syzbot

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BUG: KCSAN: data-race in generic_fillattr / generic_write_end

write to 0xffff8881099bc700 of 8 bytes by task 7072 on cpu 0:
 i_size_write include/linux/fs.h:901 [inline]
 generic_write_end+0xb4/0x360 fs/buffer.c:2240
 ext4_da_write_end+0x4df/0x690 fs/ext4/inode.c:3012
 generic_perform_write+0x253/0x3d0 mm/filemap.c:3957
 ext4_buffered_write_iter+0x240/0x3e0 fs/ext4/file.c:300
 ext4_file_write_iter+0xdd/0x10f0
 __kernel_write_iter+0x162/0x3c0 fs/read_write.c:517
 dump_emit_page fs/coredump.c:888 [inline]
 dump_user_range+0x25d/0x490 fs/coredump.c:915
 elf_core_dump+0x1a73/0x1b90 fs/binfmt_elf.c:2142
 do_coredump+0x1029/0x1890 fs/coredump.c:764
 get_signal+0xd65/0xff0 kernel/signal.c:2862
 arch_do_signal_or_restart+0x89/0x2a0 arch/x86/kernel/signal.c:308
 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:310
 irqentry_exit+0x12/0x40 kernel/entry/common.c:413
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:570

read to 0xffff8881099bc700 of 8 bytes by task 3093 on cpu 1:
 i_size_read include/linux/fs.h:879 [inline]
 generic_fillattr+0x13f/0x1e0 fs/stat.c:58
 ext4_getattr+0x384/0x4f0 fs/ext4/inode.c:5566
 ext4_file_getattr+0x4a/0x160 fs/ext4/inode.c:5577
 vfs_getattr_nosec+0x1e3/0x3c0 fs/stat.c:133
 vfs_getattr fs/stat.c:170 [inline]
 vfs_statx+0x156/0x300 fs/stat.c:242
 vfs_fstatat fs/stat.c:276 [inline]
 vfs_lstat include/linux/fs.h:2913 [inline]
 __do_sys_newlstat fs/stat.c:432 [inline]
 __se_sys_newlstat+0x6c/0x280 fs/stat.c:426
 __x64_sys_newlstat+0x31/0x40 fs/stat.c:426
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x0000000001123000 -> 0x0000000001124000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 3093 Comm: syz-executor.3 Not tainted 6.4.0-syzkaller-01371-g04fc8904d5d1 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
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