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authorDarren Hart <dvhltc@us.ibm.com>2008-12-30 04:43:21 +0100
committerIngo Molnar <mingo@elte.hu>2009-01-02 23:10:44 +0100
commit90621c40cc4ab7b0a414311ce37e7cc7173403b6 (patch)
tree3f5797462898f3f85bad1a31df04e671df8aadd3
parentfutex: make futex_(get|put)_key() calls symmetric (diff)
downloadlinux-90621c40cc4ab7b0a414311ce37e7cc7173403b6.tar.xz
linux-90621c40cc4ab7b0a414311ce37e7cc7173403b6.zip
futex: catch certain assymetric (get|put)_futex_key calls
Impact: add debug check Following up on my previous key reference accounting patches, this patch will catch puts on keys that haven't been "got". This won't catch nested get/put mismatches though. Build and boot tested, with minimal desktop activity and a run of the open_posix_testsuite in LTP for testing. No warnings logged. Signed-off-by: Darren Hart <dvhltc@us.ibm.com> Cc: <stable@kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r--kernel/futex.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/kernel/futex.c b/kernel/futex.c
index c5ac55cc0c16..206d4c906885 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -170,8 +170,11 @@ static void get_futex_key_refs(union futex_key *key)
*/
static void drop_futex_key_refs(union futex_key *key)
{
- if (!key->both.ptr)
+ if (!key->both.ptr) {
+ /* If we're here then we tried to put a key we failed to get */
+ WARN_ON_ONCE(1);
return;
+ }
switch (key->both.offset & (FUT_OFF_INODE|FUT_OFF_MMSHARED)) {
case FUT_OFF_INODE: