futex: add WARN_ON to catch certain assymetric (get|put)_futex_key calls
PATCH 1/1 futex: add WARN_ON to catch certain assymetric (get|put)_futex_key calls
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.
---
kernel/futex.c | 5 ++++- 1 files changed, 4 insertions(+), 1 deletions(-)
kernel/futex.c +4 -1
@@ -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 (1 );return ; + }switch (key->both.offset & (FUT_OFF_INODE |FUT_OFF_MMSHARED )) {case FUT_OFF_INODE :
Ingo Molnar
AppliedQuoted 7 lines · Darren Hart
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_testsuitein LTP for testing. No warnings logged.
Quoted 8 lines
Signed-off-by Darren Hart <[email protected]>Cc "Peter Zijlstra" <[email protected]>Cc "Thomas Gleixner" <[email protected]>Cc "Rusty Russell" <[email protected]>---
kernel/futex.c | 5 ++++- 1 files changed, 4 insertions(+), 1 deletions(-)
applied to tip/core/futexes, thanks!
I changed this:
kernel/futex.c static void get_futex_key_refs(union futex_key *key) · line 176
Quoted 2 lines
kernel/futex.c +1
-0+WARN_ON (1 );return ;
to WARN_ON_ONCE() - warning once per bootup is good enough for kerneloops.org to pick it up, while a ton of warnings add no extra (other than to inconvenience the user, or even make the system unworkable).
Ingo