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- commit ad84851746243d85f9be59703e9bee0f5c5f8eba
- Author: Willy Tarreau <w@1wt.eu>
- Date: Wed Feb 14 14:16:28 2018 +0100
-
- BUG/MEDIUM: threads: fix the double CAS implementation for ARMv7
-
- Commit f61f0cb ("MINOR: threads: Introduce double-width CAS on x86_64
- and arm.") introduced the double CAS. But the ARMv7 version is bogus,
- it uses the value of the pointers instead of dereferencing them. When
- lucky, it simply doesn't build due to impossible registers combinations.
- Otherwise it will immediately crash at run time when facing traffic.
-
- No backport is needed, this bug was introduced in 1.9-dev.
-
- (cherry picked from commit 41ccb194d1d14669e0592e5373ef5776f099e82a)
- [wt: backported only to keep safe code eventhough we don't use
- this function in 1.8]
- Signed-off-by: Willy Tarreau <w@1wt.eu>
-
- diff --git a/include/common/hathreads.h b/include/common/hathreads.h
- index 543ab95c..4e72848e 100644
- --- a/include/common/hathreads.h
- +++ b/include/common/hathreads.h
- @@ -766,7 +766,7 @@ __ha_barrier_full(void)
- __asm __volatile("dmb" ::: "memory");
- }
-
- -static __inline int __ha_cas_dw(void *target, void *compare, void *set)
- +static __inline int __ha_cas_dw(void *target, void *compare, const void *set)
- {
- uint64_t previous;
- int tmp;
- @@ -780,7 +780,7 @@ static __inline int __ha_cas_dw(void *target, void *compare, void *set)
- "cmpeq %1, #1;"
- "beq 1b;"
- : "=&r" (previous), "=&r" (tmp)
- - : "r" (compare), "r" (set), "r" (target)
- + : "r" (*(uint64_t *)compare), "r" (*(uint64_t *)set), "r" (target)
- : "memory", "cc");
- tmp = (previous == *(uint64_t *)compare);
- *(uint64_t *)compare = previous;
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