From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oo1-f80.google.com (mail-oo1-f80.google.com [209.85.161.80]) (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 CC74C361651 for ; Fri, 14 Aug 2026 03:07:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.80 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786676864; cv=none; b=J41Lne6tL2FFqOnkuQf1uVfbFbl25NbphI4IZrt5WyetjT3LBFsE/qHxdNthsao1Aeq5fdrDo8qSkdAuomnJ9Hz73aqwov828imy2BtinP7xx5Tf7ZWhDvjkZud0giCjXdbBqWZJGY9b39lXxBpHvX3128JPzYEd2fjPE/uppZo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786676864; c=relaxed/simple; bh=bCpOcqbHtU10mfuqaRyfjl8tUHXL1EJx0UlkRJD2ulA=; h=MIME-Version:Date:In-Reply-To:Message-ID:Subject:From:To: Content-Type; 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2002:a05:6820:1889:b0:6b0:1b86:fb0 with SMTP id 006d021491bc7-6b0d68c187cmr2619526eaf.31.1786676861669; Thu, 13 Aug 2026 20:07:41 -0700 (PDT) Date: Thu, 13 Aug 2026 20:07:41 -0700 In-Reply-To: <6a7a82f8.01d0871a.3a0d52.00b9.GAE@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a7e867d.e5d9fd66.2f6faa.0012.GAE@google.com> Subject: Re: [syzbot] [serial?] KASAN: slab-use-after-free Write in release_tty From: syzbot To: gregkh@linuxfoundation.org, jirislaby@kernel.org, linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" syzbot has found a reproducer for the following issue on: HEAD commit: 3aa1dcaa4f6f Revert "wifi: mt76: Disable napi when removin.. git tree: upstream console+strace: https://syzkaller.appspot.com/x/log.txt?x=13405279580000 kernel config: https://syzkaller.appspot.com/x/.config?x=158601bb8cb292dd dashboard link: https://syzkaller.appspot.com/bug?extid=bca09f5d8b843bbf7571 compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=115c5ac6580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13320279580000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/7b68a8c2f502/disk-3aa1dcaa.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/facf5b434f86/vmlinux-3aa1dcaa.xz kernel image: https://storage.googleapis.com/syzbot-assets/51aa0bb3bd0b/bzImage-3aa1dcaa.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+bca09f5d8b843bbf7571@syzkaller.appspotmail.com ================================================================== BUG: KASAN: slab-use-after-free in release_tty+0x36b/0x560 drivers/tty/tty_io.c:1584 Write of size 8 at addr ffff888027479120 by task syz-executor331/5612 CPU: 1 UID: 0 PID: 5612 Comm: syz-executor331 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 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 release_tty+0x36b/0x560 drivers/tty/tty_io.c:1584 tty_release_struct+0xb8/0xd0 drivers/tty/tty_io.c:1692 tty_release+0xc6b/0x1680 drivers/tty/tty_io.c:1852 __fput+0x42a/0xa80 fs/file_table.c:512 fput_close_sync+0x11f/0x240 fs/file_table.c:617 __do_sys_close fs/open.c:1511 [inline] __se_sys_close fs/open.c:1496 [inline] __x64_sys_close+0x7e/0x110 fs/open.c:1496 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f5468aadc0e Code: 08 0f 85 65 e1 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 90 41 57 41 56 4d 89 c6 41 55 4d 89 cd 41 54 55 53 48 83 ec 08 RSP: 002b:00007ffe95c075a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000003 RAX: ffffffffffffffda RBX: 000055558acba400 RCX: 00007f5468aadc0e RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 0000000000000008 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000000182c2 R13: 00000000000182f4 R14: 00007f5468b4ab2c R15: 00007f5468b4ab20 Allocated by task 5613: 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+0x3d2/0x6b0 mm/slub.c:5489 _kmalloc_noprof include/linux/slab.h:988 [inline] _kzalloc_noprof include/linux/slab.h:1309 [inline] gs_port_alloc drivers/usb/gadget/function/u_serial.c:1218 [inline] gserial_alloc_line_no_console+0x23a/0x6e0 drivers/usb/gadget/function/u_serial.c:1298 gserial_alloc_line+0x18/0x90 drivers/usb/gadget/function/u_serial.c:1332 acm_alloc_instance+0xc7/0x140 drivers/usb/gadget/function/f_acm.c:891 try_get_usb_function_instance drivers/usb/gadget/functions.c:28 [inline] usb_get_function_instance+0xe3/0x2f0 drivers/usb/gadget/functions.c:44 function_make+0x127/0x360 drivers/usb/gadget/configfs.c:626 configfs_mkdir+0x4f6/0x9e0 fs/configfs/dir.c:1360 vfs_mkdir+0x402/0x620 fs/namei.c:5276 filename_mkdirat+0x289/0x520 fs/namei.c:5309 __do_sys_mkdirat fs/namei.c:5330 [inline] __se_sys_mkdirat+0x35/0x150 fs/namei.c:5327 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 5613: 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:2677 [inline] slab_free mm/slub.c:6377 [inline] kfree+0x1c5/0x6c0 mm/slub.c:6692 gserial_free_port+0x248/0x2c0 drivers/usb/gadget/function/u_serial.c:1262 gserial_free_line+0xc3/0x1f0 drivers/usb/gadget/function/u_serial.c:1279 acm_free_instance+0x39/0x60 drivers/usb/gadget/function/f_acm.c:875 usb_put_function_instance+0x90/0xb0 drivers/usb/gadget/functions.c:77 config_item_cleanup fs/configfs/item.c:128 [inline] config_item_release+0x13a/0x2d0 fs/configfs/item.c:137 configfs_rmdir+0x885/0x950 fs/configfs/dir.c:1571 vfs_rmdir+0x3e9/0x6b0 fs/namei.c:5381 filename_rmdir+0x292/0x520 fs/namei.c:5438 __do_sys_rmdir fs/namei.c:5461 [inline] __se_sys_rmdir+0x2e/0x140 fs/namei.c:5458 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888027479000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 288 bytes inside of freed 2048-byte region [ffff888027479000, ffff888027479800) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x27478 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 ffff88813ffb2000 dead000000000100 dead000000000122 raw: 0000000000000000 0000000800080008 00000000f5000000 0000000000000000 head: 0080000000000040 ffff88813ffb2000 dead000000000100 dead000000000122 head: 0000000000000000 0000000800080008 00000000f5000000 0000000000000000 head: 0080000000000003 fffffffffffffe01 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 765, tgid 765 (kworker/u8:6), ts 8666777166, free_ts 8122171962 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1859 prep_new_page mm/page_alloc.c:1867 [inline] get_page_from_freelist+0x262a/0x26a0 mm/page_alloc.c:3946 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5304 alloc_slab_page mm/slub.c:3266 [inline] allocate_slab+0x79/0x5e0 mm/slub.c:3380 new_slab mm/slub.c:3426 [inline] refill_objects+0x2d8/0x350 mm/slub.c:7310 refill_sheaf mm/slub.c:2804 [inline] __pcs_replace_empty_main+0x330/0x690 mm/slub.c:4675 alloc_from_pcs mm/slub.c:4773 [inline] slab_alloc_node mm/slub.c:4905 [inline] __do_kmalloc_node mm/slub.c:5333 [inline] __kmalloc_noprof+0x544/0x780 mm/slub.c:5359 _kmalloc_noprof include/linux/slab.h:992 [inline] _kzalloc_noprof include/linux/slab.h:1309 [inline] scsi_alloc_target+0x138/0xbc0 drivers/scsi/scsi_scan.c:505 __scsi_scan_target+0x164/0xe10 drivers/scsi/scsi_scan.c:1780 scsi_scan_channel drivers/scsi/scsi_scan.c:1885 [inline] scsi_scan_host_selected+0x36e/0x680 drivers/scsi/scsi_scan.c:1914 do_scsi_scan_host drivers/scsi/scsi_scan.c:2047 [inline] do_scan_async+0x10e/0x660 drivers/scsi/scsi_scan.c:2057 async_run_entry_fn+0x9d/0x430 kernel/async.c:129 process_one_work kernel/workqueue.c:3322 [inline] process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 page last free pid 10 tgid 10 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1406 [inline] free_pages_prepare+0x946/0xa40 mm/page_alloc.c:1451 __free_contig_range_common+0x174/0x340 mm/page_alloc.c:6897 __free_contig_range mm/page_alloc.c:6942 [inline] free_pages_bulk+0x48/0x120 mm/page_alloc.c:5257 vm_area_free_pages mm/vmalloc.c:3461 [inline] vfree+0x26f/0x510 mm/vmalloc.c:3510 delayed_vfree_work+0x55/0x80 mm/vmalloc.c:3414 process_one_work kernel/workqueue.c:3322 [inline] process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Memory state around the buggy address: ffff888027479000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888027479080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888027479100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888027479180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888027479200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== --- If you want syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing.