

CPU: 1 UID: 0 PID: 25604 Comm: syz.1.6642 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 kasan_report+0x118/0x150 mm/kasan/report.c:595
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x2b0/0x2c0 mm/kasan/generic.c:189
 instrument_atomic_read include/linux/instrumented.h:68 [inline]
 atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline]
 buffer_busy fs/buffer.c:2886 [inline]
 drop_buffers+0x65/0x4f0 fs/buffer.c:2898
 try_to_free_buffers+0x1e1/0x2d0 fs/buffer.c:2952
 shrink_folio_list+0x20ac/0x4cd0 mm/vmscan.c:1518
 evict_folios+0x47f2/0x58b0 mm/vmscan.c:4744
 try_to_shrink_lruvec+0x8a3/0xb50 mm/vmscan.c:4907
 shrink_one+0x21b/0x7c0 mm/vmscan.c:4952
 shrink_many mm/vmscan.c:5015 [inline]
 lru_gen_shrink_node mm/vmscan.c:5093 [inline]
 shrink_node+0x314e/0x3760 mm/vmscan.c:6078
 shrink_zones mm/vmscan.c:6336 [inline]
 do_try_to_free_pages+0x668/0x1960 mm/vmscan.c:6398
 try_to_free_pages+0x8a2/0xdd0 mm/vmscan.c:6644
 __perform_reclaim mm/page_alloc.c:4310 [inline]
 __alloc_pages_direct_reclaim+0x144/0x300 mm/page_alloc.c:4332
 __alloc_pages_slowpath+0x5ff/0xce0 mm/page_alloc.c:4781
 __alloc_frozen_pages_noprof+0x319/0x370 mm/page_alloc.c:5161
 __alloc_pages_noprof mm/page_alloc.c:5182 [inline]
 __folio_alloc_noprof+0x18/0x120 mm/page_alloc.c:5192
 alloc_charge_folio+0x3c7/0x830 mm/khugepaged.c:1088
 collapse_huge_page mm/khugepaged.c:1132 [inline]
 hpage_collapse_scan_pmd+0x1298/0x3c60 mm/khugepaged.c:1436
 madvise_collapse+0x3d1/0xa40 mm/khugepaged.c:2813
 madvise_vma_behavior+0xec8/0x3af0 mm/madvise.c:1358
 madvise_walk_vmas+0x51c/0xa30 mm/madvise.c:1669
 madvise_do_behavior+0x38e/0x550 mm/madvise.c:1885
 do_madvise+0x1bc/0x270 mm/madvise.c:1978
 __do_sys_madvise mm/madvise.c:1987 [inline]
 __se_sys_madvise mm/madvise.c:1985 [inline]
 __x64_sys_madvise+0xa7/0xc0 mm/madvise.c:1985
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f110f38ebe9
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:00007f1110201038 EFLAGS: 00000246 ORIG_RAX: 000000000000001c
RAX: ffffffffffffffda RBX: 00007f110f5b5fa0 RCX: 00007f110f38ebe9
RDX: 0000000000000019 RSI: 0000000000600003 RDI: 0000200000000000
RBP: 00007f110f411e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f110f5b6038 R14: 00007f110f5b5fa0 R15: 00007ffc63835488
 </TASK>
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