From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-io1-f77.google.com (mail-io1-f77.google.com [209.85.166.77]) (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 8E98E25A328 for ; Mon, 12 May 2025 09:11:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.166.77 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747041084; cv=none; b=QEjDu3TPq4Yfvy4WP5n7Vdd1SnrCeId4N7uxhDNrnVgoU/q7Xuh95nGwhk4yp/dZoMH+kPiJmBK1OmB6S7nrskti96BYr1iL3QsPQD6oiQdUAbYCmh0qhhG/CjXMBxrBcT6F9CI7YFcfKGEENHFtWnw7Zhtw4QObsDh8CBQsUt4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747041084; c=relaxed/simple; bh=lYVHLSFZ30uPD9HCKWzeRsxqM7TREbjRmxECdkqqcV4=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; 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List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6602:29d3:b0:862:fe54:df4e with SMTP id ca18e2360f4ac-867635af384mr1265132339f.7.1747041080644; Mon, 12 May 2025 02:11:20 -0700 (PDT) Date: Mon, 12 May 2025 02:11:20 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6821bb38.050a0220.f2294.0056.GAE@google.com> Subject: [syzbot] [mm?] [ext4?] INFO: rcu detected stall in ext4_end_io_rsv_work (3) From: syzbot To: akpm@linux-foundation.org, linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, syzkaller-bugs@googlegroups.com, willy@infradead.org Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 707df3375124 Merge tag 'media/v6.15-2' of git://git.kernel.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=16c2a82f980000 kernel config: https://syzkaller.appspot.com/x/.config?x=b39cb28b0a399ed3 dashboard link: https://syzkaller.appspot.com/bug?extid=bb842a51b5abbae5a245 compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1050b8f4580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12a169b3980000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/1920aeaaff98/disk-707df337.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/5a54d789a59a/vmlinux-707df337.xz kernel image: https://storage.googleapis.com/syzbot-assets/e40767312770/bzImage-707df337.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+bb842a51b5abbae5a245@syzkaller.appspotmail.com rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (3 ticks this GP) idle=1d3c/1/0x4000000000000000 softirq=14732/14732 fqs=0 rcu: (detected by 1, t=10502 jiffies, g=6677, q=10638 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 3557 Comm: kworker/u8:8 Not tainted 6.15.0-rc5-syzkaller-00038-g707df3375124 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/29/2025 Workqueue: ext4-rsv-conversion ext4_end_io_rsv_work RIP: 0010:__kasan_check_write+0x8/0x20 mm/kasan/shadow.c:37 Code: f0 ff ff 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 0c 24 <89> f6 ba 01 00 00 00 e9 4c f0 ff ff 66 66 2e 0f 1f 84 00 00 00 00 RSP: 0018:ffffc90000007da0 EFLAGS: 00000086 RAX: 0000000000000000 RBX: ffff8880b8427840 RCX: ffffffff81985b4d RDX: 00000000ffffffff RSI: 0000000000000004 RDI: ffff8880b8427840 RBP: 1ffff92000000fb6 R08: 4d4df099ab2b819a R09: 0000000000000001 R10: 0000000000000002 R11: 0000000000000000 R12: ffff8880b8427848 R13: ffff8880b8427850 R14: ffff888070874340 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8881249df000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055558c02f650 CR3: 000000000e180000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: instrument_atomic_read_write include/linux/instrumented.h:96 [inline] atomic_try_cmpxchg_acquire include/linux/atomic/atomic-instrumented.h:1300 [inline] queued_spin_lock include/asm-generic/qspinlock.h:111 [inline] do_raw_spin_lock+0x11d/0x2b0 kernel/locking/spinlock_debug.c:116 __run_hrtimer kernel/time/hrtimer.c:1765 [inline] __hrtimer_run_queues+0x2bc/0xad0 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline] __sysvec_apic_timer_interrupt+0x108/0x3f0 arch/x86/kernel/apic/apic.c:1055 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1049 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:folio_zone include/linux/mm.h:1967 [inline] RIP: 0010:zone_stat_mod_folio include/linux/vmstat.h:432 [inline] RIP: 0010:__folio_end_writeback+0x186/0xe60 mm/page-writeback.c:3068 Code: 89 e2 be 15 00 00 00 48 89 df e8 05 0b 33 00 9c 5d 81 e5 00 02 00 00 31 ff 48 89 ee e8 73 50 c5 ff 48 85 ed 0f 85 90 07 00 00 f5 54 c5 ff 48 89 da 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 RSP: 0018:ffffc9000cea7950 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffffea0001f6ec40 RCX: ffffffff81f5e1a4 RDX: ffff888032bb2440 RSI: ffffffff81f5e1b2 RDI: 0000000000000007 RBP: 0000000000000000 R08: 0000000000000007 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 00000000ffffffff R13: 0000000000000001 R14: ffffffffffffffff R15: ffffea0001f6ec00 folio_end_writeback+0x18f/0x560 mm/filemap.c:1648 ext4_finish_bio+0x78f/0xa20 fs/ext4/page-io.c:144 ext4_release_io_end+0x119/0x3a0 fs/ext4/page-io.c:159 ext4_end_io_end+0x13e/0x4a0 fs/ext4/page-io.c:210 ext4_do_flush_completed_IO fs/ext4/page-io.c:287 [inline] ext4_end_io_rsv_work+0x205/0x380 fs/ext4/page-io.c:302 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g6677 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=4991 rcu: rcu_preempt kthread starved for 10502 jiffies! g6677 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0 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:28728 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x116f/0x5de0 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6860 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2046 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2248 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 --- This report is generated by a bot. 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