From: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
commit af73483f4e8b6f5c68c9aa63257bdd929a9c194a upstream.
The IDA usually detects double-frees, but that detection failed to
consider the case when there are no nearby IDs allocated and so we have a
NULL bitmap rather than simply having a clear bit. Add some tests to the
test-suite to be sure we don't inadvertently reintroduce this problem.
Unfortunately they're quite noisy so include a message to disregard
the warnings.
Reported-by: Zhenghan Wang <wzhmmmmm@xxxxxxxxx>
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Hugo SIMELIERE <hsimeliere.opensource@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
lib/idr.c | 2 +-
lib/test_ida.c | 40 ++++++++++++++++++++++++++++++++++++++++
2 files changed, 41 insertions(+), 1 deletion(-)
--- a/lib/idr.c
+++ b/lib/idr.c
@@ -471,7 +471,7 @@ static void ida_remove(struct ida *ida,
} else {
btmp = bitmap->bitmap;
}
- if (!test_bit(offset, btmp))
+ if (!bitmap || !test_bit(offset, btmp))
goto err;
__clear_bit(offset, btmp);
--- a/lib/test_ida.c
+++ b/lib/test_ida.c
@@ -150,6 +150,45 @@ static void ida_check_conv(struct ida *i
IDA_BUG_ON(ida, !ida_is_empty(ida));
}
+/*
+ * Check various situations where we attempt to free an ID we don't own.
+ */
+static void ida_check_bad_free(struct ida *ida)
+{
+ unsigned long i;
+
+ printk("vvv Ignore \"not allocated\" warnings\n");
+ /* IDA is empty; all of these will fail */
+ ida_free(ida, 0);
+ for (i = 0; i < 31; i++)
+ ida_free(ida, 1 << i);
+
+ /* IDA contains a single value entry */
+ IDA_BUG_ON(ida, ida_alloc_min(ida, 3, GFP_KERNEL) != 3);
+ ida_free(ida, 0);
+ for (i = 0; i < 31; i++)
+ ida_free(ida, 1 << i);
+
+ /* IDA contains a single bitmap */
+ IDA_BUG_ON(ida, ida_alloc_min(ida, 1023, GFP_KERNEL) != 1023);
+ ida_free(ida, 0);
+ for (i = 0; i < 31; i++)
+ ida_free(ida, 1 << i);
+
+ /* IDA contains a tree */
+ IDA_BUG_ON(ida, ida_alloc_min(ida, (1 << 20) - 1, GFP_KERNEL) != (1 << 20) - 1);
+ ida_free(ida, 0);
+ for (i = 0; i < 31; i++)
+ ida_free(ida, 1 << i);
+ printk("^^^ \"not allocated\" warnings over\n");
+
+ ida_free(ida, 3);
+ ida_free(ida, 1023);
+ ida_free(ida, (1 << 20) - 1);
+
+ IDA_BUG_ON(ida, !ida_is_empty(ida));
+}
+
static DEFINE_IDA(ida);
static int ida_checks(void)
@@ -162,6 +201,7 @@ static int ida_checks(void)
ida_check_leaf(&ida, 1024 * 64);
ida_check_max(&ida);
ida_check_conv(&ida);
+ ida_check_bad_free(&ida);
printk("IDA: %u of %u tests passed\n", tests_passed, tests_run);
return (tests_run != tests_passed) ? 0 : -EINVAL;
Patches currently in stable-queue which might be from willy@xxxxxxxxxxxxx are
queue-4.19/ida-fix-crash-in-ida_free-when-the-bitmap-is-empty.patch
