linux-kernel - Re: kmemleak panic

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Message-ID: <d4facdc2-0581-929f-caa2-b9efa9bd8f97@arm.com>
Date:   Mon, 21 Jan 2019 12:19:27 +0000
From:   Robin Murphy <robin.murphy@....com>
To:     Marc Gonzalez <marc.w.gonzalez@...e.fr>,
        Catalin Marinas <catalin.marinas@....com>,
        Rob Herring <robh+dt@...nel.org>,
        Frank Rowand <frowand.list@...il.com>,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        Bjorn Andersson <bjorn.andersson@...aro.org>
Cc:     Mark Rutland <mark.rutland@....com>, Arnd Bergmann <arnd@...db.de>,
        Ard Biesheuvel <ard.biesheuvel@...aro.org>,
        Oscar Salvador <osalvador@...e.de>,
        Wei Yang <richard.weiyang@...il.com>,
        Michal Hocko <mhocko@...e.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Sri Krishna chowdary <schowdary@...dia.com>,
        Qian Cai <cai@....pw>, LKML <linux-kernel@...r.kernel.org>
Subject: Re: kmemleak panic

On 21/01/2019 11:57, Marc Gonzalez wrote:
[...]
> # echo dump=0xffffffc021e00000 > /sys/kernel/debug/kmemleak
> kmemleak: Object 0xffffffc021e00000 (size 2097152):
> kmemleak:   comm "swapper/0", pid 0, jiffies 4294892296
> kmemleak:   min_count = 0
> kmemleak:   count = 0
> kmemleak:   flags = 0x1
> kmemleak:   checksum = 0
> kmemleak:   backtrace:
>       kmemleak_alloc_phys+0x48/0x60
>       memblock_alloc_range_nid+0x8c/0xa4
>       memblock_alloc_base_nid+0x4c/0x60
>       __memblock_alloc_base+0x3c/0x4c
>       early_init_dt_alloc_reserved_memory_arch+0x54/0xa4
>       fdt_init_reserved_mem+0x308/0x3ec
>       early_init_fdt_scan_reserved_mem+0x88/0xb0
>       arm64_memblock_init+0x1dc/0x254
>       setup_arch+0x1c8/0x4ec
>       start_kernel+0x84/0x44c
>       0xffffffffffffffff

OK, so via the __va(phys) call in kmemleak_alloc_phys(), you end up with 
the linear map address of a no-map reservation, which unsurprisingly 
turns out not to be mapped. Is there a way to tell kmemleak that it 
can't scan within a particular object?

Robin.