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Date:   Sat, 12 Aug 2023 18:34:34 -0700
In-Reply-To: <20230813010800.1071-1-hdanton@sina.com>
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Subject: Re: [syzbot] [udf?] KASAN: use-after-free Read in udf_sync_fs
From:   syzbot <syzbot+82df44ede2faca24c729@syzkaller.appspotmail.com>
To:     hdanton@sina.com, linux-kernel@vger.kernel.org,
        syzkaller-bugs@googlegroups.com
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Hello,

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

------------[ cut here ]------------
WARNING: CPU: 1 PID: 5372 at fs/udf/super.c:2341 udf_sync_fs+0x321/0x450
Modules linked in:
CPU: 1 PID: 5372 Comm: syz-executor.0 Not tainted 6.5.0-rc5-syzkaller-00296-gf8de32cc060b-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
RIP: 0010:udf_sync_fs+0x321/0x450 fs/udf/super.c:2340
Code: 04 25 28 00 00 00 48 3b 84 24 80 00 00 00 0f 85 34 01 00 00 31 c0 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 cf ad 88 fe <0f> 0b e9 78 fe ff ff 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c 8c fd ff
RSP: 0018:ffffc900064b7be0 EFLAGS: 00010293
RAX: ffffffff83030a61 RBX: 0000000000000200 RCX: ffff888022cabb80
RDX: 0000000000000000 RSI: 0000000000000200 RDI: 0000000000004e25
RBP: ffffc900064b7cb0 R08: ffffffff830308d2 R09: 1ffffffff1d30e8d
R10: dffffc0000000000 R11: fffffbfff1d30e8e R12: 0000000000004e25
R13: ffff88802baba018 R14: ffffc900064b7c40 R15: ffff8880679f7000
FS:  0000555555808480(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555555811938 CR3: 000000002b2fe000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 sync_filesystem+0xec/0x220 fs/sync.c:56
 generic_shutdown_super+0x6f/0x340 fs/super.c:472
 kill_block_super+0x68/0xa0 fs/super.c:1417
 deactivate_locked_super+0xa4/0x110 fs/super.c:330
 cleanup_mnt+0x426/0x4c0 fs/namespace.c:1254
 task_work_run+0x24a/0x300 kernel/task_work.c:179
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xd9/0x100 kernel/entry/common.c:171
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:204
 __syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline]
 syscall_exit_to_user_mode+0x64/0x280 kernel/entry/common.c:297
 do_syscall_64+0x4d/0xc0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f506367de17
Code: b0 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 0f 1f 44 00 00 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 b0 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffc04cedad8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f506367de17
RDX: 0000000000000000 RSI: 000000000000000a RDI: 00007ffc04cedb90
RBP: 00007ffc04cedb90 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffc04ceec50
R13: 00007f50636c73b9 R14: 0000000000014bdb R15: 0000000000000007
 </TASK>


Tested on:

commit:         f8de32cc Merge tag 'tpmdd-v6.5-rc7' of git://git.kerne..
git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=134267c3a80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=171b698bc2e613cf
dashboard link: https://syzkaller.appspot.com/bug?extid=82df44ede2faca24c729
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=13debc65a80000