Re: kmemleak panic

[Prateek Patel]

On 1/21/2019 7:24 PM, Marc Gonzalez wrote:
> On 21/01/2019 14:35, Rob Herring wrote:
>
> > On Mon, Jan 21, 2019 at 6:19 AM Robin Murphy wrote:
> > > 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?

Yes, kmemleak_no_scan() do this which is done in patch 
https://patchwork.ozlabs.org/patch/995367/

This was done to avoid kmemleak scanning on the blocks which are nomaped 
and should not have linear mapping created in kernel page table.

> > There was this patch posted[1]. I never got a reply, so it hasn't been applied.
> >
> > Rob
> >
> > https://patchwork.ozlabs.org/patch/995367/
> It is worth noting that the author's email address appears to be dead.
> <schowdary@xxxxxxxxxx>: host hqemgate08.nvidia.com[216.228.121.117] said:
> 550 #5.1.0 Address rejected. (in reply to RCPT TO command)
>
> Adding a few nvidia devs for comment.