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BUG: KCSAN: data-race in __delete_from_page_cache / shmem_getpage_gfp

write to 0xffff88812ba82de0 of 8 bytes by task 3541 on cpu 0:
 page_cache_delete mm/filemap.c:147 [inline]
 __delete_from_page_cache+0x1de/0x280 mm/filemap.c:232
 __remove_mapping+0x35b/0x470 mm/vmscan.c:1174
 shrink_page_list+0x15c2/0x2670 mm/vmscan.c:1746
 reclaim_pages+0x478/0x640 mm/vmscan.c:2482
 madvise_cold_or_pageout_pte_range+0x646/0x690 mm/madvise.c:475
 walk_pmd_range mm/pagewalk.c:128 [inline]
 walk_pud_range mm/pagewalk.c:205 [inline]
 walk_p4d_range mm/pagewalk.c:240 [inline]
 walk_pgd_range mm/pagewalk.c:277 [inline]
 __walk_page_range+0x93f/0x10e0 mm/pagewalk.c:379
 walk_page_range+0x131/0x300 mm/pagewalk.c:475
 madvise_pageout_page_range mm/madvise.c:528 [inline]
 madvise_pageout mm/madvise.c:565 [inline]
 madvise_vma mm/madvise.c:993 [inline]
 do_madvise+0xa0b/0x1140 mm/madvise.c:1202
 __do_sys_madvise mm/madvise.c:1228 [inline]
 __se_sys_madvise mm/madvise.c:1226 [inline]
 __x64_sys_madvise+0x5d/0x70 mm/madvise.c:1226
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88812ba82de0 of 8 bytes by task 3535 on cpu 1:
 shmem_recalc_inode mm/shmem.c:364 [inline]
 shmem_getpage_gfp+0xfd9/0x13d0 mm/shmem.c:1945
 shmem_fault+0xcf/0x470 mm/shmem.c:2113
 __do_fault mm/memory.c:3858 [inline]
 do_shared_fault mm/memory.c:4227 [inline]
 do_fault mm/memory.c:4305 [inline]
 handle_pte_fault mm/memory.c:4559 [inline]
 __handle_mm_fault mm/memory.c:4694 [inline]
 handle_mm_fault+0xc81/0x1580 mm/memory.c:4792
 do_user_addr_fault+0x609/0xbe0 arch/x86/mm/fault.c:1397
 handle_page_fault arch/x86/mm/fault.c:1485 [inline]
 exc_page_fault+0x91/0x220 arch/x86/mm/fault.c:1541
 asm_exc_page_fault+0x1e/0x30
 copy_user_enhanced_fast_string+0xe/0x40
 copy_user_generic arch/x86/include/asm/uaccess_64.h:37 [inline]
 raw_copy_to_user arch/x86/include/asm/uaccess_64.h:58 [inline]
 _copy_to_user+0x77/0x90 lib/usercopy.c:33
 copy_to_user include/linux/uaccess.h:200 [inline]
 extract_crng_user drivers/char/random.c:1074 [inline]
 urandom_read_nowarn+0x1ec/0x350 drivers/char/random.c:1811
 __do_sys_getrandom drivers/char/random.c:2008 [inline]
 __se_sys_getrandom drivers/char/random.c:1983 [inline]
 __x64_sys_getrandom+0xd6/0x130 drivers/char/random.c:1983
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00000000000007b0 -> 0x00000000000007ae

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 3535 Comm: syz-executor.2 Not tainted 5.15.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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