KASAN: slab-use-after-free Read in disable_device

Status: upstream: reported on 2026/08/17 02:58
Subsystems: kernel
Labels: prio:high actionable
[Documentation on labels]
Reported-by: syzbot+4393dfdddf166f2de2b0@syzkaller.appspotmail.com
First crash: 16d, last: 1h26m
▶ ▼ ✨ AI Jobs (2)
ID Workflow Result Correct Bug Created Started Finished Revision
ae15561f moderation Actionable: ✅ ❓ KASAN: slab-use-after-free Read in disable_device 2026/08/17 02:15 2026/08/17 02:15 2026/08/17 02:57 746171ee
3d0cefb4 assessment-security DenialOfService: ✅ Exploitable: ✅ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ✅ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ KASAN: slab-use-after-free Read in disable_device 2026/08/14 00:12 2026/08/14 00:12 2026/08/14 00:17 0165196a
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Title Replies (including bot) Last reply
[syzbot] [kernel?] KASAN: slab-use-after-free Read in disable_device 0 (1) 2026/08/17 02:58

Sample crash report:
==================================================================
BUG: KASAN: slab-use-after-free in kobject_uevent_net_broadcast lib/kobject_uevent.c:415 [inline]
BUG: KASAN: slab-use-after-free in kobject_uevent_env+0x1383/0x18b0 lib/kobject_uevent.c:611
Read of size 8 at addr ffff88802a8e74d0 by task syz.3.532/8608

CPU: 0 UID: 0 PID: 8608 Comm: syz.3.532 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
Call Trace:
 <TASK>
 __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+0x13d/0x4b0 mm/kasan/report.c:482
 kasan_report+0xdf/0x1c0 mm/kasan/report.c:595
 kobject_uevent_net_broadcast lib/kobject_uevent.c:415 [inline]
 kobject_uevent_env+0x1383/0x18b0 lib/kobject_uevent.c:611
 device_del+0x605/0x9b0 drivers/base/core.c:3983
 remove_one_compat_dev drivers/infiniband/core/device.c:1036 [inline]
 remove_compat_devs drivers/infiniband/core/device.c:1047 [inline]
 disable_device+0x1ea/0x280 drivers/infiniband/core/device.c:1339
 __ib_unregister_device+0x2b4/0x480 drivers/infiniband/core/device.c:1571
 ib_unregister_device_and_put+0x5a/0x80 drivers/infiniband/core/device.c:1636
 nldev_dellink+0x308/0x440 drivers/infiniband/core/nldev.c:1902
 rdma_nl_rcv_msg+0x392/0x6f0 drivers/infiniband/core/netlink.c:195
 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: 0023:0xf7f33fec
Code: Unable to access opcode bytes at 0xf7f33fc2.
RSP: 002b:00000000f53b050c EFLAGS: 00000292 ORIG_RAX: 0000000000000172
RAX: ffffffffffffffda RBX: 000000000000000b RCX: 00000000800002c0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000292 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>

Allocated by task 8595:
 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
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __kmalloc_cache_noprof+0x2e7/0x6b0 mm/slub.c:5484
 _kmalloc_noprof include/linux/slab.h:988 [inline]
 _kzalloc_noprof include/linux/slab.h:1309 [inline]
 uevent_net_init+0xd3/0x330 lib/kobject_uevent.c:782
 ops_init+0x1e2/0x5f0 net/core/net_namespace.c:137
 setup_net+0x118/0x3a0 net/core/net_namespace.c:450
 copy_net_ns+0x46f/0x7c0 net/core/net_namespace.c:583
 create_new_namespaces+0x3ea/0xac0 kernel/nsproxy.c:132
 unshare_nsproxy_namespaces+0xf2/0x220 kernel/nsproxy.c:234
 ksys_unshare+0x4a2/0xa70 kernel/fork.c:3292
 __do_sys_unshare kernel/fork.c:3356 [inline]
 __se_sys_unshare kernel/fork.c:3354 [inline]
 __ia32_sys_unshare+0x30/0x40 kernel/fork.c:3354
 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

Freed by task 5784:
 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:2678 [inline]
 slab_free mm/slub.c:6372 [inline]
 kfree+0x22b/0x6c0 mm/slub.c:6687
 ops_exit_list net/core/net_namespace.c:200 [inline]
 ops_undo_list+0x2ee/0xab0 net/core/net_namespace.c:253
 cleanup_net+0x499/0x920 net/core/net_namespace.c:706
 process_one_work+0xac7/0x1b10 kernel/workqueue.c:3387
 process_scheduled_works kernel/workqueue.c:3470 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3551
 kthread+0x373/0x450 kernel/kthread.c:436
 ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

The buggy address belongs to the object at ffff88802a8e74c0
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 16 bytes inside of
 freed 32-byte region [ffff88802a8e74c0, ffff88802a8e74e0)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2a8e7
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000000 ffff88801c042780 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800400040 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2800(GFP_NOWAIT|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5874, tgid 5874 (modprobe), ts 49992942403
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1871
 prep_new_page mm/page_alloc.c:1879 [inline]
 get_page_from_freelist+0x110d/0x35b0 mm/page_alloc.c:3943
 __alloc_frozen_pages_noprof+0x2eb/0x3300 mm/page_alloc.c:5436
 alloc_slab_page mm/slub.c:3267 [inline]
 allocate_slab mm/slub.c:3382 [inline]
 new_slab+0xa5/0x640 mm/slub.c:3428
 refill_objects+0xe3/0x410 mm/slub.c:7305
 refill_sheaf mm/slub.c:2805 [inline]
 __pcs_replace_empty_main+0x372/0x680 mm/slub.c:4677
 alloc_from_pcs mm/slub.c:4775 [inline]
 slab_alloc_node mm/slub.c:4907 [inline]
 __kmalloc_cache_noprof+0x47b/0x6b0 mm/slub.c:5480
 _kmalloc_noprof include/linux/slab.h:988 [inline]
 slab_free_hook mm/slub.c:2630 [inline]
 slab_free mm/slub.c:6372 [inline]
 kmem_cache_free+0x40f/0x6b0 mm/slub.c:6499
 tear_down_vmas+0x2a5/0x610 mm/mmap.c:1277
 exit_mmap+0x469/0xa00 mm/mmap.c:1335
 __mmput+0x12a/0x410 kernel/fork.c:1193
 mmput+0x67/0x80 kernel/fork.c:1216
 exit_mm kernel/exit.c:614 [inline]
 do_exit+0x8b1/0x2ae0 kernel/exit.c:996
 do_group_exit+0xd5/0x2a0 kernel/exit.c:1151
 __do_sys_exit_group kernel/exit.c:1162 [inline]
 __se_sys_exit_group kernel/exit.c:1160 [inline]
 __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1160
 x64_sys_call+0x1567/0x1570 arch/x86/include/generated/asm/syscalls_64.h:232
page last free pid 5874 tgid 5874 ts 49992308151 stack trace:
 reset_page_owner include/linux/page_owner.h:26 [inline]
 __free_pages_prepare mm/page_alloc.c:1418 [inline]
 __free_frozen_pages+0x79f/0x10f0 mm/page_alloc.c:2962
 tlb_batch_list_free mm/mmu_gather.c:161 [inline]
 tlb_finish_mmu+0x27d/0x810 mm/mmu_gather.c:552
 exit_mmap+0x454/0xa00 mm/mmap.c:1328
 __mmput+0x12a/0x410 kernel/fork.c:1193
 mmput+0x67/0x80 kernel/fork.c:1216
 exit_mm kernel/exit.c:614 [inline]
 do_exit+0x8b1/0x2ae0 kernel/exit.c:996
 do_group_exit+0xd5/0x2a0 kernel/exit.c:1151
 __do_sys_exit_group kernel/exit.c:1162 [inline]
 __se_sys_exit_group kernel/exit.c:1160 [inline]
 __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1160
 x64_sys_call+0x1567/0x1570 arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x121/0x770 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff88802a8e7380: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
 ffff88802a8e7400: fa fb fb fb fc fc fc fc 00 00 00 00 fc fc fc fc
>ffff88802a8e7480: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
                                                 ^
 ffff88802a8e7500: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
 ffff88802a8e7580: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
==================================================================

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/24 11:18 upstream 0a0d1d55dad5 b55bd4c3 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: slab-use-after-free Read in disable_device
2026/08/29 11:15 net-next 1b78070aaef6 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce KASAN: slab-use-after-free Read in disable_device
2026/08/24 21:10 linux-next 4b18edbd8e70 23caa175 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce KASAN: slab-use-after-free Read in disable_device
2026/08/12 13:46 linux-next 5e6de6a2b522 7ae4acc7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root KASAN: slab-use-after-free Read in disable_device
* Struck through repros no longer work on HEAD.