From: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
To: Christophe Leroy <christophe.leroy@c-s.fr>,
benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au
Cc: linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH] powerpc/mm: Fix kernel crash on page table free
Date: Fri, 15 Jun 2018 15:45:23 +0530 [thread overview]
Message-ID: <186c9af6-17d1-d28f-a53c-3bf58d69ada1@linux.ibm.com> (raw)
In-Reply-To: <1bbbfc4d-c47c-2383-454c-430a014beb9e@c-s.fr>
On 06/15/2018 03:24 AM, Christophe Leroy wrote:
>
>
> On 05/30/2018 12:32 PM, Aneesh Kumar K.V wrote:
>> Fix the below crash on BookE 64. pgtable_page_dtor expects struct page
>> *arg.
>>
>> Also call the destructor on non book3s platforms correctly. This free
>> up the
>> split ptl locks correctly if we had allocated them before.
>>
>> Call Trace:
>> [c0000000f30c7520] [c00000000021eeec] .kmem_cache_free+0x9c/0x44c
>> (unreliable)
>> [c0000000f30c75c0] [c0000000001ee07c] .ptlock_free+0x1c/0x30
>> [c0000000f30c7630] [c0000000001ee260] .tlb_remove_table+0xdc/0x224
>> [c0000000f30c76c0] [c0000000001ee640] .free_pgd_range+0x298/0x500
>> [c0000000f30c77d0] [c000000000232afc] .shift_arg_pages+0x10c/0x1e0
>> [c0000000f30c7910] [c000000000232dd0] .setup_arg_pages+0x200/0x25c
>> [c0000000f30c79c0] [c0000000002ad4fc] .load_elf_binary+0x450/0x16c8
>> [c0000000f30c7b10] [c000000000234914]
>> .search_binary_handler.part.11+0x9c/0x248
>> [c0000000f30c7bb0] [c00000000023595c]
>> .do_execveat_common.isra.13+0x868/0xc18
>> [c0000000f30c7cb0] [c00000000000184c] .run_init_process+0x34/0x4c
>> [c0000000f30c7d30] [c000000000001880] .try_to_run_init_process+0x1c/0x68
>> [c0000000f30c7db0] [c000000000002bd8] .kernel_init+0xdc/0x130
>> [c0000000f30c7e30] [c0000000000009dc] .ret_from_kernel_thread+0x58/0x7c
>>
>> Fixes: 702346768 ("powerpc/mm/nohash: Remove pte fragment dependency
>> from nohash")
>> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
>> ---
>> arch/powerpc/include/asm/book3s/32/pgalloc.h | 1 +
>> arch/powerpc/include/asm/nohash/32/pgalloc.h | 1 +
>> arch/powerpc/include/asm/nohash/64/pgalloc.h | 2 +-
>> 3 files changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/powerpc/include/asm/book3s/32/pgalloc.h
>> b/arch/powerpc/include/asm/book3s/32/pgalloc.h
>> index 5073cc75f1c8..6a6673907e45 100644
>> --- a/arch/powerpc/include/asm/book3s/32/pgalloc.h
>> +++ b/arch/powerpc/include/asm/book3s/32/pgalloc.h
>> @@ -99,6 +99,7 @@ static inline void pte_free(struct mm_struct *mm,
>> pgtable_t ptepage)
>> static inline void pgtable_free(void *table, unsigned index_size)
>> {
>> if (!index_size) {
>> + pgtable_page_dtor(virt_to_page(table));
>
> __pte_free_tlb() already calls pgtable_page_dtor(table) before calling
> pgtable_free() via pgtable_free_tlb().
>
> Is it normal to call it twice ?
No. We should call pgtable_page_dtor only in the rcu callback. So we
should remove it from __pte_free_tlb().
>
>> free_page((unsigned long)table);
>> } else {
>> BUG_ON(index_size > MAX_PGTABLE_INDEX_SIZE);
>> diff --git a/arch/powerpc/include/asm/nohash/32/pgalloc.h
>> b/arch/powerpc/include/asm/nohash/32/pgalloc.h
>> index 29d37bd1f3b3..1707781d2f20 100644
>> --- a/arch/powerpc/include/asm/nohash/32/pgalloc.h
>> +++ b/arch/powerpc/include/asm/nohash/32/pgalloc.h
>> @@ -100,6 +100,7 @@ static inline void pte_free(struct mm_struct *mm,
>> pgtable_t ptepage)
>> static inline void pgtable_free(void *table, unsigned index_size)
>> {
>> if (!index_size) {
>> + pgtable_page_dtor(virt_to_page(table));
>
> Same here
I don't have the facility to test anything other than book3s64. Can you
do a patch for this?
-aneesh
prev parent reply other threads:[~2018-06-15 10:15 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-30 12:32 [PATCH] powerpc/mm: Fix kernel crash on page table free Aneesh Kumar K.V
2018-06-01 15:55 ` Michael Ellerman
2018-06-14 21:54 ` [PATCH] " Christophe Leroy
2018-06-15 10:15 ` Aneesh Kumar K.V [this message]
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