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| author | Jean-Sébastien Pédron <dumbbell@FreeBSD.org> | 2023-01-15 14:56:48 +0000 |
|---|---|---|
| committer | Jean-Sébastien Pédron <dumbbell@FreeBSD.org> | 2023-02-16 11:55:13 +0000 |
| commit | b2bea8bf56a8f8de612b6fdb0d14fdebe4414af6 (patch) | |
| tree | 1d6fdc1c8204d325eba566ce5b57f201ef2ac24b | |
| parent | cc32cc0f8e965b5c3d0a7ac6595ae97997a76d1b (diff) | |
| download | src-b2bea8bf56a8f8de612b6fdb0d14fdebe4414af6.tar.gz src-b2bea8bf56a8f8de612b6fdb0d14fdebe4414af6.zip | |
linuxkpi: Fix `atomic_long_sub()` overflow
By (ab)using `atomic_long_add_return()`, `atomic_long_sub()` was making
the atomic long overflow. Indeed the underlying FreeBSD atomic is based
on an unsigned long.
Reviewed by: manu
Approved by: manu
Differential Revision: https://reviews.freebsd.org/D38090
(cherry picked from commit 9491ea7c68221ca7bc5e369ebb57660886ef1b13)
| -rw-r--r-- | sys/compat/linuxkpi/common/include/asm/atomic-long.h | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/sys/compat/linuxkpi/common/include/asm/atomic-long.h b/sys/compat/linuxkpi/common/include/asm/atomic-long.h index f8bd9edfccf9..aeec6edd707d 100644 --- a/sys/compat/linuxkpi/common/include/asm/atomic-long.h +++ b/sys/compat/linuxkpi/common/include/asm/atomic-long.h @@ -41,7 +41,7 @@ typedef struct { } atomic_long_t; #define atomic_long_add(i, v) atomic_long_add_return((i), (v)) -#define atomic_long_sub(i, v) atomic_long_add_return(-(i), (v)) +#define atomic_long_sub(i, v) atomic_long_sub_return((i), (v)) #define atomic_long_inc_return(v) atomic_long_add_return(1, (v)) #define atomic_long_inc_not_zero(v) atomic_long_add_unless((v), 1, 0) @@ -51,6 +51,12 @@ atomic_long_add_return(long i, atomic_long_t *v) return i + atomic_fetchadd_long(&v->counter, i); } +static inline long +atomic_long_sub_return(long i, atomic_long_t *v) +{ + return atomic_fetchadd_long(&v->counter, -i) - i; +} + static inline void atomic_long_set(atomic_long_t *v, long i) { |