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Tue, 07 Apr 2026 07:32:04 -0700 (PDT) From: "Ritesh Harjani (IBM)" To: linuxppc-dev@lists.ozlabs.org, Haren Myneni Cc: Madhavan Srinivasan , Christophe Leroy , Venkat Rao Bagalkote , Nicholas Piggin , linux-kernel@vger.kernel.org, "Ritesh Harjani (IBM)" Subject: [RFC v1 2/6] pseries/papr-hvpipe: Fix the usage of copy_to_user() Date: Tue, 7 Apr 2026 20:01:36 +0530 Message-ID: <7e618bc382608acc390054786e3119db2856822b.1775569027.git.ritesh.list@gmail.com> X-Mailer: git-send-email 2.50.1 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit copy_to_user() return bytes_not_copied to the user buffer. If there was an error writing bytes into the user buffer, i.e. if copy_to_user returns a non-zero value, then we simply return -EFAULT from the ->read() call. Signed-off-by: Ritesh Harjani (IBM) --- arch/powerpc/platforms/pseries/papr-hvpipe.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/arch/powerpc/platforms/pseries/papr-hvpipe.c b/arch/powerpc/platforms/pseries/papr-hvpipe.c index ef10f5a5a4fa..fffebbae113c 100644 --- a/arch/powerpc/platforms/pseries/papr-hvpipe.c +++ b/arch/powerpc/platforms/pseries/papr-hvpipe.c @@ -206,10 +206,11 @@ static int hvpipe_rtas_recv_msg(char __user *buf, int size) bytes_written, size); bytes_written = size; } - ret = copy_to_user(buf, + if (copy_to_user(buf, rtas_work_area_raw_buf(work_area), - bytes_written); - if (!ret) + bytes_written)) + ret = -EFAULT; + else ret = bytes_written; } } else { @@ -376,7 +377,7 @@ static ssize_t papr_hvpipe_handle_read(struct file *file, ret = copy_to_user(buf, &hdr, HVPIPE_HDR_LEN); if (ret) - return ret; + return -EFAULT; /* * Message event has payload, so get the payload with -- 2.39.5