syzbot

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BUG: KCSAN: data-race in __filemap_add_folio / nr_blockdev_pages

read-write to 0xffff8881004c1e70 of 8 bytes by task 3306 on cpu 1:
 __filemap_add_folio+0x5b9/0x7d0 mm/filemap.c:928
 filemap_add_folio+0x98/0x1b0 mm/filemap.c:969
 do_read_cache_folio+0xd6/0x5b0 mm/filemap.c:3852
 read_cache_folio+0x3c/0x50 mm/filemap.c:3917
 read_mapping_folio include/linux/pagemap.h:995 [inline]
 read_part_sector+0x6f/0x130 block/partitions/core.c:722
 read_lba+0x100/0x1e0 block/partitions/efi.c:248
 alloc_read_gpt_header block/partitions/efi.c:316 [inline]
 is_gpt_valid+0x76/0x3e0 block/partitions/efi.c:343
 find_valid_gpt block/partitions/efi.c:618 [inline]
 efi_partition+0x181/0x1400 block/partitions/efi.c:720
 check_partition block/partitions/core.c:141 [inline]
 blk_add_partitions block/partitions/core.c:589 [inline]
 bdev_disk_changed+0x4b9/0xcb0 block/partitions/core.c:693
 blkdev_get_whole+0x1f5/0x2d0 block/bdev.c:748
 bdev_open+0x280/0x7e0 block/bdev.c:957
 blkdev_open+0x259/0x290 block/fops.c:652
 do_dentry_open+0x646/0xa20 fs/open.c:956
 vfs_open+0x37/0x1e0 fs/open.c:1086
 do_open fs/namei.c:3880 [inline]
 path_openat+0x1c5e/0x2170 fs/namei.c:4039
 do_filp_open+0x109/0x230 fs/namei.c:4066
 do_sys_openat2+0xa6/0x110 fs/open.c:1429
 do_sys_open fs/open.c:1444 [inline]
 __do_sys_openat fs/open.c:1460 [inline]
 __se_sys_openat fs/open.c:1455 [inline]
 __x64_sys_openat+0xf2/0x120 fs/open.c:1455
 x64_sys_call+0x1af/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:258
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd0/0x1a0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881004c1e70 of 8 bytes by task 3394 on cpu 0:
 nr_blockdev_pages+0x7e/0xd0 block/bdev.c:523
 si_meminfo+0x87/0xd0 mm/show_mem.c:80
 update_defense_level+0x47/0x5c0 net/netfilter/ipvs/ip_vs_ctl.c:102
 defense_work_handler+0x1f/0x80 net/netfilter/ipvs/ip_vs_ctl.c:235
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0x4ce/0x9d0 kernel/workqueue.c:3319
 worker_thread+0x582/0x770 kernel/workqueue.c:3400
 kthread+0x489/0x510 kernel/kthread.c:464
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

value changed: 0x0000000000000005 -> 0x0000000000000006

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3394 Comm: kworker/0:6 Not tainted 6.15.0-rc6-syzkaller-00085-gc94d59a126cb #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
Workqueue: events_long defense_work_handler
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