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Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Omar Sandoval , Jacob Lalonde , Shuah Khan , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linuxppc-dev@lists.ozlabs.org References: <20260820-work-coredump-sparse-v2-0-ba32dd718c51@kernel.org> <20260820-work-coredump-sparse-v2-20-ba32dd718c51@kernel.org> Content-Language: en-US From: R Nageswara Sastry In-Reply-To: <20260820-work-coredump-sparse-v2-20-ba32dd718c51@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-Authority-Analysis: v=2.4 cv=E7T9Y6dl c=1 sm=1 tr=0 ts=6aa18402 cx=c_pps a=5BHTudwdYE3Te8bg5FgnPg==:117 a=5BHTudwdYE3Te8bg5FgnPg==:17 a=yvCvHZBkMPEFi-hM:21 a=IkcTkHD0fZMA:10 a=VdqzKS8jKosA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=V8glGbnc2Ofi9Qvn3v5h:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=4b849oTNI3KMiQfRc2UA:9 a=QEXdDO2ut3YA:10 X-Proofpoint-Spam-Info: AW1haW4tMjYwOTA5MDE3OCBTYWx0ZWRfXwMOKEAOnufqd SGF+DFNNDavrSKHi0O55IeVnCJpxKsk8JMbNAF5YjDffOGYM/iiFNdwXrgZVLI0UDW6amkSRT5j c9kaVzcekM8HfLv/ujde5QoSFy27w1A= X-Proofpoint-ORIG-GUID: uESFL6ZdpJh2pism_iCO0yEFf0a3Syt_ X-Proofpoint-GUID: __IvkGFV-gsBehoP4a6j6PMjApE_YReo X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwOTA5MDE3OCBTYWx0ZWRfX/iNiFzIMlsZz vhZswCktN33AMgFoktb9LL5NRjECPckotB7sYlKRHixcGDrGmwbwJRTNqzWXvCfuKKH/1Vg2QCQ 8hQD/dbozyCxmL0Q3700Jkgjt6UKvN+RR1lv+CUymuOSjwlQdJCfOnWoUrHZ2mqPaCGB8ZT5P79 w4Q4xbl5UZ7AOJ0ymI476D+Z2RWtcMKXyg+whwzAt9CP8wkvgK0nZvLV6p6knx1+dOznQPOrA2x y2lcagUJTdgEg6BJV/rcanXJ8zdZzWKyovhqmlXjqR/783N9/sIQiUKd6DCYcdn3O3+86whqkAG mNsxGHAUxqiOVRREXXESX3xNuwV0LbP3emO3JHxwjAPr5Wcn3U9L8E/apkJTpPcy5jtMutmT9Jn 7z6XzIc52t8Six/81f6YKFmgnsv//JznOwzvNaAZzb4IGU/TCtDVl/xJ1SElyzqYimrd63JB+vy T1Ol686LKB8o4lg23IA== 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=2026-09-08_03,2026-09-09_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 phishscore=0 spamscore=0 suspectscore=0 priorityscore=1501 bulkscore=0 impostorscore=0 malwarescore=0 lowpriorityscore=0 adultscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2609090178 On 20.08.2026 4:39 AM, Christian Brauner wrote: > The crashing_child_sparse() helper touches the first page of the > mapping. That forces everything behind it to be a trailing hole. This is > easy to handle. Make the test more difficult meaningful by also touchin > the last page. This causes the hole to sit between two populated pages. > > Signed-off-by: Christian Brauner (Amutable) Tested-by: R Nageswara Sastry System: ppc64le LPAR (IBM POWER), Linux 7.3-rc2 > --- > tools/testing/selftests/coredump/coredump_test_helpers.c | 10 ++++++---- > 1 file changed, 6 insertions(+), 4 deletions(-) > > diff --git a/tools/testing/selftests/coredump/coredump_test_helpers.c b/tools/testing/selftests/coredump/coredump_test_helpers.c > index 45d76fa0f469..89f3954c5607 100644 > --- a/tools/testing/selftests/coredump/coredump_test_helpers.c > +++ b/tools/testing/selftests/coredump/coredump_test_helpers.c > @@ -58,14 +58,16 @@ void crashing_child_sparse(size_t size) > char *p; > > /* > - * Touch the first page only. The whole mapping is dumped because > - * it has been written to, but all of it save that one page is a > - * hole. > + * Touch the first and the last page. This will cause the whole mapping > + * to be dumped because it has been written to. Everything between > + * those two pages is a hole though. > */ > p = mmap(NULL, size, PROT_READ | PROT_WRITE, > MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE, -1, 0); > - if (p != MAP_FAILED) > + if (p != MAP_FAILED) { > p[0] = 'x'; > + p[size - 1] = 'x'; > + } > > /* crash on purpose */ > *(volatile int *)NULL = 0; > -- Thanks and Regards R.Nageswara Sastry