I tested the kernel-6.8 on my machine and found that the crashkernel memory reservation range is consistent with kernel-5.10. However, it's strange that when crashkernel=512M, the kernel still allocates two memory segments for crashkernel, as seen in the logs: [ 0.022640] crashkernel low memory reserved: 0x49000000 - 0x59000000 (256 MB) [ 0.022641] crashkernel reserved: 0x000000c01f000000 - 0x000000c03f000000 (512 MB) But only one segment is shown in /proc/iomem: c01f000000-c03effffff : Crash kernel Moreover, the conflicting address 53cbd000-53ccffff is still reserved by someone else: 53cbd000-53ccffff : Reserved [ 0.029843] e820: update [mem 0x53cbd000-0x53ccffff] usable ==> reserved It seems there is a kernel bug here. If you need the complete log, I can send it later. --------- On 03/19/24 at 4:22pm, Baoquan He wrote: > On 03/19/24 at 07:24am, chenhaixiang (A) wrote: > > Thank you for your reply! > > The kernel version on my machine is kernel-5.10, and the kexec-tools version is > kexec-tools-2.0.27. > > However, my issue seems to be a bit different. On my machine, I can see the > crashkernel memory segment in /proc/iomem. However, for some reason, > within the address range allocated for crashkernel, there is also a segment > marked as 'Reserved' (I'm not sure who marked it). In this scenario, kexec-tools > calculates the CRASH MEMORY RANGES incorrectly. > > ``` > > crashkernel region can't be reserved again once it's allocated and reserved in > memblock. There must be something wrong with the code. You can try upstream > kernel and kexec-tools to see if it exists too. Since you are using an old kernel and > could be on a distros, we may not be able to cover it. Sorry about that. > > If you want to debug to find out the reason, I can help give suggestions. > > > cat /proc/iomem > > 2d4fd058-58ffffff : System RAM > > 49000000-58ffffff : Crash kernel > > 53cbd000-53ccffff : Reserved > > ``` > > I'm not sure if the crashkernel memory segment should not include other > markings, and if not supported, whether kexec-tools should raise an error. > > Thanks > > Chen Haixiang > > ---------- > > On 03/19/24 at 9:38qm, Baoquan He wrote: > > > Hi, > > > > > > On 03/18/24 at 12:00pm, chenhaixiang (A) wrote: > > > > Dear kexec Community Members, > > > > > > > > I encountered an issue while using kexec-tools on my x86_64 machine. > > > > When there is a segment marked as 'reserved' within the memory > > > > range > > > allocated for the crash kernel in /proc/iomem,the output appears as follows: > > > > 2d4fd058-60efefff : System RAM > > > > 2d4fd058-58ffffff : System RAM > > > > 49000000-58ffffff : Crash kernel > > > > 53cbd000-53ccffff : Reserved > > > > > > What kernel are you using? the version of kernel, and kexec-tools? > > > > > > If you are testing on the latest mainline kernel, you could meet the > > > issue Dave have met and fixed in below patch: > > > > > > [PATCH] x86/kexec: do not update E820 kexec table for setup_data > > > https://lore.kernel.org/all/ZeZ2Kos-OOZNSrmO@xxxxxxxxxxxxxxxxxxxxxxx > > > at.com/ > > > T/#u > > > > > > Thanks > > > Baoquan > > > > > > > > > > > The crash_memory_range array will encounter incorrect address ranges: > > > > CRASH MEMORY RANGES > > > > 000000002d4fd058-0000000048ffffff (0) > > > > 0000000053cbd000-0000000048ffffff (1) > > > > 0000000059000000-0000000053ccffff (0) > > > > > > > > Read the code, I noticed that the get_crash_memory_ranges() > > > > function > > > invokes exclude_region() to handle the splitting of memory regions, > > > but it seems unable to properly handle the scenario described above. > > > > The code logic is as follows: > > > > ... > > > > if (start < mend && end > mstart) { > > > > if (start != mstart && end != mend) { > > > > /* Split memory region */ > > > > crash_memory_range[i].end = start - 1; > > > > temp_region.start = end + 1; > > > > temp_region.end = mend; > > > > temp_region.type = RANGE_RAM; > > > > tidx = i+1; > > > > } else if (start != mstart) > > > > crash_memory_range[i].end = start - 1; > > > > else > > > > crash_memory_range[i].start = end + 1; > > > > } > > > > ... > > > > If start < mstart < mend < end, resulting in > > > > crash_memory_range[i].end > > > becoming less than crash_memory_range[i].start, leading to incorrect > > > address ranges. > > > > I would like to know if this behavior is reasonable and whether it > > > > is necessary to > > > validate the address ranges for compliance at the end. > > > > > > > > Thank you for your time and assistance. > > > > > > > > Chen Haixiang > > > > > > > > _______________________________________________ > > > > kexec mailing list > > > > kexec@xxxxxxxxxxxxxxxxxxx > > > > http://lists.infradead.org/mailman/listinfo/kexec > > > > > > _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
