BUG: soft lockup in tun_chr_write_iter

Status: auto-obsoleted due to no activity on 2024/10/25 22:12
Reported-by: syzbot+b757f3252c952e0abbba@syzkaller.appspotmail.com
First crash: 756d, last: 756d
▶ ▼ Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.6 INFO: rcu detected stall in tun_chr_write_iter 1 1 51d 51d 0/2 upstream: reported on 2026/07/02 23:03
upstream INFO: rcu detected stall in tun_chr_write_iter net 1 1 696d 695d 0/29 auto-obsoleted due to no activity on 2024/12/25 20:05
linux-5.15 INFO: rcu detected stall in tun_chr_write_iter 1 1 65d 65d 0/3 upstream: reported on 2026/06/19 04:37

Sample crash report:
watchdog: BUG: soft lockup - CPU#0 stuck for 226s! [syz.2.790:3021]
Modules linked in:
CPU: 0 PID: 3021 Comm: syz.2.790 Not tainted 5.15.151-syzkaller-00127-g4edafe6c0231 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
RIP: 0010:native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
RIP: 0010:arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
RIP: 0010:kvm_wait+0x147/0x180 arch/x86/kernel/kvm.c:918
Code: 4c 89 e8 48 c1 e8 03 42 0f b6 04 20 84 c0 44 8b 74 24 1c 75 34 41 0f b6 45 00 44 38 f0 75 10 66 90 0f 00 2d 2b 02 13 04 fb f4 <e9> 24 ff ff ff fb e9 1e ff ff ff 44 89 e9 80 e1 07 38 c1 7c a3 4c
RSP: 0018:ffffc90000c7f2a0 EFLAGS: 00000246
RAX: 0000000000000001 RBX: 1ffff9200018fe58 RCX: 1ffffffff0d5aa9c
RDX: 0000000000000001 RSI: 0000000000000001 RDI: ffff8881f7038ad4
RBP: ffffc90000c7f350 R08: dffffc0000000000 R09: ffffed103ee0715b
R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000
R13: ffff8881f7038ad4 R14: 0000000000000001 R15: 1ffff9200018fe5c
FS:  00007f28104ed6c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000508f0000 CR3: 000000011edf0000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 </IRQ>
 <TASK>
 pv_wait arch/x86/include/asm/paravirt.h:597 [inline]
 pv_wait_node kernel/locking/qspinlock_paravirt.h:325 [inline]
 __pv_queued_spin_lock_slowpath+0x41b/0xc40 kernel/locking/qspinlock.c:473
 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:585 [inline]
 queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:51 [inline]
 queued_spin_lock include/asm-generic/qspinlock.h:85 [inline]
 do_raw_spin_lock include/linux/spinlock.h:187 [inline]
 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:136 [inline]
 _raw_spin_lock_bh+0x139/0x1b0 kernel/locking/spinlock.c:178
 sock_hash_delete_elem+0xb1/0x2f0 net/core/sock_map.c:937
 bpf_prog_2c29ac5cdc6b1842+0x3a/0x5b0
 bpf_dispatcher_nop_func include/linux/bpf.h:785 [inline]
 __bpf_prog_run include/linux/filter.h:625 [inline]
 bpf_prog_run include/linux/filter.h:632 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:1880 [inline]
 bpf_trace_run4+0x13f/0x270 kernel/trace/bpf_trace.c:1919
 __bpf_trace_mm_page_alloc+0xbf/0xf0 include/trace/events/kmem.h:201
 trace_mm_page_alloc include/trace/events/kmem.h:201 [inline]
 __alloc_pages+0x3cb/0x8f0 mm/page_alloc.c:5799
 __alloc_pages_node include/linux/gfp.h:591 [inline]
 alloc_pages_node include/linux/gfp.h:605 [inline]
 alloc_pages include/linux/gfp.h:618 [inline]
 kmalloc_order+0x4a/0x160 mm/slab_common.c:975
 kmalloc_order_trace+0x1a/0xb0 mm/slab_common.c:994
 kmalloc_large include/linux/slab.h:532 [inline]
 __kmalloc_track_caller+0x19b/0x260 mm/slub.c:4938
 kmalloc_reserve net/core/skbuff.c:357 [inline]
 pskb_expand_head+0x113/0x1240 net/core/skbuff.c:1727
 __skb_grow include/linux/skbuff.h:2892 [inline]
 tun_napi_alloc_frags drivers/net/tun.c:1462 [inline]
 tun_get_user+0x13b3/0x3aa0 drivers/net/tun.c:1815
 tun_chr_write_iter+0x1e1/0x2e0 drivers/net/tun.c:2019
 call_write_iter include/linux/fs.h:2204 [inline]
 new_sync_write fs/read_write.c:507 [inline]
 vfs_write+0xd5d/0x1110 fs/read_write.c:594
 ksys_write+0x199/0x2c0 fs/read_write.c:647
 __do_sys_write fs/read_write.c:659 [inline]
 __se_sys_write fs/read_write.c:656 [inline]
 __x64_sys_write+0x7b/0x90 fs/read_write.c:656
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f281188e299
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f28104ed048 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f2811a1d058 RCX: 00007f281188e299
RDX: 000000000000fdef RSI: 0000000020000380 RDI: 0000000000000006
RBP: 00007f28118fb8e6 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000006e R14: 00007f2811a1d058 R15: 00007ffe40d849e8
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 3017 Comm: syz.2.790 Not tainted 5.15.151-syzkaller-00127-g4edafe6c0231 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
RIP: 0010:native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
RIP: 0010:arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
RIP: 0010:kvm_wait+0x147/0x180 arch/x86/kernel/kvm.c:918
Code: 4c 89 e8 48 c1 e8 03 42 0f b6 04 20 84 c0 44 8b 74 24 1c 75 34 41 0f b6 45 00 44 38 f0 75 10 66 90 0f 00 2d 2b 02 13 04 fb f4 <e9> 24 ff ff ff fb e9 1e ff ff ff 44 89 e9 80 e1 07 38 c1 7c a3 4c
RSP: 0018:ffffc90000b560a0 EFLAGS: 00000246
RAX: 0000000000000003 RBX: 1ffff9200016ac18 RCX: ffffffff8155068f
RDX: dffffc0000000000 RSI: 0000000000000003 RDI: ffff88810a112318
RBP: ffffc90000b56150 R08: dffffc0000000000 R09: ffffed1021422464
R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000
R13: ffff88810a112318 R14: 0000000000000003 R15: 1ffff9200016ac1c
FS:  00007f281050e6c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000508f0000 CR3: 000000011edf0000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 pv_wait arch/x86/include/asm/paravirt.h:597 [inline]
 pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:470 [inline]
 __pv_queued_spin_lock_slowpath+0x6bc/0xc40 kernel/locking/qspinlock.c:508
 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:585 [inline]
 queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:51 [inline]
 queued_spin_lock include/asm-generic/qspinlock.h:85 [inline]
 do_raw_spin_lock include/linux/spinlock.h:187 [inline]
 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:136 [inline]
 _raw_spin_lock_bh+0x139/0x1b0 kernel/locking/spinlock.c:178
 sock_hash_delete_elem+0xb1/0x2f0 net/core/sock_map.c:937
 bpf_prog_2c29ac5cdc6b1842+0x3a/0x5b0
 bpf_dispatcher_nop_func include/linux/bpf.h:785 [inline]
 __bpf_prog_run include/linux/filter.h:625 [inline]
 bpf_prog_run include/linux/filter.h:632 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:1880 [inline]
 bpf_trace_run4+0x13f/0x270 kernel/trace/bpf_trace.c:1919
 __bpf_trace_mm_page_alloc+0xbf/0xf0 include/trace/events/kmem.h:201
 trace_mm_page_alloc include/trace/events/kmem.h:201 [inline]
 __alloc_pages+0x3cb/0x8f0 mm/page_alloc.c:5799
 __alloc_pages_node include/linux/gfp.h:591 [inline]
 alloc_pages_node include/linux/gfp.h:605 [inline]
 alloc_pages include/linux/gfp.h:618 [inline]
 __stack_depot_save+0x38d/0x470 lib/stackdepot.c:326
 stack_depot_save+0xe/0x10 lib/stackdepot.c:383
 save_stack+0x104/0x1e0 mm/page_owner.c:140
 __set_page_owner+0x28/0x2e0 mm/page_owner.c:200
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x1a3/0x1b0 mm/page_alloc.c:2605
 prep_new_page+0x1b/0x110 mm/page_alloc.c:2611
 get_page_from_freelist+0x3550/0x35d0 mm/page_alloc.c:4485
 __alloc_pages+0x27e/0x8f0 mm/page_alloc.c:5777
 __alloc_pages_node include/linux/gfp.h:591 [inline]
 alloc_pages_node include/linux/gfp.h:605 [inline]
 alloc_pages include/linux/gfp.h:618 [inline]
 __stack_depot_save+0x38d/0x470 lib/stackdepot.c:326
 kasan_save_stack mm/kasan/common.c:39 [inline]
 kasan_set_track+0x5d/0x70 mm/kasan/common.c:45
 kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:370
 ____kasan_slab_free+0x126/0x160 mm/kasan/common.c:365
 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:373
 kasan_slab_free include/linux/kasan.h:193 [inline]
 slab_free_hook mm/slub.c:1723 [inline]
 slab_free_freelist_hook+0xbd/0x190 mm/slub.c:1749
 slab_free mm/slub.c:3519 [inline]
 kfree+0xc8/0x220 mm/slub.c:4579
 sk_psock_free_link include/linux/skmsg.h:420 [inline]
 sock_map_del_link net/core/sock_map.c:160 [inline]
 sock_map_unref+0x352/0x4d0 net/core/sock_map.c:182
 sock_hash_delete_elem+0x274/0x2f0 net/core/sock_map.c:941
 bpf_prog_2c29ac5cdc6b1842+0x3a/0x5b0
 bpf_dispatcher_nop_func include/linux/bpf.h:785 [inline]
 __bpf_prog_run include/linux/filter.h:625 [inline]
 bpf_prog_run include/linux/filter.h:632 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:1880 [inline]
 bpf_trace_run4+0x13f/0x270 kernel/trace/bpf_trace.c:1919
 __bpf_trace_mm_page_alloc+0xbf/0xf0 include/trace/events/kmem.h:201
 trace_mm_page_alloc include/trace/events/kmem.h:201 [inline]
 __alloc_pages+0x3cb/0x8f0 mm/page_alloc.c:5799
 allocate_slab mm/slub.c:1932 [inline]
 new_slab+0x9a/0x4e0 mm/slub.c:1995
 ___slab_alloc+0x39e/0x830 mm/slub.c:3028
 __slab_alloc+0x4a/0x90 mm/slub.c:3115
 slab_alloc_node mm/slub.c:3206 [inline]
 slab_alloc mm/slub.c:3248 [inline]
 __kmalloc+0x16d/0x270 mm/slub.c:4423
 __kmalloc_node include/linux/slab.h:469 [inline]
 kmalloc_node include/linux/slab.h:626 [inline]
 kvmalloc_node+0x1f0/0x4d0 mm/util.c:628
 kvmalloc include/linux/mm.h:851 [inline]
 kvmalloc_array include/linux/mm.h:869 [inline]
 __ptr_ring_init_queue_alloc include/linux/ptr_ring.h:471 [inline]
 ptr_ring_init include/linux/ptr_ring.h:489 [inline]
 skb_array_init include/linux/skb_array.h:182 [inline]
 pfifo_fast_init+0x25e/0x7a0 net/sched/sch_generic.c:806
 qdisc_create_dflt+0x144/0x3e0 net/sched/sch_generic.c:957
 mq_init+0x2c8/0x6b0 net/sched/sch_mq.c:90
 qdisc_create_dflt+0x144/0x3e0 net/sched/sch_generic.c:957
 attach_default_qdiscs net/sched/sch_generic.c:1136 [inline]
 dev_activate+0x127/0x1140 net/sched/sch_generic.c:1190
 __dev_open+0x3bf/0x4e0 net/core/dev.c:1522
 __dev_change_flags+0x1db/0x6e0 net/core/dev.c:8817
 dev_change_flags+0x8c/0x1a0 net/core/dev.c:8888
 dev_ifsioc+0x147/0x10c0 net/core/dev_ioctl.c:324
 dev_ioctl+0x54d/0xe70 net/core/dev_ioctl.c:587
 sock_do_ioctl+0x34f/0x5a0 net/socket.c:1154
 sock_ioctl+0x455/0x740 net/socket.c:1257
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl+0x114/0x190 fs/ioctl.c:860
 __x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:860
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f281188e299
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f281050e048 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f2811a1cf80 RCX: 00007f281188e299
RDX: 0000000020000080 RSI: 0000000000008914 RDI: 0000000000000009
RBP: 00007f28118fb8e6 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f2811a1cf80 R15: 00007ffe40d849e8
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/07/27 22:09 android13-5.15-lts 4edafe6c0231 46eb10b7 .config console log report info ci2-android-5-15-perf BUG: soft lockup in tun_chr_write_iter
* Struck through repros no longer work on HEAD.