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Thu, 1 Oct 2026 04:17:58 +0000 (GMT) Message-ID: <9af9f47d-b99e-46d4-bb6c-06d28b037a34@linux.ibm.com> Date: Thu, 1 Oct 2026 09:47:56 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 09/11] powerpc/papr_scm: Return the string length from the sysfs show functions To: Kees Cook , Bill Wendling Cc: "Christophe Leroy (CS GROUP)" , =?UTF-8?Q?Uwe_Kleine-K=C3=B6nig?= , linuxppc-dev@lists.ozlabs.org, Michael Ellerman , Nicholas Piggin , Shivaprasad G Bhat , Thorsten Blum , Andy Shevchenko , Steven Rostedt , nikitash.mariiaw@gmail.com, Greg KH , linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org References: <20260930235231.out.387-kees@kernel.org> <20260930235247.157921-9-kees@kernel.org> Content-Language: en-US From: Madhavan Srinivasan In-Reply-To: <20260930235247.157921-9-kees@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Proofpoint-Spam-Info: AW1haW4tMjYxMDAxMDAxNiBTYWx0ZWRfX6FsMoRD4CcsF 6vSCZe6HpN3lttd6FWuf1EcxP+QvtROnkvjBgKTgHeqagH5md1URabZGny8amSX5YgqOUTWHskt y6D4Ulhs2QbhMvPIX15+pFG41szuWbg= X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYxMDAxMDAxNiBTYWx0ZWRfX1rZ+6AhcJBIv GmZZtmcZl1Pgw6hyxMC7cxo7/5MWt0MFg6n1EN0YXuKhHzZYy1ioyjUjoDnu5/tNZYbibffvUoc u6r/dTofzrlKdpk2494mLCwvA/AMkUdHCHRbJLHWlGaKa6ZSRnjsY2WTUGwrfbYbnjdgyPPOCvl RMavMUWmKAxXjFsCCBQTmEpR3CRMZ5nGHI1gCpIf3EpEbqGcx4z69TkbmC+4nXIlxjvZJ+DjcvK k0mUIBjXEAMRo3msDFPbgqt9P71V2tHXTGm28hfjbjftuYmhWlYR9nUy2NR54ErtOrpy06dkzGa kknctgD5BsYZVi2DJqILw7bgiE0iNmQY6QAlawLuRkplpVK+/i07QSoJJ7g00JziGBF0w8BmPro dPbAY0vhnPafYeEbvReGp4cdZE61F63J0x3vWhdwW2U9M3R6lTp0AA/cawzykmVL8DEayHOl7y8 pP8gS2uBQU5HnOfqhNQ== X-Proofpoint-GUID: VGbzrGZZBKGE2sx6cZHjFeLt9an1RaHv X-Authority-Analysis: v=2.4 cv=RKcmjIi+ c=1 sm=1 tr=0 ts=6abddefe cx=c_pps a=GFwsV6G8L6GxiO2Y/PsHdQ==:117 a=GFwsV6G8L6GxiO2Y/PsHdQ==:17 a=IkcTkHD0fZMA:10 a=660iZSQnnn4A:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=iQ6ETzBq9ecOQQE5vZCe:22 a=QyXUC8HyAAAA:8 a=VwQbUJbxAAAA:8 a=_Rns151wsaknvw-dtMgA:9 a=QEXdDO2ut3YA:10 X-Proofpoint-ORIG-GUID: ukRtnVfRL8ufVcKHebXtglGLxoRaJDZh X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-10-01_02,2026-09-21_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1011 priorityscore=1501 spamscore=0 bulkscore=0 impostorscore=0 adultscore=0 lowpriorityscore=0 suspectscore=0 malwarescore=0 phishscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2609040000 definitions=main-2610010016 On 10/1/26 5:22 AM, Kees Cook wrote: > perf_stats_show() and flags_show() build their output with a seq_buf > and return seq_buf_used(), which may include the trailing NUL byte > when the seq_buf has overflowed. Use seq_buf_strlen() instead. > > Build tested ARCH=powerpc ppc64_defconfig with GCC powerpc64-linux-gnu > 16.1.0: > arch/powerpc/platforms/pseries/papr_scm.o > > Assisted-by: LLM > Reviewed-by: Andy Shevchenko > Signed-off-by: Kees Cook > --- > arch/powerpc/platforms/pseries/papr_scm.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/arch/powerpc/platforms/pseries/papr_scm.c b/arch/powerpc/platforms/pseries/papr_scm.c > index 75da96c08cdd..b03cfd8528f5 100644 > --- a/arch/powerpc/platforms/pseries/papr_scm.c > +++ b/arch/powerpc/platforms/pseries/papr_scm.c > @@ -1108,7 +1108,7 @@ static ssize_t perf_stats_show(struct device *dev, > > free_stats: > kfree(stats); > - return rc ? rc : (ssize_t)seq_buf_used(&s); > + return rc ?: (ssize_t)seq_buf_strlen(&s); > } > static DEVICE_ATTR_ADMIN_RO(perf_stats); > > @@ -1150,7 +1150,7 @@ static ssize_t flags_show(struct device *dev, > if (seq_buf_used(&s)) this can also be seq_buf_strlen instead > seq_buf_printf(&s, "\n"); > > - return seq_buf_used(&s); > + return seq_buf_strlen(&s); > } > DEVICE_ATTR_RO(flags); >