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.
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reply other threads:[~2026-07-31 6:35 UTC|newest]
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