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BUG: KCSAN: data-race in delete_from_page_cache_batch / nr_blockdev_pages

read-write to 0xffff8881004c43f0 of 8 bytes by task 12279 on cpu 0:
 page_cache_delete_batch mm/filemap.c:316 [inline]
 delete_from_page_cache_batch+0x4fe/0x720 mm/filemap.c:335
 truncate_inode_pages_range+0x1c7/0x6c0 mm/truncate.c:327
 truncate_inode_pages+0x24/0x30 mm/truncate.c:407
 kill_bdev block/bdev.c:91 [inline]
 blkdev_flush_mapping+0xa5/0x1a0 block/bdev.c:674
 blkdev_put_whole block/bdev.c:681 [inline]
 bdev_release+0x2f9/0x420 block/bdev.c:1106
 blkdev_release+0x15/0x20 block/fops.c:660
 __fput+0x2ac/0x640 fs/file_table.c:465
 ____fput+0x1c/0x30 fs/file_table.c:493
 task_work_run+0x13c/0x1b0 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0xa8/0x120 kernel/entry/common.c:218
 do_syscall_64+0xd6/0x1c0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881004c43f0 of 8 bytes by task 13939 on cpu 1:
 nr_blockdev_pages+0x7c/0xd0 block/bdev.c:485
 si_meminfo+0x87/0xd0 mm/show_mem.c:80
 handshake_net_init+0x7e/0x160 net/handshake/netlink.c:184
 ops_init+0x21e/0x2d0 net/core/net_namespace.c:138
 setup_net+0x14f/0x610 net/core/net_namespace.c:364
 copy_net_ns+0x5a3/0x740 net/core/net_namespace.c:518
 create_new_namespaces+0x228/0x430 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0xe6/0x120 kernel/nsproxy.c:228
 ksys_unshare+0x3d3/0x700 kernel/fork.c:3337
 __do_sys_unshare kernel/fork.c:3408 [inline]
 __se_sys_unshare kernel/fork.c:3406 [inline]
 __x64_sys_unshare+0x1f/0x30 kernel/fork.c:3406
 x64_sys_call+0x2c93/0x2e10 arch/x86/include/generated/asm/syscalls_64.h:273
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000000000001 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 13939 Comm: syz.1.3580 Not tainted 6.14.0-syzkaller-10764-gaa918db707fb #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
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