KASAN: slab-out-of-bounds Read in dummy_free_request

Status: upstream: reported on 2026/07/24 22:09
Reported-by: syzbot+e024d7c98824bafa72eb@syzkaller.appspotmail.com
First crash: 10d, last: 12h02m
Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: slab-out-of-bounds Read in dummy_free_request usb prio:normal 17 114 31m 6d21h 0/29 upstream: reported on 2026/07/29 00:19
linux-5.15 KASAN: slab-out-of-bounds Read in dummy_free_request 17 4 4d05h 10d 0/3 upstream: reported on 2026/07/24 21:58
linux-6.6 KASAN: slab-out-of-bounds Read in dummy_free_request 17 2 1d19h 4d03h 0/2 upstream: reported on 2026/07/31 17:51

Sample crash report:
configfs-gadget.g1 gadget.0: uvc: uvc_function_bind()
configfs-gadget.g1 gadget.0: uvc: Unable to allocate streaming EP
==================================================================
BUG: KASAN: slab-out-of-bounds in list_empty include/linux/list.h:292 [inline]
BUG: KASAN: slab-out-of-bounds in dummy_free_request+0x3b/0x70 drivers/usb/gadget/udc/dummy_hcd.c:690
Read of size 8 at addr ffff888026cdf3f0 by task syz.3.2829/14692

CPU: 1 PID: 14692 Comm: syz.3.2829 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:316 [inline]
 print_report+0xa8/0x210 mm/kasan/report.c:420
 kasan_report+0x10b/0x140 mm/kasan/report.c:524
 list_empty include/linux/list.h:292 [inline]
 dummy_free_request+0x3b/0x70 drivers/usb/gadget/udc/dummy_hcd.c:690
 uvc_function_bind+0xa37/0x12f0 drivers/usb/gadget/function/f_uvc.c:789
 usb_add_function+0x2d9/0x980 drivers/usb/gadget/composite.c:337
 configfs_composite_bind+0xa02/0xf60 drivers/usb/gadget/configfs.c:1409
 gadget_bind_driver+0x2af/0x760 drivers/usb/gadget/udc/core.c:1651
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x24a/0xb40 drivers/base/dd.c:638
 __driver_probe_device+0x1f5/0x390 drivers/base/dd.c:804
 driver_probe_device+0x4f/0x420 drivers/base/dd.c:834
 __driver_attach+0x43d/0x6c0 drivers/base/dd.c:1220
 bus_for_each_dev+0x182/0x1f0 drivers/base/bus.c:303
 bus_add_driver+0x324/0x5d0 drivers/base/bus.c:620
 driver_register+0x32d/0x430 drivers/base/driver.c:246
 usb_gadget_register_driver_owner+0xf5/0x260 drivers/usb/gadget/udc/core.c:1730
 gadget_dev_desc_UDC_store+0x1c3/0x2e0 drivers/usb/gadget/configfs.c:290
 flush_write_buffer fs/configfs/file.c:207 [inline]
 configfs_write_iter+0x30b/0x400 fs/configfs/file.c:229
 call_write_iter include/linux/fs.h:2265 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x482/0x9a0 fs/read_write.c:584
 ksys_write+0x14d/0x260 fs/read_write.c:637
 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: 0033:0x7f67e4b9e019
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:00007f67e5b10028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f67e4e25fa0 RCX: 00007f67e4b9e019
RDX: 000000000000000c RSI: 00002000000004c0 RDI: 0000000000000003
RBP: 00007f67e4c3500c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f67e4e26038 R14: 00007f67e4e25fa0 R15: 00007ffcfaba1a78
 </TASK>

Allocated by task 14293:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
 ____kasan_kmalloc mm/kasan/common.c:375 [inline]
 __kasan_kmalloc+0x8e/0xa0 mm/kasan/common.c:384
 kmalloc include/linux/slab.h:563 [inline]
 __hw_addr_create net/core/dev_addr_lists.c:60 [inline]
 __hw_addr_add_ex+0x1f4/0x700 net/core/dev_addr_lists.c:118
 __hw_addr_add net/core/dev_addr_lists.c:135 [inline]
 dev_addr_init+0x143/0x220 net/core/dev_addr_lists.c:558
 alloc_netdev_mqs+0x26a/0xf10 net/core/dev.c:10787
 rtnl_create_link+0x2fd/0xb90 net/core/rtnetlink.c:3309
 rtnl_newlink_create net/core/rtnetlink.c:3426 [inline]
 __rtnl_newlink net/core/rtnetlink.c:3656 [inline]
 rtnl_newlink+0x13c6/0x1f90 net/core/rtnetlink.c:3669
 rtnetlink_rcv_msg+0x863/0xfb0 net/core/rtnetlink.c:6166
 netlink_rcv_skb+0x1ef/0x440 net/netlink/af_netlink.c:2516
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x7ad/0x920 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x8ad/0xbd0 net/netlink/af_netlink.c:1877
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:730 [inline]
 ____sys_sendmsg+0x5ed/0x9a0 net/socket.c:2519
 ___sys_sendmsg+0x2a2/0x360 net/socket.c:2573
 __sys_sendmsg net/socket.c:2602 [inline]
 __do_sys_sendmsg net/socket.c:2611 [inline]
 __se_sys_sendmsg+0x1c3/0x2b0 net/socket.c:2609
 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

Last potentially related work creation:
 kasan_save_stack+0x3a/0x60 mm/kasan/common.c:46
 __kasan_record_aux_stack+0xb2/0xc0 mm/kasan/generic.c:486
 kvfree_call_rcu+0x103/0x890 kernel/rcu/tree.c:3405
 kernfs_unlink_open_file+0x456/0x500 fs/kernfs/file.c:653
 kernfs_fop_release+0x12a/0x190 fs/kernfs/file.c:825
 __fput+0x20a/0x8b0 fs/file_table.c:320
 task_work_run+0x1d0/0x260 kernel/task_work.c:203
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Second to last potentially related work creation:
 kasan_save_stack+0x3a/0x60 mm/kasan/common.c:46
 __kasan_record_aux_stack+0xb2/0xc0 mm/kasan/generic.c:486
 kvfree_call_rcu+0x103/0x890 kernel/rcu/tree.c:3405
 kernfs_unlink_open_file+0x456/0x500 fs/kernfs/file.c:653
 kernfs_fop_release+0x12a/0x190 fs/kernfs/file.c:825
 __fput+0x20a/0x8b0 fs/file_table.c:320
 task_work_run+0x1d0/0x260 kernel/task_work.c:203
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

The buggy address belongs to the object at ffff888026cdf300
 which belongs to the cache kmalloc-128 of size 128
The buggy address is located 112 bytes to the right of
 128-byte region [ffff888026cdf300, ffff888026cdf380)

The buggy address belongs to the physical page:
page:ffffea00009b37c0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x26cdf
flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000200 ffffea0001603180 dead000000000004 ffff8880174418c0
raw: 0000000000000000 0000000000100010 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 0x112cc0(GFP_USER|__GFP_NOWARN|__GFP_NORETRY), pid 5831, tgid 5831 (udevd), ts 330599429573, free_ts 329678345247
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x173/0x1a0 mm/page_alloc.c:2560
 prep_new_page mm/page_alloc.c:2567 [inline]
 get_page_from_freelist+0x206b/0x2180 mm/page_alloc.c:4358
 __alloc_pages+0x1ec/0x4f0 mm/page_alloc.c:5658
 alloc_slab_page+0x5d/0x180 mm/slub.c:1799
 allocate_slab mm/slub.c:1944 [inline]
 new_slab+0x87/0x2d0 mm/slub.c:1997
 ___slab_alloc+0xbc5/0x1240 mm/slub.c:3154
 __slab_alloc mm/slub.c:3240 [inline]
 slab_alloc_node mm/slub.c:3325 [inline]
 __kmem_cache_alloc_node+0x126/0x270 mm/slub.c:3398
 kmalloc_trace+0x26/0xe0 mm/slab_common.c:1026
 kmalloc include/linux/slab.h:563 [inline]
 kzalloc include/linux/slab.h:699 [inline]
 kernfs_get_open_node fs/kernfs/file.c:592 [inline]
 kernfs_fop_open+0x78c/0xc60 fs/kernfs/file.c:760
 do_dentry_open+0x7dd/0x10b0 fs/open.c:882
 do_open fs/namei.c:3634 [inline]
 path_openat+0x2674/0x2f10 fs/namei.c:3791
 do_filp_open+0x1ee/0x420 fs/namei.c:3818
 do_sys_openat2+0x14b/0x4f0 fs/open.c:1320
 do_sys_open fs/open.c:1336 [inline]
 __do_sys_openat fs/open.c:1352 [inline]
 __se_sys_openat fs/open.c:1347 [inline]
 __x64_sys_openat+0x135/0x160 fs/open.c:1347
 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
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1487 [inline]
 free_pcp_prepare mm/page_alloc.c:1537 [inline]
 free_unref_page_prepare+0x8e5/0x9e0 mm/page_alloc.c:3414
 free_unref_page+0x2e/0x3f0 mm/page_alloc.c:3509
 free_slab mm/slub.c:2036 [inline]
 discard_slab mm/slub.c:2042 [inline]
 __unfreeze_partials+0x188/0x1e0 mm/slub.c:2591
 put_cpu_partial+0x17c/0x250 mm/slub.c:2667
 qlink_free mm/kasan/quarantine.c:168 [inline]
 qlist_free_all+0x76/0xe0 mm/kasan/quarantine.c:187
 kasan_quarantine_reduce+0x144/0x160 mm/kasan/quarantine.c:294
 __kasan_slab_alloc+0x1e/0x80 mm/kasan/common.c:306
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook+0x4b/0x490 mm/slab.h:737
 slab_alloc_node mm/slub.c:3359 [inline]
 slab_alloc mm/slub.c:3367 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3374 [inline]
 kmem_cache_alloc+0x18b/0x2f0 mm/slub.c:3383
 getname_flags+0xb7/0x500 fs/namei.c:139
 do_sys_openat2+0xdd/0x4f0 fs/open.c:1314
 do_sys_open fs/open.c:1336 [inline]
 __do_sys_openat fs/open.c:1352 [inline]
 __se_sys_openat fs/open.c:1347 [inline]
 __x64_sys_openat+0x135/0x160 fs/open.c:1347
 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

Memory state around the buggy address:
 ffff888026cdf280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888026cdf300: 00 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc
>ffff888026cdf380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                                             ^
 ffff888026cdf400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888026cdf480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================

Crashes (10):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/04 09:31 linux-6.1.y fb28aa725e05 9451e17e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: slab-out-of-bounds Read in dummy_free_request
2026/07/31 06:02 linux-6.1.y fb28aa725e05 aaffb173 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: slab-out-of-bounds Read in dummy_free_request
2026/07/31 05:42 linux-6.1.y fb28aa725e05 aaffb173 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: slab-out-of-bounds Read in dummy_free_request
2026/07/31 05:15 linux-6.1.y fb28aa725e05 aaffb173 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: slab-out-of-bounds Read in dummy_free_request
2026/07/29 13:00 linux-6.1.y dc5c83b7f5f8 19622d9d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: slab-out-of-bounds Read in dummy_free_request
2026/07/24 23:37 linux-6.1.y dc5c83b7f5f8 dd737a83 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: slab-out-of-bounds Read in dummy_free_request
2026/07/24 23:37 linux-6.1.y dc5c83b7f5f8 dd737a83 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: slab-out-of-bounds Read in dummy_free_request
2026/07/24 23:36 linux-6.1.y dc5c83b7f5f8 dd737a83 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: slab-out-of-bounds Read in dummy_free_request
2026/07/24 22:09 linux-6.1.y dc5c83b7f5f8 dd737a83 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: slab-out-of-bounds Read in dummy_free_request
2026/07/24 22:09 linux-6.1.y dc5c83b7f5f8 dd737a83 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: slab-out-of-bounds Read in dummy_free_request
* Struck through repros no longer work on HEAD.