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([2a01:e11:5400:7400:d70c:eed6:c2c4:fae7]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-42e96a56fddsm144297025e9.46.2024.09.30.02.06.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 30 Sep 2024 02:06:35 -0700 (PDT) From: Gianfranco Trad To: gianf.trad@gmail.com Cc: akpm@linux-foundation.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, skhan@linuxfoundation.org, syzbot+4089e577072948ac5531@syzkaller.appspotmail.com, willy@infradead.org Subject: [PATCH v2] Fix NULL pointer dereference in read_cache_folio Date: Mon, 30 Sep 2024 11:02:26 +0200 Message-ID: <20240930090225.28517-2-gianf.trad@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240929230548.370027-3-gianf.trad@gmail.com> References: <20240929230548.370027-3-gianf.trad@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Add check on filler to prevent NULL pointer dereference condition in read_cache_folio[1]. [1] https://syzkaller.appspot.com/bug?extid=3D4089e577072948ac5531 Reported-by: syzbot+4089e577072948ac5531@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=3D4089e577072948ac5531 Tested-by: syzbot+4089e577072948ac5531@syzkaller.appspotmail.com Signed-off-by: Gianfranco Trad --- Notes: changes in v2: - refactored check on filler. mm/filemap.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/mm/filemap.c b/mm/filemap.c index 4f3753f0a158..88de8029133c 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -2360,6 +2360,8 @@ static int filemap_read_folio(struct file *file, fill= er_t filler, /* Start the actual read. The read will unlock the page. */ if (unlikely(workingset)) psi_memstall_enter(&pflags); + if (!filler) + return -EIO; error =3D filler(file, folio); if (unlikely(workingset)) psi_memstall_leave(&pflags); --=20 2.43.0