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Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.99.1 #2 (Red Hat Linux)) id 1wY7od-00000004HxS-1vwK; Fri, 12 Jun 2026 19:45:20 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id C408E30036F; Fri, 12 Jun 2026 21:45:18 +0200 (CEST) Date: Fri, 12 Jun 2026 21:45:18 +0200 From: Peter Zijlstra To: syzbot Cc: bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, linux-kernel@vger.kernel.org, mingo@redhat.com, syzkaller-bugs@googlegroups.com, tglx@kernel.org, x86@kernel.org Subject: Re: [syzbot] [kernel?] WARNING in update_curr_idle Message-ID: <20260612194518.GE42921@noisy.programming.kicks-ass.net> References: <6a2c4b8f.be3f099c.2836ae.0001.GAE@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <6a2c4b8f.be3f099c.2836ae.0001.GAE@google.com> On Fri, Jun 12, 2026 at 11:10:23AM -0700, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: ec039126b7fa Add linux-next specific files for 20260611 > git tree: linux-next > console output: https://syzkaller.appspot.com/x/log.txt?x=14d128ae580000 > kernel config: https://syzkaller.appspot.com/x/.config?x=5aaa5302b37e7e10 > dashboard link: https://syzkaller.appspot.com/bug?extid=e671c2192fed8645642e > compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 > > Unfortunately, I don't have any reproducer for this issue yet. > > Downloadable assets: > disk image: https://storage.googleapis.com/syzbot-assets/4f58c704a9e9/disk-ec039126.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/bf67100d5618/vmlinux-ec039126.xz > kernel image: https://storage.googleapis.com/syzbot-assets/bf93fe076f41/bzImage-ec039126.xz > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+e671c2192fed8645642e@syzkaller.appspotmail.com > > ------------[ cut here ]------------ > rq->clock_update_flags < RQCF_ACT_SKIP > WARNING: kernel/sched/sched.h:1792 at assert_clock_updated kernel/sched/sched.h:1792 [inline], CPU#1: swapper/1/0 > WARNING: kernel/sched/sched.h:1792 at rq_clock_task kernel/sched/sched.h:1806 [inline], CPU#1: swapper/1/0 > WARNING: kernel/sched/sched.h:1792 at update_curr_idle+0x1cf/0x260 kernel/sched/idle.c:554, CPU#1: swapper/1/0 > Modules linked in: > CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Tainted: G L syzkaller #0 PREEMPT_{RT,(full)} > Tainted: [L]=SOFTLOCKUP > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 > RIP: 0010:assert_clock_updated kernel/sched/sched.h:1792 [inline] > RIP: 0010:rq_clock_task kernel/sched/sched.h:1806 [inline] > RIP: 0010:update_curr_idle+0x1cf/0x260 kernel/sched/idle.c:554 > Code: e8 03 42 80 3c 20 00 74 08 48 89 df e8 3a 98 97 00 48 8b 3b 4c 89 f6 4c 89 fa 5b 41 5c 41 5d 41 5e 41 5f 5d e9 52 38 01 00 90 <0f> 0b 90 e9 01 ff ff ff 90 0f 0b 90 e9 d3 fe ff ff 48 c7 c1 40 84 > RSP: 0018:ffffc900001e7bf8 EFLAGS: 00010097 > RAX: 0000000000000000 RBX: ffff8880b873ba40 RCX: 0000000000000002 > RDX: ffff888037668000 RSI: ffffffff8d8bd52f RDI: ffffffff8baa5680 > RBP: ffffc900001e7e30 R08: ffff8880b873c91f R09: 0000000000000000 > R10: ffff8880b873c910 R11: ffffffff8199c020 R12: dffffc0000000000 > R13: ffffffff8d8f3158 R14: ffff88801da9dd00 R15: ffff8880b873c620 > FS: 0000000000000000(0000) GS:ffff888125fb8000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 000000110c42f07e CR3: 0000000040078000 CR4: 00000000003526f0 > Call Trace: > > put_prev_task_idle+0xd/0x20 kernel/sched/idle.c:485 > put_prev_set_next_task kernel/sched/sched.h:2769 [inline] > pick_next_task kernel/sched/core.c:6442 [inline] > __schedule+0x3da0/0x5550 kernel/sched/core.c:7143 > schedule_idle+0x51/0x90 kernel/sched/core.c:7348 > do_idle+0x4a6/0x540 kernel/sched/idle.c:384 > cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:454 > start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:312 > common_startup_64+0x13e/0x157 > > > > --- > 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 While this looks a bit different from the known reports, it might be the same since the config has SCHED_CORE=y #syz fix: c095741713d1 sched/fair: Fix newidle vs core-sched