On 9/15/26 14:53, Breno Leitao wrote: > A frame a kexec handed over is flagged as it reaches the allocator, long > before its memory block exists, so memblk_nr_poison_inc() had nowhere to > count it. Walk the block once when it is created and take the count from > the page flag instead. > > Without it an unpoison later subtracts from a counter that was never > incremented and wraps it, which then refuses memory_block_online() for > good. > > Only a block created online needs the walk. A hotplugged one is created > before its pages are, so there is nothing to find, and its frames are > counted by num_poisoned_pages_inc() as they are flagged. > > Signed-off-by: Breno Leitao <[email protected]> > --- > drivers/base/memory.c | 35 +++++++++++++++++++++++++++++++++++ > 1 file changed, 35 insertions(+) > > diff --git a/drivers/base/memory.c b/drivers/base/memory.c > index 5eead3346f1e32..49a33ddbb2e717 100644 > --- a/drivers/base/memory.c > +++ b/drivers/base/memory.c > @@ -220,11 +220,16 @@ int memory_notify(enum memory_block_state state, void > *v) > > #if defined(CONFIG_MEMORY_FAILURE) && defined(CONFIG_MEMORY_HOTPLUG) > static unsigned long memblk_nr_poison(struct memory_block *mem); > +static void memblk_nr_poison_init(struct memory_block *mem); > #else > static inline unsigned long memblk_nr_poison(struct memory_block *mem) > { > return 0; > } > + > +static inline void memblk_nr_poison_init(struct memory_block *mem) > +{ > +} > #endif > > /* > @@ -807,6 +812,7 @@ static int add_memory_block(unsigned long block_id, int > nid, unsigned long state > mem->state = state; > mem->nid = nid; > INIT_LIST_HEAD(&mem->group_next); > + memblk_nr_poison_init(mem); > > #ifndef CONFIG_NUMA > if (state == MEM_ONLINE) > @@ -1251,4 +1257,33 @@ static unsigned long memblk_nr_poison(struct > memory_block *mem) > { > return atomic_long_read(&mem->nr_hwpoison); > } > + > +/* > + * Frames a kexec handed over are flagged as they reach the allocator, long > + * before this block exists, so memblk_nr_poison_inc() had nowhere to count > + * them. Take them from the page flag instead. > + */ > +static void memblk_nr_poison_init(struct memory_block *mem) > +{ > + unsigned long pfn = section_nr_to_pfn(mem->start_section_nr); > + unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block; > + unsigned long i, nr_poison = 0; > + > + /* A hotplugged block is created before its pages are online. */ > + if (mem->state != MEM_ONLINE) > + return; > + > + if (!range_contains_poisoned_memory(PFN_PHYS(pfn), > + nr_pages << PAGE_SHIFT)) > + return; > + > + for (i = 0; i < nr_pages; i++) { > + struct page *page = pfn_to_online_page(pfn + i); > + > + if (page && PageHWPoison(page)) > + nr_poison++; > + }
That just slows down boot unnecessarily on 99.9999999999999999999% of all systems out there. -- Cheers, David
