Re: [PATCH v2 3/3] arm: extend pfn_valid to take into accound freed memory map alignment
From: Tony Lindgren <tony@atomide.com>
Date: 2021-06-29 08:54:11
Also in:
linux-mm, linux-omap, lkml, regressions
Hi, * Mike Rapoport [off-list ref] [210629 05:33]:
On Mon, Jun 28, 2021 at 06:26:26PM +0300, Tony Lindgren wrote:quoted
* Mike Rapoport [off-list ref] [210628 14:07]:quoted
Can you please send log with 'memblock=debug' added to the command line?Sure, log now available at: http://muru.com/beagle-x15.txtHmm, 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 [ 13.145751] pfn_valid(__sync_icache_dcache+0x2c/0x138): pfn: fffb8: is_map: 1 overlaps: 0 [ 13.153991] pfn_valid(__sync_icache_dcache+0x2c/0x138): pfn: fffb9: is_map: 1 overlaps: 0 [ 13.162200] pfn_valid(__sync_icache_dcache+0x2c/0x138): pfn: fffba: is_map: 1 overlaps: 0 [ 13.170440] pfn_valid(__sync_icache_dcache+0x2c/0x138): pfn: fffbb: is_map: 1 overlaps: 0 [ 13.178680] pfn_valid(__sync_icache_dcache+0x2c/0x138): pfn: fffbc: is_map: 1 overlaps: 0 [ 13.186920] pfn_valid(__sync_icache_dcache+0x2c/0x138): pfn: fffbd: is_map: 1 overlaps: 0 [ 13.195159] pfn_valid(__sync_icache_dcache+0x2c/0x138): pfn: fffbe: is_map: 1 overlaps: 0 [ 13.203399] pfn_valid(__sync_icache_dcache+0x2c/0x138): pfn: fffbf: is_map: 1 overlaps: 0 [ 13.211639] pfn_valid(__sync_icache_dcache+0x2c/0x138): pfn: fff00: 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. Regards, Tony
quoted hunk ↗ jump to hunk
diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c index 6162a070a410..66985fc3e730 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); 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-- Sincerely yours, Mike.
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