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Subject[PATCH 4.19 162/190] resource: Include resource end in walk_*() interfaces
[ 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

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))

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 <>
Signed-off-by: Borislav Petkov <>
CC: Andrew Morton <>
CC: Brijesh Singh <>
CC: Dan Williams <>
CC: H. Peter Anvin <>
CC: Lianbo Jiang <>
CC: Takashi Iwai <>
CC: Thomas Gleixner <>
CC: Tom Lendacky <>
CC: Vivek Goyal <>
CC: Yaowei Bai <>
CC: x86-ml <>
Signed-off-by: Sasha Levin <>
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)

- * 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;
- if ((p->end >= start) && (p->start < end))
+ if ((p->end >= start) && (p->start <= end))


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