syzbot

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BUG: KCSAN: data-race in __mark_inode_dirty / writeback_single_inode

write to 0xffff8881088a1628 of 8 bytes by task 13902 on cpu 0:
 writeback_single_inode+0x10e/0x4a0 fs/fs-writeback.c:1769
 sync_inode_metadata+0x5c/0x90 fs/fs-writeback.c:2842
 __generic_file_fsync+0xf9/0x140 fs/libfs.c:1527
 fat_file_fsync+0x4c/0x100 fs/fat/file.c:191
 vfs_fsync_range+0x122/0x140 fs/sync.c:188
 generic_write_sync include/linux/fs.h:2816 [inline]
 generic_file_write_iter+0x191/0x1d0 mm/filemap.c:4151
 iter_file_splice_write+0x5e6/0x970 fs/splice.c:743
 do_splice_from fs/splice.c:941 [inline]
 direct_splice_actor+0x16c/0x2c0 fs/splice.c:1164
 splice_direct_to_actor+0x305/0x670 fs/splice.c:1108
 do_splice_direct_actor fs/splice.c:1207 [inline]
 do_splice_direct+0xd7/0x150 fs/splice.c:1233
 do_sendfile+0x3ab/0x950 fs/read_write.c:1295
 __do_sys_sendfile64 fs/read_write.c:1362 [inline]
 __se_sys_sendfile64 fs/read_write.c:1348 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1348
 x64_sys_call+0xfc3/0x2e00 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881088a1628 of 8 bytes by task 13906 on cpu 1:
 __mark_inode_dirty+0x19f/0x7e0 fs/fs-writeback.c:2508
 fat_update_time+0x1f5/0x210 fs/fat/misc.c:357
 inode_update_time fs/inode.c:1981 [inline]
 touch_atime+0x14f/0x350 fs/inode.c:2054
 file_accessed include/linux/fs.h:2480 [inline]
 filemap_splice_read+0x8b0/0x920 mm/filemap.c:2950
 do_splice_read fs/splice.c:985 [inline]
 splice_direct_to_actor+0x26c/0x670 fs/splice.c:1089
 do_splice_direct_actor fs/splice.c:1207 [inline]
 do_splice_direct+0xd7/0x150 fs/splice.c:1233
 do_sendfile+0x3ab/0x950 fs/read_write.c:1295
 __do_sys_sendfile64 fs/read_write.c:1362 [inline]
 __se_sys_sendfile64 fs/read_write.c:1348 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1348
 x64_sys_call+0xfc3/0x2e00 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000000000007 -> 0x0000000000000080

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 13906 Comm: syz.2.2955 Not tainted 6.10.0-syzkaller-12710-g3a7e02c040b1 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
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