From: syzbot <syzbot+599d4e8994a656eafe15@syzkaller.appspotmail.com>
To: gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org,
linux-usb@vger.kernel.org, syzkaller-bugs@googlegroups.com
Subject: [syzbot] [usb?] KASAN: slab-use-after-free Read in find_endpoint
Date: Thu, 30 Jul 2026 23:35:37 -0700 [thread overview]
Message-ID: <6a6c4239.5cf34cee.28a846.0009.GAE@google.com> (raw)
Hello,
syzbot found the following issue on:
HEAD commit: f5098b6bae76 Linux 7.2-rc5
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12597fde580000
kernel config: https://syzkaller.appspot.com/x/.config?x=145fa60d73086782
dashboard link: https://syzkaller.appspot.com/bug?extid=599d4e8994a656eafe15
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/2113dcf433f6/disk-f5098b6b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/413e673b7de4/vmlinux-f5098b6b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/fc40c1b83e80/bzImage-f5098b6b.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+599d4e8994a656eafe15@syzkaller.appspotmail.com
==================================================================
BUG: KASAN: slab-use-after-free in find_endpoint+0x2a3/0x2c0 drivers/usb/gadget/udc/dummy_hcd.c:1618
Read of size 1 at addr ffff8880359f2912 by task kworker/0:5/18466
CPU: 0 UID: 0 PID: 18466 Comm: kworker/0:5 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Workqueue: events request_firmware_work_func
Call Trace:
<IRQ>
__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
find_endpoint+0x2a3/0x2c0 drivers/usb/gadget/udc/dummy_hcd.c:1618
dummy_timer+0x500/0x36f0 drivers/usb/gadget/udc/dummy_hcd.c:1890
__run_hrtimer kernel/time/hrtimer.c:2032 [inline]
__hrtimer_run_queues+0x462/0x9c0 kernel/time/hrtimer.c:2096
hrtimer_run_softirq+0x17d/0x2c0 kernel/time/hrtimer.c:2113
handle_softirqs+0x1ea/0x9b0 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0x162/0x210 kernel/softirq.c:735
irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
sysvec_apic_timer_interrupt+0xa3/0xc0 arch/x86/kernel/apic/apic.c:1062
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:__orc_find+0xae/0xf0 arch/x86/kernel/unwind_orc.c:111
Code: 63 13 48 01 da 49 39 d5 73 af 4c 8d 63 fc 49 39 ec 73 b2 4d 29 f7 49 c1 ff 02 4b 8d 14 7f 48 8d 04 50 48 83 c4 08 5b 5d 41 5c <41> 5d 41 5e 41 5f e9 87 f5 05 0a 48 83 c4 08 31 c0 5b 5d 41 5c 41
RSP: 0018:ffffc900041ef628 EFLAGS: 00000292
RAX: ffffffff92308310 RBX: 0000000000000001 RCX: dffffc0000000000
RDX: 000000000000000f RSI: 0000000000000000 RDI: ffffffff91836d10
RBP: ffffc900041ef700 R08: ffffffff92308340 R09: 0000000000000007
R10: 0000000000000200 R11: 00000000000680ae R12: ffffc900041ef708
R13: ffffffff8780ae85 R14: ffffffff91836d10 R15: 0000000000000005
orc_find arch/x86/kernel/unwind_orc.c:238 [inline]
unwind_next_frame+0x2ec/0x2090 arch/x86/kernel/unwind_orc.c:510
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
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]
__do_kmalloc_node mm/slub.c:5334 [inline]
__kmalloc_noprof+0x322/0x820 mm/slub.c:5359
_kmalloc_noprof include/linux/slab.h:992 [inline]
usb_alloc_urb+0x66/0xa0 drivers/usb/core/urb.c:75
ath9k_hif_usb_alloc_rx_urbs drivers/net/wireless/ath/ath9k/hif_usb.c:897 [inline]
ath9k_hif_usb_alloc_urbs+0x5e4/0xfa0 drivers/net/wireless/ath/ath9k/hif_usb.c:1034
ath9k_hif_usb_dev_init drivers/net/wireless/ath/ath9k/hif_usb.c:1124 [inline]
ath9k_hif_usb_firmware_cb+0x146/0x530 drivers/net/wireless/ath/ath9k/hif_usb.c:1252
request_firmware_work_func+0x13f/0x440 drivers/base/firmware_loader/main.c:1164
process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
process_scheduled_works kernel/workqueue.c:3405 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
Allocated by task 29727:
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:4584 [inline]
kmem_cache_alloc_bulk_noprof+0x352/0x890 mm/slub.c:7435
__io_alloc_req_refill+0x9e/0x330 io_uring/io_uring.c:988
io_alloc_req io_uring/io_uring.h:536 [inline]
io_submit_sqes.cold+0xf6/0x301 io_uring/io_uring.c:2046
__do_sys_io_uring_enter+0xa88/0x1b10 io_uring/io_uring.c:2646
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Freed by task 27397:
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:2677 [inline]
slab_free_after_rcu_debug+0xdf/0x170 mm/slub.c:6439
rcu_do_batch kernel/rcu/tree.c:2645 [inline]
rcu_core+0x5a2/0x10d0 kernel/rcu/tree.c:2897
handle_softirqs+0x1ea/0x9b0 kernel/softirq.c:622
do_softirq kernel/softirq.c:523 [inline]
do_softirq+0xac/0xe0 kernel/softirq.c:510
__local_bh_enable_ip+0xf8/0x120 kernel/softirq.c:450
local_bh_enable include/linux/bottom_half.h:33 [inline]
__alloc_skb+0x5db/0x710 net/core/skbuff.c:699
alloc_skb include/linux/skbuff.h:1384 [inline]
alloc_uevent_skb+0x7d/0x210 lib/kobject_uevent.c:289
uevent_net_broadcast_untagged lib/kobject_uevent.c:326 [inline]
kobject_uevent_net_broadcast lib/kobject_uevent.c:410 [inline]
kobject_uevent_env+0xd2d/0x18b0 lib/kobject_uevent.c:611
device_del+0x605/0x9b0 drivers/base/core.c:3979
device_unregister+0x1d/0xe0 drivers/base/core.c:4002
hci_conn_del_sysfs+0xb9/0x1a0 net/bluetooth/hci_sysfs.c:79
hci_conn_cleanup net/bluetooth/hci_conn.c:170 [inline]
hci_conn_del+0x506/0x1180 net/bluetooth/hci_conn.c:1306
hci_abort_conn_sync+0x7d9/0xb20 net/bluetooth/hci_sync.c:5850
abort_conn_sync+0x142/0x350 net/bluetooth/hci_conn.c:3163
hci_cmd_sync_work+0x1c0/0x470 net/bluetooth/hci_sync.c:332
process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
process_scheduled_works kernel/workqueue.c:3405 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Last potentially related work creation:
kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
kasan_record_aux_stack+0xa7/0xc0 mm/kasan/generic.c:556
slab_free_hook mm/slub.c:2638 [inline]
slab_free mm/slub.c:6377 [inline]
kmem_cache_free+0x427/0x6b0 mm/slub.c:6504
__io_req_caches_free+0x1a6/0x220 io_uring/io_uring.c:2148
io_req_caches_free io_uring/io_uring.c:2160 [inline]
io_ring_exit_work+0x42a/0xd7a io_uring/io_uring.c:2363
process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
process_scheduled_works kernel/workqueue.c:3405 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 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 ffff8880359f28c0
which belongs to the cache io_kiocb of size 248
The buggy address is located 82 bytes inside of
freed 248-byte region [ffff8880359f28c0, ffff8880359f29b8)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x359f2
memcg:ffff8880359f2f01
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000000 ffff888142ef6c80 dead000000000100 dead000000000122
raw: 0000000000000000 00000008000c000c 00000000f5000000 ffff8880359f2f01
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x52cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 29727, tgid 29719 (syz.0.6860), ts 1428916787567, free_ts 1428553365645
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1859
prep_new_page mm/page_alloc.c:1867 [inline]
get_page_from_freelist+0xf48/0x3530 mm/page_alloc.c:3946
__alloc_frozen_pages_noprof+0x299/0x2dc0 mm/page_alloc.c:5304
alloc_slab_page mm/slub.c:3266 [inline]
allocate_slab mm/slub.c:3380 [inline]
new_slab+0xa2/0x640 mm/slub.c:3426
refill_objects+0xe3/0x410 mm/slub.c:7310
__kmem_cache_alloc_bulk+0x3c/0x120 mm/slub.c:7346
kmem_cache_alloc_bulk_noprof+0x48b/0x890 mm/slub.c:7413
__io_alloc_req_refill+0x9e/0x330 io_uring/io_uring.c:988
io_alloc_req io_uring/io_uring.h:536 [inline]
io_submit_sqes.cold+0xf6/0x301 io_uring/io_uring.c:2046
__do_sys_io_uring_enter+0xa88/0x1b10 io_uring/io_uring.c:2646
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 29721 tgid 29719 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
__free_pages_prepare mm/page_alloc.c:1406 [inline]
__free_frozen_pages+0x79f/0x1090 mm/page_alloc.c:2950
__pagetable_free include/linux/mm.h:3695 [inline]
pagetable_free include/linux/mm.h:3719 [inline]
pagetable_dtor_free include/linux/mm.h:3818 [inline]
__tlb_remove_table include/asm-generic/tlb.h:221 [inline]
__tlb_remove_table_free mm/mmu_gather.c:228 [inline]
tlb_remove_table_rcu+0x2cf/0x380 mm/mmu_gather.c:291
rcu_do_batch kernel/rcu/tree.c:2645 [inline]
rcu_core+0x5a2/0x10d0 kernel/rcu/tree.c:2897
handle_softirqs+0x1ea/0x9b0 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0x162/0x210 kernel/softirq.c:735
irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
sysvec_apic_timer_interrupt+0xa3/0xc0 arch/x86/kernel/apic/apic.c:1062
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
Memory state around the buggy address:
ffff8880359f2800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc
ffff8880359f2880: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
>ffff8880359f2900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8880359f2980: fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc fc
ffff8880359f2a00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess):
0: 63 13 movsxd (%rbx),%edx
2: 48 01 da add %rbx,%rdx
5: 49 39 d5 cmp %rdx,%r13
8: 73 af jae 0xffffffb9
a: 4c 8d 63 fc lea -0x4(%rbx),%r12
e: 49 39 ec cmp %rbp,%r12
11: 73 b2 jae 0xffffffc5
13: 4d 29 f7 sub %r14,%r15
16: 49 c1 ff 02 sar $0x2,%r15
1a: 4b 8d 14 7f lea (%r15,%r15,2),%rdx
1e: 48 8d 04 50 lea (%rax,%rdx,2),%rax
22: 48 83 c4 08 add $0x8,%rsp
26: 5b pop %rbx
27: 5d pop %rbp
28: 41 5c pop %r12
* 2a: 41 5d pop %r13 <-- trapping instruction
2c: 41 5e pop %r14
2e: 41 5f pop %r15
30: e9 87 f5 05 0a jmp 0xa05f5bc
35: 48 83 c4 08 add $0x8,%rsp
39: 31 c0 xor %eax,%eax
3b: 5b pop %rbx
3c: 5d pop %rbp
3d: 41 5c pop %r12
3f: 41 rex.B
---
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
reply other threads:[~2026-07-31 6:35 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=6a6c4239.5cf34cee.28a846.0009.GAE@google.com \
--to=syzbot+599d4e8994a656eafe15@syzkaller.appspotmail.com \
--cc=gregkh@linuxfoundation.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-usb@vger.kernel.org \
--cc=syzkaller-bugs@googlegroups.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.