From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oi2-f1.google.com (mail-oi2-f1.google.com [74.125.231.193]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 160172D97A6 for ; Sat, 22 Aug 2026 02:22:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.231.193 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787365369; cv=none; b=pUmeZHUXH9pFB31cWrmtVZcju1U9cynDEye6g3A1OVfmaxI5NYKgvv8hh+O9+Dzv2Ww08/L8Qa1TZ3mYhLY33Zw11rYW8nOZ6PjLPTKU2qX8MPp0KUTpKvznwkiV/KMX1aA6DLLceGQWg1oTcCF+uTWUPyPSilFhflkQoE8FZfQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787365369; c=relaxed/simple; bh=8VIVV5Gwtk6AiJPYuHMiGkztl8kPFGQCbd/uFeQHOPw=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=WA2ivFwJ4Z1XD3zFm68CHf75xmFPDLE1jgXgFfCUUm+527b7iwr88DtvLixMKvXQoAYQ87X6lc+cHC//hBTV5tPycKGC7/ZSspc59xWrG5oLpTKbJagfgeWsKm93OwiFipFx5zMxBpp9+YhZlq1J7yV5SrkFh519pTw9KanMD8g= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=74.125.231.193 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-oi2-f1.google.com with SMTP id 5614622812f47-4960a23d5e1so638568b6e.1 for ; Fri, 21 Aug 2026 19:22:46 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1787365366; x=1787970166; h=content-type:to:from:subject:message-id:date:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=LfjivAHT6jmvjSHIEKQAC5+k/gRivMHBG8qkHdI+2Cs=; b=T3/mwXtjYQbncmrTBsj5ERaBK8TLFBDkvp6H3eEdlk/tQZTf9Lc08fJ1uUYf2nBiD2 HUx7M3BT/M1sUu0xP3Tu+jZXBa2Fws346fOgB7vfnGmc6PdMs1Dn1TwScDqSB3iJxY7/ BxZa9cerYLsFiheLjjfm/5m8ZwNV94aFsMDV6xPtd1C/pfBtpcab12CeKT0YQCsMAQp4 V6btD3JOTPv11JWgCk57ukYmovOog/R/m5ljU4ZzL5m6G8Ma2ZwptZcIEjxae4emrLaZ ayqpO8+oD+/0Xd3/Thus/mmVQdUanZi1tWjlu0XhiU2T0gViBRgcI8R1zElXSENOEiDx 7zAg== X-Forwarded-Encrypted: i=1; AHgh+RrQMe1dlfneJaCteOzTT9ZFQu7sKyrLnHLx2CAx1dBdaa053aCSi4iEI2HIMohh4SGAqmVUIlw/1nIBAcY=@vger.kernel.org X-Gm-Message-State: AFuF++lTPYJjXXg7vjoQPXByM6IytkiM9sIwm+CLvLNDZjH0u7gNyjoI QhlbRLWBZcslBGaORoPFVRXC3r7DaDM4IBZ+Xt6uvFTphRVW2vbi23oFmqRBQjyyrnbOFidQkcH Uhim2lfc+K3IEmtbcaWCLeMaGDala9iKD431tpwvU0hzOjGwC9uv7PLZMXyo= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6808:c14a:b0:4aa:d5f:123e with SMTP id 5614622812f47-4b309a47942mr4642882b6e.9.1787365365895; Fri, 21 Aug 2026 19:22:45 -0700 (PDT) Date: Fri, 21 Aug 2026 19:22:45 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a8907f5.dbb3a75c.13dd47.0027.GAE@google.com> Subject: [syzbot] [usb?] KASAN: slab-use-after-free Read in dummy_timer From: syzbot To: gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 7079a12d7506 Add linux-next specific files for 20260820 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=16defa25580000 kernel config: https://syzkaller.appspot.com/x/.config?x=61cbaf6d30cb97db dashboard link: https://syzkaller.appspot.com/bug?extid=ba7702afee9d7d1375f0 compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/37f483d86dfc/disk-7079a12d.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/2b2d02ae6b4b/vmlinux-7079a12d.xz kernel image: https://storage.googleapis.com/syzbot-assets/ae5e9209582e/bzImage-7079a12d.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+ba7702afee9d7d1375f0@syzkaller.appspotmail.com ================================================================== BUG: KASAN: slab-use-after-free in find_endpoint drivers/usb/gadget/udc/dummy_hcd.c:1618 [inline] BUG: KASAN: slab-use-after-free in dummy_timer+0xcdb/0x4cf0 drivers/usb/gadget/udc/dummy_hcd.c:1890 Read of size 1 at addr ffff8880279f9127 by task syz.0.380/6887 CPU: 0 UID: 0 PID: 6887 Comm: syz.0.380 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description+0x55/0x1e0 mm/kasan/report.c:378 print_report+0x58/0x70 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 find_endpoint drivers/usb/gadget/udc/dummy_hcd.c:1618 [inline] dummy_timer+0xcdb/0x4cf0 drivers/usb/gadget/udc/dummy_hcd.c:1890 __run_hrtimer kernel/time/hrtimer.c:2068 [inline] __hrtimer_run_queues+0x3bc/0xa10 kernel/time/hrtimer.c:2125 hrtimer_run_softirq+0x1e3/0x2e0 kernel/time/hrtimer.c:2142 handle_softirqs+0x226/0x860 kernel/softirq.c:645 __do_softirq kernel/softirq.c:679 [inline] invoke_softirq kernel/softirq.c:519 [inline] __irq_exit_rcu+0xcb/0x220 kernel/softirq.c:767 irq_exit_rcu+0x9/0x30 kernel/softirq.c:784 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1062 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:211 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x47/0x80 kernel/locking/spinlock.c:221 Code: f7 e8 5d 6a b3 f5 f7 c3 00 02 00 00 74 05 e8 c0 a2 df f5 9c 58 a9 00 02 00 00 75 29 f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 14 86 a4 f5 65 48 8b 05 bc ce c8 07 48 85 c0 74 18 5b 41 5e e9 RSP: 0018:ffffc9000398fd08 EFLAGS: 00000206 RAX: 0000000000000006 RBX: 0000000000000282 RCX: 8000000000000001 RDX: 0000000000000006 RSI: ffffffff8e586ce4 RDI: 0000000000000001 RBP: ffffc9000398fea8 R08: ffffffff909ba57f R09: 1ffffffff21374af R10: dffffc0000000000 R11: fffffbfff21374b0 R12: dffffc0000000000 R13: 1ffff92000731fac R14: ffff888069752910 R15: ffffc9000398fda0 hiddev_ioctl+0x1097/0x16f0 drivers/hid/usbhid/hiddev.c:726 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f32ba19e0d9 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:00007f32bafd6028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f32ba425fa0 RCX: 00007f32ba19e0d9 RDX: 0000200000000400 RSI: 00000000400c4808 RDI: 0000000000000008 RBP: 00007f32ba235024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f32ba426038 R14: 00007f32ba425fa0 R15: 00007ffdf6daec98 Allocated by task 6607: 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] __do_kmalloc_node mm/slub.c:5414 [inline] __kmalloc_noprof+0x36b/0x720 mm/slub.c:5439 _kmalloc_noprof include/linux/slab.h:995 [inline] usb_copy_descriptors+0xf7/0x320 drivers/usb/gadget/config.c:82 f_midi2_bind+0x2736/0x2c40 drivers/usb/gadget/function/f_midi2.c:2026 usb_add_function+0x2e1/0x9f0 drivers/usb/gadget/composite.c:333 configfs_composite_bind+0xde0/0x1410 drivers/usb/gadget/configfs.c:1802 gadget_bind_driver+0x2ca/0x9e0 drivers/usb/gadget/udc/core.c:1662 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x254/0xae0 drivers/base/dd.c:706 __driver_probe_device+0x1e8/0x360 drivers/base/dd.c:868 driver_probe_device+0x4f/0x240 drivers/base/dd.c:898 __driver_attach+0x339/0x600 drivers/base/dd.c:1292 bus_for_each_dev+0x23b/0x2c0 drivers/base/bus.c:383 bus_add_driver+0x345/0x670 drivers/base/bus.c:763 driver_register+0x23a/0x320 drivers/base/driver.c:174 usb_gadget_register_driver_owner+0xf9/0x270 drivers/usb/gadget/udc/core.c:1752 gadget_dev_desc_UDC_store+0x1c9/0x2f0 drivers/usb/gadget/configfs.c:300 flush_write_buffer fs/configfs/file.c:207 [inline] configfs_write_iter+0x337/0x430 fs/configfs/file.c:229 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x612/0xba0 fs/read_write.c:687 ksys_write+0x150/0x270 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 6759: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:584 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:2748 [inline] slab_free mm/slub.c:6499 [inline] kfree+0x1c5/0x650 mm/slub.c:6792 usb_free_descriptors include/linux/usb/gadget.h:903 [inline] usb_free_all_descriptors+0x78/0x110 drivers/usb/gadget/config.c:151 purge_configs_funcs+0x248/0x3d0 drivers/usb/gadget/configfs.c:1600 configfs_composite_unbind+0xa4/0x1c0 drivers/usb/gadget/configfs.c:1846 gadget_unbind_driver+0x1cb/0x410 drivers/usb/gadget/udc/core.c:1724 device_remove drivers/base/dd.c:616 [inline] __device_release_driver drivers/base/dd.c:1349 [inline] device_release_driver_internal+0x48b/0x880 drivers/base/dd.c:1372 driver_detach+0x1f3/0x2d0 drivers/base/dd.c:1435 bus_remove_driver+0x226/0x320 drivers/base/bus.c:832 usb_gadget_unregister_driver+0x4e/0x70 drivers/usb/gadget/udc/core.c:1784 unregister_gadget drivers/usb/gadget/configfs.c:263 [inline] gadget_dev_desc_UDC_store+0x17a/0x2f0 drivers/usb/gadget/configfs.c:290 flush_write_buffer fs/configfs/file.c:207 [inline] configfs_write_iter+0x337/0x430 fs/configfs/file.c:229 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x612/0xba0 fs/read_write.c:687 ksys_write+0x150/0x270 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff8880279f9000 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 295 bytes inside of freed 512-byte region [ffff8880279f9000, ffff8880279f9200) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x279f8 head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000040 ffff88813ff15c80 dead000000000100 dead000000000122 raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88813ff15c80 dead000000000100 dead000000000122 head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000002 ffffffffffffff01 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000004 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5615, tgid 5615 (syz-executor), ts 90656481770 set_page_owner include/linux/page_owner.h:33 [inline] post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1871 prep_new_page mm/page_alloc.c:1879 [inline] get_page_from_freelist+0x2209/0x2280 mm/page_alloc.c:3943 __alloc_frozen_pages_noprof+0x217/0x5a0 mm/page_alloc.c:5436 alloc_slab_page mm/slub.c:3347 [inline] allocate_slab+0x7d/0x620 mm/slub.c:3462 new_slab mm/slub.c:3513 [inline] refill_objects+0x2d5/0x350 mm/slub.c:7410 refill_sheaf mm/slub.c:2885 [inline] __pcs_replace_empty_main+0x2c8/0x6c0 mm/slub.c:4774 alloc_from_pcs mm/slub.c:4850 [inline] slab_alloc_node mm/slub.c:4984 [inline] __do_kmalloc_node mm/slub.c:5413 [inline] __kmalloc_noprof+0x47b/0x720 mm/slub.c:5439 _kmalloc_noprof include/linux/slab.h:995 [inline] _kzalloc_noprof include/linux/slab.h:1312 [inline] fib6_info_alloc+0x30/0xf0 net/ipv6/ip6_fib.c:155 ip6_route_info_create+0x149/0x890 net/ipv6/route.c:3833 ip6_route_add+0x49/0x1b0 net/ipv6/route.c:3962 addrconf_add_mroute+0x2d1/0x370 net/ipv6/addrconf.c:2568 addrconf_add_dev net/ipv6/addrconf.c:2586 [inline] inet6_addr_add+0x2b8/0xb50 net/ipv6/addrconf.c:3056 inet6_rtm_newaddr+0x9fc/0xe00 net/ipv6/addrconf.c:5095 rtnetlink_rcv_msg+0x802/0xc00 net/core/rtnetlink.c:7132 netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2556 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x7bd/0x940 net/netlink/af_netlink.c:1345 page last free pid 5327 tgid 5327 ts 55156601657 stack trace: reset_page_owner include/linux/page_owner.h:26 [inline] __free_pages_prepare mm/page_alloc.c:1418 [inline] __free_frozen_pages+0xc93/0xd90 mm/page_alloc.c:2962 __slab_free+0x274/0x2c0 mm/slub.c:5815 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x99/0x100 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:4683 [inline] slab_alloc_node mm/slub.c:4996 [inline] __do_kmalloc_node mm/slub.c:5413 [inline] __kmalloc_noprof+0x307/0x720 mm/slub.c:5439 _kmalloc_noprof include/linux/slab.h:995 [inline] tomoyo_realpath_from_path+0xef/0x640 security/tomoyo/realpath.c:251 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path_perm+0x283/0x560 security/tomoyo/file.c:827 security_inode_getattr+0x12b/0x310 security/security.c:1895 vfs_getattr fs/stat.c:259 [inline] vfs_fstat fs/stat.c:281 [inline] __do_sys_newfstat fs/stat.c:551 [inline] __se_sys_newfstat fs/stat.c:546 [inline] __x64_sys_newfstat+0x133/0x270 fs/stat.c:546 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff8880279f9000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880279f9080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880279f9100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880279f9180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880279f9200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ================================================================== ---------------- Code disassembly (best guess): 0: f7 e8 imul %eax 2: 5d pop %rbp 3: 6a b3 push $0xffffffffffffffb3 5: f5 cmc 6: f7 c3 00 02 00 00 test $0x200,%ebx c: 74 05 je 0x13 e: e8 c0 a2 df f5 call 0xf5dfa2d3 13: 9c pushf 14: 58 pop %rax 15: a9 00 02 00 00 test $0x200,%eax 1a: 75 29 jne 0x45 1c: f7 c3 00 02 00 00 test $0x200,%ebx 22: 74 01 je 0x25 24: fb sti 25: bf 01 00 00 00 mov $0x1,%edi * 2a: e8 14 86 a4 f5 call 0xf5a48643 <-- trapping instruction 2f: 65 48 8b 05 bc ce c8 mov %gs:0x7c8cebc(%rip),%rax # 0x7c8cef3 36: 07 37: 48 85 c0 test %rax,%rax 3a: 74 18 je 0x54 3c: 5b pop %rbx 3d: 41 5e pop %r14 3f: e9 .byte 0xe9 --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup