syzbot

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BUG: KCSAN: data-race in __filemap_add_folio / filemap_write_and_wait_range

read-write to 0xffff888100481830 of 8 bytes by task 4164 on cpu 1:
 __filemap_add_folio+0x5b9/0x7d0 mm/filemap.c:928
 filemap_add_folio+0x98/0x1b0 mm/filemap.c:969
 __filemap_get_folio+0x31e/0x6b0 mm/filemap.c:1990
 grow_dev_folio fs/buffer.c:1050 [inline]
 grow_buffers fs/buffer.c:1116 [inline]
 __getblk_slow fs/buffer.c:1140 [inline]
 bdev_getblk+0x16e/0x3d0 fs/buffer.c:1467
 sb_getblk_gfp include/linux/buffer_head.h:394 [inline]
 __ext4_sb_bread_gfp+0x44/0x170 fs/ext4/super.c:236
 ext4_sb_bread_unmovable fs/ext4/super.c:265 [inline]
 ext4_load_super fs/ext4/super.c:5058 [inline]
 __ext4_fill_super fs/ext4/super.c:5262 [inline]
 ext4_fill_super+0x46c/0x34e0 fs/ext4/super.c:5724
 get_tree_bdev_flags+0x291/0x300 fs/super.c:1681
 get_tree_bdev+0x1f/0x30 fs/super.c:1704
 ext4_get_tree+0x1c/0x30 fs/ext4/super.c:5756
 vfs_get_tree+0x54/0x1d0 fs/super.c:1804
 do_new_mount+0x207/0x680 fs/namespace.c:3902
 path_mount+0x4a4/0xb20 fs/namespace.c:4226
 do_mount fs/namespace.c:4239 [inline]
 __do_sys_mount fs/namespace.c:4450 [inline]
 __se_sys_mount+0x28f/0x2e0 fs/namespace.c:4427
 __x64_sys_mount+0x67/0x80 fs/namespace.c:4427
 x64_sys_call+0xd36/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:166
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888100481830 of 8 bytes by task 2996 on cpu 0:
 mapping_needs_writeback mm/filemap.c:641 [inline]
 filemap_write_and_wait_range+0x59/0x340 mm/filemap.c:690
 filemap_write_and_wait include/linux/pagemap.h:68 [inline]
 sync_blockdev block/bdev.c:260 [inline]
 bdev_release+0xeb/0x3d0 block/bdev.c:1126
 blkdev_release+0x15/0x20 block/fops.c:684
 __fput+0x298/0x650 fs/file_table.c:465
 fput_close_sync+0x6e/0x120 fs/file_table.c:570
 __do_sys_close fs/open.c:1589 [inline]
 __se_sys_close fs/open.c:1574 [inline]
 __x64_sys_close+0x56/0xf0 fs/open.c:1574
 x64_sys_call+0x2747/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:4
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000000000000 -> 0x0000000000000001

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 2996 Comm: udevd Not tainted 6.16.0-rc3-syzkaller-00121-gf02769e7f272 #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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