syzbot


KASAN: slab-use-after-free Read in raw_queue_event (2)

Status: moderation: reported on 2026/01/11 06:38
Subsystems: usb
[Documentation on labels]
Reported-by: syzbot+e033e8eb146e2a10e23f@syzkaller.appspotmail.com
First crash: 51d, last: 14d
✨ AI Jobs (2)
ID Workflow Result Correct Bug Created Started Finished Revision Error
5405e69c-2af2-42e7-be54-ceaa15c56f91 moderation Actionable: ✅  Confident: ✅  KASAN: slab-use-after-free Read in raw_queue_event (2) 2026/02/06 12:22 2026/02/06 12:22 2026/02/06 12:27 97745f52f5b9361548048f53f0b3b51b9313fedf
455cd040-4f90-46fb-b777-ffbb8774bdd0 moderation 💥 KASAN: slab-use-after-free Read in raw_queue_event (2) 2026/02/06 07:04 2026/02/06 09:18 2026/02/06 09:29 9b618abc0cd923b36c7a5ebc58a21174112d8f70 tool grepper failed: error: failed to run ["git" "grep" "--extended-regexp" "--line-number" "--show-function" "-C1" "--no-color" "->udc_stop"]: exit status 129 error: unknown switch `>' usage: git grep [<options>] [-e] <pattern> [<rev>...] [[--] <path>...] --[no-]cached search in index instead of in the work tree --no-index find in contents not managed by git --index opposite of --no-index --[no-]untracked search in both tracked and untracked files --[no-]exclude-standard ignore files specified via '.gitignore' --[no-]recurse-submodules recursively search in each submodule -v, --[no-]invert-match show non-matching lines -i, --[no-]ignore-case case insensitive matching -w, --[no-]word-regexp match patterns only at word boundaries -a, --[no-]text process binary files as text -I don't match patterns in binary files --[no-]textconv process binary files with textconv filters -r, --[no-]recursive search in subdirectories (default) --max-depth <n> descend at most <n> levels -E, --[no-]extended-regexp use extended POSIX regular expressions -G, --[no-]basic-regexp use basic POSIX regular expressions (default) -F, --[no-]fixed-strings interpret patterns as fixed strings -P, --[no-]perl-regexp use Perl-compatible regular expressions -n, --[no-]line-number show line numbers --[no-]column show column number of first match -h don't show filenames -H show filenames --[no-]full-name show filenames relative to top directory -l, --[no-]files-with-matches show only filenames instead of matching lines --[no-]name-only synonym for --files-with-matches -L, --[no-]files-without-match show only the names of files without match -z, --[no-]null print NUL after filenames -o, --[no-]only-matching show only matching parts of a line -c, --[no-]count show the number of matches instead of matching lines --[no-]color[=<when>] highlight matches --[no-]break print empty line between matches from different files --[no-]heading show filename only once above matches from same file -C, --[no-]context <n> show <n> context lines before and after matches -B, --before-context <n> show <n> context lines before matches -A, --after-context <n> show <n> context lines after matches --[no-]threads <n> use <n> worker threads -NUM shortcut for -C NUM -p, --[no-]show-function show a line with the function name before matches -W, --[no-]function-context show the surrounding function -f <file> read patterns from file -e <pattern> match <pattern> --and combine patterns specified with -e --or --not ( ) -q, --[no-]quiet indicate hit with exit status without output --[no-]all-match show only matches from files that match all patterns -O, --[no-]open-files-in-pager[=<pager>] show matching files in the pager --[no-]ext-grep allow calling of grep(1) (ignored by this build) -m, --[no-]max-count <n> maximum number of results per file args: map[Expression:->udc_stop]
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: slab-use-after-free Read in raw_queue_event usb 19 1 600d 553d 0/29 closed as dup on 2024/09/21 21:01

Sample crash report:
usb 1-1: device descriptor read/all, error -71
usb usb1-port1: attempt power cycle
==================================================================
BUG: KASAN: slab-use-after-free in raw_event_queue_add drivers/usb/gadget/legacy/raw_gadget.c:82 [inline]
BUG: KASAN: slab-use-after-free in raw_queue_event+0x292/0x2e0 drivers/usb/gadget/legacy/raw_gadget.c:240
Read of size 4 at addr ffff88803e9aaa00 by task kworker/1:8/5975

CPU: 1 UID: 0 PID: 5975 Comm: kworker/1:8 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
Workqueue: usb_hub_wq hub_event
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xba/0x230 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 raw_event_queue_add drivers/usb/gadget/legacy/raw_gadget.c:82 [inline]
 raw_queue_event+0x292/0x2e0 drivers/usb/gadget/legacy/raw_gadget.c:240
 gadget_disconnect+0x51/0xe0 drivers/usb/gadget/legacy/raw_gadget.c:388
 set_link_state+0xc0a/0x1220 drivers/usb/gadget/udc/dummy_hcd.c:471
 dummy_hub_control+0xafc/0x1a00 drivers/usb/gadget/udc/dummy_hcd.c:-1
 rh_call_control drivers/usb/core/hcd.c:656 [inline]
 rh_urb_enqueue drivers/usb/core/hcd.c:821 [inline]
 usb_hcd_submit_urb+0xdbe/0x1b50 drivers/usb/core/hcd.c:1542
 usb_start_wait_urb+0x12b/0x510 drivers/usb/core/message.c:59
 usb_internal_control_msg drivers/usb/core/message.c:103 [inline]
 usb_control_msg+0x232/0x3e0 drivers/usb/core/message.c:154
 usb_clear_port_feature drivers/usb/core/hub.c:456 [inline]
 usb_hub_set_port_power drivers/usb/core/hub.c:894 [inline]
 hub_port_connect drivers/usb/core/hub.c:5607 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5707 [inline]
 port_event drivers/usb/core/hub.c:5871 [inline]
 hub_event+0x2dc0/0x4f60 drivers/usb/core/hub.c:5953
 process_one_work kernel/workqueue.c:3275 [inline]
 process_scheduled_works+0xaec/0x17a0 kernel/workqueue.c:3358
 worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439
 kthread+0x388/0x470 kernel/kthread.c:467
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 6025:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __kmalloc_cache_noprof+0x3a6/0x690 mm/slub.c:5297
 kmalloc_noprof include/linux/slab.h:962 [inline]
 kzalloc_noprof include/linux/slab.h:1204 [inline]
 dev_new drivers/usb/gadget/legacy/raw_gadget.c:193 [inline]
 raw_open+0x8d/0x530 drivers/usb/gadget/legacy/raw_gadget.c:435
 misc_open+0x2de/0x350 drivers/char/misc.c:163
 chrdev_open+0x4d0/0x5f0 fs/char_dev.c:411
 do_dentry_open+0x83d/0x13e0 fs/open.c:949
 vfs_open+0x3b/0x350 fs/open.c:1081
 do_open fs/namei.c:4671 [inline]
 path_openat+0x2e3d/0x38a0 fs/namei.c:4830
 do_file_open+0x23e/0x4a0 fs/namei.c:4859
 do_sys_openat2+0x113/0x200 fs/open.c:1366
 do_sys_open fs/open.c:1372 [inline]
 __do_sys_openat fs/open.c:1388 [inline]
 __se_sys_openat fs/open.c:1383 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1383
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 6024:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2670 [inline]
 slab_free mm/slub.c:6082 [inline]
 kfree+0x1c1/0x690 mm/slub.c:6399
 kref_put include/linux/kref.h:65 [inline]
 raw_release+0x191/0x260 drivers/usb/gadget/legacy/raw_gadget.c:474
 __fput+0x45e/0xa80 fs/file_table.c:469
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x69b/0x2320 kernel/exit.c:971
 do_group_exit+0x21b/0x2d0 kernel/exit.c:1112
 get_signal+0x125c/0x1310 kernel/signal.c:3034
 arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop+0x86/0x480 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
 do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88803e9aa000
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 2560 bytes inside of
 freed 4096-byte region [ffff88803e9aa000, ffff88803e9ab000)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x3e9a8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x80000000000040(head|node=0|zone=1)
page_type: f5(slab)
raw: 0080000000000040 ffff88813fe0e140 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000040004 00000000f5000000 0000000000000000
head: 0080000000000040 ffff88813fe0e140 dead000000000100 dead000000000122
head: 0000000000000000 0000000000040004 00000000f5000000 0000000000000000
head: 0080000000000003 ffffea0000fa6a01 00000000ffffffff 00000000ffffffff
head: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd2820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1221, tgid 1221 (kworker/u8:6), ts 91396353102, free_ts 91022075648
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x228/0x280 mm/page_alloc.c:1884
 prep_new_page mm/page_alloc.c:1892 [inline]
 get_page_from_freelist+0x28bb/0x2950 mm/page_alloc.c:3950
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5245
 alloc_pages_mpol+0xd1/0x380 mm/mempolicy.c:2486
 alloc_slab_page mm/slub.c:3236 [inline]
 allocate_slab+0x83/0x660 mm/slub.c:3411
 new_slab mm/slub.c:3469 [inline]
 ___slab_alloc+0x150/0x640 mm/slub.c:4334
 __slab_alloc_node mm/slub.c:4400 [inline]
 slab_alloc_node mm/slub.c:4776 [inline]
 __do_kmalloc_node mm/slub.c:5176 [inline]
 __kmalloc_node_track_caller_noprof+0x29d/0x7e0 mm/slub.c:5285
 kmalloc_reserve+0x136/0x290 net/core/skbuff.c:608
 __alloc_skb+0x204/0x390 net/core/skbuff.c:690
 alloc_skb include/linux/skbuff.h:1383 [inline]
 nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:818 [inline]
 nsim_dev_trap_report drivers/net/netdevsim/dev.c:875 [inline]
 nsim_dev_trap_report_work+0x29f/0xbc0 drivers/net/netdevsim/dev.c:921
 process_one_work kernel/workqueue.c:3275 [inline]
 process_scheduled_works+0xaec/0x17a0 kernel/workqueue.c:3358
 worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439
 kthread+0x388/0x470 kernel/kthread.c:467
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
page last free pid 6022 tgid 6022 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1433 [inline]
 __free_frozen_pages+0xfd0/0x1160 mm/page_alloc.c:2973
 __slab_free+0x24f/0x2a0 mm/slub.c:5490
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x97/0x100 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4459 [inline]
 slab_alloc_node mm/slub.c:4788 [inline]
 __do_kmalloc_node mm/slub.c:5176 [inline]
 __kvmalloc_node_noprof+0x371/0x8e0 mm/slub.c:6668
 seq_buf_alloc fs/seq_file.c:38 [inline]
 seq_read_iter+0x203/0xe20 fs/seq_file.c:210
 new_sync_read fs/read_write.c:493 [inline]
 vfs_read+0x58b/0xa70 fs/read_write.c:574
 ksys_read+0x156/0x270 fs/read_write.c:717
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff88803e9aa900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88803e9aa980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88803e9aaa00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff88803e9aaa80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88803e9aab00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/02/13 16:07 upstream c22e26bd0906 6a673c50 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: slab-use-after-free Read in raw_queue_event
2026/01/07 06:34 upstream f0b9d8eb98df d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: slab-use-after-free Read in raw_queue_event
* Struck through repros no longer work on HEAD.