On 08/12/24 at 09:46am, Sourabh Jain wrote: ...... > --- > > Changelog: > > Since v1: https://lore.kernel.org/all/20240805050829.297171-1-sourabhjain@xxxxxxxxxxxxx/ > - Update crash_hotplug sysfs document as suggested by Petr T > - Update an error message in crash_handle_hotplug_event and > crash_check_hotplug_support function. > > --- ...... > diff --git a/kernel/crash_core.c b/kernel/crash_core.c > index 63cf89393c6e..c1048893f4b6 100644 > --- a/kernel/crash_core.c > +++ b/kernel/crash_core.c > @@ -505,7 +505,7 @@ int crash_check_hotplug_support(void) > crash_hotplug_lock(); > /* Obtain lock while reading crash information */ > if (!kexec_trylock()) { > - pr_info("kexec_trylock() failed, elfcorehdr may be inaccurate\n"); > + pr_info("kexec_trylock() failed, kdump image may be inaccurate\n"); Wondering why this need be updated. > crash_hotplug_unlock(); > return 0; > } > @@ -520,18 +520,25 @@ int crash_check_hotplug_support(void) > } > > /* > - * To accurately reflect hot un/plug changes of cpu and memory resources > - * (including onling and offlining of those resources), the elfcorehdr > - * (which is passed to the crash kernel via the elfcorehdr= parameter) > - * must be updated with the new list of CPUs and memories. > + * To accurately reflect hot un/plug changes of CPU and Memory resources > + * (including onling and offlining of those resources), the relevant > + * kexec segments must be updated with latest CPU and Memory resources. > * > - * In order to make changes to elfcorehdr, two conditions are needed: > - * First, the segment containing the elfcorehdr must be large enough > - * to permit a growing number of resources; the elfcorehdr memory size > - * is based on NR_CPUS_DEFAULT and CRASH_MAX_MEMORY_RANGES. > - * Second, purgatory must explicitly exclude the elfcorehdr from the > - * list of segments it checks (since the elfcorehdr changes and thus > - * would require an update to purgatory itself to update the digest). > + * Architectures must ensure two things for all segments that need > + * updating during hotplug events: > + * > + * 1. Segments must be large enough to accommodate a growing number of > + * resources. > + * 2. Exclude the segments from SHA verification. > + * > + * For example, on most architectures, the elfcorehdr (which is passed > + * to the crash kernel via the elfcorehdr= parameter) must include the > + * new list of CPUs and memory. To make changes to the elfcorehdr, it > + * should be large enough to permit a growing number of CPU and Memory > + * resources. One can estimate the elfcorehdr memory size based on > + * NR_CPUS_DEFAULT and CRASH_MAX_MEMORY_RANGES. The elfcorehdr is > + * excluded from SHA verification by default if the architecture > + * supports crash hotplug. > */ > static void crash_handle_hotplug_event(unsigned int hp_action, unsigned int cpu, void *arg) > { > @@ -540,7 +547,7 @@ static void crash_handle_hotplug_event(unsigned int hp_action, unsigned int cpu, > crash_hotplug_lock(); > /* Obtain lock while changing crash information */ > if (!kexec_trylock()) { > - pr_info("kexec_trylock() failed, elfcorehdr may be inaccurate\n"); > + pr_info("kexec_trylock() failed, kdump image may be inaccurate\n"); > crash_hotplug_unlock(); > return; > } > -- > 2.45.2 > _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
