syzbot

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BUG: KCSAN: data-race in __delete_from_page_cache / shmem_recalc_inode

write to 0xffff8880b7828868 of 8 bytes by task 15415 on cpu 0:
 page_cache_delete mm/filemap.c:153 [inline]
 __delete_from_page_cache+0x1e4/0x490 mm/filemap.c:238
 __remove_mapping+0x2ea/0x540 mm/vmscan.c:925
 shrink_page_list+0x1148/0x2a40 mm/vmscan.c:1424
 reclaim_pages+0x5de/0x830 mm/vmscan.c:2138
 madvise_cold_or_pageout_pte_range+0xc31/0x1b20 mm/madvise.c:379
 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+0xa6e/0x1550 mm/pagewalk.c:331
 walk_page_range+0x14c/0x280 mm/pagewalk.c:427
 madvise_pageout_page_range mm/madvise.c:520 [inline]
 madvise_pageout+0x15e/0x200 mm/madvise.c:556
 madvise_vma mm/madvise.c:945 [inline]
 do_madvise mm/madvise.c:1127 [inline]
 do_madvise+0x865/0x12c0 mm/madvise.c:1053
 __do_sys_madvise mm/madvise.c:1153 [inline]
 __se_sys_madvise mm/madvise.c:1151 [inline]
 __x64_sys_madvise+0x48/0x60 mm/madvise.c:1151
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8880b7828868 of 8 bytes by task 15425 on cpu 1:
 shmem_recalc_inode+0x50/0x180 mm/shmem.c:306
 shmem_getpage_gfp+0x5ca/0x16c0 mm/shmem.c:1885
 shmem_fault+0x117/0x4b0 mm/shmem.c:2062
 __do_fault+0xa8/0x1e0 mm/memory.c:3450
 do_read_fault mm/memory.c:3846 [inline]
 do_fault mm/memory.c:3975 [inline]
 handle_pte_fault mm/memory.c:4215 [inline]
 __handle_mm_fault+0x295c/0x2da0 mm/memory.c:4345
 handle_mm_fault+0x21c/0x540 mm/memory.c:4382
 faultin_page mm/gup.c:879 [inline]
 __get_user_pages+0x533/0x11c0 mm/gup.c:1098
 populate_vma_page_range+0xdc/0x100 mm/gup.c:1430
 __mm_populate+0x168/0x2b0 mm/gup.c:1478
 mm_populate include/linux/mm.h:2562 [inline]
 vm_mmap_pgoff+0x185/0x190 mm/util.c:511
 ksys_mmap_pgoff+0x96/0x420 mm/mmap.c:1595
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 15425 Comm: syz-executor.1 Not tainted 5.7.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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