From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oi1-f206.google.com (mail-oi1-f206.google.com [209.85.167.206]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4AD2C7080D for ; Sat, 22 Aug 2026 00:10:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.167.206 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787357432; cv=none; b=KfQhgNmZV4HE/HSZ5tvbg4jsZoFrxA13NQSb1jrWDXYnGxbsIJh28SKfahJUVkfh68lkfc3H6vyofluY2d0lPbkUOVgP9lqwUoz4qeGsX5WLTEWb7efoNzD4Jez5+UQd5+avjUHk28oCJXyKSPbfgwlGtaN7qby0EDmnX6Gg9Lg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787357432; c=relaxed/simple; bh=XAwwFxuRPmGpR9OgpYBfNCYENrXvwtp+pz8WfKq9zlA=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; 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2002:a05:6808:5142:b0:4b2:8da1:3be4 with SMTP id 5614622812f47-4b2ef25eb99mr11944086b6e.9.1787357429238; Fri, 21 Aug 2026 17:10:29 -0700 (PDT) Date: Fri, 21 Aug 2026 17:10:29 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a88e8f5.91706f20.16b6e3.02ab.GAE@google.com> Subject: [syzbot] [block?] INFO: rcu detected stall in blkdev_common_ioctl (4) From: syzbot To: axboe@kernel.dk, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 24ef02f934ee net: page_pool: fix UAF in __page_pool_releas.. git tree: net console output: https://syzkaller.appspot.com/x/log.txt?x=108b3a79580000 kernel config: https://syzkaller.appspot.com/x/.config?x=2ca5f2f2c4197664 dashboard link: https://syzkaller.appspot.com/bug?extid=9d041b75d7063b71360d compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=149dd69e580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17063949580000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/7a991674b71f/disk-24ef02f9.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/67041713f1b8/vmlinux-24ef02f9.xz kernel image: https://storage.googleapis.com/syzbot-assets/670139f0d1da/bzImage-24ef02f9.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+9d041b75d7063b71360d@syzkaller.appspotmail.com rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=1e8c/1/0x4000000000000000 softirq=16934/16934 fqs=1 rcu: (detected by 0, t=10505 jiffies, g=16269, q=1004 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 4979 Comm: udevd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:check_region_inline mm/kasan/generic.c:185 [inline] RIP: 0010:kasan_check_range+0x20/0x2c0 mm/kasan/generic.c:200 Code: 90 90 90 90 90 90 90 90 90 90 0f 1f 40 d6 55 41 57 41 56 41 55 41 54 53 b0 01 48 85 f6 0f 84 ae 01 00 00 4c 8d 04 37 49 39 f8 <0f> 82 36 02 00 00 49 b9 00 00 00 00 00 80 ff ff eb 0d cc cc cc 49 RSP: 0018:ffffc90000a08d00 EFLAGS: 00000002 RAX: 1ffff1100ef95601 RBX: 0000000000000010 RCX: ffffffff8bce3acf RDX: 0000000000000001 RSI: 0000000000000010 RDI: ffff888077cab308 RBP: 0000000000000000 R08: ffff888077cab318 R09: 1ffffffff20af1e6 R10: dffffc0000000000 R11: fffffbfff20af1e7 R12: 1ffff110170e5060 R13: ffff888077cab300 R14: ffff888077cab308 R15: ffff8880b8728358 FS: 00007feea5050880(0000) GS:ffff888125049000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055558c1f44e8 CR3: 000000007e048000 CR4: 00000000003526f0 Call Trace: __asan_memset+0x22/0x50 mm/kasan/shadow.c:84 rb_link_node include/linux/rbtree.h:96 [inline] __rb_add include/linux/rbtree.h:238 [inline] rb_add_linked include/linux/rbtree.h:281 [inline] timerqueue_linked_add+0x23f/0x2e0 lib/timerqueue.c:96 enqueue_hrtimer+0x18e/0x2c0 kernel/time/hrtimer.c:1117 __run_hrtimer kernel/time/hrtimer.c:2048 [inline] __hrtimer_run_queues+0x4ce/0xa10 kernel/time/hrtimer.c:2096 hrtimer_interrupt+0x448/0x910 kernel/time/hrtimer.c:2215 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline] __sysvec_apic_timer_interrupt+0x102/0x430 arch/x86/kernel/apic/apic.c:1068 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1062 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:blkdev_common_ioctl+0x1cb1/0x3250 block/ioctl.c:712 Code: 8b 7c 24 10 66 c7 47 0c f8 f8 e9 0e f8 ff ff e8 15 c3 10 fd 41 bc ff ff ff ff 48 8b 7c 24 10 66 c7 47 10 f8 f8 e9 f3 f7 ff ff fa c2 10 fd 48 8b 5c 24 18 48 83 c3 10 48 89 d8 48 c1 e8 03 42 RSP: 0018:ffffc9000202fac0 EFLAGS: 00000246 RAX: ffffffff84b62dc6 RBX: 0000000000000000 RCX: 0000000000000000 RDX: ffff88807f680000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc9000202fdf0 R08: ffff8880238950b3 R09: 1ffff11004712a16 R10: dffffc0000000000 R11: ffffed1004712a17 R12: 0000000000000009 R13: dffffc0000000000 R14: ffff8880238950b0 R15: fffff52000405f60 blkdev_ioctl+0x528/0x740 block/ioctl.c:791 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7feea491d378 Code: 00 00 48 8d 44 24 08 48 89 54 24 e0 48 89 44 24 c0 48 8d 44 24 d0 48 89 44 24 c8 b8 10 00 00 00 c7 44 24 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 07 89 d0 c3 0f 1f 40 00 48 8b 15 49 3a 0d RSP: 002b:00007ffcb96a5f68 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000055a9cc3c2180 RCX: 00007feea491d378 RDX: 0000000000000000 RSI: 000000000000125f RDI: 000000000000000c RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000000c R13: 000055a9ade72100 R14: 0000000000000000 R15: 00007ffcb96a6160 rcu: rcu_preempt kthread timer wakeup didn't happen for 10499 jiffies! g16269 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=1 timer-softirq=3345 rcu: rcu_preempt kthread starved for 10500 jiffies! g16269 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=1 rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior. rcu: RCU grace-period kthread stack dump: task:rcu_preempt state:I stack:27496 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7326 schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2123 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2325 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 --- 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 syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing. 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