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BUG: KCSAN: data-race in ext4_setattr / filemap_fault

write to 0xffff88813c20d818 of 8 bytes by task 30096 on cpu 1:
 i_size_write include/linux/fs.h:916 [inline]
 ext4_setattr+0xd7f/0xef0 fs/ext4/inode.c:5498
 notify_change+0x8a3/0xac0 fs/attr.c:398
 do_truncate+0xe8/0x130 fs/open.c:64
 handle_truncate fs/namei.c:3082 [inline]
 do_open fs/namei.c:3430 [inline]
 path_openat+0x1914/0x1e90 fs/namei.c:3559
 do_filp_open+0xe9/0x200 fs/namei.c:3586
 do_sys_openat2+0xa3/0x290 fs/open.c:1200
 do_sys_open fs/open.c:1216 [inline]
 __do_sys_creat fs/open.c:1290 [inline]
 __se_sys_creat fs/open.c:1284 [inline]
 __x64_sys_creat+0x62/0x80 fs/open.c:1284
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88813c20d818 of 8 bytes by task 30087 on cpu 0:
 i_size_read include/linux/fs.h:894 [inline]
 filemap_fault+0x8b/0x9e0 mm/filemap.c:3053
 __do_fault mm/memory.c:3857 [inline]
 do_shared_fault mm/memory.c:4226 [inline]
 do_fault mm/memory.c:4304 [inline]
 handle_pte_fault mm/memory.c:4558 [inline]
 __handle_mm_fault mm/memory.c:4693 [inline]
 handle_mm_fault+0xf56/0x1a50 mm/memory.c:4791
 do_user_addr_fault+0x609/0xbe0 arch/x86/mm/fault.c:1390
 handle_page_fault arch/x86/mm/fault.c:1475 [inline]
 exc_page_fault+0x91/0x220 arch/x86/mm/fault.c:1531
 asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:568
 copy_user_enhanced_fast_string+0xe/0x40 arch/x86/lib/copy_user_64.S:205
 copy_user_generic arch/x86/include/asm/uaccess_64.h:37 [inline]
 raw_copy_to_user arch/x86/include/asm/uaccess_64.h:58 [inline]
 copyout lib/iov_iter.c:157 [inline]
 copy_page_to_iter_iovec lib/iov_iter.c:228 [inline]
 __copy_page_to_iter lib/iov_iter.c:801 [inline]
 copy_page_to_iter+0x2ef/0x940 lib/iov_iter.c:829
 filemap_read+0xed6/0x1210 mm/filemap.c:2686
 generic_file_read_iter+0x75/0x2c0 mm/filemap.c:2782
 ext4_file_read_iter+0x1db/0x290 fs/ext4/file.c:73
 call_read_iter include/linux/fs.h:2157 [inline]
 new_sync_read fs/read_write.c:404 [inline]
 vfs_read+0x651/0x730 fs/read_write.c:485
 ksys_read+0xce/0x180 fs/read_write.c:623
 __do_sys_read fs/read_write.c:633 [inline]
 __se_sys_read fs/read_write.c:631 [inline]
 __x64_sys_read+0x3e/0x50 fs/read_write.c:631
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0000000000208200 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 30087 Comm: syz-executor.3 Tainted: G        W         5.14.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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