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BUG: KCSAN: data-race in __delete_from_page_cache / shmem_getpage_gfp

read-write to 0xffff88800ffd4558 of 8 bytes by task 10460 on cpu 1:
 page_cache_delete mm/filemap.c:154 [inline]
 __delete_from_page_cache+0x26e/0x340 mm/filemap.c:239
 __remove_mapping+0x3e4/0x480 mm/vmscan.c:928
 shrink_page_list+0x17f8/0x2410 mm/vmscan.c:1433
 reclaim_pages+0x40c/0x540 mm/vmscan.c:2156
 madvise_cold_or_pageout_pte_range+0xcaf/0x14a0 mm/madvise.c:473
 walk_pmd_range mm/pagewalk.c:89 [inline]
 walk_pud_range mm/pagewalk.c:160 [inline]
 walk_p4d_range mm/pagewalk.c:193 [inline]
 walk_pgd_range mm/pagewalk.c:229 [inline]
 __walk_page_range+0xa0b/0x1310 mm/pagewalk.c:331
 walk_page_range+0x111/0x2e0 mm/pagewalk.c:427
 madvise_vma mm/madvise.c:520 [inline]
 do_madvise+0x61e/0xdc0 mm/madvise.c:1132
 __do_sys_madvise mm/madvise.c:1158 [inline]
 __se_sys_madvise mm/madvise.c:1156 [inline]
 __x64_sys_madvise+0x5d/0x70 mm/madvise.c:1156
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88800ffd4558 of 8 bytes by task 10465 on cpu 0:
 shmem_recalc_inode mm/shmem.c:367 [inline]
 shmem_getpage_gfp+0xb9a/0x1960 mm/shmem.c:1937
 shmem_fault+0x16c/0x450 mm/shmem.c:2114
 __do_fault mm/memory.c:3625 [inline]
 do_read_fault+0x403/0x760 mm/memory.c:4019
 do_fault mm/memory.c:4147 [inline]
 handle_pte_fault mm/memory.c:4387 [inline]
 __handle_mm_fault mm/memory.c:4522 [inline]
 handle_mm_fault+0xff1/0x17b0 mm/memory.c:4620
 faultin_page mm/gup.c:851 [inline]
 __get_user_pages+0xa32/0xff0 mm/gup.c:1070
 populate_vma_page_range mm/gup.c:1403 [inline]
 __mm_populate+0x24d/0x380 mm/gup.c:1451
 mm_populate include/linux/mm.h:2591 [inline]
 vm_mmap_pgoff+0x14c/0x1d0 mm/util.c:524
 ksys_mmap_pgoff+0xe1/0x380 mm/mmap.c:1634
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 10465 Comm: syz-executor.5 Not tainted 5.11.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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