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| author | Kumar Kartikeya Dwivedi <memxor@gmail.com> | 2026-01-22 14:59:11 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2026-02-27 02:00:47 +0300 |
| commit | df570284cb3be52a70e54e89de62ad2d39d67299 (patch) | |
| tree | bb3516c16e98103dd6d38e69ab7e13b211270308 /include/asm-generic | |
| parent | 074c1c58698bd53b6d600b382c5f91c72f5abcaf (diff) | |
| download | linux-df570284cb3be52a70e54e89de62ad2d39d67299.tar.xz | |
rqspinlock: Fix TAS fallback lock entry creation
[ Upstream commit 82f3b142c99cf44c7b1e70b7720169c646b9760f ]
The TAS fallback can be invoked directly when queued spin locks are
disabled, and through the slow path when paravirt is enabled for queued
spin locks. In the latter case, the res_spin_lock macro will attempt the
fast path and already hold the entry when entering the slow path. This
will lead to creation of extraneous entries that are not released, which
may cause false positives for deadlock detection.
Fix this by always preceding invocation of the TAS fallback in every
case with the grabbing of the held lock entry, and add a comment to make
note of this.
Fixes: c9102a68c070 ("rqspinlock: Add a test-and-set fallback")
Reported-by: Amery Hung <ameryhung@gmail.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Tested-by: Amery Hung <ameryhung@gmail.com>
Link: https://lore.kernel.org/r/20260122115911.3668985-1-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'include/asm-generic')
| -rw-r--r-- | include/asm-generic/rqspinlock.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/asm-generic/rqspinlock.h b/include/asm-generic/rqspinlock.h index 0f2dcbbfee2f..5c5cf2f7fc39 100644 --- a/include/asm-generic/rqspinlock.h +++ b/include/asm-generic/rqspinlock.h @@ -191,7 +191,7 @@ static __always_inline int res_spin_lock(rqspinlock_t *lock) #else -#define res_spin_lock(lock) resilient_tas_spin_lock(lock) +#define res_spin_lock(lock) ({ grab_held_lock_entry(lock); resilient_tas_spin_lock(lock); }) #endif /* CONFIG_QUEUED_SPINLOCKS */ |