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: 56d, last: 18d
▶ ▼ 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 prio:normal usb 17 162 22d 52d 0/29 upstream: reported on 2026/07/29 00:19
linux-5.15 KASAN: slab-out-of-bounds Read in dummy_free_request 17 7 38d 56d 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 47d 49d 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:709
Read of size 8 at addr ffff8880580fdff0 by task syz.2.632/7679

CPU: 1 PID: 7679 Comm: syz.2.632 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:709
 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:2271 [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: 0033:0x7f737659e159
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:00007f7377409028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f7376826180 RCX: 00007f737659e159
RDX: 000000000000000b RSI: 0000200000000680 RDI: 0000000000000007
RBP: 00007f7376635024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7376826218 R14: 00007f7376826180 R15: 00007ffca0a6cb88
 </TASK>

Allocated by task 5951:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
 __kasan_slab_alloc+0x6b/0x80 mm/kasan/common.c:329
 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
 fdb_create+0x37/0x1230 net/bridge/br_fdb.c:391
 fdb_add_local+0x121/0x240 net/bridge/br_fdb.c:432
 br_fdb_add_local+0x36/0x50 net/bridge/br_fdb.c:840
 __vlan_add+0x5cc/0x2740 net/bridge/br_vlan.c:334
 br_vlan_add+0x42e/0x910 net/bridge/br_vlan.c:803
 __vlan_add+0x3ee/0x2740 net/bridge/br_vlan.c:292
 nbp_vlan_add+0x25e/0x3b0 net/bridge/br_vlan.c:1341
 br_vlan_info+0xfd/0x460 net/bridge/br_netlink.c:689
 br_process_vlan_info+0x545/0x7f0 net/bridge/br_netlink.c:752
 br_afspec+0x1fd/0x5d0 net/bridge/br_netlink.c:820
 br_setlink+0x346/0x810 net/bridge/br_netlink.c:1081
 rtnl_bridge_setlink+0x4ba/0x720 net/core/rtnetlink.c:5117
 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

The buggy address belongs to the object at ffff8880580fdf00
 which belongs to the cache bridge_fdb_cache of size 128
The buggy address is located 112 bytes to the right of
 128-byte region [ffff8880580fdf00, ffff8880580fdf80)

The buggy address belongs to the physical page:
page:ffffea0001603f40 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x580fd
flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000200 0000000000000000 dead000000000122 ffff88814c244dc0
raw: 0000000000000000 0000000000150015 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 0x112a20(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_HARDWALL), pid 5951, tgid 5947 (syz.4.290), ts 282746479347, free_ts 282065534805
 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]
 slab_alloc mm/slub.c:3367 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3374 [inline]
 kmem_cache_alloc+0x111/0x2f0 mm/slub.c:3383
 fdb_create+0x37/0x1230 net/bridge/br_fdb.c:391
 fdb_add_local+0x121/0x240 net/bridge/br_fdb.c:432
 br_fdb_add_local+0x36/0x50 net/bridge/br_fdb.c:840
 __vlan_add+0x5cc/0x2740 net/bridge/br_vlan.c:334
 br_vlan_add+0x42e/0x910 net/bridge/br_vlan.c:803
 __vlan_add+0x3ee/0x2740 net/bridge/br_vlan.c:292
 nbp_vlan_add+0x25e/0x3b0 net/bridge/br_vlan.c:1341
 br_vlan_info+0xfd/0x460 net/bridge/br_netlink.c:689
 br_process_vlan_info+0x545/0x7f0 net/bridge/br_netlink.c:752
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
 tlb_batch_list_free mm/mmu_gather.c:76 [inline]
 tlb_finish_mmu+0x13a/0x220 mm/mmu_gather.c:397
 exit_mmap+0x388/0x970 mm/mmap.c:3262
 __mmput+0x118/0x3a0 kernel/fork.c:1210
 exit_mm+0x24d/0x350 kernel/exit.c:572
 do_exit+0x958/0x2570 kernel/exit.c:874
 do_group_exit+0x229/0x2e0 kernel/exit.c:1030
 get_signal+0x1259/0x1340 kernel/signal.c:2880
 arch_do_signal_or_restart+0xc4/0x1310 arch/x86/kernel/signal.c:871
 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 irqentry_exit_to_user_mode+0x5/0x30 kernel/entry/common.c:316
 exc_page_fault+0x88/0x100 arch/x86/mm/fault.c:1485
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:608

Memory state around the buggy address:
 ffff8880580fde80: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
 ffff8880580fdf00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8880580fdf80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                                             ^
 ffff8880580fe000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880580fe080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================

Crashes (19):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/31 21:54 linux-6.1.y d64a499eea6b 316d9396 .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
2026/08/18 04:02 linux-6.1.y e4f7d8be268e 1e72964b .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
2026/08/17 22:06 linux-6.1.y e4f7d8be268e 905244d6 .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
2026/08/17 21:44 linux-6.1.y e4f7d8be268e 905244d6 .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
2026/08/17 20:33 linux-6.1.y e4f7d8be268e 905244d6 .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
2026/08/07 14:36 linux-6.1.y e4f7d8be268e e4ef95d6 .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
2026/08/04 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
2026/08/13 22:23 linux-6.1.y e4f7d8be268e b13552fe .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
2026/08/13 22:23 linux-6.1.y e4f7d8be268e b13552fe .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
2026/08/05 16:52 linux-6.1.y fb28aa725e05 52aa2820 .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 23:37 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.