syzbot

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BUG: KCSAN: data-race in shmem_add_to_page_cache / shmem_writepage

read-write to 0xffff8881387c6918 of 8 bytes by task 12371 on cpu 1:
 shmem_add_to_page_cache+0x40a/0x510 mm/shmem.c:742
 shmem_swapin_folio+0x852/0xa40 mm/shmem.c:1811
 shmem_get_folio_gfp+0x264/0x1200 mm/shmem.c:1893
 shmem_get_folio mm/shmem.c:2081 [inline]
 shmem_file_read_iter+0x164/0x570 mm/shmem.c:2647
 do_iter_read+0x4ac/0x7c0 fs/read_write.c:795
 vfs_readv fs/read_write.c:915 [inline]
 do_preadv+0x159/0x230 fs/read_write.c:1007
 __do_sys_preadv fs/read_write.c:1057 [inline]
 __se_sys_preadv fs/read_write.c:1052 [inline]
 __x64_sys_preadv+0x58/0x60 fs/read_write.c:1052
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff8881387c6918 of 8 bytes by task 12347 on cpu 0:
 shmem_recalc_inode mm/shmem.c:360 [inline]
 shmem_writepage+0x618/0xb40 mm/shmem.c:1435
 pageout mm/vmscan.c:1355 [inline]
 shrink_folio_list+0x195e/0x2550 mm/vmscan.c:2015
 reclaim_folio_list+0x7b/0x1d0 mm/vmscan.c:2801
 reclaim_pages+0x220/0x280 mm/vmscan.c:2837
 madvise_cold_or_pageout_pte_range+0x95e/0x9c0 mm/madvise.c:530
 walk_pmd_range mm/pagewalk.c:143 [inline]
 walk_pud_range mm/pagewalk.c:221 [inline]
 walk_p4d_range mm/pagewalk.c:256 [inline]
 walk_pgd_range+0x7f4/0xe20 mm/pagewalk.c:293
 __walk_page_range+0xc2/0x320 mm/pagewalk.c:395
 walk_page_range+0x2c7/0x3f0 mm/pagewalk.c:521
 madvise_pageout_page_range mm/madvise.c:589 [inline]
 madvise_pageout mm/madvise.c:616 [inline]
 madvise_vma_behavior mm/madvise.c:1038 [inline]
 madvise_walk_vmas mm/madvise.c:1267 [inline]
 do_madvise+0x1eea/0x29b0 mm/madvise.c:1447
 __do_sys_madvise mm/madvise.c:1460 [inline]
 __se_sys_madvise mm/madvise.c:1458 [inline]
 __x64_sys_madvise+0x60/0x70 mm/madvise.c:1458
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x00000000000001d7 -> 0x00000000000001d8

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 12347 Comm: syz-executor.3 Not tainted 6.5.0-rc7-syzkaller-00182-g3b35375f19fe #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
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