Commit a98959fd authored Sep 27, 2018 by Bjorn Helgaas Committed by Borislav Petkov Oct 09, 2018

resource: Include resource end in walk_*() interfaces



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: 58c1b5b0 ("[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

parent 51fbf14f

kernel/resource.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -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;
		}

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