syzbot

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BUG: KCSAN: data-race in generic_fillattr / inode_update_timestamps

read to 0xffff88813799fba0 of 8 bytes by task 3286 on cpu 1:
 inode_get_atime include/linux/fs.h:1535 [inline]
 generic_fillattr+0x16f/0x2f0 fs/stat.c:60
 shmem_getattr+0x17b/0x200 mm/shmem.c:1139
 vfs_getattr_nosec fs/stat.c:135 [inline]
 vfs_getattr fs/stat.c:176 [inline]
 vfs_fstat+0x1b5/0x460 fs/stat.c:198
 vfs_fstatat+0x85/0x100 fs/stat.c:300
 __do_sys_newfstatat fs/stat.c:468 [inline]
 __se_sys_newfstatat+0x58/0x260 fs/stat.c:462
 __x64_sys_newfstatat+0x55/0x60 fs/stat.c:462
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x59/0x120 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

write to 0xffff88813799fba0 of 8 bytes by task 4611 on cpu 0:
 inode_set_atime_to_ts include/linux/fs.h:1541 [inline]
 inode_update_timestamps+0x4d1/0x560 fs/inode.c:1876
 generic_update_time fs/inode.c:1898 [inline]
 inode_update_time fs/inode.c:1918 [inline]
 touch_atime+0x15c/0x2d0 fs/inode.c:1990
 file_accessed include/linux/fs.h:2437 [inline]
 shmem_file_read_iter+0x4b3/0x550 mm/shmem.c:2873
 call_read_iter include/linux/fs.h:2079 [inline]
 new_sync_read fs/read_write.c:395 [inline]
 vfs_read+0x5ab/0x6a0 fs/read_write.c:476
 ksys_read+0xeb/0x1a0 fs/read_write.c:619
 __do_sys_read fs/read_write.c:629 [inline]
 __se_sys_read fs/read_write.c:627 [inline]
 __x64_sys_read+0x42/0x50 fs/read_write.c:627
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x59/0x120 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x00000000181e15c1 -> 0x0000000019e7d941

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 4611 Comm: udevd Not tainted 6.8.0-rc1-syzkaller-00331-gcd2286fc5775 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
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blk_print_req_error: 8 callbacks suppressed
I/O error, dev loop4, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0
I/O error, dev loop4, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0