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Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: <67b75198.050a0220.14d86d.02e2.GAE@google.com> References: <67b75198.050a0220.14d86d.02e2.GAE@google.com> To: syzbot Cc: dhowells@redhat.com, Dominique Martinet , jlayton@kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, netfs@lists.linux.dev, syzkaller-bugs@googlegroups.com Subject: Re: [syzbot] [netfs?] kernel BUG in folio_unlock (3) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <2453210.1740559313.1@warthog.procyon.org.uk> Content-Transfer-Encoding: quoted-printable Date: Wed, 26 Feb 2025 08:41:53 +0000 Message-ID: <2453211.1740559313@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 syzbot wrote: > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=3D141b4ba45800= 00 I'm not sure how this would even work. memcpy((void*)0x4000000001c0, "syz\000", 4); memcpy((void*)0x400000000480, "./file0\000", 8); memcpy((void*)0x4000000004c0, "9p\000", 3); memcpy((void*)0x400000000c00, "\x56\xc7\x8e\x3c\x73\x3d\x76\x69\x72\x74\x69\x6f\x2c\x6e\x6f\x65= \x78" "\x74\x65\x6e\x64\x2c\x61\x63\x63\x81\x73\x73\x3d\x61\x6e\x79\x2c= \x63" "\x61\x63\x68\x65\x3d\x66\x73\x63\x61\x63\x68\x65\x2c\x76\x65\x72= \x73" "\x69\x6f\x6e\x3d\x39\x70\x32\x30\x30\x30\x2e\x75", 63); syscall(__NR_mount, /*src=3D*/0x4000000001c0ul, /*dst=3D*/0x400000000480= ul, /*type=3D*/0x4000000004c0ul, /*flags=3D*/0ul, /*opts=3D*/0x40000= 0000c00ul); The options string is rubbish: [pid 8084] mount("syz", "./file0", "9p", 0, "V\307\216