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    Subject[PATCH AUTOSEL 4.19 142/167] resource: Include resource end in walk_*() interfaces
    Date
    From: Bjorn Helgaas <bhelgaas@google.com>

    [ Upstream commit a98959fdbda1849a01b2150bb635ed559ec06700 ]

    find_next_iomem_res() finds an iomem resource that covers part of a range
    described by "start, end". All callers expect that range to be inclusive,
    i.e., both start and end are included, but find_next_iomem_res() doesn't
    handle the end address correctly.

    If it finds an iomem resource that contains exactly the end address, it
    skips it, e.g., if "start, end" is [0x0-0x10000] and there happens to be an
    iomem resource [mem 0x10000-0x10000] (the single byte at 0x10000), we skip
    it:

    find_next_iomem_res(...)
    {
    start = 0x0;
    end = 0x10000;
    for (p = next_resource(...)) {
    # p->start = 0x10000;
    # p->end = 0x10000;
    # we *should* return this resource, but this condition is false:
    if ((p->end >= start) && (p->start < end))
    break;

    Adjust find_next_iomem_res() so it allows a resource that includes the
    single byte at the end of the range. This is a corner case that we
    probably don't see in practice.

    Fixes: 58c1b5b07907 ("[PATCH] memory hotadd fixes: find_next_system_ram catch range fix")
    Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
    Signed-off-by: Borislav Petkov <bp@suse.de>
    CC: Andrew Morton <akpm@linux-foundation.org>
    CC: Brijesh Singh <brijesh.singh@amd.com>
    CC: Dan Williams <dan.j.williams@intel.com>
    CC: H. Peter Anvin <hpa@zytor.com>
    CC: Lianbo Jiang <lijiang@redhat.com>
    CC: Takashi Iwai <tiwai@suse.de>
    CC: Thomas Gleixner <tglx@linutronix.de>
    CC: Tom Lendacky <thomas.lendacky@amd.com>
    CC: Vivek Goyal <vgoyal@redhat.com>
    CC: Yaowei Bai <baiyaowei@cmss.chinamobile.com>
    CC: bhe@redhat.com
    CC: dan.j.williams@intel.com
    CC: dyoung@redhat.com
    CC: kexec@lists.infradead.org
    CC: mingo@redhat.com
    CC: x86-ml <x86@kernel.org>
    Link: http://lkml.kernel.org/r/153805812254.1157.16736368485811773752.stgit@bhelgaas-glaptop.roam.corp.google.com
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    kernel/resource.c | 4 ++--
    1 file changed, 2 insertions(+), 2 deletions(-)

    diff --git a/kernel/resource.c b/kernel/resource.c
    index 30e1bc68503b5..155ec873ea4d1 100644
    --- a/kernel/resource.c
    +++ b/kernel/resource.c
    @@ -319,7 +319,7 @@ int release_resource(struct resource *old)
    EXPORT_SYMBOL(release_resource);

    /*
    - * Finds the lowest iomem resource existing within [res->start.res->end).
    + * Finds the lowest iomem resource existing within [res->start..res->end].
    * The caller must specify res->start, res->end, res->flags, and optionally
    * desc. If found, returns 0, res is overwritten, if not found, returns -1.
    * This function walks the whole tree and not just first level children until
    @@ -352,7 +352,7 @@ static int find_next_iomem_res(struct resource *res, unsigned long desc,
    p = NULL;
    break;
    }
    - if ((p->end >= start) && (p->start < end))
    + if ((p->end >= start) && (p->start <= end))
    break;
    }

    --
    2.20.1
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