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Date:   Thu, 25 Feb 2021 18:07:06 +0200
From:   Mike Rapoport <rppt@linux.ibm.com>
To:     George Kennedy <george.kennedy@oracle.com>
Cc:     David Hildenbrand <david@redhat.com>,
        Andrey Konovalov <andreyknvl@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Vincenzo Frascino <vincenzo.frascino@arm.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Konrad Rzeszutek Wilk <konrad@darnok.org>,
        Will Deacon <will.deacon@arm.com>,
        Andrey Ryabinin <aryabinin@virtuozzo.com>,
        Alexander Potapenko <glider@google.com>,
        Marco Elver <elver@google.com>,
        Peter Collingbourne <pcc@google.com>,
        Evgenii Stepanov <eugenis@google.com>,
        Branislav Rankov <Branislav.Rankov@arm.com>,
        Kevin Brodsky <kevin.brodsky@arm.com>,
        Christoph Hellwig <hch@infradead.org>,
        kasan-dev <kasan-dev@googlegroups.com>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Linux Memory Management List <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Dhaval Giani <dhaval.giani@oracle.com>
Subject: Re: [PATCH] mm, kasan: don't poison boot memory
Message-ID: <20210225160706.GD1854360@linux.ibm.com>
References: <20210223200914.GH1741768@linux.ibm.com>
 <af06267d-00cd-d4e0-1985-b06ce7c993a3@oracle.com>
 <20210223213237.GI1741768@linux.ibm.com>
 <450a9895-a2b4-d11b-97ca-1bd33d5308d4@oracle.com>
 <20210224103754.GA1854360@linux.ibm.com>
 <9b7251d1-7b90-db4f-fa5e-80165e1cbb4b@oracle.com>
 <20210225085300.GB1854360@linux.ibm.com>
 <9973d0e2-e28b-3f8a-5f5d-9d142080d141@oracle.com>
 <20210225145700.GC1854360@linux.ibm.com>
 <bb444ddb-d60d-114f-c2fe-64e5fb34102d@oracle.com>
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On Thu, Feb 25, 2021 at 10:22:44AM -0500, George Kennedy wrote:
> 
> > > > > On 2/24/2021 5:37 AM, Mike Rapoport wrote:
>
> Applied just your latest patch, but same failure.
> 
> I thought there was an earlier comment (which I can't find now) that stated
> that memblock_reserve() wouldn't reserve the page, which is what's needed
> here.

Actually, I think that memblock_reserve() should be just fine, but it seems
I'm missing something in address calculation each time.

What would happen if you stuck

	memblock_reserve(0xbe453000, PAGE_SIZE);

say, at the beginning of find_ibft_region()?
 
> [?? 30.308229] iBFT detected..
> [?? 30.308796]
> ==================================================================
> [?? 30.308890] BUG: KASAN: use-after-free in ibft_init+0x134/0xc33
> [?? 30.308890] Read of size 4 at addr ffff8880be453004 by task swapper/0/1
> [?? 30.308890]
> [?? 30.308890] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 5.11.0-f9593a0 #12
> [?? 30.308890] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
> 0.0.0 02/06/2015
> [?? 30.308890] Call Trace:
> [?? 30.308890]? dump_stack+0xdb/0x120
> [?? 30.308890]? ? ibft_init+0x134/0xc33
> [?? 30.308890]? print_address_description.constprop.7+0x41/0x60
> [?? 30.308890]? ? ibft_init+0x134/0xc33
> [?? 30.308890]? ? ibft_init+0x134/0xc33
> [?? 30.308890]? kasan_report.cold.10+0x78/0xd1
> [?? 30.308890]? ? ibft_init+0x134/0xc33
> [?? 30.308890]? __asan_report_load_n_noabort+0xf/0x20
> [?? 30.308890]? ibft_init+0x134/0xc33
> [?? 30.308890]? ? write_comp_data+0x2f/0x90
> [?? 30.308890]? ? ibft_check_initiator_for+0x159/0x159
> [?? 30.308890]? ? write_comp_data+0x2f/0x90
> [?? 30.308890]? ? ibft_check_initiator_for+0x159/0x159
> [?? 30.308890]? do_one_initcall+0xc4/0x3e0
> [?? 30.308890]? ? perf_trace_initcall_level+0x3e0/0x3e0
> [?? 30.308890]? ? unpoison_range+0x14/0x40
> [?? 30.308890]? ? ____kasan_kmalloc.constprop.5+0x8f/0xc0
> [?? 30.308890]? ? kernel_init_freeable+0x420/0x652
> [?? 30.308890]? ? __kasan_kmalloc+0x9/0x10
> [?? 30.308890]? ? __sanitizer_cov_trace_pc+0x21/0x50
> [?? 30.308890]? kernel_init_freeable+0x596/0x652
> [?? 30.308890]? ? console_on_rootfs+0x7d/0x7d
> [?? 30.308890]? ? __sanitizer_cov_trace_pc+0x21/0x50
> [?? 30.308890]? ? rest_init+0xf0/0xf0
> [?? 30.308890]? kernel_init+0x16/0x1d0
> [?? 30.308890]? ? rest_init+0xf0/0xf0
> [?? 30.308890]? ret_from_fork+0x22/0x30
> [?? 30.308890]
> [?? 30.308890] The buggy address belongs to the page:
> [?? 30.308890] page:0000000001b7b17c refcount:0 mapcount:0
> mapping:0000000000000000 index:0x1 pfn:0xbe453
> [?? 30.308890] flags: 0xfffffc0000000()
> [?? 30.308890] raw: 000fffffc0000000 ffffea0002ef9788 ffffea0002f91488
> 0000000000000000
> [?? 30.308890] raw: 0000000000000001 0000000000000000 00000000ffffffff
> 0000000000000000
> [?? 30.308890] page dumped because: kasan: bad access detected
> [?? 30.308890] page_owner tracks the page as freed
> [?? 30.308890] page last allocated via order 0, migratetype Movable,
> gfp_mask 0x100dca(GFP_HIGHUSER_MOVABLE|__GFP_ZERO), pid 204, ts 28121288605
> [?? 30.308890]? prep_new_page+0xfb/0x140
> [?? 30.308890]? get_page_from_freelist+0x3503/0x5730
> [?? 30.308890]? __alloc_pages_nodemask+0x2d8/0x650
> [?? 30.308890]? alloc_pages_vma+0xe2/0x560
> [?? 30.308890]? __handle_mm_fault+0x930/0x26c0
> [?? 30.308890]? handle_mm_fault+0x1f9/0x810
> [?? 30.308890]? do_user_addr_fault+0x6f7/0xca0
> [?? 30.308890]? exc_page_fault+0xaf/0x1a0
> [?? 30.308890]? asm_exc_page_fault+0x1e/0x30
> [?? 30.308890] page last free stack trace:
> [?? 30.308890]? free_pcp_prepare+0x122/0x290
> [?? 30.308890]? free_unref_page_list+0xe6/0x490
> [?? 30.308890]? release_pages+0x2ed/0x1270
> [?? 30.308890]? free_pages_and_swap_cache+0x245/0x2e0
> [?? 30.308890]? tlb_flush_mmu+0x11e/0x680
> [?? 30.308890]? tlb_finish_mmu+0xa6/0x3e0
> [?? 30.308890]? exit_mmap+0x2b3/0x540
> [?? 30.308890]? mmput+0x11d/0x450
> [?? 30.308890]? do_exit+0xaa6/0x2d40
> [?? 30.308890]? do_group_exit+0x128/0x340
> [?? 30.308890]? __x64_sys_exit_group+0x43/0x50
> [?? 30.308890]? do_syscall_64+0x37/0x50
> [?? 30.308890]? entry_SYSCALL_64_after_hwframe+0x44/0xa9
> [?? 30.308890]
> [?? 30.308890] Memory state around the buggy address:
> [?? 30.308890]? ffff8880be452f00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff
> ff ff
> [?? 30.308890]? ffff8880be452f80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff
> ff ff
> [?? 30.308890] >ffff8880be453000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff
> ff ff
> [?? 30.308890]??????????????????? ^
> [?? 30.308890]? ffff8880be453080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff
> ff ff
> [?? 30.308890]? ffff8880be453100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff
> ff ff
> [?? 30.308890]
> ==================================================================
> 
> George
> 

-- 
Sincerely yours,
Mike.