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BUG: KCSAN: data-race in shmem_file_read_iter / shmem_write_end

write to 0xffff88811dd832c0 of 8 bytes by task 7280 on cpu 0:
 i_size_write include/linux/fs.h:932 [inline]
 shmem_write_end+0x9a/0x470 mm/shmem.c:2741
 generic_perform_write+0x267/0x410 mm/filemap.c:3939
 shmem_file_write_iter+0xc8/0xe0 mm/shmem.c:2893
 call_write_iter include/linux/fs.h:2085 [inline]
 new_sync_write fs/read_write.c:497 [inline]
 vfs_write+0x430/0x6b0 fs/read_write.c:590
 ksys_write+0xeb/0x1a0 fs/read_write.c:643
 __do_sys_write fs/read_write.c:655 [inline]
 __se_sys_write fs/read_write.c:652 [inline]
 __x64_sys_write+0x42/0x50 fs/read_write.c:652
 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

read to 0xffff88811dd832c0 of 8 bytes by task 7301 on cpu 1:
 i_size_read include/linux/fs.h:910 [inline]
 shmem_file_read_iter+0x1ee/0x550 mm/shmem.c:2810
 call_read_iter include/linux/fs.h:2079 [inline]
 new_sync_read fs/read_write.c:395 [inline]
 vfs_read+0x34c/0x480 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: 0x0000000002035000 -> 0x000000000203b000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 7301 Comm: syz-executor.3 Not tainted 6.7.0-syzkaller-06264-g70d201a40823 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
==================================================================
==================================================================
BUG: KCSAN: data-race in shmem_file_read_iter / shmem_write_end

write to 0xffff88811dd832c0 of 8 bytes by task 7280 on cpu 0:
 i_size_write include/linux/fs.h:932 [inline]
 shmem_write_end+0x9a/0x470 mm/shmem.c:2741
 generic_perform_write+0x267/0x410 mm/filemap.c:3939
 shmem_file_write_iter+0xc8/0xe0 mm/shmem.c:2893
 call_write_iter include/linux/fs.h:2085 [inline]
 new_sync_write fs/read_write.c:497 [inline]
 vfs_write+0x430/0x6b0 fs/read_write.c:590
 ksys_write+0xeb/0x1a0 fs/read_write.c:643
 __do_sys_write fs/read_write.c:655 [inline]
 __se_sys_write fs/read_write.c:652 [inline]
 __x64_sys_write+0x42/0x50 fs/read_write.c:652
 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

read to 0xffff88811dd832c0 of 8 bytes by task 7301 on cpu 1:
 i_size_read include/linux/fs.h:910 [inline]
 shmem_file_read_iter+0x3b0/0x550 mm/shmem.c:2777
 call_read_iter include/linux/fs.h:2079 [inline]
 new_sync_read fs/read_write.c:395 [inline]
 vfs_read+0x34c/0x480 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: 0x0000000003db2000 -> 0x0000000003db5000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 7301 Comm: syz-executor.3 Not tainted 6.7.0-syzkaller-06264-g70d201a40823 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
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