From: Octavian Purdila <octavian.purdila@intel.com>
Date: Sat, 21 Jul 2012 00:55:16 +0000 (+1000)
Subject: resource: make sure requested range is included in the root range
X-Git-Tag: next-20120725~1^2~12
X-Git-Url: https://git.kernelconcepts.de/?p=karo-tx-linux.git;a=commitdiff_plain;h=22402851bd2c4af0801879be8ee1532f72399533

resource: make sure requested range is included in the root range

When the requested range is outside of the root range the logic in
__reserve_region_with_split will cause an infinite recursion which will
overflow the stack as seen in the warning bellow.

This particular stack overflow was caused by requesting the
(100000000-107ffffff) range while the root range was (0-ffffffff).  In
this case __request_resource would return the whole root range as conflict
range (i.e.  0-ffffffff).  Then, the logic in __reserve_region_with_split
would continue the recursion requesting the new range as (conflict->end+1,
end) which incidentally in this case equals the originally requested
range.

This patch aborts looking for an usable range when the request does not
intersect with the root range.  When the request partially overlaps with
the root range, it ajust the request to fall in the root range and then
continues with the new request.

When the request is modified or aborted errors and a stack trace are
logged to allow catching the errors in the upper layers.

[    5.968374] WARNING: at kernel/sched.c:4129 sub_preempt_count+0x63/0x89()
[    5.975150] Modules linked in:
[    5.978184] Pid: 1, comm: swapper Not tainted 3.0.22-mid27-00004-gb72c817 #46
[    5.985324] Call Trace:
[    5.987759]  [<c1039dfc>] ? console_unlock+0x17b/0x18d
[    5.992891]  [<c1039620>] warn_slowpath_common+0x48/0x5d
[    5.998194]  [<c1031758>] ? sub_preempt_count+0x63/0x89
[    6.003412]  [<c1039644>] warn_slowpath_null+0xf/0x13
[    6.008453]  [<c1031758>] sub_preempt_count+0x63/0x89
[    6.013499]  [<c14d60c4>] _raw_spin_unlock+0x27/0x3f
[    6.018453]  [<c10c6349>] add_partial+0x36/0x3b
[    6.022973]  [<c10c7c0a>] deactivate_slab+0x96/0xb4
[    6.027842]  [<c14cf9d9>] __slab_alloc.isra.54.constprop.63+0x204/0x241
[    6.034456]  [<c103f78f>] ? kzalloc.constprop.5+0x29/0x38
[    6.039842]  [<c103f78f>] ? kzalloc.constprop.5+0x29/0x38
[    6.045232]  [<c10c7dc9>] kmem_cache_alloc_trace+0x51/0xb0
[    6.050710]  [<c103f78f>] ? kzalloc.constprop.5+0x29/0x38
[    6.056100]  [<c103f78f>] kzalloc.constprop.5+0x29/0x38
[    6.061320]  [<c17b45e9>] __reserve_region_with_split+0x1c/0xd1
[    6.067230]  [<c17b4693>] __reserve_region_with_split+0xc6/0xd1
...
[    7.179057]  [<c17b4693>] __reserve_region_with_split+0xc6/0xd1
[    7.184970]  [<c17b4779>] reserve_region_with_split+0x30/0x42
[    7.190709]  [<c17a8ebf>] e820_reserve_resources_late+0xd1/0xe9
[    7.196623]  [<c17c9526>] pcibios_resource_survey+0x23/0x2a
[    7.202184]  [<c17cad8a>] pcibios_init+0x23/0x35
[    7.206789]  [<c17ca574>] pci_subsys_init+0x3f/0x44
[    7.211659]  [<c1002088>] do_one_initcall+0x72/0x122
[    7.216615]  [<c17ca535>] ? pci_legacy_init+0x3d/0x3d
[    7.221659]  [<c17a27ff>] kernel_init+0xa6/0x118
[    7.226265]  [<c17a2759>] ? start_kernel+0x334/0x334
[    7.231223]  [<c14d7482>] kernel_thread_helper+0x6/0x10

Signed-off-by: Octavian Purdila <octavian.purdila@intel.com>
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/kernel/resource.c b/kernel/resource.c
index dc8b47764443..34d45886ee84 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -7,6 +7,8 @@
  * Arbitrary resource management.
  */
 
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
 #include <linux/export.h>
 #include <linux/errno.h>
 #include <linux/ioport.h>
@@ -791,8 +793,28 @@ void __init reserve_region_with_split(struct resource *root,
 		resource_size_t start, resource_size_t end,
 		const char *name)
 {
+	int abort = 0;
+
 	write_lock(&resource_lock);
-	__reserve_region_with_split(root, start, end, name);
+	if (root->start > start || root->end < end) {
+		pr_err("requested range [0x%llx-0x%llx] not in root %pr\n",
+		       (unsigned long long)start, (unsigned long long)end,
+		       root);
+		if (start > root->end || end < root->start)
+			abort = 1;
+		else {
+			if (end > root->end)
+				end = root->end;
+			if (start < root->start)
+				start = root->start;
+			pr_err("fixing request to [0x%llx-0x%llx]\n",
+			       (unsigned long long)start,
+			       (unsigned long long)end);
+		}
+		dump_stack();
+	}
+	if (!abort)
+		__reserve_region_with_split(root, start, end, name);
 	write_unlock(&resource_lock);
 }