KCSAN: data-race in fifo_open / wait_for_partner

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3bb61aa6 Merge tag 'arm64-fixes' of git://git.kernel.org/p..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14e5ea73500000
kernel config: https://syzkaller.appspot.com/x/.config?x=c949fed53798f819
dashboard link: https://syzkaller.appspot.com/bug?extid=d20383ba7e99a111910b
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project.git 913f6005669cfb590c99865a90bc51ed0983d09d)
CC: [linux-...@vger.kernel.org linux-...@vger.kernel.org vi...@zeniv.linux.org.uk]

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d20383...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in fifo_open / wait_for_partner

read-write to 0xffff888009b13430 of 4 bytes by task 30689 on cpu 0:
put_pipe_info fs/pipe.c:688 [inline]
fifo_open+0x2a2/0x5d0 fs/pipe.c:1196
do_dentry_open+0x520/0x870 fs/open.c:817
vfs_open+0x43/0x50 fs/open.c:931
do_open fs/namei.c:3252 [inline]
path_openat+0x1844/0x20a0 fs/namei.c:3369
do_filp_open+0xbd/0x1d0 fs/namei.c:3396
do_sys_openat2+0xa3/0x240 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

read to 0xffff888009b13430 of 4 bytes by task 30695 on cpu 1:
pipe_lock_nested fs/pipe.c:65 [inline]
pipe_lock fs/pipe.c:74 [inline]
wait_for_partner+0xdd/0x1a0 fs/pipe.c:1063
fifo_open+0x4c8/0x5d0 fs/pipe.c:1151
do_dentry_open+0x520/0x870 fs/open.c:817
vfs_open+0x43/0x50 fs/open.c:931
do_open fs/namei.c:3252 [inline]
path_openat+0x1844/0x20a0 fs/namei.c:3369
do_filp_open+0xbd/0x1d0 fs/namei.c:3396
file_open_name+0x25b/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

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 30695 Comm: syz-executor.3 Not tainted 5.10.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.