[syzbot] [rdma?] WARNING: refcount bug in iwpm_find_nlmsg_request

[syzbot] [rdma?] WARNING: refcount bug in iwpm_find_nlmsg_request

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    548e7bcd0c54 Merge tag 'ceph-for-7.3-rc1' of https://githu..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11644c15580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=85bc5cc2fc7394d9
dashboard link: https://syzkaller.appspot.com/bug?extid=bd317784d628820741b5
compiler:       gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
userspace arch: i386

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-548e7bcd.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/33981fd8947d/vmlinux-548e7bcd.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d17bd4bd3299/bzImage-548e7bcd.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+bd317784d628820741b5@syzkaller.appspotmail.com

netlink: 16 bytes leftover after parsing attributes in process `syz.2.3511'.
iwpm_mapping_error_cb: Received msg seq = 0 err code = 5 client = 2
------------[ cut here ]------------
refcount_t: addition on 0; use-after-free.
WARNING: lib/refcount.c:25 at refcount_warn_saturate+0x111/0x130 lib/refcount.c:25, CPU#0: syz.2.3511/18531
Modules linked in:
CPU: 0 UID: 0 PID: 18531 Comm: syz.2.3511 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
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+0x111/0x130 lib/refcount.c:25
Code: 06 e8 53 6d e3 fc 48 8d 3d dc 53 28 0c 67 48 0f b9 3a e8 42 6d e3 fc 5b 5d c3 cc cc cc cc e8 36 6d e3 fc 48 8d 3d cf 53 28 0c <67> 48 0f b9 3a e8 25 6d e3 fc 5b 5d e9 ce 8f a8 06 48 89 df e8 46
RSP: 0000:ffffc90007ddf448 EFLAGS: 00010087
RAX: 0000000000001c55 RBX: ffff888024890878 RCX: ffffc9000c001000
RDX: 0000000000080000 RSI: ffffffff8527c5fa RDI: ffffffff915019d0
RBP: 0000000000000002 R08: 0000000000000005 R09: 0000000000000004
R10: 0000000000000002 R11: 000000000000001f R12: ffff888024890878
R13: dffffc0000000000 R14: 0000000000000283 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888096968000(0063) knlGS:00000000f5456b40
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 00000000f73d8568 CR3: 00000000774e3000 CR4: 0000000000352ef0
DR0: 0000000000000009 DR1: 0000000000000009 DR2: 0000000000000003
DR3: 0000000000000008 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __refcount_add include/linux/refcount.h:289 [inline]
 __refcount_inc include/linux/refcount.h:366 [inline]
 refcount_inc include/linux/refcount.h:383 [inline]
 kref_get include/linux/kref.h:45 [inline]
 iwpm_find_nlmsg_request+0x13d/0x160 drivers/infiniband/core/iwpm_util.c:360
 iwpm_mapping_error_cb.cold+0x97/0x277 drivers/infiniband/core/iwpm_msg.c:794
 netlink_dump+0x532/0xd00 net/netlink/af_netlink.c:2331
 __netlink_dump_start+0x6d6/0x990 net/netlink/af_netlink.c:2446
 netlink_dump_start include/linux/netlink.h:341 [inline]
 rdma_nl_rcv_msg+0x568/0x6f0 drivers/infiniband/core/netlink.c:190
 rdma_nl_rcv_skb.constprop.0.isra.0+0x2cb/0x410 drivers/infiniband/core/netlink.c:239
 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
 netlink_unicast+0x585/0x850 net/netlink/af_netlink.c:1345
 netlink_sendmsg+0x8b0/0xda0 net/netlink/af_netlink.c:1900
 sock_sendmsg_nosec net/socket.c:800 [inline]
 __sock_sendmsg net/socket.c:815 [inline]
 ____sys_sendmsg+0xa4d/0xbe0 net/socket.c:2713
 ___sys_sendmsg+0x190/0x1e0 net/socket.c:2767
 __sys_sendmsg+0x160/0x210 net/socket.c:2799
 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:79 [inline]
 __do_fast_syscall_32+0x13a/0x8b0 arch/x86/entry/syscall_32.c:291
 do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:316
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf7f94fec
Code: Unable to access opcode bytes at 0xf7f94fc2.
RSP: 002b:00000000f545650c EFLAGS: 00000292 ORIG_RAX: 0000000000000172
RAX: ffffffffffffffda RBX: 0000000000000007 RCX: 0000000080000100
RDX: 0000000000000004 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000292 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
----------------
Code disassembly (best guess), 1 bytes skipped:
   0:	e8 53 6d e3 fc       	call   0xfce36d58
   5:	48 8d 3d dc 53 28 0c 	lea    0xc2853dc(%rip),%rdi        # 0xc2853e8
   c:	67 48 0f b9 3a       	ud1    (%edx),%rdi
  11:	e8 42 6d e3 fc       	call   0xfce36d58
  16:	5b                   	pop    %rbx
  17:	5d                   	pop    %rbp
  18:	c3                   	ret
  19:	cc                   	int3
  1a:	cc                   	int3
  1b:	cc                   	int3
  1c:	cc                   	int3
  1d:	e8 36 6d e3 fc       	call   0xfce36d58
  22:	48 8d 3d cf 53 28 0c 	lea    0xc2853cf(%rip),%rdi        # 0xc2853f8
* 29:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2e:	e8 25 6d e3 fc       	call   0xfce36d58
  33:	5b                   	pop    %rbx
  34:	5d                   	pop    %rbp
  35:	e9 ce 8f a8 06       	jmp    0x6a89008
  3a:	48 89 df             	mov    %rbx,%rdi
  3d:	e8                   	.byte 0xe8
  3e:	46                   	rex.RX


---
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