Messages in this thread | | | From | Ard Biesheuvel <> | Date | Sat, 31 Oct 2020 11:47:42 +0100 | Subject | Re: [PATCH] ARM, xtensa: highmem: avoid clobbering non-page aligned memory reservations |
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On Sat, 31 Oct 2020 at 11:33, Russell King - ARM Linux admin <linux@armlinux.org.uk> wrote: > > On Sat, Oct 31, 2020 at 11:43:45AM +0200, Mike Rapoport wrote: > > From: Ard Biesheuvel <ardb@kernel.org> > > > > free_highpages() iterates over the free memblock regions in high > > memory, and marks each page as available for the memory management > > system. > > > > Until commit cddb5ddf2b76 ("arm, xtensa: simplify initialization of > > high memory pages") it rounded beginning of each region upwards and end of > > each region downwards. > > > > However, after that commit free_highmem() rounds the beginning and end of > > each region downwards, and we may end up freeing a page that is > > memblock_reserve()d, resulting in memory corruption. > > > > Restore the original rounding of the region boundaries to avoid freeing > > reserved pages. > > > > Fixes: cddb5ddf2b76 ("arm, xtensa: simplify initialization of high memory pages") > > Link: https://lore.kernel.org/r/20201029110334.4118-1-ardb@kernel.org/ > > Signed-off-by: Ard Biesheuvel <ardb@kernel.org> > > Co-developed-by: Mike Rapoport <rppt@linux.ibm.com> > > Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> > > --- > > > > Max, Russell, > > > > Please let me know how do you prefer to take it upstream. > > If needed this can go via memblock tree. > > > > v2: fix words order in the commit message > > I really don't understand what is going on here; there seems to be a > total disconnect of communication between yourself and Ard. Ard has > already submitted a different patch for this to the patch system > already, sent yesterday. > > https://www.armlinux.org.uk/developer/patches/viewpatch.php?id=9021/1 > > Please discuss between yourselves how you want to solve the problem, > and then submit an agreed and tested patch to those of us upstream; > please don't make it for those upstream to pick one of your patches > as you are at present. >
Apologies for creating this confusion. I posted a patch and dropped it into the patch system when I found the bug.
However, only when Florian asked about a 'fixes' tag, I went back to the history, and realized that the issue was introduced by Mike during the most recent merge window, and affects xtensa as well.
I don't have a preference which patch gets applied, though, so please indicate your preference, and we will adapt accordingly.
> > > > arch/arm/mm/init.c | 4 ++-- > > arch/xtensa/mm/init.c | 4 ++-- > > 2 files changed, 4 insertions(+), 4 deletions(-) > > > > diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c > > index d57112a276f5..c23dbf8bebee 100644 > > --- a/arch/arm/mm/init.c > > +++ b/arch/arm/mm/init.c > > @@ -354,8 +354,8 @@ static void __init free_highpages(void) > > /* set highmem page free */ > > for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE, > > &range_start, &range_end, NULL) { > > - unsigned long start = PHYS_PFN(range_start); > > - unsigned long end = PHYS_PFN(range_end); > > + unsigned long start = PFN_UP(range_start); > > + unsigned long end = PFN_DOWN(range_end); > > > > /* Ignore complete lowmem entries */ > > if (end <= max_low) > > diff --git a/arch/xtensa/mm/init.c b/arch/xtensa/mm/init.c > > index c6fc83efee0c..8731b7ad9308 100644 > > --- a/arch/xtensa/mm/init.c > > +++ b/arch/xtensa/mm/init.c > > @@ -89,8 +89,8 @@ static void __init free_highpages(void) > > /* set highmem page free */ > > for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE, > > &range_start, &range_end, NULL) { > > - unsigned long start = PHYS_PFN(range_start); > > - unsigned long end = PHYS_PFN(range_end); > > + unsigned long start = PFN_UP(range_start); > > + unsigned long end = PFN_DOWN(range_end); > > > > /* Ignore complete lowmem entries */ > > if (end <= max_low) > > -- > > 2.28.0 > > > > > > -- > RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ > FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!
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