KASAN: use-after-free Read in uea_upload_pre_firmware

Status: upstream: reported C repro on 2026/07/26 07:02
Reported-by: syzbot+0e1162200a0f6516ee37@syzkaller.appspotmail.com
Fix commit: f92832262718 usb: atm: ueagle-atm: reject descriptors that confuse probe and disconnect
Patched on: [ci2-linux-5-15-kasan ci2-linux-5-15-kasan-perf], missing on: [ci2-linux-5-15-kasan-arm64]
First crash: 69d, last: 49d
Fix bisection: fixed by (bisect log) :
commit f92832262718443feb4e5df2bf70424ba842629e
Author: Diego Fernando Mancera Gomez <diegomancera.dev@gmail.com>
Date: Fri Jul 17 08:07:04 2026 +0000

  usb: atm: ueagle-atm: reject descriptors that confuse probe and disconnect

  
▶ ▼ Bug presence (1)
Date Name Commit Repro Result
2026/09/05 upstream (ToT) 0d9ff90a5422 C Failed due to an error; will retry later
▶ ▼ Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 KASAN: use-after-free Read in uea_upload_pre_firmware 19 syz, C error 2 69d 69d 0/3 upstream: reported C repro on 2026/07/26 08:23
upstream KASAN: slab-use-after-free Read in uea_upload_pre_firmware prio:high usb 19 syz, C error 76 55d 96d 0/29 upstream: reported C repro on 2026/06/29 21:09

Sample crash report:
==================================================================
BUG: KASAN: use-after-free in interface_to_usbdev include/linux/usb.h:719 [inline]
BUG: KASAN: use-after-free in uea_upload_pre_firmware+0x89/0x7c0 drivers/usb/atm/ueagle-atm.c:603
Read of size 8 at addr ffff888074b23070 by task kworker/0:14/4922

CPU: 0 PID: 4922 Comm: kworker/0:14 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: events request_firmware_work_func
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 print_address_description+0x60/0x2d0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0xdf/0x130 mm/kasan/report.c:451
 interface_to_usbdev include/linux/usb.h:719 [inline]
 uea_upload_pre_firmware+0x89/0x7c0 drivers/usb/atm/ueagle-atm.c:603
 request_firmware_work_func+0xe8/0x1a0 drivers/base/firmware_loader/main.c:1129
 process_one_work+0x867/0xff0 kernel/workqueue.c:2310
 worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>

Allocated by task 4231:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:434 [inline]
 ____kasan_kmalloc mm/kasan/common.c:513 [inline]
 __kasan_kmalloc+0xaf/0xe0 mm/kasan/common.c:522
 kmalloc include/linux/slab.h:607 [inline]
 kzalloc include/linux/slab.h:738 [inline]
 usb_set_configuration+0x3b6/0x2030 drivers/usb/core/message.c:2051
 usb_generic_driver_probe+0x89/0x150 drivers/usb/core/generic.c:238
 usb_probe_device+0x126/0x250 drivers/usb/core/driver.c:293
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x276/0xc70 drivers/base/dd.c:595
 __driver_probe_device+0x1f5/0x390 drivers/base/dd.c:775
 driver_probe_device+0x4f/0x420 drivers/base/dd.c:805
 __device_attach_driver+0x2b0/0x500 drivers/base/dd.c:927
 bus_for_each_drv+0x184/0x210 drivers/base/bus.c:429
 __device_attach+0x2a7/0x480 drivers/base/dd.c:999
 bus_probe_device+0xba/0x1d0 drivers/base/bus.c:489
 device_add+0xbcf/0x1050 drivers/base/core.c:3427
 usb_new_device+0x9f6/0x15d0 drivers/usb/core/hub.c:2632
 hub_port_connect drivers/usb/core/hub.c:5497 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5637 [inline]
 port_event drivers/usb/core/hub.c:5799 [inline]
 hub_event+0x2b8d/0x5260 drivers/usb/core/hub.c:5881
 process_one_work+0x867/0xff0 kernel/workqueue.c:2310
 worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

Freed by task 4231:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:46
 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360
 ____kasan_slab_free+0xd5/0x110 mm/kasan/common.c:366
 kasan_slab_free include/linux/kasan.h:230 [inline]
 slab_free_hook mm/slub.c:1710 [inline]
 slab_free_freelist_hook+0xec/0x170 mm/slub.c:1736
 slab_free mm/slub.c:3504 [inline]
 kfree+0xef/0x2a0 mm/slub.c:4564
 device_release+0x92/0x1c0 drivers/base/core.c:-1
 kobject_cleanup lib/kobject.c:713 [inline]
 kobject_release lib/kobject.c:744 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x217/0x450 lib/kobject.c:761
 usb_disable_device+0x612/0x8a0 drivers/usb/core/message.c:1479
 usb_disconnect+0x33c/0x8a0 drivers/usb/core/hub.c:2287
 hub_port_connect drivers/usb/core/hub.c:5341 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5637 [inline]
 port_event drivers/usb/core/hub.c:5799 [inline]
 hub_event+0x1d64/0x5260 drivers/usb/core/hub.c:5881
 process_one_work+0x867/0xff0 kernel/workqueue.c:2310
 process_scheduled_works kernel/workqueue.c:2373 [inline]
 worker_thread+0xd93/0x12a0 kernel/workqueue.c:2459
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

Last potentially related work creation:
 kasan_save_stack+0x35/0x60 mm/kasan/common.c:38
 kasan_record_aux_stack+0xb8/0x100 mm/kasan/generic.c:348
 __call_rcu kernel/rcu/tree.c:3011 [inline]
 call_rcu+0x189/0x900 kernel/rcu/tree.c:3091
 qdisc_put net/sched/sch_generic.c:1047 [inline]
 shutdown_scheduler_queue net/sched/sch_generic.c:1100 [inline]
 netdev_for_each_tx_queue include/linux/netdevice.h:2388 [inline]
 dev_shutdown+0x19e/0x700 net/sched/sch_generic.c:1408
 unregister_netdevice_many+0xa59/0x1a40 net/core/dev.c:11153
 ieee80211_remove_interfaces+0x44b/0x700 net/mac80211/iface.c:2160
 ieee80211_unregister_hw+0x55/0x220 net/mac80211/main.c:1400
 mac80211_hwsim_del_radio+0x282/0x470 drivers/net/wireless/mac80211_hwsim.c:3472
 hwsim_exit_net+0x589/0x650 drivers/net/wireless/mac80211_hwsim.c:4242
 ops_exit_list net/core/net_namespace.c:172 [inline]
 cleanup_net+0x703/0xba0 net/core/net_namespace.c:635
 process_one_work+0x867/0xff0 kernel/workqueue.c:2310
 worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

Second to last potentially related work creation:
 kasan_save_stack+0x35/0x60 mm/kasan/common.c:38
 kasan_record_aux_stack+0xb8/0x100 mm/kasan/generic.c:348
 kvfree_call_rcu+0x105/0x7f0 kernel/rcu/tree.c:3600
 drop_sysctl_table+0x359/0x4e0 fs/proc/proc_sysctl.c:1685
 unregister_sysctl_table+0x87/0x130 fs/proc/proc_sysctl.c:1723
 __devinet_sysctl_unregister net/ipv4/devinet.c:2626 [inline]
 devinet_exit_net+0xe2/0x220 net/ipv4/devinet.c:2769
 ops_exit_list net/core/net_namespace.c:172 [inline]
 cleanup_net+0x703/0xba0 net/core/net_namespace.c:635
 process_one_work+0x867/0xff0 kernel/workqueue.c:2310
 worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

The buggy address belongs to the object at ffff888074b23000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 112 bytes inside of
 2048-byte region [ffff888074b23000, ffff888074b23800)
The buggy address belongs to the page:
page:ffffea0001d2c800 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x74b20
head:ffffea0001d2c800 order:3 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 ffffea0001993400 0000000300000003 ffff888016c42000
raw: 0000000000000000 0000000000080008 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 4189, ts 63631493176, free_ts 63629778276
 prep_new_page mm/page_alloc.c:2426 [inline]
 get_page_from_freelist+0x24f6/0x2670 mm/page_alloc.c:4192
 __alloc_pages+0x1ee/0x480 mm/page_alloc.c:5501
 alloc_slab_page mm/slub.c:1780 [inline]
 allocate_slab mm/slub.c:1917 [inline]
 new_slab+0xc0/0x4b0 mm/slub.c:1980
 ___slab_alloc+0x807/0xdd0 mm/slub.c:3013
 __slab_alloc mm/slub.c:3100 [inline]
 slab_alloc_node mm/slub.c:3191 [inline]
 slab_alloc mm/slub.c:3233 [inline]
 kmem_cache_alloc_trace+0xf9/0x290 mm/slub.c:3250
 kmalloc include/linux/slab.h:607 [inline]
 kmalloc_array include/linux/slab.h:646 [inline]
 netdev_create_hash net/core/dev.c:11470 [inline]
 netdev_init+0x103/0x1f0 net/core/dev.c:11490
 ops_init+0x360/0x5f0 net/core/net_namespace.c:138
 setup_net+0x39e/0xa10 net/core/net_namespace.c:333
 copy_net_ns+0x33e/0x5b0 net/core/net_namespace.c:503
 create_new_namespaces+0x3ce/0x700 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0x116/0x160 kernel/nsproxy.c:226
 ksys_unshare+0x4f6/0x8e0 kernel/fork.c:3177
 __do_sys_unshare kernel/fork.c:3254 [inline]
 __se_sys_unshare kernel/fork.c:3252 [inline]
 __x64_sys_unshare+0x34/0x40 kernel/fork.c:3252
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1340 [inline]
 free_pcp_prepare mm/page_alloc.c:1391 [inline]
 free_unref_page_prepare+0x637/0x6c0 mm/page_alloc.c:3317
 free_unref_page+0x8f/0x2a0 mm/page_alloc.c:3396
 free_nonslab_page+0xde/0x150 mm/slub.c:3540
 skb_free_head net/core/skbuff.c:655 [inline]
 skb_release_data+0x667/0x830 net/core/skbuff.c:677
 skb_release_all net/core/skbuff.c:742 [inline]
 __kfree_skb net/core/skbuff.c:756 [inline]
 consume_skb+0xa2/0x100 net/core/skbuff.c:914
 skb_free_datagram+0x25/0xe0 net/core/datagram.c:325
 netlink_recvmsg+0x5dd/0xe50 net/netlink/af_netlink.c:1998
 ____sys_recvmsg+0x2ca/0x5b0 net/socket.c:-1
 ___sys_recvmsg+0x213/0x5c0 net/socket.c:2707
 __sys_recvmsg net/socket.c:2737 [inline]
 __do_sys_recvmsg net/socket.c:2747 [inline]
 __se_sys_recvmsg net/socket.c:2744 [inline]
 __x64_sys_recvmsg+0x201/0x2d0 net/socket.c:2744
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

Memory state around the buggy address:
 ffff888074b22f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888074b22f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888074b23000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                             ^
 ffff888074b23080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888074b23100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/14 22:10 linux-5.15.y aabd761612db 6f9b3e89 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in uea_upload_pre_firmware
2026/07/26 11:55 linux-5.15.y 674f684f7c61 492bab15 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in uea_upload_pre_firmware
2026/07/26 07:01 linux-5.15.y 674f684f7c61 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in uea_upload_pre_firmware
* Struck through repros no longer work on HEAD.