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BUG: KCSAN: data-race in fifo_open / pipe_wait

write to 0xffff8880a235c7f0 of 4 bytes by task 7828 on cpu 0:
 put_pipe_info fs/pipe.c:707 [inline]
 fifo_open+0x2f7/0x780 fs/pipe.c:1177
 do_dentry_open+0x52d/0x890 fs/open.c:817
 vfs_open+0x43/0x50 fs/open.c:931
 do_open fs/namei.c:3251 [inline]
 path_openat+0x1844/0x20a0 fs/namei.c:3368
 do_filp_open+0xbd/0x1d0 fs/namei.c:3395
 file_open_name+0x258/0x280 fs/open.c:1113
 acct_on kernel/acct.c:207 [inline]
 __do_sys_acct kernel/acct.c:286 [inline]
 __se_sys_acct+0xec/0x420 kernel/acct.c:273
 __x64_sys_acct+0x1b/0x20 kernel/acct.c:273
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8880a235c7f0 of 4 bytes by task 7818 on cpu 1:
 pipe_lock_nested fs/pipe.c:65 [inline]
 pipe_lock fs/pipe.c:74 [inline]
 pipe_wait+0xf8/0x140 fs/pipe.c:125
 wait_for_partner fs/pipe.c:1043 [inline]
 fifo_open+0x5c7/0x780 fs/pipe.c:1132
 do_dentry_open+0x52d/0x890 fs/open.c:817
 vfs_open+0x43/0x50 fs/open.c:931
 do_open fs/namei.c:3251 [inline]
 path_openat+0x1844/0x20a0 fs/namei.c:3368
 do_filp_open+0xbd/0x1d0 fs/namei.c:3395
 do_sys_openat2+0x33b/0x500 fs/open.c:1168
 do_sys_open fs/open.c:1184 [inline]
 __do_sys_creat fs/open.c:1258 [inline]
 __se_sys_creat fs/open.c:1252 [inline]
 __x64_sys_creat+0x62/0x80 fs/open.c:1252
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 7818 Comm: syz-executor.1 Not tainted 5.9.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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