syzbot

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BUG: KCSAN: data-race in shmem_get_folio_gfp / shmem_setattr

write to 0xffff888138162d58 of 8 bytes by task 5555 on cpu 0:
 i_size_write include/linux/fs.h:888 [inline]
 shmem_setattr+0x3b0/0x4e0 mm/shmem.c:1115
 notify_change+0x8c3/0x930 fs/attr.c:482
 do_truncate+0x116/0x150 fs/open.c:66
 do_sys_ftruncate+0x293/0x390 fs/open.c:194
 __do_sys_ftruncate fs/open.c:205 [inline]
 __se_sys_ftruncate fs/open.c:203 [inline]
 __x64_sys_ftruncate+0x33/0x40 fs/open.c:203
 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

read to 0xffff888138162d58 of 8 bytes by task 5543 on cpu 1:
 i_size_read include/linux/fs.h:866 [inline]
 shmem_get_folio_gfp+0x16b/0x1120 mm/shmem.c:1870
 shmem_get_folio mm/shmem.c:2068 [inline]
 shmem_file_read_iter+0x15e/0x570 mm/shmem.c:2633
 call_read_iter include/linux/fs.h:1845 [inline]
 generic_file_splice_read+0xe3/0x290 fs/splice.c:402
 do_splice_to fs/splice.c:885 [inline]
 splice_direct_to_actor+0x25a/0x5f0 fs/splice.c:956
 do_splice_direct+0x104/0x180 fs/splice.c:1065
 do_sendfile+0x3b8/0x950 fs/read_write.c:1255
 __do_sys_sendfile64 fs/read_write.c:1323 [inline]
 __se_sys_sendfile64 fs/read_write.c:1309 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1309
 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: 0x0000000001000000 -> 0x0000000000000086

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 5543 Comm: syz-executor.2 Not tainted 6.3.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
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