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with SMTP id 006d021491bc7-6a30d8fb717mr5126658eaf.59.1783062211048; Fri, 03 Jul 2026 00:03:31 -0700 (PDT) Date: Fri, 03 Jul 2026 00:03:31 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a475ec3.6912059f.e0473.000a.GAE@google.com> Subject: [syzbot] [mm?] INFO: rcu detected stall in unmap_region From: syzbot To: akpm@linux-foundation.org, jannh@google.com, liam@infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, ljs@kernel.org, netdev@vger.kernel.org, pfalcato@suse.de, syzkaller-bugs@googlegroups.com, vbabka@kernel.org Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 32f1c2bbb26a net: airoha: dma map xmit frags with skb_frag.. git tree: net console output: https://syzkaller.appspot.com/x/log.txt?x=116c2c0a580000 kernel config: https://syzkaller.appspot.com/x/.config?x=86ba763b42fa66a dashboard link: https://syzkaller.appspot.com/bug?extid=2ad5ec205a38c46522b3 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=132f5861580000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/7b7c3a22a8ed/disk-32f1c2bb.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/168b43c87305/vmlinux-32f1c2bb.xz kernel image: https://storage.googleapis.com/syzbot-assets/70704720d284/bzImage-32f1c2bb.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+2ad5ec205a38c46522b3@syzkaller.appspotmail.com rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=6664/1/0x4000000000000000 softirq=17730/17732 fqs=2 rcu: (detected by 1, t=10502 jiffies, g=17101, q=1895 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 6010 Comm: modprobe Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:lock_release+0x5/0x3c0 kernel/locking/lockdep.c:5876 Code: e9 4f fe ff ff 41 bf 2f 00 00 00 e9 06 ff ff ff 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 55 <41> 57 41 56 41 55 41 54 53 48 83 ec 30 49 89 f5 49 89 fe 65 48 8b RSP: 0018:ffffc90000007db0 EFLAGS: 00000082 RAX: 932ea09fa7cced00 RBX: 0000000000000092 RCX: 0000000000000002 RDX: 0000000000000001 RSI: ffffffff81b30e19 RDI: ffffffff9a73d4c8 RBP: ffff88807e29b300 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff52000000f98 R12: ffff8880b86281c0 R13: dffffc0000000000 R14: ffffffff9a73d4b0 R15: ffff8880b8628350 FS: 0000000000000000(0000) GS:ffff888125226000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffae81e84e8 CR3: 000000007ee52000 CR4: 00000000003526f0 Call Trace: __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:176 [inline] _raw_spin_unlock_irqrestore+0x1b/0x80 kernel/locking/spinlock.c:198 debug_hrtimer_deactivate kernel/time/hrtimer.c:490 [inline] __run_hrtimer kernel/time/hrtimer.c:2000 [inline] __hrtimer_run_queues+0x239/0xa10 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:do_zap_pte_range mm/memory.c:1819 [inline] RIP: 0010:zap_pte_range mm/memory.c:1934 [inline] RIP: 0010:zap_pmd_range mm/memory.c:2020 [inline] RIP: 0010:zap_pud_range mm/memory.c:2048 [inline] RIP: 0010:zap_p4d_range mm/memory.c:2069 [inline] RIP: 0010:__zap_vma_range+0xfbd/0x4f10 mm/memory.c:2109 Code: 4c 89 64 24 30 4c 89 e6 48 83 e6 9f 31 ff e8 3a 4a ad ff 4d 89 e7 49 83 e4 9f 75 2f 48 8b 44 24 10 4c 01 e8 48 83 f8 01 74 28 3e 45 ad ff 48 83 c3 08 49 ff c5 4d 89 f4 eb a3 4d 89 ef e8 2a RSP: 0018:ffffc90003287000 EFLAGS: 00000286 RAX: ffffffffffffff73 RBX: ffff888034e9d190 RCX: ffff88802dcf1f00 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc900032872f0 R08: ffff888078979803 R09: 1ffff1100f12f300 R10: dffffc0000000000 R11: ffffed100f12f301 R12: 0000000000000000 R13: 0000000000000032 R14: dffffc0000000000 R15: 0000000000000000 unmap_vmas+0x390/0x550 mm/memory.c:2178 unmap_region+0x208/0x330 mm/vma.c:488 vms_clear_ptes mm/vma.c:1303 [inline] vms_clean_up_area mm/vma.c:1315 [inline] __mmap_setup mm/vma.c:2476 [inline] __mmap_region mm/vma.c:2756 [inline] mmap_region+0xc62/0x2310 mm/vma.c:2860 do_mmap+0xc3b/0x10c0 mm/mmap.c:560 vm_mmap_pgoff+0x272/0x4e0 mm/util.c:581 ksys_mmap_pgoff+0x4dc/0x760 mm/mmap.c:606 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: 0033:0x7ffae8219242 Code: 08 00 04 00 00 eb e2 90 41 f7 c1 ff 0f 00 00 75 27 55 89 cd 53 48 89 fb 48 85 ff 74 33 41 89 ea 48 89 df b8 09 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 5e 5b 5d c3 0f 1f 00 c7 05 46 40 01 00 16 00 RSP: 002b:00007ffec64cd428 EFLAGS: 00000206 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007ffae7f73000 RCX: 00007ffae8219242 RDX: 0000000000000005 RSI: 000000000014e000 RDI: 00007ffae7f73000 RBP: 0000000000000812 R08: 0000000000000000 R09: 0000000000028000 R10: 0000000000000812 R11: 0000000000000206 R12: 00007ffec64cd478 R13: 00007ffae81ed5f0 R14: 00007ffec64cdc60 R15: 00000fffd8c99a88 rcu: rcu_preempt kthread starved for 10477 jiffies! g17101 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R running task stack:28192 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 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 UID: 0 PID: 4992 Comm: udevd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0x10b0/0x14b0 kernel/smp.c:892 Code: c0 75 73 41 8b 1e 89 de 83 e6 01 31 ff e8 d8 1e 0c 00 83 e3 01 48 bb 00 00 00 00 00 fc ff df 75 07 e8 84 1a 0c 00 eb 37 f3 90 <41> 0f b6 04 1c 84 c0 75 10 41 f7 06 01 00 00 00 74 1e e8 69 1a 0c RSP: 0018:ffffc90003837580 EFLAGS: 00000293 RAX: ffffffff81ba5717 RBX: dffffc0000000000 RCX: ffff88807e5a0000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc900038376a8 R08: ffffffff9032d2f7 R09: 1ffffffff2065a5e R10: dffffc0000000000 R11: fffffbfff2065a5f R12: 1ffff110170c85fd R13: ffff8880b873c448 R14: ffff8880b8642fe8 R15: 0000000000000000 FS: 00007fdd3255d880(0000) GS:ffff888125326000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00002c919703e000 CR3: 000000007e7f2000 CR4: 00000000003526f0 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1057 __flush_tlb_multi arch/x86/include/asm/paravirt.h:46 [inline] flush_tlb_multi arch/x86/mm/tlb.c:1361 [inline] flush_tlb_mm_range+0x5c4/0x1090 arch/x86/mm/tlb.c:1451 dup_mmap+0x1786/0x1d90 mm/mmap.c:1905 dup_mm kernel/fork.c:1538 [inline] copy_mm+0x11a/0x480 kernel/fork.c:1590 copy_process+0x1e99/0x43f0 kernel/fork.c:2288 kernel_clone+0x2d7/0x940 kernel/fork.c:2747 __do_sys_clone kernel/fork.c:2888 [inline] __se_sys_clone kernel/fork.c:2872 [inline] __x64_sys_clone+0x1b6/0x230 kernel/fork.c:2872 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: 0033:0x7fdd31ef1636 Code: 89 df e8 6d e8 f6 ff 45 31 c0 31 d2 31 f6 64 48 8b 04 25 10 00 00 00 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 52 89 c5 85 c0 75 31 64 48 8b 04 25 10 00 00 RSP: 002b:00007ffcd95f6670 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007ffcd95f6678 RCX: 00007fdd31ef1636 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000564712dd5910 R08: 0000000000000000 R09: 0000564712ddd8e0 R10: 00007fdd3255db50 R11: 0000000000000246 R12: 00007ffcd95f6a30 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 --- This report is generated by a bot. 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