Hi, On Tue, Jun 29, 2021 at 11:54:02AM +0300, Tony Lindgren wrote: > Hi, > > * Mike Rapoport <rppt@xxxxxxxxxxxxx> [210629 05:33]: > > On Mon, Jun 28, 2021 at 06:26:26PM +0300, Tony Lindgren wrote: > > > * Mike Rapoport <rppt@xxxxxxxxxxxxx> [210628 14:07]: > > > > Can you please send log with 'memblock=debug' added to the command line? > > > > > > Sure, log now available at: > > > > > > http://muru.com/beagle-x15.txt > > > > Hmm, no clues yet :( > > > > Do you have CONFIG_DEBUG_VM, CONFIG_DEBUG_VM_PGFLAGS and > > CONFIG_PAGE_POISONING enabled in your config? > > If not, can you please enable them and see if any of VM_BUG_* triggers? > > OK enabled, and no errors or warnings are triggered. > > > Do you use FLATMEM or SPARSEMEM in your config? > > Looks like make omap2plus_defconfig enables FLATMEM: > > $ grep -e SPARSEMEM -e FLATMEM .config > CONFIG_ARCH_FLATMEM_ENABLE=y > CONFIG_ARCH_SPARSEMEM_ENABLE=y > CONFIG_FLATMEM_MANUAL=y > # CONFIG_SPARSEMEM_MANUAL is not set > CONFIG_FLATMEM=y > > > Let's try seeing what PFNs get false results from pfn_valid, maybe this > > will give a better lead. > > With your patch below, system boots with lots of the following: > > [ 13.058654] Freeing unused kernel image (initmem) memory: 1024K > ... > [ 13.129211] pfn_valid(__sync_icache_dcache+0x2c/0x138): pfn: fffb6: is_map: 1 overlaps: 0 > [ 13.137481] pfn_valid(__sync_icache_dcache+0x2c/0x138): pfn: fffb7: is_map: 1 overlaps: 0 ... > Then changing console loglevel to 0 boots system to login prompt. But I'm > seeing some init processes segfaulting during start-up. As it seems, the new version of pfn_valid() decides that last pages are not valid because of the overflow in memblock_overlaps_region(). As the result, __sync_icache_dcache() skips flushing these pages. The patch below should fix this. I've left the prints for now, hopefully they will not appear anymore. diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c index 6162a070a410..7ba22d23eca4 100644 --- a/arch/arm/mm/init.c +++ b/arch/arm/mm/init.c @@ -126,10 +126,16 @@ int pfn_valid(unsigned long pfn) { phys_addr_t addr = __pfn_to_phys(pfn); unsigned long pageblock_size = PAGE_SIZE * pageblock_nr_pages; + bool overlaps = memblock_overlaps_region(&memblock.memory, + ALIGN_DOWN(addr, pageblock_size), + pageblock_size - 1); if (__phys_to_pfn(addr) != pfn) return 0; + if (memblock_is_map_memory(addr) != overlaps) + pr_info("%s(%pS): pfn: %lx: is_map: %d overlaps: %d\n", __func__, (void *)_RET_IP_, pfn, memblock_is_map_memory(addr), overlaps); + /* * If address less than pageblock_size bytes away from a present * memory chunk there still will be a memory map entry for it @@ -137,7 +143,7 @@ int pfn_valid(unsigned long pfn) */ if (memblock_overlaps_region(&memblock.memory, ALIGN_DOWN(addr, pageblock_size), - pageblock_size)) + pageblock_size - 1)) return 1; return 0; -- Sincerely yours, Mike.
