[moderation] [kernel?] KCSAN: data-race in ipc_set_key_private / selinux_shm_shmctl

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 45ec2f5f6ed3 Merge tag 'mtd/fixes-for-6.8-rc7' of git://gi..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14613522180000
kernel config: https://syzkaller.appspot.com/x/.config?x=53006d590acdf777
dashboard link: https://syzkaller.appspot.com/bug?extid=4ef6c25720bf4c579fcf
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [linux-...@vger.kernel.org]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/b99c38992fd6/disk-45ec2f5f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/be66849a660f/vmlinux-45ec2f5f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/f3ca66323870/bzImage-45ec2f5f.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+4ef6c2...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in ipc_set_key_private / selinux_shm_shmctl

write to 0xffff88816242ba0c of 4 bytes by task 2538 on cpu 0:
ipc_set_key_private+0x26/0x40 ipc/util.c:525
do_shm_rmid ipc/shm.c:133 [inline]
shmctl_down+0x15b/0x1e0 ipc/shm.c:1019
ksys_shmctl ipc/shm.c:1286 [inline]
__do_sys_shmctl ipc/shm.c:1297 [inline]
__se_sys_shmctl+0x28f/0x400 ipc/shm.c:1295
__x64_sys_shmctl+0x43/0x50 ipc/shm.c:1295
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff88816242ba0c of 4 bytes by task 2537 on cpu 1:
ipc_has_perm security/selinux/hooks.c:6008 [inline]
selinux_shm_shmctl+0x193/0x260 security/selinux/hooks.c:6212
security_shm_shmctl+0x3f/0x70 security/security.c:3781
shmctl_do_lock+0x95/0x450 ipc/shm.c:1179
ksys_shmctl ipc/shm.c:1289 [inline]
__do_sys_shmctl ipc/shm.c:1297 [inline]
__se_sys_shmctl+0x262/0x400 ipc/shm.c:1295
__x64_sys_shmctl+0x43/0x50 ipc/shm.c:1295
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x798dd821 -> 0x00000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 2537 Comm: syz-executor.3 Tainted: G W 6.8.0-rc6-syzkaller-00011-g45ec2f5f6ed3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
==================================================================


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[syzbot]

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