syzbot

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BUG: KCSAN: data-race in __mark_inode_dirty / __mark_inode_dirty

write to 0xffff888106860740 of 8 bytes by task 14093 on cpu 0:
 __mark_inode_dirty+0x256/0x7e0 fs/fs-writeback.c:2508
 fat_update_time+0x1fe/0x210 fs/fat/misc.c:357
 inode_update_time fs/inode.c:1919 [inline]
 __file_update_time fs/inode.c:2109 [inline]
 file_update_time+0x21e/0x2c0 fs/inode.c:2139
 __generic_file_write_iter+0x4f/0x120 mm/filemap.c:4050
 generic_file_write_iter+0x7d/0x1d0 mm/filemap.c:4095
 call_write_iter include/linux/fs.h:2110 [inline]
 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+0x3b9/0x970 fs/read_write.c:1295
 __do_sys_sendfile64 fs/read_write.c:1356 [inline]
 __se_sys_sendfile64 fs/read_write.c:1348 [inline]
 __x64_sys_sendfile64+0xbd/0x150 fs/read_write.c:1348
 x64_sys_call+0x2c67/0x2d30 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888106860740 of 8 bytes by task 14099 on cpu 1:
 __mark_inode_dirty+0x58/0x7e0 fs/fs-writeback.c:2459
 fat_update_time+0x1fe/0x210 fs/fat/misc.c:357
 inode_update_time fs/inode.c:1919 [inline]
 touch_atime+0x14f/0x350 fs/inode.c:1992
 file_accessed include/linux/fs.h:2459 [inline]
 filemap_splice_read+0x8b0/0x920 mm/filemap.c:2926
 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+0x3b9/0x970 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+0x2c67/0x2d30 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000000000000 -> 0x0000000000000007

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 14099 Comm: syz-executor.3 Tainted: G        W          6.9.0-rc4-syzkaller-00266-g977b1ef51866 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
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