syzbot

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BUG: KCSAN: data-race in generic_fillattr / generic_update_time

write to 0xffff8880543941c8 of 16 bytes by task 17151 on cpu 1:
 generic_update_time+0x5c/0x270 fs/inode.c:1669
 update_time+0x7d/0x90 fs/inode.c:1695
 touch_atime+0x13f/0x150 fs/inode.c:1766
 file_accessed include/linux/fs.h:2226 [inline]
 shmem_file_read_iter+0x74a/0x850 mm/shmem.c:2628
 call_read_iter include/linux/fs.h:1901 [inline]
 new_sync_read+0x306/0x450 fs/read_write.c:415
 __vfs_read+0x9e/0xb0 fs/read_write.c:428
 vfs_read fs/read_write.c:462 [inline]
 vfs_read+0x13e/0x2b0 fs/read_write.c:447
 ksys_read+0xc5/0x1a0 fs/read_write.c:588
 __do_sys_read fs/read_write.c:598 [inline]
 __se_sys_read fs/read_write.c:596 [inline]
 __x64_sys_read+0x49/0x60 fs/read_write.c:596
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8880543941c8 of 16 bytes by task 17257 on cpu 0:
 generic_fillattr+0x120/0x1e0 fs/stat.c:45
 shmem_getattr+0xce/0x160 mm/shmem.c:997
 vfs_getattr_nosec+0x127/0x160 fs/stat.c:83
 vfs_getattr+0x53/0x70 fs/stat.c:120
 vfs_statx_fd+0x74/0xc0 fs/stat.c:147
 vfs_fstat include/linux/fs.h:3295 [inline]
 __do_sys_newfstat+0x46/0xa0 fs/stat.c:388
 __se_sys_newfstat fs/stat.c:385 [inline]
 __x64_sys_newfstat+0x37/0x50 fs/stat.c:385
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 17257 Comm: systemd-udevd Not tainted 5.7.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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