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Wed, 12 Aug 2026 03:12:10 +0000 (GMT) Received: from smtpav04.fra02v.mail.ibm.com (smtpav04.fra02v.mail.ibm.com [10.20.54.103]) by smtprelay05.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 67C3C5W350856292 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 12 Aug 2026 03:12:05 GMT Received: from smtpav04.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 45F7620040; Wed, 12 Aug 2026 03:12:05 +0000 (GMT) Received: from smtpav04.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id B91862004D; Wed, 12 Aug 2026 03:12:01 +0000 (GMT) Received: from [9.123.14.142] (unknown [9.123.14.142]) by smtpav04.fra02v.mail.ibm.com (Postfix) with ESMTP; Wed, 12 Aug 2026 03:12:01 +0000 (GMT) Message-ID: Date: Wed, 12 Aug 2026 08:41:59 +0530 X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] powerpc/kexec_file: Use inclusive range checks in add_usable_mem() To: Thorsten Blum Cc: Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , "Christophe Leroy (CS GROUP)" , Hari Bathini , Aditya Gupta , Jinjie Ruan , Thiago Jung Bauermann , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org References: <20260809162403.18142-2-thorsten.blum@linux.dev> Content-Language: en-US From: Sourabh Jain In-Reply-To: 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-Details-Enc: AW1haW4tMjYwODEyMDAyMSBTYWx0ZWRfX7vYn22qtBf+R NV05vUAyfkWKwSKz8F76muRJPFRJ7iHMnP8JHrmMgIc0iEQNp91YKKiIM/35whRLBV5sTa3T8e8 nHemB2EJ4/Q3/p/uR7nzKCAo8+snfdkIdkV1GJif5bQEYnLIgsUxYQCC3Uo05tohhnpLh6ydjgB lOPqIL3GJUX47BYsJZaQPkhexKvizQhMc1jEyI7KZdqtBPAfMruEGWYwLR4JdjK8ZpJ/NXsJjXX kmTnsFGeZ/xd+TIOpLplma1JGufjmiFZYPKs0MkA23y3O63P55cw8fpDDSYUB5Qezxf2iii5WIv LJbfA+L9ckrISEcbNHcMRRxrx9xLPI66kS7UrxZPXxfq93ZtFlIjhuJLRQKF/GBkBZZ4+RZYizx nU+A1KAdstd1WGqvvpNaLVGlHzcccNcBdhNFva09xLs+lu4WpT3O1NPH0O+qbLgdHnFbzKLHLS5 i+HL0zzpN1BrHXnoN3g== X-Proofpoint-ORIG-GUID: Umdw_SqfciE71JtB2jUmxEcJIxp9JETH X-Proofpoint-Spam-Info: AW1haW4tMjYwODEyMDAyMSBTYWx0ZWRfX5Y7NDk1XFuYg lUOX01giTNWC1k8UiHuFsi5kGjboQV73DXXDuJjRzy0xEMYjvi+aredv2VDgd4MH787BMgN33pz mOJ7pEaeCOcjGzkrP8o7qgEhlcYSPMc= X-Authority-Analysis: v=2.4 cv=IfK3n2qa c=1 sm=1 tr=0 ts=6a7be48c cx=c_pps a=GFwsV6G8L6GxiO2Y/PsHdQ==:117 a=GFwsV6G8L6GxiO2Y/PsHdQ==:17 a=IkcTkHD0fZMA:10 a=Sv0fKeRqtYgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=U7nrCbtTmkRpXpFmAIza:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=jj04caz6BRDygnwrFwgA:9 a=QEXdDO2ut3YA:10 X-Proofpoint-GUID: 4VbLhUPN4kK0ZTQh0zwe7qYkUa317ppU 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=2026-08-12_01,2026-08-10_03,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 priorityscore=1501 impostorscore=0 bulkscore=0 clxscore=1015 lowpriorityscore=0 adultscore=0 malwarescore=0 spamscore=0 suspectscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608120021 On 11/08/26 16:25, Thorsten Blum wrote: > On Tue, Aug 11, 2026 at 11:51:46AM +0530, Sourabh Jain wrote: >> On 09/08/26 21:54, Thorsten Blum wrote: >>> add_usable_mem() adds usable memory ranges for the kdump kernel. >>> >>> The ranges are inclusive, but the partial overlap check uses exclusive >>> comparisons. This skips ranges with base == loc_end or end == loc_base. >>> Use inclusive comparisons instead. >>> >>> Fixes: 7c64e21a1c5a ("powerpc/kexec_file: Restrict memory usage of kdump kernel") >>> Signed-off-by: Thorsten Blum >>> --- >>> arch/powerpc/kexec/file_load_64.c | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/arch/powerpc/kexec/file_load_64.c b/arch/powerpc/kexec/file_load_64.c >>> index 8c72e12ea44e..f9e872693ca7 100644 >>> --- a/arch/powerpc/kexec/file_load_64.c >>> +++ b/arch/powerpc/kexec/file_load_64.c >>> @@ -113,7 +113,7 @@ static int add_usable_mem(struct umem_info *um_info, u64 base, u64 end) >>> loc_end = um_info->ranges[i].end; >>> if (loc_base >= base && loc_end <= end) >>> add = true; >>> - else if (base < loc_end && end > loc_base) { >>> + else if (base <= loc_end && end >= loc_base) { >> This is interesting. The updated condition basically handles exactly a >> one-byte overlap on either side of the usable memory ranges. In practice, >> it is very unlikely that we would have such usable memory and LMB ranges. >> >> Thorsten, have you encountered any problem that led you to propose this fix? > Found by inspection only and I agree that this is unlikely in practice, > which is why I didn't cc stable. Same for the other patch [1]. > > Thanks for the review. > > [1] https://lore.kernel.org/r/20260810145827.157972-3-thorsten.blum@linux.dev/ The changes look good to me. Feel free to add: Reviewed-by: Sourabh Jain