Re: [syzbot] [serial?] KASAN: slab-use-after-free Write in tty_init_dev

[syzbot <syzbot+fe63e4d633540f230624@syzkaller.appspotmail.com>]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
WARNING in gs_close

------------[ cut here ]------------
1
WARNING: drivers/usb/gadget/function/u_serial.c:738 at gs_close+0x44c/0xca0 drivers/usb/gadget/function/u_serial.c:738, CPU#2: syz-executor933/6041
Modules linked in:
CPU: 2 UID: 0 PID: 6041 Comm: syz-executor933 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:gs_close+0x44c/0xca0 drivers/usb/gadget/function/u_serial.c:738
Code: 00 c7 83 d0 04 00 00 00 00 00 00 e9 03 02 00 00 e8 19 50 21 fa 31 ff 44 89 ee e8 7f 4a 21 fa 45 85 ed 75 62 e8 05 50 21 fa 90 <0f> 0b 90 e8 fc 4f 21 fa 48 89 ef e8 54 69 e8 03 48 8b 0c 24 48 b8
RSP: 0018:ffffc90003f376f0 EFLAGS: 00010093
RAX: 0000000000000000 RBX: ffff8880257b6000 RCX: 0000000000000001
RDX: ffff88802b12cb00 RSI: ffffffff87eac10b RDI: ffff88802b12cb00
RBP: ffff8880257b6388 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880257b6184
R13: 0000000000000000 R14: ffff88803a24a000 R15: 0000000000000000
FS:  00007f6c62ee46c0(0000) GS:ffff8880d5d5d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000560a83265d20 CR3: 000000003538f000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 tty_release+0x40e/0x1300 drivers/tty/tty_io.c:1718
 tty_open+0x31d/0xe20 drivers/tty/tty_io.c:2119
 chrdev_open+0x234/0x6a0 fs/char_dev.c:411
 do_dentry_open+0x6ab/0x14d0 fs/open.c:996
 vfs_open+0x82/0x3f0 fs/open.c:1101
 do_open fs/namei.c:4837 [inline]
 path_openat+0x19fa/0x2440 fs/namei.c:5000
 do_file_open+0x20e/0x430 fs/namei.c:5029
 do_sys_openat2+0x10f/0x1e0 fs/open.c:1417
 do_sys_open fs/open.c:1423 [inline]
 __do_sys_openat fs/open.c:1439 [inline]
 __se_sys_openat fs/open.c:1434 [inline]
 __x64_sys_openat+0x12d/0x210 fs/open.c:1434
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f6c6373aa1e
Code: 08 0f 85 f5 e2 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 <c3> 90 41 57 41 56 4d 89 c6 41 55 4d 89 cd 41 54 55 53 48 83 ec 08
RSP: 002b:00007f6c62ee4158 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f6c62ee46c0 RCX: 00007f6c6373aa1e
RDX: 0000000000000002 RSI: 00007f6c63786028 RDI: ffffffffffffff9c
RBP: 0000000000000021 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: ffffffffffffffd0
R13: 0000000000000000 R14: 00007ffeaabd1a60 R15: 00007ffeaabd1b48
 </TASK>


Tested on:

commit:         893e1178 Merge tag 'x86_urgent_for_7.3-rc3' of git://g..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12235749580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=8c5c3949d762a91f
dashboard link: https://syzkaller.appspot.com/bug?extid=fe63e4d633540f230624
compiler:       gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
patch:          https://syzkaller.appspot.com/x/patch.diff?x=130c2c8e580000