On 04.03.20 18:03, Marshall Midden wrote: > I know a translator is required - trying... Mark - is this better than > typical? > > Problem: kdump is not finishing, hangs twirling ... iKVM > Found: Power failure. Qlogic/Cavium/Marvell driver crash, but no kernel > dump. v5.3.8+local. > Reproduce: Boot, "echo c > /proc/sysrq-trigger" > Last known working release: v5.2.x (any of them). > First release failure: v5.3-rc1 > Tried many versions up to v5.6-rc4 (2020-03-01). > > Repository: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git > System: Supermicro X10 dual socket x86_64, 64g/256g/512g (different > systems/MB/CPUs). > UserLand: RedHat7.5 > Tried (did not fix) kexec-tools fetched Feb 25th, 2020 from: > git://git.kernel.org/pub/scm/utils/kernel/kexec/kexec-tools.git > <http://git.kernel.org/pub/scm/utils/kernel/kexec/kexec-tools.git> > .config: No modules, except those listed below (only 10 "=m"). > No modules in initramfs, /etc/dracut.conf.d/xxxx: > omit_drivers+="qla2xxx nfs_layout_flexfiles" > omit_drivers+=" tcm_loop tcm_fc target_core_mod iscsi_target_mod > target_core_file" > omit_drivers+=" target_core_iblock target_core_mod target_core_pscsi" > > Commit where problem appeared (git bisect): > commit 326e1b8f83a4318b09033ef754f40c785aed5e68 > Author: Dan Williams <dan.j.williams@xxxxxxxxx > <mailto:dan.j.williams@xxxxxxxxx>> > Date: Thu Jul 18 15:58:00 2019 -0700 > ------------------------------------------------------------------------------ > -rw------- 1 root root 2174976 Feb 28 13:33 vmcore-incomplete > -rw-r--r-- 1 root root 87611 Feb 28 13:33 vmcore-dmesg.txt > verses > -rw------- 1 root root 1186929986 Mar 3 18:57 vmcore > -rw-r--r-- 1 root root 181709 Mar 3 18:57 vmcore-dmesg.txt > ------------------------------------------------------------------------------ > What am I breaking -- if I comment out the usage of early_section(ms) > in file mm/sparse.c -- although kdump's seems to work fine, etc. > // bool section_is_early = early_section(ms); > ... > // if (!section_is_early) { > kfree(ms->usage); > ms->usage = NULL; > // } > ------------------------------------------------------------------------------ > Humor: > commit 5f9e832c137075045d15cd6899ab0505cfb2ca4b (tag: v5.3-rc1) > Author: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx > <mailto:torvalds@xxxxxxxxxxxxxxxxxxxx>> > Date: Sun Jul 21 14:05:38 2019 -0700 > Linus 5.3-rc1 > ^ > Horror: > No one else has run into this since the end of July? > ------------------------------------------------------------------------------ > Full git show below: > > commit 326e1b8f83a4318b09033ef754f40c785aed5e68 > Author: Dan Williams <dan.j.williams@xxxxxxxxx > <mailto:dan.j.williams@xxxxxxxxx>> > Date: Thu Jul 18 15:58:00 2019 -0700 > > mm/sparsemem: introduce a SECTION_IS_EARLY flag > > In preparation for sub-section hotplug, track whether a given section > was created during early memory initialization, or later via memory > hotplug. This distinction is needed to maintain the coarse expectation > that pfn_valid() returns true for any pfn within a given section even if > that section has pages that are reserved from the page allocator. > > For example one of the of goals of subsection hotplug is to support > cases where the system physical memory layout collides System RAM and > PMEM within a section. Several pfn_valid() users expect to just check > if a section is valid, but they are not careful to check if the given > pfn is within a "System RAM" boundary and instead expect pgdat > information to further validate the pfn. > > Rather than unwind those paths to make their pfn_valid() queries more > precise a follow on patch uses the SECTION_IS_EARLY flag to maintain the > traditional expectation that pfn_valid() returns true for all early > sections. > > Link: > https://lore.kernel.org/lkml/1560366952-10660-1-git-send-email-cai@xxxxxx/ > Link: > http://lkml.kernel.org/r/156092350358.979959.5817209875548072819.stgit@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx > Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx > <mailto:dan.j.williams@xxxxxxxxx>> > Reported-by: Qian Cai <cai@xxxxxx <mailto:cai@xxxxxx>> > Tested-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx > <mailto:aneesh.kumar@xxxxxxxxxxxxx>> [ppc64] > Reviewed-by: Oscar Salvador <osalvador@xxxxxxx > <mailto:osalvador@xxxxxxx>> > Cc: Michal Hocko <mhocko@xxxxxxxx <mailto:mhocko@xxxxxxxx>> > Cc: Logan Gunthorpe <logang@xxxxxxxxxxxx <mailto:logang@xxxxxxxxxxxx>> > Cc: David Hildenbrand <david@xxxxxxxxxx <mailto:david@xxxxxxxxxx>> > Cc: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx > <mailto:pasha.tatashin@xxxxxxxxxx>> > Cc: Jane Chu <jane.chu@xxxxxxxxxx <mailto:jane.chu@xxxxxxxxxx>> > Cc: Jeff Moyer <jmoyer@xxxxxxxxxx <mailto:jmoyer@xxxxxxxxxx>> > Cc: Jérôme Glisse <jglisse@xxxxxxxxxx <mailto:jglisse@xxxxxxxxxx>> > Cc: Jonathan Corbet <corbet@xxxxxxx <mailto:corbet@xxxxxxx>> > Cc: Mike Rapoport <rppt@xxxxxxxxxxxxx <mailto:rppt@xxxxxxxxxxxxx>> > Cc: Toshi Kani <toshi.kani@xxxxxxx <mailto:toshi.kani@xxxxxxx>> > Cc: Vlastimil Babka <vbabka@xxxxxxx <mailto:vbabka@xxxxxxx>> > Cc: Wei Yang <richardw.yang@xxxxxxxxxxxxxxx > <mailto:richardw.yang@xxxxxxxxxxxxxxx>> > Cc: Jason Gunthorpe <jgg@xxxxxxxxxxxx <mailto:jgg@xxxxxxxxxxxx>> > Cc: Christoph Hellwig <hch@xxxxxx <mailto:hch@xxxxxx>> > Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx > <mailto:akpm@xxxxxxxxxxxxxxxxxxxx>> > Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx > <mailto:torvalds@xxxxxxxxxxxxxxxxxxxx>> > > diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h > index 2520336bdfd1..4be40634238b 100644 > --- a/include/linux/mmzone.h > +++ b/include/linux/mmzone.h > @@ -1260,7 +1260,8 @@ extern size_t mem_section_usage_size(void); > #define SECTION_MARKED_PRESENT (1UL<<0) > #define SECTION_HAS_MEM_MAP (1UL<<1) > #define SECTION_IS_ONLINE (1UL<<2) > -#define SECTION_MAP_LAST_BIT (1UL<<3) > +#define SECTION_IS_EARLY (1UL<<3) > +#define SECTION_MAP_LAST_BIT (1UL<<4) > #define SECTION_MAP_MASK (~(SECTION_MAP_LAST_BIT-1)) > #define SECTION_NID_SHIFT 3 > > @@ -1286,6 +1287,11 @@ static inline int valid_section(struct > mem_section *section) > return (section && (section->section_mem_map & > SECTION_HAS_MEM_MAP)); > } > > +static inline int early_section(struct mem_section *section) > +{ > + return (section && (section->section_mem_map & SECTION_IS_EARLY)); > +} > + > static inline int valid_section_nr(unsigned long nr) > { > return valid_section(__nr_to_section(nr)); > diff --git a/mm/sparse.c b/mm/sparse.c > index 41bef8e1f65c..6d23a526279a 100644 > --- a/mm/sparse.c > +++ b/mm/sparse.c > @@ -288,11 +288,11 @@ struct page *sparse_decode_mem_map(unsigned long > coded_mem_map, unsigned long pn > > static void __meminit sparse_init_one_section(struct mem_section *ms, > unsigned long pnum, struct page *mem_map, > - struct mem_section_usage *usage) > + struct mem_section_usage *usage, unsigned long flags) > { > ms->section_mem_map &= ~SECTION_MAP_MASK; > - ms->section_mem_map |= sparse_encode_mem_map(mem_map, pnum) | > - SECTION_HAS_MEM_MAP; > + ms->section_mem_map |= sparse_encode_mem_map(mem_map, pnum) > + | SECTION_HAS_MEM_MAP | flags; > ms->usage = usage; > } > > @@ -497,7 +497,8 @@ static void __init sparse_init_nid(int nid, unsigned > long pnum_begin, > goto failed; > } > check_usemap_section_nr(nid, usage); > - sparse_init_one_section(__nr_to_section(pnum), pnum, > map, usage); > + sparse_init_one_section(__nr_to_section(pnum), pnum, > map, usage, > + SECTION_IS_EARLY); > usage = (void *) usage + mem_section_usage_size(); > } > sparse_buffer_fini(); > @@ -732,7 +733,7 @@ int __meminit sparse_add_one_section(int nid, > unsigned long start_pfn, > > set_section_nid(section_nr, nid); > section_mark_present(ms); > - sparse_init_one_section(ms, section_nr, memmap, usage); > + sparse_init_one_section(ms, section_nr, memmap, usage, 0); > > out: > if (ret < 0) { > @@ -772,19 +773,16 @@ static inline void clear_hwpoisoned_pages(struct > page *memmap, int nr_pages) > } > #endif > > -static void free_section_usage(struct page *memmap, > +static void free_section_usage(struct mem_section *ms, struct page *memmap, > struct mem_section_usage *usage, struct vmem_altmap *altmap) > { > - struct page *usage_page; > - > if (!usage) > return; > > - usage_page = virt_to_page(usage); > /* > * Check to see if allocation came from hot-plug-add > */ > - if (PageSlab(usage_page) || PageCompound(usage_page)) { > + if (!early_section(ms)) { > kfree(usage); > if (memmap) > __kfree_section_memmap(memmap, altmap); > @@ -816,6 +814,6 @@ void sparse_remove_one_section(struct mem_section > *ms, unsigned long map_offset, > > clear_hwpoisoned_pages(memmap + map_offset, > PAGES_PER_SECTION - map_offset); > - free_section_usage(memmap, usage, altmap); > + free_section_usage(ms, memmap, usage, altmap); > } > #endif /* CONFIG_MEMORY_HOTPLUG */ > I am most probably missing some context here. But we do have commit 8068df3b60373c390198f660574ea14c8098de57 Author: David Hildenbrand <david@xxxxxxxxxx> Date: Mon Jan 13 16:29:07 2020 -0800 mm/memory_hotplug: don't free usage map when removing a re-added early section Does that fix your issue? -- Thanks, David / dhildenb
