This patch addresses potential data races involving access to the
slh_first field in the QSLIST_INSERT_HEAD_ATOMIC macro.
Fixes: c740ad92d0 ("QSLIST: add lock-free operations")
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2902
Signed-off-by: Vitalii Mordan <mor...@ispras.ru>
---
include/qemu/queue.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/include/qemu/queue.h b/include/qemu/queue.h
index e029e7bf66..b0dbc3c6e2 100644
--- a/include/qemu/queue.h
+++ b/include/qemu/queue.h
@@ -217,7 +217,8 @@ struct {
\
#define QSLIST_INSERT_HEAD_ATOMIC(head, elm, field) do { \
typeof(elm) save_sle_next; \
do { \
- save_sle_next = (elm)->field.sle_next = (head)->slh_first; \
+ save_sle_next = qatomic_read(&(head)->slh_first); \
+ (elm)->field.sle_next = save_sle_next; \
} while (qatomic_cmpxchg(&(head)->slh_first, save_sle_next, (elm)) !=\
save_sle_next); \
} while (/*CONSTCOND*/0)
--
2.34.1
