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BUG: KCSAN: data-race in mark_buffer_dirty_inode / mark_buffer_dirty_inode

write to 0xffff88813f782400 of 8 bytes by task 9880 on cpu 0:
 mark_buffer_dirty_inode+0x190/0x1c0 fs/buffer.c:685
 fat_mirror_bhs+0x247/0x340 fs/fat/fatent.c:398
 fat_alloc_clusters+0x973/0xa60 fs/fat/fatent.c:543
 fat_add_cluster fs/fat/inode.c:108 [inline]
 __fat_get_block fs/fat/inode.c:155 [inline]
 fat_get_block+0x25c/0x5e0 fs/fat/inode.c:190
 __block_write_begin_int+0x3b7/0xf40 fs/buffer.c:2119
 __block_write_begin fs/buffer.c:2168 [inline]
 block_write_begin+0x7b/0x170 fs/buffer.c:2227
 cont_write_begin+0x479/0x690 fs/buffer.c:2582
 fat_write_begin+0x61/0xf0 fs/fat/inode.c:230
 cont_expand_zero fs/buffer.c:2509 [inline]
 cont_write_begin+0x182/0x690 fs/buffer.c:2572
 fat_write_begin+0x61/0xf0 fs/fat/inode.c:230
 generic_cont_expand_simple+0xa7/0x140 fs/buffer.c:2473
 fat_cont_expand+0x3a/0x160 fs/fat/file.c:223
 fat_setattr+0x2a9/0x840 fs/fat/file.c:513
 notify_change+0x866/0x8e0 fs/attr.c:499
 do_truncate+0x116/0x150 fs/open.c:66
 do_sys_ftruncate+0x2ba/0x3b0 fs/open.c:194
 __do_sys_ftruncate fs/open.c:205 [inline]
 __se_sys_ftruncate fs/open.c:203 [inline]
 __x64_sys_ftruncate+0x33/0x40 fs/open.c:203
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff88813f782400 of 8 bytes by task 9896 on cpu 1:
 mark_buffer_dirty_inode+0x96/0x1c0 fs/buffer.c:681
 fat_mirror_bhs+0x247/0x340 fs/fat/fatent.c:398
 fat_alloc_clusters+0x973/0xa60 fs/fat/fatent.c:543
 fat_add_cluster fs/fat/inode.c:108 [inline]
 __fat_get_block fs/fat/inode.c:155 [inline]
 fat_get_block+0x25c/0x5e0 fs/fat/inode.c:190
 __block_write_begin_int+0x3b7/0xf40 fs/buffer.c:2119
 __block_write_begin fs/buffer.c:2168 [inline]
 block_write_begin+0x7b/0x170 fs/buffer.c:2227
 cont_write_begin+0x479/0x690 fs/buffer.c:2582
 fat_write_begin+0x61/0xf0 fs/fat/inode.c:230
 generic_perform_write+0x1c9/0x410 mm/filemap.c:3918
 __generic_file_write_iter+0xa1/0x120 mm/filemap.c:4013
 generic_file_write_iter+0x7d/0x1c0 mm/filemap.c:4039
 __kernel_write_iter+0x162/0x390 fs/read_write.c:517
 dump_emit_page fs/coredump.c:888 [inline]
 dump_user_range+0x25d/0x480 fs/coredump.c:915
 elf_core_dump+0x1a85/0x1ba0 fs/binfmt_elf.c:2077
 do_coredump+0x102a/0x1890 fs/coredump.c:764
 get_signal+0xdb5/0x10a0 kernel/signal.c:2890
 arch_do_signal_or_restart+0x95/0x4b0 arch/x86/kernel/signal.c:309
 exit_to_user_mode_loop+0x6f/0xe0 kernel/entry/common.c:168
 exit_to_user_mode_prepare+0x6c/0xb0 kernel/entry/common.c:204
 irqentry_exit_to_user_mode+0x9/0x20 kernel/entry/common.c:309
 irqentry_exit+0x12/0x40 kernel/entry/common.c:412
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:570

value changed: 0x0000000000000000 -> 0xffff888140aa6670

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 9896 Comm: syz-executor.0 Not tainted 6.7.0-rc3-syzkaller-00284-g815fb87b7530 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023
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