On 6/22/23 06:45, Ondřej Surý via lttng-dev wrote:
(Sorry, I missed closing brackets in both macros, so resending fixed patch...)
The cds_lfht_for_each_entry and cds_lfht_for_each_entry_duplicate macros
would call caa_container_of() macro on NULL pointer. This is not a
problem under normal circumstances as the check in the for loop fails
and the loop-statement is not called with invalid (pos) value.
However AddressSanitizer doesn't like that and complains about this:
runtime error: applying non-zero offset 18446744073709551056 to null
pointer
Move the cds_lfht_iter_get_node(iter) != NULL from the cond-expression
of the for loop into both init-clause and iteration-expression as
conditional operator and check for (pos) value in the cond-expression
instead.
I've taken the liberty to reimplement this with a new helper "cds_lfht_entry".
Can you review and try the following commits please ?
https://review.lttng.org/c/userspace-rcu/+/10445 compiler.h: Introduce
caa_unqual_scalar_typeof
https://review.lttng.org/c/userspace-rcu/+/10446 Avoid calling caa_container_of
on NULL pointer in cds_lfht macros
Thanks!
Mathieu
Signed-off-by: Ondřej Surý <ond...@sury.org>
---
include/urcu/rculfhash.h | 20 ++++++++++----------
1 file changed, 10 insertions(+), 10 deletions(-)
diff --git a/include/urcu/rculfhash.h b/include/urcu/rculfhash.h
index fbd33cc..64cc18f 100644
--- a/include/urcu/rculfhash.h
+++ b/include/urcu/rculfhash.h
@@ -546,22 +546,22 @@ void cds_lfht_resize(struct cds_lfht *ht, unsigned long
new_size);
#define cds_lfht_for_each_entry(ht, iter, pos, member) \
for (cds_lfht_first(ht, iter), \
- pos = caa_container_of(cds_lfht_iter_get_node(iter), \
- __typeof__(*(pos)), member); \
- cds_lfht_iter_get_node(iter) != NULL; \
+ pos = (cds_lfht_iter_get_node(iter) != NULL ?
caa_container_of(cds_lfht_iter_get_node(iter), \
+ __typeof__(*(pos)), member) : NULL);
\
+ pos != NULL; \
cds_lfht_next(ht, iter), \
- pos = caa_container_of(cds_lfht_iter_get_node(iter), \
- __typeof__(*(pos)), member))
+ pos = (cds_lfht_iter_get_node(iter) != NULL ?
caa_container_of(cds_lfht_iter_get_node(iter), \
+ __typeof__(*(pos)), member) : NULL))
#define cds_lfht_for_each_entry_duplicate(ht, hash, match, key, \
iter, pos, member) \
for (cds_lfht_lookup(ht, hash, match, key, iter), \
- pos = caa_container_of(cds_lfht_iter_get_node(iter), \
- __typeof__(*(pos)), member); \
- cds_lfht_iter_get_node(iter) != NULL; \
+ pos = (cds_lfht_iter_get_node(iter) != NULL ?
caa_container_of(cds_lfht_iter_get_node(iter), \
+ __typeof__(*(pos)), member) : NULL);
\
+ pos != NULL; \
cds_lfht_next_duplicate(ht, match, key, iter), \
- pos = caa_container_of(cds_lfht_iter_get_node(iter), \
- __typeof__(*(pos)), member))
+ pos = (cds_lfht_iter_get_node(iter) != NULL ?
caa_container_of(cds_lfht_iter_get_node(iter), \
+ __typeof__(*(pos)), member) : NULL))
#ifdef __cplusplus
}
--
Mathieu Desnoyers
EfficiOS Inc.
https://www.efficios.com
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