==================================================================
BUG: KCSAN: data-race in generic_file_read_iter / truncate_setsize

write to 0xffff888128e45050 of 8 bytes by task 12743 on cpu 0:
 i_size_write include/linux/fs.h:888 [inline]
 truncate_setsize+0x3a/0x90 mm/truncate.c:839
 simple_setattr+0xb8/0xc0 fs/libfs.c:503
 notify_change+0x82b/0xb00 fs/attr.c:336
 do_truncate+0xfb/0x180 fs/open.c:64
 handle_truncate fs/namei.c:3083 [inline]
 do_last fs/namei.c:3496 [inline]
 path_openat+0x12e0/0x3150 fs/namei.c:3607
 do_filp_open+0x11e/0x1b0 fs/namei.c:3637
 do_sys_openat2+0x4f5/0x620 fs/open.c:1149
 do_sys_open+0xa3/0x110 fs/open.c:1165
 ksys_open include/linux/syscalls.h:1386 [inline]
 __do_sys_creat fs/open.c:1233 [inline]
 __se_sys_creat fs/open.c:1231 [inline]
 __x64_sys_creat+0x45/0x60 fs/open.c:1231
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888128e45050 of 8 bytes by task 12730 on cpu 1:
 generic_file_buffered_read mm/filemap.c:2084 [inline]
 generic_file_read_iter+0x860/0x1440 mm/filemap.c:2302
 call_read_iter include/linux/fs.h:1895 [inline]
 generic_file_splice_read+0x35c/0x500 fs/splice.c:313
 do_splice_to+0xf2/0x130 fs/splice.c:892
 splice_direct_to_actor+0x1b6/0x540 fs/splice.c:971
 do_splice_direct+0x161/0x1e0 fs/splice.c:1080
 do_sendfile+0x384/0x7f0 fs/read_write.c:1520
 __do_sys_sendfile64 fs/read_write.c:1575 [inline]
 __se_sys_sendfile64 fs/read_write.c:1567 [inline]
 __x64_sys_sendfile64+0xbe/0x140 fs/read_write.c:1567
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 12730 Comm: syz-executor.3 Not tainted 5.6.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================