syzbot


INFO: rcu detected stall in isotp_release

Status: upstream: reported syz repro on 2025/09/10 12:53
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+686d51bd8ca5cd966d07@syzkaller.appspotmail.com
First crash: 2d17h, last: 2d03h
Bug presence (2)
Date Name Commit Repro Result
2025/09/11 linux-6.1.y (ToT) f97f1002271b syz [report] INFO: rcu detected stall in isotp_release
2025/09/11 upstream (ToT) 7aac71907bde syz Didn't crash

Sample crash report:
rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 0-.... } 2680 jiffies s: 59393 root: 0x1/.
rcu: blocking rcu_node structures (internal RCU debug):
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 31135 Comm: syz.2.12222 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:irqentry_enter+0x36/0x50 kernel/entry/common.c:386
Code: ff ff ff eb 22 65 48 8b 05 d7 23 eb 75 0f b6 58 2c 48 8b 7c 24 08 e8 19 f9 ff ff f6 c3 02 75 0b 66 90 e8 6d e2 6f f7 31 c0 5b <c3> e8 64 09 00 00 e8 5f e2 6f f7 b0 01 5b c3 66 2e 0f 1f 84 00 00
RSP: 0018:ffffc900000078f8 EFLAGS: 00000046
RAX: 0000000000000000 RBX: ffffc90000007918 RCX: 939532a5b9070700
RDX: 0000000000000000 RSI: ffffffff8adefa80 RDI: ffffffff8adefa40
RBP: 0000000000000000 R08: dffffc0000000000 R09: fffffbfff1c3ee4e
R10: fffffbfff1c3ee4e R11: 1ffffffff1c3ee4d R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS:  00007fa6d75fe6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000002e507000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 sysvec_irq_work+0xa/0xc0 arch/x86/kernel/irq_work.c:17
 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:728
RIP: 0010:rcu_read_unlock_special+0x84/0x500 kernel/rcu/tree_plugin.h:685
Code: f1 f1 f1 00 f2 f2 f2 4a 89 04 2b 66 42 c7 44 2b 09 f3 f3 42 c6 44 2b 0b f3 65 44 8b 35 2d 97 96 7e 41 f7 c6 00 00 f0 00 74 45 <48> c7 44 24 40 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b
RSP: 0018:ffffc900000079c0 EFLAGS: 00000206
RAX: 939532a5b9070700 RBX: 1ffff92000000f40 RCX: 939532a5b9070700
RDX: dffffc0000000000 RSI: ffffffff8a8c0300 RDI: ffffffff8adefaa0
RBP: ffffc90000007ac0 R08: dffffc0000000000 R09: ffffed10171c6afa
R10: ffffed10171c6afa R11: 1ffff110171c6af9 R12: 0000000000000246
R13: dffffc0000000000 R14: ffff8880b8e3b900 R15: 0000000000000001
 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:426
 rcu_read_unlock include/linux/rcupdate.h:823 [inline]
 process_backlog+0x3ff/0x6e0 net/core/dev.c:6024
 __napi_poll+0xc0/0x460 net/core/dev.c:6590
 napi_poll net/core/dev.c:6657 [inline]
 net_rx_action+0x5b1/0xad0 net/core/dev.c:6771
 handle_softirqs+0x2a1/0x920 kernel/softirq.c:596
 __do_softirq kernel/softirq.c:630 [inline]
 invoke_softirq kernel/softirq.c:470 [inline]
 __irq_exit_rcu+0x12f/0x220 kernel/softirq.c:679
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:691
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
 sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xa5/0x100 kernel/locking/spinlock.c:194
Code: 74 05 e8 be d1 65 f7 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f6 44 24 21 02 75 4b f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> 66 5b 36 f7 65 8b 05 67 14 e1 75 85 c0 74 3c 48 c7 04 24 0e 36
RSP: 0018:ffffc90003bb7b20 EFLAGS: 00000206
RAX: 939532a5b9070700 RBX: 0000000000000a02 RCX: 939532a5b9070700
RDX: dffffc0000000000 RSI: ffffffff8a8c0300 RDI: 0000000000000001
RBP: ffffc90003bb7ba0 R08: dffffc0000000000 R09: ffffed10171c6afa
R10: ffffed10171c6afa R11: 1ffff110171c6af9 R12: dffffc0000000000
R13: ffff8880590c0000 R14: ffffffff96ec9f30 R15: 1ffff92000776f64
 __debug_check_no_obj_freed lib/debugobjects.c:988 [inline]
 debug_check_no_obj_freed+0x515/0x530 lib/debugobjects.c:1009
 free_pages_prepare mm/page_alloc.c:1465 [inline]
 __free_pages_ok+0x358/0xc40 mm/page_alloc.c:1715
 free_large_kmalloc+0xfd/0x190 mm/slab_common.c:913
 sk_prot_free net/core/sock.c:2086 [inline]
 __sk_destruct+0x49c/0x630 net/core/sock.c:2172
 sock_put include/net/sock.h:2036 [inline]
 isotp_release+0x788/0x930 net/can/isotp.c:1201
 __sock_release net/socket.c:654 [inline]
 sock_release+0x7b/0x140 net/socket.c:682
 __sys_socketpair+0x4fb/0x540 net/socket.c:-1
 __do_sys_socketpair net/socket.c:1786 [inline]
 __se_sys_socketpair net/socket.c:1783 [inline]
 __x64_sys_socketpair+0x97/0xb0 net/socket.c:1783
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fa6d7f8eba9
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:00007fa6d75fe038 EFLAGS: 00000246 ORIG_RAX: 0000000000000035
RAX: ffffffffffffffda RBX: 00007fa6d81d5fa0 RCX: 00007fa6d7f8eba9
RDX: 0000000000000006 RSI: 0000000000000002 RDI: 000000000000001d
RBP: 00007fa6d8011e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000200000000300 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa6d81d6038 R14: 00007fa6d81d5fa0 R15: 00007ffed6b3fd98
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/09/10 12:53 linux-6.1.y f97f1002271b fdeaa69b .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in isotp_release
* Struck through repros no longer work on HEAD.