[moderation] [sctp?] WARNING: refcount bug in sctp_transport_put (6)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 66182ca873a4 Merge tag 'net-7.1-rc4' of git://git.kernel.o..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10ebdf6c580000
kernel config: https://syzkaller.appspot.com/x/.config?x=59da38148f3a3d24
dashboard link: https://syzkaller.appspot.com/bug?extid=c0217e797c3dc836a952
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
CC: [da...@davemloft.net edum...@google.com ho...@kernel.org ku...@kernel.org linux-...@vger.kernel.org linux...@vger.kernel.org lucie...@gmail.com marcelo...@gmail.com net...@vger.kernel.org pab...@redhat.com]

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-66182ca8.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a9b01f2ddb8c/vmlinux-66182ca8.xz
kernel image: https://storage.googleapis.com/syzbot-assets/1dd5263b1cc2/bzImage-66182ca8.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c0217e...@syzkaller.appspotmail.com

------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: lib/refcount.c:28 at refcount_warn_saturate+0xf4/0x130 lib/refcount.c:28, CPU#0: swapper/0/0
Modules linked in:
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:refcount_warn_saturate+0xf4/0x130 lib/refcount.c:28
Code: cc e8 b0 3a 0f fd 48 8d 3d 49 e7 e8 0b 67 48 0f b9 3a e8 9f 3a 0f fd 5b 5d e9 d8 66 94 06 e8 93 3a 0f fd 48 8d 3d 3c e7 e8 0b <67> 48 0f b9 3a e8 82 3a 0f fd 5b 5d c3 cc cc cc cc e8 76 3a 0f fd
RSP: 0018:ffffc90000007c18 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff88805ea27020 RCX: ffffffff84f963bb
RDX: ffffffff8e4955c0 RSI: ffffffff84f9644d RDI: ffffffff90e24b90
RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000004
R10: 0000000000000003 R11: 0000000000000000 R12: ffff88805ea27020
R13: 1ffff92000000f8d R14: ffffffff8ac3d620 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff8880d6370000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000087b000 CR3: 0000000051ad7000 CR4: 0000000000352ef0
Call Trace:
<IRQ>
__refcount_sub_and_test include/linux/refcount.h:400 [inline]
__refcount_dec_and_test include/linux/refcount.h:432 [inline]
refcount_dec_and_test include/linux/refcount.h:450 [inline]
sctp_transport_put+0x134/0x180 net/sctp/transport.c:476
call_timer_fn+0x19a/0x640 kernel/time/timer.c:1748
expire_timers kernel/time/timer.c:1799 [inline]
__run_timers+0x75f/0xaf0 kernel/time/timer.c:2374
__run_timer_base kernel/time/timer.c:2386 [inline]
__run_timer_base kernel/time/timer.c:2378 [inline]
run_timer_base+0x114/0x190 kernel/time/timer.c:2395
run_timer_softirq+0x1a/0x50 kernel/time/timer.c:2405
handle_softirqs+0x1ea/0xa00 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0x162/0x210 kernel/softirq.c:735
irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline]
sysvec_apic_timer_interrupt+0xa3/0xc0 arch/x86/kernel/apic/apic.c:1061
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:63
Code: c6 92 02 e9 c3 42 03 00 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa eb 07 0f 00 2d a3 f1 20 00 fb f4 <c3> cc cc cc cc 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffffff8e407e00 EFLAGS: 00000202
RAX: 00000000000e8cd5 RBX: ffffffff8e4955c0 RCX: ffffffff8b8aa095
RDX: 0000000000000000 RSI: ffffffff8df215d0 RDI: ffffffff8c1c3800
RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed100d4867b5
R10: ffff88806a433dab R11: 0000000000000000 R12: 0000000000000000
R13: fffffbfff1c92ab8 R14: 0000000000000000 R15: ffffffff90d7bc50
arch_safe_halt arch/x86/include/asm/paravirt.h:62 [inline]
default_idle+0x9/0x10 arch/x86/kernel/process.c:767
default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:199 [inline]
do_idle+0x464/0x590 kernel/sched/idle.c:352
cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:451
rest_init+0x251/0x260 init/main.c:762
start_kernel+0x484/0x490 init/main.c:1220
x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
x86_64_start_kernel+0x12b/0x130 arch/x86/kernel/head64.c:291
common_startup_64+0x13e/0x148
</TASK>
----------------
Code disassembly (best guess):
0: cc int3
1: e8 b0 3a 0f fd call 0xfd0f3ab6
6: 48 8d 3d 49 e7 e8 0b lea 0xbe8e749(%rip),%rdi # 0xbe8e756
d: 67 48 0f b9 3a ud1 (%edx),%rdi
12: e8 9f 3a 0f fd call 0xfd0f3ab6
17: 5b pop %rbx
18: 5d pop %rbp
19: e9 d8 66 94 06 jmp 0x69466f6
1e: e8 93 3a 0f fd call 0xfd0f3ab6
23: 48 8d 3d 3c e7 e8 0b lea 0xbe8e73c(%rip),%rdi # 0xbe8e766
* 2a: 67 48 0f b9 3a ud1 (%edx),%rdi <-- trapping instruction
2f: e8 82 3a 0f fd call 0xfd0f3ab6
34: 5b pop %rbx
35: 5d pop %rbp
36: c3 ret
37: cc int3
38: cc int3
39: cc int3
3a: cc int3
3b: e8 76 3a 0f fd call 0xfd0f3ab6


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