Messages in this thread Patch in this message | | | Date | Tue, 19 Apr 2022 10:36:56 +0200 | From | David Hildenbrand <> | Subject | Re: [x86/pgtable] d1ec551f87: BUG:Bad_page_map_in_process |
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On 19.04.22 10:22, David Hildenbrand wrote: > On 19.04.22 09:59, kernel test robot wrote: >> >> >> Greeting, >> >> FYI, we noticed the following commit (built with clang-15): >> >> commit: d1ec551f874e1663bfe76b994c0010a4566cf936 ("x86/pgtable: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE") >> https://github.com/hnaz/linux-mm master >> >> in testcase: trinity >> version: trinity-static-i386-x86_64-1c734c75-1_2020-01-06 >> with following parameters: >> >> runtime: 300s >> group: group-01 >> >> test-description: Trinity is a linux system call fuzz tester. >> test-url: http://codemonkey.org.uk/projects/trinity/ >> >> >> on test machine: qemu-system-i386 -enable-kvm -cpu SandyBridge -smp 2 -m 4G >> >> caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace): >> >> >> >> If you fix the issue, kindly add following tag >> Reported-by: kernel test robot <oliver.sang@intel.com> >> >> >> [ 40.201103][ T5099] BUG: Bad page map in process trinity-c7 pte:1713003a pmd:7ff71067 >> [ 40.201999][ T5099] addr:096e7000 vm_flags:00100073 anon_vma:bff0aa00 mapping:00000000 index:96e7 >> [ 40.202718][ T5099] file:(null) fault:0x0 mmap:0x0 readpage:0x0 >> [ 40.203229][ T5099] CPU: 0 PID: 5099 Comm: trinity-c7 Not tainted 5.18.0-rc2-mm1-00053-gd1ec551f874e #1 >> [ 40.203952][ T5099] Call Trace: >> [ 40.204195][ T5099] ? dump_stack_lvl (??:?) >> [ 40.204581][ T5099] ? dump_stack (??:?) >> [ 40.204970][ T5099] ? print_bad_pte (memory.c:?) >> [ 40.205384][ T5099] ? unmap_page_range (??:?) >> [ 40.205843][ T5099] ? unmap_single_vma (memory.c:?) >> [ 40.206271][ T5099] ? unmap_vmas (??:?) >> [ 40.206647][ T5099] ? exit_mmap (??:?) >> [ 40.207032][ T5099] ? __mmput (fork.c:?) >> [ 40.207405][ T5099] ? mmput (??:?) >> [ 40.207751][ T5099] ? exit_mm (exit.c:?) >> [ 40.208121][ T5099] ? do_exit (??:?) >> [ 40.208497][ T5099] ? do_group_exit (??:?) >> [ 40.208905][ T5099] ? trace_hardirqs_on (??:?) >> [ 40.209345][ T5099] ? get_signal (??:?) >> [ 40.209750][ T5099] ? arch_do_signal_or_restart (??:?) >> [ 40.210287][ T5099] ? exit_to_user_mode_loop (common.c:?) >> [ 40.210778][ T5099] ? exit_to_user_mode_prepare (common.c:?) >> [ 40.211302][ T5099] ? syscall_exit_to_user_mode (??:?) >> [ 40.211808][ T5099] ? ret_from_fork (??:?) >> [ 40.212268][ T5099] Disabling lock debugging due to kernel taint >> [ 40.231123][ T5097] BUG: Bad page map in process trinity-c5 pte:171e0a3e pmd:0a8d3067 >> [ 40.231770][ T5099] BUG: Bad page map in process trinity-c7 pte:1713023a pmd:7ff71067 >> [ 40.231883][ T5097] addr:36ed5000 vm_flags:000000fb anon_vma:00000000 mapping:485d0d80 index:1 >> [ 40.232611][ T5099] addr:096e8000 vm_flags:00100073 anon_vma:bff0ab18 mapping:00000000 index:96e8 >> [ 40.233429][ T5097] file:dev/zero fault:shmem_fault mmap:shmem_mmap readpage:0x0 >> [ 40.234271][ T5099] file:(null) fault:0x0 mmap:0x0 readpage:0x0 >> [ 40.234971][ T5097] CPU: 1 PID: 5097 Comm: trinity-c5 Tainted: G B 5.18.0-rc2-mm1-00053-gd1ec551f874e #1 >> [ 40.236510][ T5097] Call Trace: > > This is 32bit (i386) I assume. I wonder if something about the 32bit swp > layout is special and we have to restrict it to 64bit here. >
Staring at arch/x86/include/asm/pgtable-2level.h, I think that's the case: The swp type effectively starts at "_PAGE_BIT_PRESENT + 1" which should be bit 1.
Let's restrict this to x86-64 for now.
I think this is similar to CONFIG_HAVE_ARCH_SOFT_DIRTY, which depends on 64 bit.
The following should do the trick:
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h index e42e668153e9..a1c555abed26 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -1291,7 +1291,7 @@ static inline void update_mmu_cache_pud(struct vm_area_struct *vma, unsigned long addr, pud_t *pud) { } - +#ifdef _PAGE_SWP_EXCLUSIVE #define __HAVE_ARCH_PTE_SWP_EXCLUSIVE static inline pte_t pte_swp_mkexclusive(pte_t pte) { @@ -1307,6 +1307,7 @@ static inline pte_t pte_swp_clear_exclusive(pte_t pte) { return pte_clear_flags(pte, _PAGE_SWP_EXCLUSIVE); } +#endif /* _PAGE_SWP_EXCLUSIVE */ #ifdef CONFIG_HAVE_ARCH_SOFT_DIRTY static inline pte_t pte_swp_mksoft_dirty(pte_t pte) diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h index 54a8f370046d..95403ae1f2e5 100644 --- a/arch/x86/include/asm/pgtable_types.h +++ b/arch/x86/include/asm/pgtable_types.h @@ -83,10 +83,12 @@ #define _PAGE_SOFT_DIRTY (_AT(pteval_t, 0)) #endif +#ifdef CONFIG_64BIT /* - * We borrow bit 3 to remember PG_anon_exclusive. + * We borrow bit 3 on x86-64 to remember PG_anon_exclusive. */ #define _PAGE_SWP_EXCLUSIVE _PAGE_PWT +#endif /* CONFIG_64BIT */ /* * Tracking soft dirty bit when a page goes to a swap is tricky.
Thoughts?
-- Thanks,
David / dhildenb
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