From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ot1-f78.google.com (mail-ot1-f78.google.com [209.85.210.78]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EFDF2331209 for ; Tue, 31 Mar 2026 19:19:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.78 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774984767; cv=none; b=oHdsxsEGh6z5M/BcSiF1iIC3gvx8lKqJi2xTF4ewejpko2xgGJByi2Imu2eQ1HIxF7WW0GxZndN/OocQQKBJgXKd9tcLAiZkrKevC0Eyjz8YdExr0W7AC01HbU09c8bVowX0aNmLJfVSsVtJwn+6ItDfoDsZaGoNNsAN511wlCY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774984767; c=relaxed/simple; bh=gaIZJecD7ma60cDpNZKqVnMxQqcmWQuqpTGy/dbBo44=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=X3YVp8cmqj13qKpngatbZ3ZIwDziSSQFnbJbG8hGJWg3K/2VKNHQ9NCakDdVsjjW8zDM/gx6l1wZfOGCEUt2nCLRSUs/UwuI3ze6HK1XKRCPrb3KibIlEv6m0vwGD2UD3/VSBvlG6hhL8hD/u3qB4bqoMpfz1jdmj704+UQ5ioU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=209.85.210.78 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-ot1-f78.google.com with SMTP id 46e09a7af769-7d7510702e6so16794325a34.3 for ; Tue, 31 Mar 2026 12:19:25 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1774984765; x=1775589565; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=LY/R9mURx+pPbug2NJHiluq/tfa+Bf+Yd4kZ80ndOrQ=; b=qiIddjHJJB/O8eMBStmQkquklbmwARcSSgG8SGbvfyn6DLATalMUuZ06Bs90lBXIaX 2wwce5TI3pwStfaJ5f1sUPv3CRgC8jvfG0GDRmkCJlPWItstXKV60GlScdDAEgLNoNw2 n/nDRVQQwIp5HjxwoM4C4LKtxaJl2duSCe+RcQueOuDEQ/VW9OtJGNwp2QG/92yRyAEW YpuUNirOtl+BLeIzlB64yPQM6C9UPU1BtGa2dAEI3d8cK0aB+J5/ii0uebfcCih51BHF xMbyFM/5LRzYvaJRRKSU1yy6WbDcHLOv/sgwv5bLNgKVSkC1HtYpxPlC/rhc38r7/f1z H8XA== X-Forwarded-Encrypted: i=1; AJvYcCUdTW9LuKlTnCQLbqInxU6S4F6v/o5WMWMUMKQeevy23nFAzHsSqbclB5G8Bj+SXRgnl4OPvkQ=@vger.kernel.org X-Gm-Message-State: AOJu0Yz0mGd1BS1S68fx9QXc+s5cFfyzpmUgJxvX4NIWW3+ewzyGNwqa nWX1nbQXtGFayoZGaRBm6AmGmbNS64tpFBRLmNsUO9B52TbywybEd5H6R1qUDye6hps49rJeQ1z g3xoJGw+LhHgHy38MSJ9WclNgupe/JERIguofWPcgf/5AtmRA/YQacAQL0y8= Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:4b90:b0:67e:438d:f688 with SMTP id 006d021491bc7-67fabd020f3mr273884eaf.49.1774984764934; Tue, 31 Mar 2026 12:19:24 -0700 (PDT) Date: Tue, 31 Mar 2026 12:19:24 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <69cc1e3c.050a0220.183828.0031.GAE@google.com> Subject: [syzbot] [hams?] KASAN: slab-use-after-free Read in ax25cmp (2) From: syzbot To: davem@davemloft.net, edumazet@google.com, horms@kernel.org, kuba@kernel.org, linux-hams@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, pabeni@redhat.com, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 7aaa8047eafd Linux 7.0-rc6 git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=11f71a48580000 kernel config: https://syzkaller.appspot.com/x/.config?x=5a3e5e8c17cc174e dashboard link: https://syzkaller.appspot.com/bug?extid=abd2b69348e2d9b107a1 compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/4e96235a659c/disk-7aaa8047.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/2dbf138efd1a/vmlinux-7aaa8047.xz kernel image: https://storage.googleapis.com/syzbot-assets/c0528de45bad/bzImage-7aaa8047.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+abd2b69348e2d9b107a1@syzkaller.appspotmail.com ================================================================== BUG: KASAN: slab-use-after-free in ax25cmp+0x17b/0x1d0 net/ax25/ax25_addr.c:119 Read of size 1 at addr ffff8880589bdc08 by task syz-executor/30916 CPU: 1 UID: 0 PID: 30916 Comm: syz-executor Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x156/0x4c9 mm/kasan/report.c:482 kasan_report+0xdf/0x1e0 mm/kasan/report.c:595 ax25cmp+0x17b/0x1d0 net/ax25/ax25_addr.c:119 ax25_find_cb+0x142/0x410 net/ax25/af_ax25.c:236 ax25_send_frame+0x157/0xb70 net/ax25/ax25_out.c:55 rose_send_frame+0xfa/0x2a0 net/rose/rose_link.c:106 rose_transmit_restart_request+0x1b8/0x250 net/rose/rose_link.c:198 rose_t0timer_expiry+0x1d/0x150 net/rose/rose_link.c:83 call_timer_fn+0x19a/0x670 kernel/time/timer.c:1748 expire_timers kernel/time/timer.c:1799 [inline] __run_timers+0x757/0xb30 kernel/time/timer.c:2373 __run_timer_base kernel/time/timer.c:2385 [inline] __run_timer_base kernel/time/timer.c:2377 [inline] run_timer_base+0x114/0x190 kernel/time/timer.c:2394 run_timer_softirq+0x1a/0x50 kernel/time/timer.c:2404 handle_softirqs+0x1eb/0x9e0 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0xef/0x150 kernel/softirq.c:723 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline] sysvec_apic_timer_interrupt+0xa3/0xc0 arch/x86/kernel/apic/apic.c:1056 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:preempt_schedule_irq+0x4b/0x90 kernel/sched/core.c:7238 Code: 00 00 00 fc ff df 48 89 eb 48 c1 eb 03 48 01 d3 f6 c4 02 75 47 bf 01 00 00 00 e8 80 b8 43 f6 e8 3b ce 7e f6 fb bf 01 00 00 00 e0 96 ff ff 9c 58 fa f6 c4 02 75 1e bf 01 00 00 00 e8 9e 56 43 RSP: 0018:ffffc90002ea7838 EFLAGS: 00000202 RAX: 0000000000051bfd RBX: ffffed101344f000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff8de79d93 RDI: 0000000000000001 RBP: ffff88809a278000 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 irqentry_exit+0x17b/0x670 kernel/entry/common.c:239 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_acquire+0x5e/0x380 kernel/locking/lockdep.c:5872 Code: 05 bb 36 29 12 83 f8 07 0f 87 f0 00 00 00 48 0f a3 05 86 bc f4 0e 0f 82 c2 02 00 00 8b 35 6e f0 f4 0e 85 f6 0f 85 dd 00 00 00 <48> 8b 44 24 30 65 48 2b 05 5d 36 29 12 0f 85 02 03 00 00 48 83 c4 RSP: 0018:ffffc90002ea7938 EFLAGS: 00000206 RAX: 0000000000000046 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff8de53c03 RDI: ffffffff8c1b1a20 RBP: ffffffff8e7e7920 R08: 0000000086db7919 R09: 0000000000000007 R10: 0000000000000200 R11: 0000000000000000 R12: 0000000000000002 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:312 [inline] rcu_read_lock include/linux/rcupdate.h:850 [inline] class_rcu_constructor include/linux/rcupdate.h:1193 [inline] unwind_next_frame+0xd1/0x1ea0 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4538 [inline] slab_alloc_node mm/slub.c:4866 [inline] kmem_cache_alloc_noprof+0x241/0x6e0 mm/slub.c:4873 alloc_filename fs/namei.c:142 [inline] do_getname+0x35/0x390 fs/namei.c:182 getname_flags fs/namei.c:225 [inline] class_filename_flags_constructor include/linux/fs.h:2541 [inline] user_path_at+0x26/0x60 fs/namei.c:3617 ksys_umount fs/namespace.c:2062 [inline] __do_sys_umount fs/namespace.c:2070 [inline] __se_sys_umount fs/namespace.c:2068 [inline] __x64_sys_umount+0x10a/0x1a0 fs/namespace.c:2068 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f502359da57 Code: a2 c7 05 9c fc 24 00 00 00 00 00 eb 96 e8 e1 12 00 00 90 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8 RSP: 002b:00007ffc8bc59ed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: ffffffffffffffda RBX: 00007f5023632048 RCX: 00007f502359da57 RDX: 0000000000000004 RSI: 0000000000000009 RDI: 00007ffc8bc5b020 RBP: 00007ffc8bc5b00c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffc8bc5b020 R13: 00007f5023632048 R14: 00000000001c31ca R15: 00007ffc8bc5b060 Allocated by task 15931: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415 kmalloc_noprof include/linux/slab.h:950 [inline] rose_add_node net/rose/rose_route.c:85 [inline] rose_rt_ioctl+0x586/0x2550 net/rose/rose_route.c:748 rose_ioctl+0x491/0x7d0 net/rose/af_rose.c:1387 sock_do_ioctl+0x118/0x280 net/socket.c:1254 sock_ioctl+0x599/0x6b0 net/socket.c:1375 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 31660: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2685 [inline] slab_free mm/slub.c:6165 [inline] kfree+0x1f6/0x6b0 mm/slub.c:6483 rose_neigh_put include/net/rose.h:166 [inline] rose_timer_expiry+0x53f/0x630 net/rose/rose_timer.c:183 call_timer_fn+0x19a/0x670 kernel/time/timer.c:1748 expire_timers kernel/time/timer.c:1799 [inline] __run_timers+0x757/0xb30 kernel/time/timer.c:2373 __run_timer_base kernel/time/timer.c:2385 [inline] __run_timer_base kernel/time/timer.c:2377 [inline] run_timer_base+0x114/0x190 kernel/time/timer.c:2394 run_timer_softirq+0x1a/0x50 kernel/time/timer.c:2404 handle_softirqs+0x1eb/0x9e0 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0xef/0x150 kernel/softirq.c:723 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline] sysvec_apic_timer_interrupt+0xa3/0xc0 arch/x86/kernel/apic/apic.c:1056 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 The buggy address belongs to the object at ffff8880589bdc00 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 8 bytes inside of freed 512-byte region [ffff8880589bdc00, ffff8880589bde00) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff8880589bf400 pfn:0x589bc head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000240(workingset|head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000240 ffff88813fe40c80 ffffea0001f2ac10 ffffea0001e4cd10 raw: ffff8880589bf400 000000080010000d 00000000f5000000 0000000000000000 head: 00fff00000000240 ffff88813fe40c80 ffffea0001f2ac10 ffffea0001e4cd10 head: ffff8880589bf400 000000080010000d 00000000f5000000 0000000000000000 head: 00fff00000000002 ffffea0001626f01 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000004 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5819, tgid 5819 (syz-executor), ts 63017728292, free_ts 14412109844 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x153/0x170 mm/page_alloc.c:1889 prep_new_page mm/page_alloc.c:1897 [inline] get_page_from_freelist+0x111d/0x3140 mm/page_alloc.c:3962 __alloc_frozen_pages_noprof+0x27c/0x2ba0 mm/page_alloc.c:5250 alloc_slab_page mm/slub.c:3292 [inline] allocate_slab mm/slub.c:3481 [inline] new_slab+0xa6/0x6b0 mm/slub.c:3539 refill_objects+0x26b/0x400 mm/slub.c:7175 refill_sheaf mm/slub.c:2812 [inline] __pcs_replace_empty_main+0x1ab/0x660 mm/slub.c:4615 alloc_from_pcs mm/slub.c:4717 [inline] slab_alloc_node mm/slub.c:4851 [inline] __kmalloc_cache_noprof+0x493/0x6f0 mm/slub.c:5375 kmalloc_noprof include/linux/slab.h:950 [inline] kzalloc_noprof include/linux/slab.h:1188 [inline] mca_alloc net/ipv6/mcast.c:871 [inline] __ipv6_dev_mc_inc+0x2f1/0xbc0 net/ipv6/mcast.c:961 ipv6_add_dev+0xb78/0x1520 net/ipv6/addrconf.c:471 addrconf_notify+0x563/0x19c0 net/ipv6/addrconf.c:3654 notifier_call_chain+0x99/0x420 kernel/notifier.c:85 call_netdevice_notifiers_info+0xbe/0x110 net/core/dev.c:2249 call_netdevice_notifiers_extack net/core/dev.c:2287 [inline] call_netdevice_notifiers net/core/dev.c:2301 [inline] register_netdevice+0x16e6/0x2210 net/core/dev.c:11474 veth_newlink+0x44a/0xa00 drivers/net/veth.c:1889 rtnl_newlink_create net/core/rtnetlink.c:3862 [inline] __rtnl_newlink net/core/rtnetlink.c:3979 [inline] rtnl_newlink+0x1494/0x2380 net/core/rtnetlink.c:4094 rtnetlink_rcv_msg+0x95e/0xe90 net/core/rtnetlink.c:6980 page last free pid 1 tgid 1 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1433 [inline] __free_frozen_pages+0x7e1/0x10d0 mm/page_alloc.c:2978 __free_pages mm/page_alloc.c:5369 [inline] free_contig_range+0xde/0x1d0 mm/page_alloc.c:7374 debug_vm_pgtable_free_huge_page mm/debug_vm_pgtable.c:980 [inline] destroy_args+0xa8/0x7a0 mm/debug_vm_pgtable.c:993 debug_vm_pgtable+0x1b66/0x34c0 mm/debug_vm_pgtable.c:1368 do_one_initcall+0x11d/0x760 init/main.c:1382 do_initcall_level init/main.c:1444 [inline] do_initcalls init/main.c:1460 [inline] do_basic_setup init/main.c:1479 [inline] kernel_init_freeable+0x6e5/0x7a0 init/main.c:1692 kernel_init+0x1f/0x1e0 init/main.c:1582 ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Memory state around the buggy address: ffff8880589bdb00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880589bdb80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8880589bdc00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880589bdc80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880589bdd00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== ---------------- Code disassembly (best guess): 0: 00 00 add %al,(%rax) 2: 00 fc add %bh,%ah 4: ff lcall (bad) 5: df 48 89 fisttps -0x77(%rax) 8: eb 48 jmp 0x52 a: c1 eb 03 shr $0x3,%ebx d: 48 01 d3 add %rdx,%rbx 10: f6 c4 02 test $0x2,%ah 13: 75 47 jne 0x5c 15: bf 01 00 00 00 mov $0x1,%edi 1a: e8 80 b8 43 f6 call 0xf643b89f 1f: e8 3b ce 7e f6 call 0xf67ece5f 24: fb sti 25: bf 01 00 00 00 mov $0x1,%edi * 2a: e8 e0 96 ff ff call 0xffff970f <-- trapping instruction 2f: 9c pushf 30: 58 pop %rax 31: fa cli 32: f6 c4 02 test $0x2,%ah 35: 75 1e jne 0x55 37: bf 01 00 00 00 mov $0x1,%edi 3c: e8 .byte 0xe8 3d: 9e sahf 3e: 56 push %rsi 3f: 43 rex.XB --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup