linux-kernel - [syzbot] [lsm?] [keyrings?] KCSAN: data-race in key_garbage_collector / key_set

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Message-ID: <6821966c.050a0220.f2294.0050.GAE@google.com>
Date: Sun, 11 May 2025 23:34:20 -0700
From: syzbot <syzbot+9defcbc1dc2f34e5b867@...kaller.appspotmail.com>
To: dhowells@...hat.com, jarkko@...nel.org, jmorris@...ei.org, 
	keyrings@...r.kernel.org, linux-kernel@...r.kernel.org, 
	linux-security-module@...r.kernel.org, paul@...l-moore.com, serge@...lyn.com, 
	syzkaller-bugs@...glegroups.com
Subject: [syzbot] [lsm?] [keyrings?] KCSAN: data-race in key_garbage_collector
 / key_set_expiry

Hello,

syzbot found the following issue on:

HEAD commit:    cd802e7e5f1e Merge tag 'for-linus' of git://git.kernel.org..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1583b768580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=6154604431d9aaf9
dashboard link: https://syzkaller.appspot.com/bug?extid=9defcbc1dc2f34e5b867
compiler:       Debian clang version 20.1.2 (++20250402124445+58df0ef89dd6-1~exp1~20250402004600.97), Debian LLD 20.1.2

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/fdb14cb5e78f/disk-cd802e7e.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/c8b91b8b365f/vmlinux-cd802e7e.xz
kernel image: https://storage.googleapis.com/syzbot-assets/69520a7040dd/bzImage-cd802e7e.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+9defcbc1dc2f34e5b867@...kaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in key_garbage_collector / key_set_expiry

write to 0xffffffff869eb168 of 8 bytes by task 3395 on cpu 1:
 key_schedule_gc security/keys/gc.c:63 [inline]
 key_garbage_collector+0x6d6/0x8f0 security/keys/gc.c:286
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0x4cb/0x9d0 kernel/workqueue.c:3319
 worker_thread+0x582/0x770 kernel/workqueue.c:3400
 kthread+0x486/0x510 kernel/kthread.c:464
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffffffff869eb168 of 8 bytes by task 4277 on cpu 0:
 key_schedule_gc security/keys/gc.c:61 [inline]
 key_set_expiry+0xea/0x190 security/keys/gc.c:78
 key_reject_and_link+0x18b/0x310 security/keys/key.c:609
 key_negate_and_link include/linux/key-type.h:188 [inline]
 complete_request_key security/keys/request_key.c:67 [inline]
 call_sbin_request_key+0x656/0x6b0 security/keys/request_key.c:216
 construct_key security/keys/request_key.c:247 [inline]
 construct_key_and_link security/keys/request_key.c:519 [inline]
 request_key_and_link+0x8bc/0xd70 security/keys/request_key.c:653
 __do_sys_request_key security/keys/keyctl.c:222 [inline]
 __se_sys_request_key+0x1df/0x290 security/keys/keyctl.c:167
 __x64_sys_request_key+0x55/0x70 security/keys/keyctl.c:167
 x64_sys_call+0x2f19/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:250
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd0/0x1a0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x7fffffffffffffff -> 0x000000006821354a

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 4277 Comm: syz.0.242 Not tainted 6.15.0-rc5-syzkaller-00353-gcd802e7e5f1e #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
==================================================================
iwpm_register_pid: Unable to send a nlmsg (client = 2)
infiniband syz1: RDMA CMA: cma_listen_on_dev, error -98


---
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