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

Status: upstream: reported on 2026/10/28 09:46
Reported-by: syzbot+f529db1ba499cdf141d7@syzkaller.appspotmail.com
First crash: 2d14h, last: 2d14h
▶ ▼ Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: slab-use-after-free Read in gadget_dev_open prio:normal usb 19 syz, C unreliable 257 22m 91d 0/29 upstream: reported C repro on 2026/07/31 06:03
linux-6.1 KASAN: use-after-free Read in gadget_dev_open origin:lts-only 19 syz, C 26 7d21h 66d 0/3 upstream: reported C repro on 2026/08/25 18:30

Sample crash report:
==================================================================
BUG: KASAN: slab-use-after-free in __lock_acquire+0x10d/0x7eb0 kernel/locking/lockdep.c:5036
Read of size 8 at addr ffff88802231c818 by task syz.3.1520/12079

CPU: 0 PID: 12079 Comm: syz.3.1520 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:364 [inline]
 print_report+0xa8/0x210 mm/kasan/report.c:468
 kasan_report+0x117/0x150 mm/kasan/report.c:581
 __lock_acquire+0x10d/0x7eb0 kernel/locking/lockdep.c:5036
 lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5790
 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:119 [inline]
 _raw_spin_lock_irq+0xaf/0xf0 kernel/locking/spinlock.c:170
 spin_lock_irq include/linux/spinlock.h:376 [inline]
 gadget_dev_open+0x4b/0x1b0 drivers/usb/gadget/legacy/inode.c:1910
 do_dentry_open+0x880/0x14b0 fs/open.c:929
 do_open fs/namei.c:3695 [inline]
 path_openat+0x284f/0x3270 fs/namei.c:3856
 do_filp_open+0x1f2/0x430 fs/namei.c:3883
 do_sys_openat2+0x134/0x1d0 fs/open.c:1422
 do_sys_open fs/open.c:1437 [inline]
 __do_sys_openat fs/open.c:1453 [inline]
 __se_sys_openat fs/open.c:1448 [inline]
 __x64_sys_openat+0x139/0x160 fs/open.c:1448
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f4ae2d9f559
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f4ae3d45028 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f4ae3025fa0 RCX: 00007f4ae2d9f559
RDX: 0000000000000002 RSI: 0000200000000180 RDI: ffffffffffffff9c
RBP: 00007f4ae2e36b20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000084 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4ae3026038 R14: 00007f4ae3025fa0 R15: 00007ffc192f3928
 </TASK>

Allocated by task 12:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:53
 ____kasan_kmalloc mm/kasan/common.c:375 [inline]
 __kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:384
 kasan_kmalloc include/linux/kasan.h:198 [inline]
 __do_kmalloc_node mm/slab_common.c:1007 [inline]
 __kmalloc+0xb7/0x240 mm/slab_common.c:1020
 kmalloc include/linux/slab.h:604 [inline]
 kzalloc include/linux/slab.h:721 [inline]
 ieee802_11_parse_elems_full+0xb9/0x20f0 net/mac80211/util.c:1616
 ieee802_11_parse_elems_crc net/mac80211/ieee80211_i.h:2342 [inline]
 ieee802_11_parse_elems net/mac80211/ieee80211_i.h:2349 [inline]
 ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1608 [inline]
 ieee80211_ibss_rx_queued_mgmt+0x4b7/0x2dc0 net/mac80211/ibss.c:1641
 ieee80211_iface_process_skb net/mac80211/iface.c:1690 [inline]
 ieee80211_iface_work+0x730/0xc90 net/mac80211/iface.c:1744
 cfg80211_wiphy_work+0x228/0x260 net/wireless/core.c:444
 process_one_work kernel/workqueue.c:2657 [inline]
 process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2734
 worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2815
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293

Freed by task 12:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:53
 kasan_save_free_info+0x28/0x40 mm/kasan/generic.c:522
 ____kasan_slab_free+0x126/0x1f0 mm/kasan/common.c:237
 kasan_slab_free include/linux/kasan.h:164 [inline]
 slab_free_hook mm/slub.c:1833 [inline]
 slab_free_freelist_hook+0x154/0x240 mm/slub.c:1859
 slab_free mm/slub.c:3853 [inline]
 __kmem_cache_free+0xba/0x1f0 mm/slub.c:3866
 ieee80211_ibss_rx_queued_mgmt+0x1ae8/0x2dc0 net/mac80211/ibss.c:-1
 ieee80211_iface_process_skb net/mac80211/iface.c:1690 [inline]
 ieee80211_iface_work+0x730/0xc90 net/mac80211/iface.c:1744
 cfg80211_wiphy_work+0x228/0x260 net/wireless/core.c:444
 process_one_work kernel/workqueue.c:2657 [inline]
 process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2734
 worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2815
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293

Last potentially related work creation:
 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:46
 __kasan_record_aux_stack+0xaf/0xc0 mm/kasan/generic.c:492
 kvfree_call_rcu+0xee/0x780 kernel/rcu/tree.c:3452
 neigh_periodic_work+0x3f6/0xd70 net/core/neighbour.c:1010
 process_one_work kernel/workqueue.c:2657 [inline]
 process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2734
 worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2815
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293

The buggy address belongs to the object at ffff88802231c800
 which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 24 bytes inside of
 freed 1024-byte region [ffff88802231c800, ffff88802231cc00)

The buggy address belongs to the physical page:
page:ffffea000088c600 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x22318
head:ffffea000088c600 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000840 ffff888018c41dc0 ffffea0001ec0000 dead000000000002
raw: 0000000000000000 0000000000100010 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 0x52820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 23, tgid 23 (kworker/1:0), ts 76594002511, free_ts 76534153873
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x1c1/0x200 mm/page_alloc.c:1582
 prep_new_page mm/page_alloc.c:1589 [inline]
 get_page_from_freelist+0x2181/0x22a0 mm/page_alloc.c:3221
 __alloc_pages+0x1f0/0x460 mm/page_alloc.c:4501
 alloc_slab_page+0x5d/0x180 mm/slub.c:1903
 allocate_slab mm/slub.c:2050 [inline]
 new_slab+0x87/0x2d0 mm/slub.c:2103
 ___slab_alloc+0xc5c/0x12f0 mm/slub.c:3275
 __slab_alloc mm/slub.c:3361 [inline]
 __slab_alloc_node mm/slub.c:3414 [inline]
 slab_alloc_node mm/slub.c:3508 [inline]
 __kmem_cache_alloc_node+0x122/0x260 mm/slub.c:3557
 __do_kmalloc_node mm/slab_common.c:1006 [inline]
 __kmalloc+0xa7/0x240 mm/slab_common.c:1020
 kmalloc include/linux/slab.h:604 [inline]
 kzalloc include/linux/slab.h:721 [inline]
 neigh_alloc net/core/neighbour.c:495 [inline]
 ___neigh_create+0x6f4/0x23d0 net/core/neighbour.c:649
 ip6_finish_output2+0x1492/0x1550 net/ipv6/ip6_output.c:130
 NF_HOOK_COND include/linux/netfilter.h:305 [inline]
 ip6_output+0x33b/0x530 net/ipv6/ip6_output.c:242
 dst_output include/net/dst.h:470 [inline]
 NF_HOOK+0x167/0x4a0 include/linux/netfilter.h:316
 mld_sendpack+0x802/0xd60 net/ipv6/mcast.c:1894
 mld_send_cr net/ipv6/mcast.c:2193 [inline]
 mld_ifc_work+0x842/0xd60 net/ipv6/mcast.c:2733
 process_one_work kernel/workqueue.c:2657 [inline]
 process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2734
 worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2815
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1182 [inline]
 free_unref_page_prepare+0x7d7/0x8f0 mm/page_alloc.c:2366
 free_unref_page+0x32/0x2e0 mm/page_alloc.c:2459
 discard_slab mm/slub.c:2149 [inline]
 __unfreeze_partials+0x1cf/0x210 mm/slub.c:2689
 put_cpu_partial+0x17c/0x250 mm/slub.c:2765
 __slab_free+0x319/0x400 mm/slub.c:3723
 qlink_free mm/kasan/quarantine.c:166 [inline]
 qlist_free_all+0x75/0xd0 mm/kasan/quarantine.c:185
 kasan_quarantine_reduce+0x143/0x160 mm/kasan/quarantine.c:292
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:306
 kasan_slab_alloc include/linux/kasan.h:188 [inline]
 slab_post_alloc_hook+0x6a/0x4d0 mm/slab.h:770
 slab_alloc_node mm/slub.c:3518 [inline]
 __kmem_cache_alloc_node+0x197/0x260 mm/slub.c:3557
 __do_kmalloc_node mm/slab_common.c:1006 [inline]
 __kmalloc+0xa7/0x240 mm/slab_common.c:1020
 kmalloc include/linux/slab.h:604 [inline]
 kzalloc include/linux/slab.h:721 [inline]
 fib6_info_alloc+0x30/0xf0 net/ipv6/ip6_fib.c:155
 ip6_route_info_create+0x455/0x1260 net/ipv6/route.c:3809
 ip6_route_add+0x28/0x160 net/ipv6/route.c:3905
 addrconf_add_mroute net/ipv6/addrconf.c:2534 [inline]
 addrconf_add_dev+0x29c/0x3b0 net/ipv6/addrconf.c:2552
 addrconf_dev_config net/ipv6/addrconf.c:3488 [inline]
 addrconf_init_auto_addrs+0x611/0xac0 net/ipv6/addrconf.c:3576

Memory state around the buggy address:
 ffff88802231c700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88802231c780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88802231c800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff88802231c880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88802231c900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/10/28 09:46 linux-6.6.y 0aebf2870d53 96923c60 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in gadget_dev_open
* Struck through repros no longer work on HEAD.