KCSAN: data-race in __close_fd / do_select

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 131ad0b6 Merge tag 'acpi-5.10-rc5' of git://git.kernel.org..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=151e7fdc500000
kernel config: https://syzkaller.appspot.com/x/.config?x=e9a6e9171a00e85a
dashboard link: https://syzkaller.appspot.com/bug?extid=62cf6c87aedb4531776e
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+62cf6c...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in __close_fd / do_select

write to 0xffff888109c77600 of 8 bytes by task 18278 on cpu 0:
instrument_write include/linux/instrumented.h:42 [inline]
__clear_bit include/asm-generic/bitops/instrumented-non-atomic.h:42 [inline]
__clear_open_fd fs/file.c:253 [inline]
__put_unused_fd fs/file.c:572 [inline]
pick_file fs/file.c:655 [inline]
__close_fd+0xcd/0x190 fs/file.c:669
__do_sys_close fs/open.c:1295 [inline]
__se_sys_close fs/open.c:1293 [inline]
__x64_sys_close+0x39/0x90 fs/open.c:1293
do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888109c77600 of 8 bytes by task 18279 on cpu 1:
max_select_fd fs/select.c:446 [inline]
do_select+0x28d/0xf30 fs/select.c:487
core_sys_select+0x41f/0x670 fs/select.c:677
do_pselect fs/select.c:759 [inline]
__do_sys_pselect6+0x1bf/0x220 fs/select.c:800
__se_sys_pselect6 fs/select.c:791 [inline]
__x64_sys_pselect6+0x74/0x80 fs/select.c:791
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: 18279 Comm: syz-executor.4 Not tainted 5.10.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 18279 Comm: syz-executor.4 Not tainted 5.10.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x116/0x15d lib/dump_stack.c:118
panic+0x1e7/0x5fa kernel/panic.c:231
kcsan_report+0x67b/0x680 kernel/kcsan/report.c:634
kcsan_setup_watchpoint+0x46a/0x4d0 kernel/kcsan/core.c:568
max_select_fd fs/select.c:446 [inline]
do_select+0x28d/0xf30 fs/select.c:487
core_sys_select+0x41f/0x670 fs/select.c:677
do_pselect fs/select.c:759 [inline]
__do_sys_pselect6+0x1bf/0x220 fs/select.c:800
__se_sys_pselect6 fs/select.c:791 [inline]
__x64_sys_pselect6+0x74/0x80 fs/select.c:791
do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45deb9
Code: 0d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 db b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fc651367c78 EFLAGS: 00000246 ORIG_RAX: 000000000000010e
RAX: ffffffffffffffda RBX: 0000000000025fc0 RCX: 000000000045deb9
RDX: 0000000000000000 RSI: 00000000200000c0 RDI: 0000000000000040
RBP: 000000000118bf78 R08: 0000000020000200 R09: 0000000000000000
R10: 0000000020000000 R11: 0000000000000246 R12: 000000000118bf2c
R13: 00007ffea136035f R14: 00007fc6513689c0 R15: 000000000118bf2c
Kernel Offset: disabled
Rebooting in 86400 seconds..


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[syzbot]

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