[moderation] [kernel?] KCSAN: data-race in prepare_signal / ptrace_attach (9)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 90b0c2b2edd1 Merge tag 'pinctrl-v6.7-1' of git://git.kerne..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=137a2560e80000
kernel config: https://syzkaller.appspot.com/x/.config?x=b1bd7bde690b6f3f
dashboard link: https://syzkaller.appspot.com/bug?extid=11f1a764218cab086b79
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [linux-...@vger.kernel.org ol...@redhat.com]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/1ffb4e861fae/disk-90b0c2b2.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/125559bc4f77/vmlinux-90b0c2b2.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a1b275f01860/bzImage-90b0c2b2.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+11f1a7...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in prepare_signal / ptrace_attach

write to 0xffff888102844130 of 4 bytes by task 12893 on cpu 0:
ptrace_attach+0x26a/0x420 kernel/ptrace.c:445
__do_sys_ptrace kernel/ptrace.c:1296 [inline]
__se_sys_ptrace+0x149/0x2a0 kernel/ptrace.c:1278
__x64_sys_ptrace+0x55/0x60 kernel/ptrace.c:1278
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff888102844130 of 4 bytes by task 12895 on cpu 1:
prepare_signal+0x258/0x660 kernel/signal.c:943
__send_signal_locked+0x2f/0x700 kernel/signal.c:1094
send_signal_locked+0x28d/0x3a0 kernel/signal.c:1257
do_send_sig_info+0x9f/0xf0 kernel/signal.c:1310
group_send_sig_info kernel/signal.c:1460 [inline]
kill_pid_info+0x86/0xd0 kernel/signal.c:1499
kill_proc_info kernel/signal.c:1516 [inline]
do_rt_sigqueueinfo kernel/signal.c:4035 [inline]
__do_sys_rt_sigqueueinfo kernel/signal.c:4051 [inline]
__se_sys_rt_sigqueueinfo+0xc7/0x110 kernel/signal.c:4044
__x64_sys_rt_sigqueueinfo+0x43/0x50 kernel/signal.c:4044
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x00000000 -> 0x00010001

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 12895 Comm: syz-executor.3 Not tainted 6.6.0-syzkaller-14142-g90b0c2b2edd1 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023
==================================================================


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[syzbot]

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