On 09/02/2020 05:12 PM, Aneesh Kumar K.V wrote: > This patch series includes fixes for debug_vm_pgtable test code so that > they follow page table updates rules correctly. The first two patches introduce > changes w.r.t ppc64. The patches are included in this series for completeness. We can > merge them via ppc64 tree if required. > > Hugetlb test is disabled on ppc64 because that needs larger change to satisfy > page table update rules. > > These tests are broken w.r.t page table update rules and results in kernel > crash as below. > > [ 21.083519] kernel BUG at arch/powerpc/mm/pgtable.c:304! > cpu 0x0: Vector: 700 (Program Check) at [c000000c6d1e76c0] > pc: c00000000009a5ec: assert_pte_locked+0x14c/0x380 > lr: c0000000005eeeec: pte_update+0x11c/0x190 > sp: c000000c6d1e7950 > msr: 8000000002029033 > current = 0xc000000c6d172c80 > paca = 0xc000000003ba0000 irqmask: 0x03 irq_happened: 0x01 > pid = 1, comm = swapper/0 > kernel BUG at arch/powerpc/mm/pgtable.c:304! > [link register ] c0000000005eeeec pte_update+0x11c/0x190 > [c000000c6d1e7950] 0000000000000001 (unreliable) > [c000000c6d1e79b0] c0000000005eee14 pte_update+0x44/0x190 > [c000000c6d1e7a10] c000000001a2ca9c pte_advanced_tests+0x160/0x3d8 > [c000000c6d1e7ab0] c000000001a2d4fc debug_vm_pgtable+0x7e8/0x1338 > [c000000c6d1e7ba0] c0000000000116ec do_one_initcall+0xac/0x5f0 > [c000000c6d1e7c80] c0000000019e4fac kernel_init_freeable+0x4dc/0x5a4 > [c000000c6d1e7db0] c000000000012474 kernel_init+0x24/0x160 > [c000000c6d1e7e20] c00000000000cbd0 ret_from_kernel_thread+0x5c/0x6c > > With DEBUG_VM disabled > > [ 20.530152] BUG: Kernel NULL pointer dereference on read at 0x00000000 > [ 20.530183] Faulting instruction address: 0xc0000000000df330 > cpu 0x33: Vector: 380 (Data SLB Access) at [c000000c6d19f700] > pc: c0000000000df330: memset+0x68/0x104 > lr: c00000000009f6d8: hash__pmdp_huge_get_and_clear+0xe8/0x1b0 > sp: c000000c6d19f990 > msr: 8000000002009033 > dar: 0 > current = 0xc000000c6d177480 > paca = 0xc00000001ec4f400 irqmask: 0x03 irq_happened: 0x01 > pid = 1, comm = swapper/0 > [link register ] c00000000009f6d8 hash__pmdp_huge_get_and_clear+0xe8/0x1b0 > [c000000c6d19f990] c00000000009f748 hash__pmdp_huge_get_and_clear+0x158/0x1b0 (unreliable) > [c000000c6d19fa10] c0000000019ebf30 pmd_advanced_tests+0x1f0/0x378 > [c000000c6d19fab0] c0000000019ed088 debug_vm_pgtable+0x79c/0x1244 > [c000000c6d19fba0] c0000000000116ec do_one_initcall+0xac/0x5f0 > [c000000c6d19fc80] c0000000019a4fac kernel_init_freeable+0x4dc/0x5a4 > [c000000c6d19fdb0] c000000000012474 kernel_init+0x24/0x160 > [c000000c6d19fe20] c00000000000cbd0 ret_from_kernel_thread+0x5c/0x6c > > Changes from v3: > * Address review feedback > * Move page table depost and withdraw patch after adding pmdlock to avoid bisect failure. This version - Builds on x86, arm64, s390, arc, powerpc and riscv (defconfig with DEBUG_VM_PGTABLE) - Runs on arm64 and x86 without any regression, atleast nothing that I have noticed - Will be great if this could get tested on s390, arc, riscv, ppc32 platforms as well + linux-riscv <linux-riscv@xxxxxxxxxxxxxxxxxxx> + linux-snps-arc@xxxxxxxxxxxxxxxxxxx <linux-snps-arc@xxxxxxxxxxxxxxxxxxx> + linux-s390@xxxxxxxxxxxxxxx + Gerald Schaefer <gerald.schaefer@xxxxxxxxxx> + Vineet Gupta <vgupta@xxxxxxxxxxxx> There is still an open git bisect issue on arm64 platform which ideally should be fixed. - Anshuman
