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DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1753713999; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=rGRLzTUBR37RB7ZFX+iCaiA4xfKqVJunDIGo5ZMzdLo=; b=1bp9LFRjKLuicYWRxhHf0UUvF5Dvs7wH5Gi1GRcW+sm3yBl4vmmtU2dn0RRMq2nsyLH26y pSCsHnuLcQ89E5IQtrWL2umHrs5e6h04jTTfpj7gLJVVSI7dQFJh0IlnUnLwUSGX50V9V1 a15+o+gp12txwooDzO6jQSCZRwVdpbxBsz2Z3JctfivnylYp7QSvLS8zJ74d8Q9esWPvVj Iz2QzlBFGTCvtwvRFSERZ/I9ppu2qBg7oCerv9XJ6l+gAYxs7Xb8OvhPk/4mOzxJAA0NIE WHwVqO9JTmNaJBochBxKyYkL17zWIHlk9xHDla+b0UxzB6X6bp3Ql8m3dl64zA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1753713999; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=rGRLzTUBR37RB7ZFX+iCaiA4xfKqVJunDIGo5ZMzdLo=; b=po27wi1u+WiOpiZCj+LIEtuESWCVVz/tQ+hxwzy/76ltxBWu3Bg2dlqcTVVHmeFc/9magM JfhZ1F1avAhef6Aw== To: syzbot , linux-kernel@vger.kernel.org, luto@kernel.org, peterz@infradead.org, syzkaller-bugs@googlegroups.com Cc: Mathieu Desnoyers Subject: Re: [syzbot] [kernel?] WARNING in sched_mm_cid_remote_clear (3) In-Reply-To: <68877998.050a0220.1a379b.0005.GAE@google.com> References: <68877998.050a0220.1a379b.0005.GAE@google.com> Date: Mon, 28 Jul 2025 16:46:38 +0200 Message-ID: <87bjp4pe41.ffs@tglx> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain On Mon, Jul 28 2025 at 06:22, syzbot wrote: CC+ Mathieu and leaving the context intact. > Hello, > > syzbot found the following issue on: > > HEAD commit: 25fae0b93d1d Merge tag 'drm-fixes-2025-07-24' of https://g.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=136930a2580000 > kernel config: https://syzkaller.appspot.com/x/.config?x=9f175a9275d2cdd7 > dashboard link: https://syzkaller.appspot.com/bug?extid=c3be4001853e1add0a03 > compiler: gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 > > Unfortunately, I don't have any reproducer for this issue yet. > > Downloadable assets: > disk image: https://storage.googleapis.com/syzbot-assets/7acf9d19f311/disk-25fae0b9.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/532080ae9996/vmlinux-25fae0b9.xz > kernel image: https://storage.googleapis.com/syzbot-assets/47473831ee3b/bzImage-25fae0b9.xz > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+c3be4001853e1add0a03@syzkaller.appspotmail.com > > ------------[ cut here ]------------ > WARNING: CPU: 1 PID: 12208 at ./include/linux/cpumask.h:135 cpu_max_bits_warn include/linux/cpumask.h:135 [inline] That means __mm_cid_put() is invoked with cid >= nr_cpu_ids .... > WARNING: CPU: 1 PID: 12208 at ./include/linux/cpumask.h:135 cpumask_check include/linux/cpumask.h:142 [inline] > WARNING: CPU: 1 PID: 12208 at ./include/linux/cpumask.h:135 cpumask_clear_cpu include/linux/cpumask.h:620 [inline] > WARNING: CPU: 1 PID: 12208 at ./include/linux/cpumask.h:135 __mm_cid_put kernel/sched/sched.h:3622 [inline] > WARNING: CPU: 1 PID: 12208 at ./include/linux/cpumask.h:135 sched_mm_cid_remote_clear+0x488/0x4f0 kernel/sched/core.c:10543 > Modules linked in: > CPU: 1 UID: 0 PID: 12208 Comm: syz.4.2719 Not tainted 6.16.0-rc7-syzkaller-00034-g25fae0b93d1d #0 PREEMPT(full) > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 > RIP: 0010:cpu_max_bits_warn include/linux/cpumask.h:135 [inline] > RIP: 0010:cpumask_check include/linux/cpumask.h:142 [inline] > RIP: 0010:cpumask_clear_cpu include/linux/cpumask.h:620 [inline] > RIP: 0010:__mm_cid_put kernel/sched/sched.h:3622 [inline] > RIP: 0010:sched_mm_cid_remote_clear+0x488/0x4f0 kernel/sched/core.c:10543 > Code: 0f 01 e8 3b 71 0e 00 eb 9d 4c 89 ef e8 f1 73 97 00 e9 67 fc ff ff e8 e7 73 97 00 e9 47 fd ff ff 89 44 24 48 e9 17 fe ff ff 90 <0f> 0b 90 e9 f0 fd ff ff e8 8b b3 fc 09 e9 06 ff ff ff 48 89 d6 48 > RSP: 0018:ffffc9000480fcc8 EFLAGS: 00010012 > RAX: 0000000000000093 RBX: ffffe8ffffc476c0 RCX: ffffffff8189c611 > RDX: 00000000ffffffff RSI: 0000000000000004 RDI: ffffc9000480fd10 > RBP: 1ffff92000901f9a R08: 0000000000000001 R09: fffff52000901fa2 > R10: 0000000000000003 R11: 0000000000000001 R12: ffff88807b22ed50 > R13: ffffe8ffffc476c8 R14: 0000000000000200 R15: ffff8880b843a2c0 > FS: 000055556f5a3500(0000) GS:ffff888124820000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 000055558d727588 CR3: 00000000668d0000 CR4: 00000000003526f0 > Call Trace: > > sched_mm_cid_remote_clear_old kernel/sched/core.c:10576 [inline] > task_mm_cid_work+0x3b4/0x910 kernel/sched/core.c:10626 > task_work_run+0x14d/0x240 kernel/task_work.c:227 > resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] > exit_to_user_mode_loop+0xeb/0x110 kernel/entry/common.c:114 > exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline] > syscall_exit_to_user_mode_work include/linux/entry-common.h:414 [inline] > syscall_exit_to_user_mode include/linux/entry-common.h:449 [inline] > do_syscall_64+0x3f6/0x4c0 arch/x86/entry/syscall_64.c:100 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > RIP: 0033:0x7f8ef99c1265 > Code: 24 0c 89 3c 24 48 89 4c 24 18 e8 f6 54 ff ff 4c 8b 54 24 18 48 8b 54 24 10 41 89 c0 8b 74 24 0c 8b 3c 24 b8 e6 00 00 00 0f 05 <44> 89 c7 48 89 04 24 e8 4f 55 ff ff 48 8b 04 24 48 83 c4 28 f7 d8 > RSP: 002b:00007ffe741fc2d0 EFLAGS: 00000293 ORIG_RAX: 00000000000000e6 > RAX: 0000000000000000 RBX: 00007f8ef9bb5fa0 RCX: 00007f8ef99c1265 > RDX: 00007ffe741fc310 RSI: 0000000000000000 RDI: 0000000000000000 > RBP: 00007f8ef9bb7ba0 R08: 0000000000000000 R09: 00007f8efa7eb000 > R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000048110 > R13: 00007f8ef9bb6080 R14: ffffffffffffffff R15: 00007ffe741fc450 > > > > --- > This report is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkaller@googlegroups.com. > > syzbot will keep track of this issue. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > > If the report is already addressed, let syzbot know by replying with: > #syz fix: exact-commit-title > > If you want to overwrite report's subsystems, reply with: > #syz set subsystems: new-subsystem > (See the list of subsystem names on the web dashboard) > > If the report is a duplicate of another one, reply with: > #syz dup: exact-subject-of-another-report > > If you want to undo deduplication, reply with: > #syz undup