KASAN: use-after-free Read in raw_process_ep_io

Status: premoderation: reported syz repro on 2026/08/19 07:29
Reported-by: syzbot+07b277b89e069e9067b0@syzkaller.appspotmail.com
First crash: 7d12h, last: 7d12h
▶ ▼ Similar bugs (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 KASAN: use-after-free Read in raw_process_ep_io origin:upstream 19 syz, C 1 23d 23d 0/3 upstream: reported C repro on 2026/08/03 09:32
android-6-12 KASAN: slab-use-after-free Read in raw_process_ep_io 19 2 4d20h 7d01h 0/1 premoderation: reported on 2026/08/19 18:22
upstream KASAN: slab-use-after-free Read in raw_process_ep_io (2) prio:normal actionable kernel 19 C 5 9d10h 28d 0/29 upstream: reported C repro on 2026/07/29 03:25
upstream KASAN: slab-use-after-free Read in raw_process_ep_io usb 19 34 661d 708d 0/29 closed as dup on 2024/09/21 21:02

Sample crash report:
==================================================================
BUG: KASAN: use-after-free in string_nocheck lib/vsprintf.c:643 [inline]
BUG: KASAN: use-after-free in string+0x20f/0x2a0 lib/vsprintf.c:725
Read of size 1 at addr ffff88810ddb14e0 by task syz.0.17/400

CPU: 1 PID: 400 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 __dump_stack+0x21/0x24 lib/dump_stack.c:88
 dump_stack_lvl+0x110/0x170 lib/dump_stack.c:106
 print_address_description+0x71/0x200 mm/kasan/report.c:316
 print_report+0x4a/0x60 mm/kasan/report.c:420
 kasan_report+0x122/0x150 mm/kasan/report.c:524
 __asan_report_load1_noabort+0x14/0x20 mm/kasan/report_generic.c:348
 string_nocheck lib/vsprintf.c:643 [inline]
 string+0x20f/0x2a0 lib/vsprintf.c:725
 vsnprintf+0xec5/0x1990 lib/vsprintf.c:2805
 snprintf+0xe5/0x140 lib/vsprintf.c:2940
 set_dev_info drivers/base/core.c:4922 [inline]
 dev_vprintk_emit+0x306/0x3e4 drivers/base/core.c:4932
 dev_printk_emit+0xeb/0x13c drivers/base/core.c:4945
 __dev_printk+0x17f/0x1b0 drivers/base/core.c:4957
 _dev_err+0x11b/0x16c drivers/base/core.c:5000
 raw_process_ep_io+0x79c/0xa00 drivers/usb/gadget/legacy/raw_gadget.c:1070
 raw_ioctl_ep_write drivers/usb/gadget/legacy/raw_gadget.c:1108 [inline]
 raw_ioctl+0x2049/0x3180 drivers/usb/gadget/legacy/raw_gadget.c:1280
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0x12f/0x1b0 fs/ioctl.c:856
 __x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:856
 x64_sys_call+0x58b/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f4a5659dd6b
Code: 00 48 89 44 24 18 31 c0 48 8d 44 24 60 c7 04 24 10 00 00 00 48 89 44 24 08 48 8d 44 24 20 48 89 44 24 10 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1c 48 8b 44 24 18 64 48 2b 04 25 28 00 00
RSP: 002b:00007f4a574d0f60 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f4a5659dd6b
RDX: 00007f4a574d0fe0 RSI: 0000000040085507 RDI: 0000000000000003
RBP: 0000000000000003 R08: 00007f4a56950320 R09: 0000000000000000
R10: 0000000000000003 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000a R14: 00007f4a56825fa0 R15: 00007ffe87e8df38
 </TASK>

Allocated by task 1:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
 kasan_save_alloc_info+0x1f/0x30 mm/kasan/generic.c:505
 ____kasan_kmalloc mm/kasan/common.c:380 [inline]
 __kasan_kmalloc+0x95/0xb0 mm/kasan/common.c:389
 kasan_kmalloc include/linux/kasan.h:212 [inline]
 __do_kmalloc_node mm/slab_common.c:938 [inline]
 __kmalloc_node_track_caller+0xb1/0x1e0 mm/slab_common.c:958
 kvasprintf+0xe8/0x1a0 lib/kasprintf.c:25
 kvasprintf_const+0xf2/0x240 lib/kasprintf.c:49
 kobject_set_name_vargs+0x61/0x110 lib/kobject.c:265
 dev_set_name+0xdf/0x130 drivers/base/core.c:3486
 usb_add_gadget+0x3d4/0x620 drivers/usb/gadget/udc/core.c:1426
 usb_add_gadget_udc_release drivers/usb/gadget/udc/core.c:1478 [inline]
 usb_add_gadget_udc+0x11a/0x150 drivers/usb/gadget/udc/core.c:1525
 dummy_udc_probe+0x6e6/0x7f0 drivers/usb/gadget/udc/dummy_hcd.c:1102
 platform_probe+0x16d/0x1f0 drivers/base/platform.c:1400
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x2d7/0x9a0 drivers/base/dd.c:639
 __driver_probe_device+0x193/0x270 drivers/base/dd.c:808
 driver_probe_device+0x54/0x3e0 drivers/base/dd.c:838
 __device_attach_driver+0x2e9/0x4a0 drivers/base/dd.c:966
 bus_for_each_drv+0x192/0x220 drivers/base/bus.c:429
 __device_attach+0x2b0/0x420 drivers/base/dd.c:1038
 device_initial_probe+0x1a/0x20 drivers/base/dd.c:1087
 bus_probe_device+0xc0/0x1f0 drivers/base/bus.c:489
 device_add+0xb0b/0xec0 drivers/base/core.c:3698
 platform_device_add+0x474/0x6d0 drivers/base/platform.c:717
 dummy_hcd_init+0xc26/0x1168 drivers/usb/gadget/udc/dummy_hcd.c:2879
 do_one_initcall+0x1d6/0x580 init/main.c:1433
 do_initcall_level+0x174/0x2df init/main.c:1506
 do_initcalls+0x50/0x92 init/main.c:1522
 do_basic_setup+0x92/0x99 init/main.c:1541
 kernel_init_freeable+0x2d1/0x42d init/main.c:1761
 kernel_init+0x1d/0x1c0 init/main.c:1649
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

Freed by task 398:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
 kasan_save_free_info+0x2b/0x40 mm/kasan/generic.c:516
 ____kasan_slab_free+0x132/0x180 mm/kasan/common.c:242
 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:250
 kasan_slab_free include/linux/kasan.h:178 [inline]
 slab_free_hook mm/slub.c:1750 [inline]
 slab_free_freelist_hook+0xc2/0x190 mm/slub.c:1776
 slab_free mm/slub.c:3712 [inline]
 __kmem_cache_free+0xb7/0x1b0 mm/slub.c:3728
 kfree+0x6f/0xf0 mm/slab_common.c:990
 kfree_const+0x39/0x40 mm/util.c:46
 kobject_cleanup lib/kobject.c:687 [inline]
 kobject_release lib/kobject.c:712 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x20e/0x280 lib/kobject.c:729
 put_device+0x1f/0x30 drivers/base/core.c:3806
 usb_put_gadget include/linux/usb/gadget.h:503 [inline]
 usb_del_gadget_udc+0x21/0x30 drivers/usb/gadget/udc/core.c:1576
 dummy_udc_remove+0x58/0x60 drivers/usb/gadget/udc/dummy_hcd.c:1123
 platform_remove+0xb8/0x110 drivers/base/platform.c:1422
 device_remove drivers/base/dd.c:548 [inline]
 __device_release_driver drivers/base/dd.c:1283 [inline]
 device_release_driver_internal+0x486/0x7e0 drivers/base/dd.c:1309
 device_driver_detach+0x3b/0x40 drivers/base/dd.c:1345
 unbind_store+0x2e5/0x300 drivers/base/bus.c:193
 drv_attr_store+0x88/0xb0 drivers/base/bus.c:77
 sysfs_kf_write+0x137/0x150 fs/sysfs/file.c:136
 kernfs_fop_write_iter+0x307/0x470 fs/kernfs/file.c:352
 call_write_iter include/linux/fs.h:2282 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x5ef/0xd00 fs/read_write.c:584
 ksys_write+0x14a/0x260 fs/read_write.c:637
 __do_sys_write fs/read_write.c:649 [inline]
 __se_sys_write fs/read_write.c:646 [inline]
 __x64_sys_write+0x7b/0x90 fs/read_write.c:646
 x64_sys_call+0x27b/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

The buggy address belongs to the object at ffff88810ddb14e0
 which belongs to the cache kmalloc-16 of size 16
The buggy address is located 0 bytes inside of
 16-byte region [ffff88810ddb14e0, ffff88810ddb14f0)

The buggy address belongs to the physical page:
page:ffffea0004376c40 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10ddb1
flags: 0x4000000000000200(slab|zone=1)
raw: 4000000000000200 dead000000000100 dead000000000122 ffff888100042480
raw: 0000000000000000 0000000000800080 00000001ffffffff 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 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 1, tgid 1 (swapper/0), ts 2628567563, free_ts 0
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x1f5/0x210 mm/page_alloc.c:2672
 prep_new_page+0x1c/0x110 mm/page_alloc.c:2679
 get_page_from_freelist+0x2ca9/0x2d20 mm/page_alloc.c:4586
 __alloc_pages+0x1fa/0x610 mm/page_alloc.c:5930
 alloc_slab_page+0x6e/0xf0 include/linux/gfp.h:-1
 allocate_slab mm/slub.c:1967 [inline]
 new_slab+0x98/0x3e0 mm/slub.c:2020
 ___slab_alloc+0x70f/0xb70 mm/slub.c:3177
 __slab_alloc+0x5e/0xa0 mm/slub.c:3263
 slab_alloc_node mm/slub.c:3348 [inline]
 __kmem_cache_alloc_node+0x204/0x2d0 mm/slub.c:3423
 __do_kmalloc_node mm/slab_common.c:937 [inline]
 __kmalloc_node_track_caller+0xa1/0x1e0 mm/slab_common.c:958
 kstrdup mm/util.c:66 [inline]
 kstrdup_const+0x5a/0xa0 mm/util.c:89
 __kernfs_new_node+0xa6/0x670 fs/kernfs/dir.c:610
 kernfs_new_node+0x150/0x260 fs/kernfs/dir.c:690
 kernfs_create_link+0xa4/0x200 fs/kernfs/symlink.c:39
 sysfs_do_create_link_sd+0x8a/0x110 fs/sysfs/symlink.c:44
 sysfs_do_create_link fs/sysfs/symlink.c:80 [inline]
 sysfs_create_link+0x68/0x80 fs/sysfs/symlink.c:92
page_owner free stack trace missing

Memory state around the buggy address:
 ffff88810ddb1380: 00 05 fc fc 00 04 fc fc 00 04 fc fc fa fb fc fc
 ffff88810ddb1400: 00 01 fc fc 00 05 fc fc 00 07 fc fc fa fb fc fc
>ffff88810ddb1480: 00 04 fc fc fa fb fc fc 00 01 fc fc fa fb fc fc
                                                       ^
 ffff88810ddb1500: 00 01 fc fc fa fb fc fc 00 01 fc fc 00 01 fc fc
 ffff88810ddb1580: fa fb fc fc fa fb fc fc 00 01 fc fc 00 05 fc fc
==================================================================
gadget @vÊ-ˆÿÿŽ: fail, usb_ep_queue returned -108

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/19 07:28 android14-6.1 92668decd5e0 1e72964b .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-android-6-1 KASAN: use-after-free Read in raw_process_ep_io
* Struck through repros no longer work on HEAD.