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AJvYcCXDQt4Lv+8iVlJcUe/BrCBfrvrGkwu38Jt2bFyqqnEnISaf4suUouOUhZkkHy2w4RlV3MkG@lists.linux.dev X-Gm-Message-State: AOJu0YxM80oi39Sxqgj0qeeznfLYrukX6k6IqN3RTQ5O5bjp9V1GSv3A wuKVk0w9iCRYwuA6oy3GvNW0w5PMVn37VgPzcGi4gQeD7MnqtIjLdc3RBYp0xqEyQ1G1BthG769 Zvt4M7LStZWi489vUpzAXmejV7zocCcEKKGLXNzOJdcBNbzuET/OB/TjWWmk= X-Google-Smtp-Source: AGHT+IGhvQdQ1rnNUg7em2QGQiFzvqEhT3LwDf6es0ungmVDt4/JphxGZD7eCFZIEomXzEnT23TdbSP+cmIP2cVrADIEKOeFTSIe Precedence: bulk X-Mailing-List: v9fs@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6e02:b49:b0:3e3:cc1b:2b5e with SMTP id e9e14a558f8ab-3e6d6acf0c9mr19983935ab.15.1755749165619; Wed, 20 Aug 2025 21:06:05 -0700 (PDT) Date: Wed, 20 Aug 2025 21:06:05 -0700 In-Reply-To: X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <68a69b2d.050a0220.3d78fd.0016.GAE@google.com> Subject: Re: [syzbot] [v9fs?] UBSAN: shift-out-of-bounds in v9fs_get_tree From: syzbot To: asmadeus@codewreck.org, ericvh@kernel.org, linux-kernel@vger.kernel.org, linux_oss@crudebyte.com, lucho@ionkov.net, sandeen@redhat.com, syzkaller-bugs@googlegroups.com, v9fs@lists.linux.dev Content-Type: text/plain; charset="UTF-8" Hello, syzbot has tested the proposed patch but the reproducer is still triggering an issue: UBSAN: shift-out-of-bounds in v9fs_get_tree ------------[ cut here ]------------ UBSAN: shift-out-of-bounds in fs/9p/vfs_super.c:57:22 shift exponent 32 is too large for 32-bit type 'int' CPU: 1 UID: 0 PID: 6530 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 ubsan_epilogue+0xa/0x40 lib/ubsan.c:233 __ubsan_handle_shift_out_of_bounds+0x386/0x410 lib/ubsan.c:494 v9fs_fill_super fs/9p/vfs_super.c:57 [inline] v9fs_get_tree+0x957/0xa90 fs/9p/vfs_super.c:125 vfs_get_tree+0x92/0x2b0 fs/super.c:1752 do_new_mount+0x2a2/0xa30 fs/namespace.c:3810 do_mount fs/namespace.c:4138 [inline] __do_sys_mount fs/namespace.c:4349 [inline] __se_sys_mount+0x317/0x410 fs/namespace.c:4326 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f6fe798ebe9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f6fe87a7038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007f6fe7bb5fa0 RCX: 00007f6fe798ebe9 RDX: 00002000000000c0 RSI: 00002000000025c0 RDI: 0000000000000000 RBP: 00007f6fe7a11e19 R08: 0000200000000280 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f6fe7bb6038 R14: 00007f6fe7bb5fa0 R15: 00007ffebc4cd908 ---[ end trace ]--- Tested on: commit: 5303936d Add linux-next specific files for 20250820 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=156cb3bc580000 kernel config: https://syzkaller.appspot.com/x/.config?x=2619a6495a03d773 dashboard link: https://syzkaller.appspot.com/bug?extid=30c83da54e948f6e9436 compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 patch: https://syzkaller.appspot.com/x/patch.diff?x=17fcd442580000