[PATCH] powerpc/mm: Fix hugetlb_free_pmd_range() and hugetlb_free_pud_range()

[Michael Ellerman]

On Sat, 12 Dec 2020 13:41:25 +0000 (UTC), Christophe Leroy wrote:
> Commit 7bfe54b5f165 ("powerpc/mm: Refactor the floor/ceiling check in
> hugetlb range freeing functions") inadvertely removed the mask
> applied to start parameter in those two functions, leading to the
> following crash on power9.
> 
> [ 7703.114640][T58070] LTP: starting hugemmap05_1 (hugemmap05 -m)
> [ 7703.157792][   C99] ------------[ cut here ]------------
> [ 7703.158279][   C99] kernel BUG at arch/powerpc/mm/book3s64/pgtable.c:387!
> [ 7703.158306][   C99] Oops: Exception in kernel mode, sig: 5 [#1]
> [ 7703.158330][   C99] LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=256 NUMA PowerNV
> [ 7703.158343][   C99] Modules linked in: vfio_pci vfio_virqfd vfio_iommu_spapr_tce vfio vfio_spapr_eeh loop kvm_hv kvm ip_tables x_tables sd_mod ahci libahci tg3 libata firmware_class libphy dm_mirror dm_region_hash dm_log dm_mod [last unloaded: dummy_del_mod]
> [ 7703.158435][   C99] CPU: 99 PID: 308 Comm: ksoftirqd/99 Tainted: G           O      5.10.0-rc7-next-20201211 #1
> [ 7703.158464][   C99] NIP:  c00000000005dbec LR: c0000000003352f4 CTR: 0000000000000000
> [ 7703.158489][   C99] REGS: c00020000bb6f830 TRAP: 0700   Tainted: G           O       (5.10.0-rc7-next-20201211)
> [ 7703.158528][   C99] MSR:  900000000282b033 <SF,HV,VEC,VSX,EE,FP,ME,IR,DR,RI,LE>  CR: 24002284  XER: 20040000
> [ 7703.158570][   C99] GPR00: c0000000003352f4 c00020000bb6fad0 c000000007f70b00 c0002000385b3ff0
> [ 7703.158570][   C99] GPR04: 0000000000000000 0000000000000003 c00020000bb6f8b4 0000000000000001
> [ 7703.158570][   C99] GPR08: 0000000000000001 0000000000000009 0000000000000008 0000000000000002
> [ 7703.158570][   C99] GPR12: 0000000024002488 c000201fff649c00 c000000007f2a20c 0000000000000000
> [ 7703.158570][   C99] GPR16: 0000000000000007 0000000000000000 c000000000194d10 c000000000194d10
> [ 7703.158570][   C99] GPR24: 0000000000000014 0000000000000015 c000201cc6e72398 c000000007fac4b4
> [ 7703.158570][   C99] GPR28: c000000007f2bf80 c000000007fac2f8 0000000000000008 c000200033870000
> [ 7703.158766][   C99] NIP [c00000000005dbec] __tlb_remove_table+0x1dc/0x1e0
> pgtable_free at arch/powerpc/mm/book3s64/pgtable.c:387
> (inlined by) __tlb_remove_table at arch/powerpc/mm/book3s64/pgtable.c:405
> [ 7703.158805][   C99] LR [c0000000003352f4] tlb_remove_table_rcu+0x54/0xa0
> [ 7703.158853][   C99] Call Trace:
> [ 7703.158872][   C99] [c00020000bb6fad0] [c00000000005db4c] __tlb_remove_table+0x13c/0x1e0 (unreliable)
> [ 7703.158890][   C99] [c00020000bb6fb00] [c0000000003352f4] tlb_remove_table_rcu+0x54/0xa0
> __tlb_remove_table_free at mm/mmu_gather.c:101
> (inlined by) tlb_remove_table_rcu at mm/mmu_gather.c:156
> [ 7703.158927][   C99] [c00020000bb6fb30] [c000000000194d7c] rcu_core+0x35c/0xbb0
> rcu_do_batch at kernel/rcu/tree.c:2502
> (inlined by) rcu_core at kernel/rcu/tree.c:2737
> [ 7703.158966][   C99] [c00020000bb6fbf0] [c00000000095a3d0] __do_softirq+0x480/0x704
> [ 7703.159006][   C99] [c00020000bb6fd10] [c0000000000cc1f4] run_ksoftirqd+0x74/0xd0
> run_ksoftirqd at kernel/softirq.c:651
> (inlined by) run_ksoftirqd at kernel/softirq.c:642
> [ 7703.159046][   C99] [c00020000bb6fd30] [c0000000001040c8] smpboot_thread_fn+0x278/0x320
> [ 7703.159096][   C99] [c00020000bb6fda0] [c0000000000fc8a4] kthread+0x1c4/0x1d0
> [ 7703.159145][   C99] [c00020000bb6fe10] [c00000000000d9fc] ret_from_kernel_thread+0x5c/0x80
> [ 7703.159183][   C99] Instruction dump:
> [ 7703.159204][   C99] 60000000 7c0802a6 3c82f8b4 7fe3fb78 38847470 f8010040 482b4fc5 60000000
> [ 7703.159248][   C99] 0fe00000 7c0802a6 fbe10028 f8010040 <0fe00000> 3c4c07f1 38422f10 7c0802a6
> [ 7703.159293][   C99] ---[ end trace 1d92a5231ba6a0d5 ]---
> 
> [...]

Applied to powerpc/next.

[1/1] powerpc/mm: Fix hugetlb_free_pmd_range() and hugetlb_free_pud_range()
      https://git.kernel.org/powerpc/c/2198d4934ee8b81341a84c9ec8bb25b4b0d02522

cheers