This is a note to let you know that I've just added the patch titled
memblock: memblock should be able to handle zero length operations
to the 3.3-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
memblock-memblock-should-be-able-to-handle-zero-length-operations.patch
and it can be found in the queue-3.3 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From b3dc627cabb33fc95f93da78457770c1b2a364d2 Mon Sep 17 00:00:00 2001
From: Tejun Heo <[email protected]>
Date: Fri, 20 Apr 2012 08:31:34 -0700
Subject: memblock: memblock should be able to handle zero length operations
From: Tejun Heo <[email protected]>
commit b3dc627cabb33fc95f93da78457770c1b2a364d2 upstream.
Commit 24aa07882b ("memblock, x86: Replace memblock_x86_reserve/
free_range() with generic ones") replaced x86 specific memblock
operations with the generic ones; unfortunately, it lost zero length
operation handling in the process making the kernel panic if somebody
tries to reserve zero length area.
There isn't much to be gained by being cranky to zero length operations
and panicking is almost the worst response. Drop the BUG_ON() in
memblock_reserve() and update memblock_add_region/isolate_range() so
that all zero length operations are handled as noops.
Signed-off-by: Tejun Heo <[email protected]>
Reported-by: Valere Monseur <[email protected]>
Bisected-by: Joseph Freeman <[email protected]>
Tested-by: Joseph Freeman <[email protected]>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=43098
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
mm/memblock.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -330,6 +330,9 @@ static int __init_memblock memblock_add_
phys_addr_t end = base + memblock_cap_size(base, &size);
int i, nr_new;
+ if (!size)
+ return 0;
+
/* special case for empty array */
if (type->regions[0].size == 0) {
WARN_ON(type->cnt != 1 || type->total_size);
@@ -430,6 +433,9 @@ static int __init_memblock memblock_isol
*start_rgn = *end_rgn = 0;
+ if (!size)
+ return 0;
+
/* we'll create at most two more regions */
while (type->cnt + 2 > type->max)
if (memblock_double_array(type) < 0)
@@ -514,7 +520,6 @@ int __init_memblock memblock_reserve(phy
(unsigned long long)base,
(unsigned long long)base + size,
(void *)_RET_IP_);
- BUG_ON(0 == size);
return memblock_add_region(_rgn, base, size, MAX_NUMNODES);
}
Patches currently in stable-queue which might be from [email protected] are
queue-3.3/memblock-memblock-should-be-able-to-handle-zero-length-operations.patch
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