WIP nabu rodriguezst configs - #2
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gmankab
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RISC-V computes vmemmap_start_pfn by rounding phys_ram_base down to VMEMMAP_ADDR_ALIGN. That alignment must therefore be expressed in the physical-address domain. Commit 476849b ("riscv/mm: align vmemmap to maximal folio size") attempted to account for the maximal folio alignment by feeding MAX_FOLIO_VMEMMAP_ALIGN directly into VMEMMAP_ADDR_ALIGN. However, MAX_FOLIO_VMEMMAP_ALIGN is measured in bytes of struct page storage, whereas VMEMMAP_ADDR_ALIGN is used to align a physical address. The mask-based compound_info encoding requires pfn_to_page(0) to be naturally aligned to MAX_FOLIO_VMEMMAP_ALIGN. Commit 9f94db4 ("mm/sparse: check memmap alignment for compound_info_has_mask()") added a check for that requirement and exposed the unit mismatch on systems such as QEMU virt, where the DRAM base is not aligned to MAX_FOLIO_NR_PAGES * PAGE_SIZE. Here is the log: [ 0.000000][ C0] ------------[ cut here ]------------ [ 0.000000][ C0] WARNING: mm/sparse.c:365 at sparse_init+0x58a/0x6fe, CPU#0: swapper/0 [ 0.000000][ C0] Modules linked in: [ 0.000000][ C0] CPU: 0 UID: 0 PID: 0 Comm: swapper Not tainted 7.2.0-rc3-g1d8304bdd65f #2 PREEMPT [ 0.000000][ C0] Hardware name: riscv-virtio,qemu (DT) [ 0.000000][ C0] epc : sparse_init+0x58a/0x6fe [ 0.000000][ C0] ra : sparse_init+0x58a/0x6fe [ 0.000000][ C0] epc : ffffffff86851c88 ra : ffffffff86851c88 sp : ffffffff88807a30 [ 0.000000][ C0] gp : ffffffff8a3bf240 tp : ffffffff88842080 t0 : ff600000ffab6000 [ 0.000000][ C0] t1 : 000000017fab6000 t2 : 65203a6573726363 s0 : ffffffff88807bc0 [ 0.000000][ C0] s1 : 000000000e000000 a0 : 0000000000000007 a1 : 0000000000000000 [ 0.000000][ C0] a2 : 0000000000000002 a3 : ffffffff86851c88 a4 : 0000000000000000 [ 0.000000][ C0] a5 : ffffffff88843080 a6 : 0000000000000003 a7 : 0000000000000000 [ 0.000000][ C0] s2 : ff60000000000000 s3 : 0040000000000000 s4 : 0004000000000000 [ 0.000000][ C0] s5 : ffffffff8a4d92e0 s6 : ff600000ffab55e0 s7 : ffffffff88384d00 [ 0.000000][ C0] s8 : 0000000000000003 s9 : ffffffff88384cc1 s10: ffffffff88384cc0 [ 0.000000][ C0] s11: ffffffff8a4daae0 t3 : ffffffff915e8b20 t4 : ffffffff915e8b20 [ 0.000000][ C0] t5 : ffffffff915e8b20 t6 : ffffffff915e8bc8 ssp : 0000000000000000 [ 0.000000][ C0] status: 0000000200000100 badaddr: ffffffff86851c88 cause: 0000000000000003 [ 0.000000][ C0] [<ffffffff86851c88>] sparse_init+0x58a/0x6fe [ 0.000000][ C0] [<ffffffff8683d396>] mm_core_init_early+0x116/0x1e30 [ 0.000000][ C0] [<ffffffff86801edc>] start_kernel+0xd2/0x848 Convert MAX_FOLIO_VMEMMAP_ALIGN to the equivalent physical alignment before using it in VMEMMAP_ADDR_ALIGN. This keeps the existing round_down() logic while making the resulting vmemmap base satisfy the mask-alignment requirement. Link: https://lore.kernel.org/20260716115326.3466926-1-xujiakai2025@iscas.ac.cn Fixes: 476849b ("riscv/mm: align vmemmap to maximal folio size") Signed-off-by: Jiakai Xu <xujiakai2025@iscas.ac.cn> Reviewed-by: Kiryl Shutsemau (Meta) <kas@kernel.org> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexandre Ghiti <alex@ghiti.fr> Cc: David Hildenbrand <david@kernel.org> Cc: Guo Ren <guoren@kernel.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Nam Cao <namcao@linutronix.de> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com> Assisted-by: YuanSheng:DeepSeek-V4-Flash Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
gmankab
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[BUG] There is a bug report that on 32bit systems (i686), btrfs crashes when trying to do zstd compression: BUG: unable to handle page fault for address: fffbc000 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page CPU: 0 UID: 0 PID: 61 Comm: kworker/u8:5 Tainted: G N 7.2.0-rc3-P3 #2 PREEMPTLAZY Hardware name: LENOVO 2007F2G/2007F2G, BIOS 79ETE7WW (2.27 ) 03/21/2011 Workqueue: btrfs-delalloc btrfs_work_helper EIP: ZSTD_compressStream2+0x221/0x5fc Call Trace: ZSTD_compressStream+0xd/0x48 zstd_compress_stream+0x8/0x10 zstd_compress_bio+0x20a/0x564 btrfs_compress_bio+0x94/0xc0 compress_file_range+0x20a/0x380 btrfs_work_helper+0xc1/0x1b4 process_scheduled_works+0x15f/0x204 worker_thread+0x10c/0x178 kthread+0xe1/0xe8 ret_from_fork+0x1d/0x14c ret_from_fork_asm+0x12/0x18 entry_INT80_32+0xf0/0xf0 CR2: 00000000fffbc000 ---[ end trace 0000000000000000 ]--- [CAUSE] Inside zstd_compress_bio(), we assume the whole page cache folio can be mapped in one go. However that assumption is not true on systems with CONFIG_HIGHMEM, the pages of the large folio can be in HIGHMEM, which needs to be mapped before access. Meanwhile zstd_compress_bio() only map the page of a large folio where the start filepos is, the remaining pages are not mapped, and accessing the remaining pages will trigger the above crash. [FIX] Do not enable large folios when the kernel has CONFIG_HIGHMEM enabled. This is the same handling for bs > ps support. Link: kdave/btrfs-progs#1146 Reported-by: Erhard Furtner <erhard_f@mailbox.org> Fixes: 9bce95e ("btrfs: move large data folios out of experimental features") Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
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