The following commit has been merged into the locking/urgent branch of tip:
Commit-ID: 59f3daffefbf48206dbf310af5472d6d7d7161df
Gitweb: https://git.kernel.org/tip/59f3daffefbf48206dbf310af5472d6d7d7161df
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Tue, 14 Nov 2023 21:36:13 +01:00
Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Tue, 14 Nov 2023 22:26:41 +01:00
futex: Fix hardcoded flags
Xi reported that commit 5694289ce183 ("futex: Flag conversion") broke
glibc's robust futex tests.
This was narrowed down to the change of FLAGS_SHARED from 0x01 to
0x10, at which point Florian noted that handle_futex_death() has a
hardcoded flags argument of 1.
Change this to: FLAGS_SIZE_32 | FLAGS_SHARED, matching how
futex_to_flags() unconditionally sets FLAGS_SIZE_32 for all legacy
futex ops.
Fixes: 5694289ce183 ("futex: Flag conversion")
Reported-by: Xi Ruoyao <xry111@xxxxxxxxxxx>
Reported-by: Florian Weimer <fweimer@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Link: https://lkml.kernel.org/r/20231114201402.GA25315@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
---
kernel/futex/core.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/kernel/futex/core.c b/kernel/futex/core.c
index 52695c5..dad981a 100644
--- a/kernel/futex/core.c
+++ b/kernel/futex/core.c
@@ -700,7 +700,8 @@ retry:
owner = uval & FUTEX_TID_MASK;
if (pending_op && !pi && !owner) {
- futex_wake(uaddr, 1, 1, FUTEX_BITSET_MATCH_ANY);
+ futex_wake(uaddr, FLAGS_SIZE_32 | FLAGS_SHARED, 1,
+ FUTEX_BITSET_MATCH_ANY);
return 0;
}
@@ -752,8 +753,10 @@ retry:
* Wake robust non-PI futexes here. The wakeup of
* PI futexes happens in exit_pi_state():
*/
- if (!pi && (uval & FUTEX_WAITERS))
- futex_wake(uaddr, 1, 1, FUTEX_BITSET_MATCH_ANY);
+ if (!pi && (uval & FUTEX_WAITERS)) {
+ futex_wake(uaddr, FLAGS_SIZE_32 | FLAGS_SHARED, 1,
+ FUTEX_BITSET_MATCH_ANY);
+ }
return 0;
}
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