BUG: soft lockup in tun_chr_read_iter

Status: auto-obsoleted due to no activity on 2024/07/28 05:11
Reported-by: syzbot+41fc64f290432b4fbb09@syzkaller.appspotmail.com
First crash: 842d, last: 842d
▶ ▼ Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 INFO: rcu detected stall in tun_chr_read_iter 1 1 330d 330d 0/3 auto-obsoleted due to no activity on 2026/01/01 00:31
upstream INFO: rcu detected stall in tun_chr_read_iter (2) net bpf prio:high 1 4 161d 307d 0/29 auto-obsoleted due to no activity on 2026/06/09 17:56

Sample crash report:
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000001
 </TASK>
watchdog: BUG: soft lockup - CPU#1 stuck for 246s! [syz-executor.3:32468]
Modules linked in:
CPU: 1 PID: 32468 Comm: syz-executor.3 Not tainted 5.15.149-syzkaller-00490-g5d96939590c0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
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 5b 03 f3 03 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:ffffc90000c9f300 EFLAGS: 00000246
RAX: 0000000000000003 RBX: 1ffff92000193e64 RCX: ffffffff8154fa7f
RDX: dffffc0000000000 RSI: 0000000000000003 RDI: ffff88812af846e8
RBP: ffffc90000c9f3b0 R08: dffffc0000000000 R09: ffffed10255f08de
R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000
R13: ffff88812af846e8 R14: 0000000000000003 R15: 1ffff92000193e68
FS:  0000555556cf3480(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fdc83ba05e3 CR3: 00000001230b0000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 </IRQ>
 <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/0x210
 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:1883 [inline]
 bpf_trace_run2+0xec/0x210 kernel/trace/bpf_trace.c:1920
 __bpf_trace_kfree+0x6f/0x90 include/trace/events/kmem.h:118
 trace_kfree include/trace/events/kmem.h:118 [inline]
 kfree+0x1f3/0x220 mm/slub.c:4569
 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/0x210
 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:1883 [inline]
 bpf_trace_run2+0xec/0x210 kernel/trace/bpf_trace.c:1920
 __bpf_trace_kfree+0x6f/0x90 include/trace/events/kmem.h:118
 trace_kfree include/trace/events/kmem.h:118 [inline]
 kfree+0x1f3/0x220 mm/slub.c:4569
 skb_free_head net/core/skbuff.c:656 [inline]
 skb_release_data+0x8a9/0xa80 net/core/skbuff.c:678
 skb_release_all net/core/skbuff.c:743 [inline]
 __kfree_skb net/core/skbuff.c:757 [inline]
 consume_skb+0xac/0x250 net/core/skbuff.c:930
 tun_do_read+0x131f/0x1ef0 drivers/net/tun.c:2217
 tun_chr_read_iter+0x211/0x360 drivers/net/tun.c:2237
 call_read_iter include/linux/fs.h:2196 [inline]
 new_sync_read fs/read_write.c:404 [inline]
 vfs_read+0xa7e/0xd40 fs/read_write.c:485
 ksys_read+0x199/0x2c0 fs/read_write.c:623
 __do_sys_read fs/read_write.c:633 [inline]
 __se_sys_read fs/read_write.c:631 [inline]
 __x64_sys_read+0x7b/0x90 fs/read_write.c:631
 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: 0033:0x7fdc83b1ab0d
Code: b0 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff eb b5 e8 78 34 00 00 0f 1f 84 00 00 00 00 00 80 3d f1 33 10 00 00 74 17 31 c0 0f 05 <48> 3d 00 f0 ff ff 77 5b c3 66 2e 0f 1f 84 00 00 00 00 00 48 83 ec
RSP: 002b:00007ffce8ecdc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007ffce8ecdc80 RCX: 00007fdc83b1ab0d
RDX: 00000000000003e8 RSI: 00007ffce8ecdc80 RDI: 00000000000000c8
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000001
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 32470 Comm: syz-executor.2 Not tainted 5.15.149-syzkaller-00490-g5d96939590c0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
RIP: 0010:native_halt arch/x86/include/asm/irqflags.h:57 [inline]
RIP: 0010:halt arch/x86/include/asm/irqflags.h:98 [inline]
RIP: 0010:kvm_wait+0x117/0x180 arch/x86/kernel/kvm.c:912
Code: 48 c1 e8 03 42 0f b6 04 20 84 c0 44 8b 74 24 1c 75 53 41 0f b6 45 00 44 38 f0 0f 85 63 ff ff ff 66 90 0f 00 2d 8a 03 f3 03 f4 <e9> 54 ff ff ff fa 4c 89 e8 48 c1 e8 03 42 0f b6 04 20 84 c0 44 8b
RSP: 0018:ffffc90000bc7240 EFLAGS: 00000046
RAX: 0000000000000001 RBX: 1ffff92000178e4c RCX: 1ffffffff0d1aa9c
RDX: 0000000000000001 RSI: 0000000000000001 RDI: ffff8881f7037ed4
RBP: ffffc90000bc72f0 R08: dffffc0000000000 R09: ffffed103ee06fdb
R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000
R13: ffff8881f7037ed4 R14: 0000000000000001 R15: 1ffff92000178e50
FS:  00007fe019d246c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2c521000 CR3: 00000001255a9000 CR4: 00000000003506b0
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_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/0x210
 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:1883 [inline]
 bpf_trace_run2+0xec/0x210 kernel/trace/bpf_trace.c:1920
 __bpf_trace_kfree+0x6f/0x90 include/trace/events/kmem.h:118
 trace_kfree include/trace/events/kmem.h:118 [inline]
 kfree+0x1f3/0x220 mm/slub.c:4569
 realloc_user_queue+0x108/0x2c0 sound/core/timer.c:1476
 snd_timer_user_open+0x101/0x180 sound/core/timer.c:1503
 snd_open+0x30e/0x380 sound/core/sound.c:169
 chrdev_open+0x4f7/0x620 fs/char_dev.c:414
 do_dentry_open+0x81c/0xfd0 fs/open.c:828
 vfs_open+0x73/0x80 fs/open.c:958
 do_open fs/namei.c:3608 [inline]
 path_openat+0x26f0/0x2f40 fs/namei.c:3742
 do_filp_open+0x21c/0x460 fs/namei.c:3769
 do_sys_openat2+0x13f/0x830 fs/open.c:1234
 do_sys_open fs/open.c:1250 [inline]
 __do_sys_openat fs/open.c:1266 [inline]
 __se_sys_openat fs/open.c:1261 [inline]
 __x64_sys_openat+0x243/0x290 fs/open.c:1261
 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: 0033:0x7fe01afb0ea9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fe019d240c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fe01b0def80 RCX: 00007fe01afb0ea9
RDX: 0000000000000000 RSI: 0000000020000000 RDI: ffffffffffffff9c
RBP: 00007fe01affd4a4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007fe01b0def80 R15: 00007ffc14e67418
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/04/29 05:01 android13-5.15-lts 5d96939590c0 07b455f9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 BUG: soft lockup in tun_chr_read_iter
* Struck through repros no longer work on HEAD.