From: Scott <[email protected]> GCC has a bug where it incorrectly elides struct initialization in inline functions when strict aliasing is enabled (-O2/-O3/-Os), causing reads from uninitialized memory. This affects both designated initializers and manual field assignment.
Add RTE_FORCE_INIT_BARRIER macro that uses an asm volatile memory barrier to prevent the compiler from incorrectly optimizing away struct initialization. Apply the workaround to pseudo-header checksum functions in rte_ip4.h, rte_ip6.h, hinic driver, and mlx5 driver. Signed-off-by: Scott Mitchell <[email protected]> --- drivers/net/hinic/hinic_pmd_tx.c | 2 ++ drivers/net/mlx5/mlx5_flow_dv.c | 2 ++ lib/eal/include/rte_common.h | 14 ++++++++++++++ lib/net/rte_ip4.h | 1 + lib/net/rte_ip6.h | 1 + 5 files changed, 20 insertions(+) diff --git a/drivers/net/hinic/hinic_pmd_tx.c b/drivers/net/hinic/hinic_pmd_tx.c index 22fb0bffaf..570715531d 100644 --- a/drivers/net/hinic/hinic_pmd_tx.c +++ b/drivers/net/hinic/hinic_pmd_tx.c @@ -725,6 +725,7 @@ hinic_ipv4_phdr_cksum(const struct rte_ipv4_hdr *ipv4_hdr, uint64_t ol_flags) rte_cpu_to_be_16(rte_be_to_cpu_16(ipv4_hdr->total_length) - rte_ipv4_hdr_len(ipv4_hdr)); } + RTE_FORCE_INIT_BARRIER(psd_hdr); return rte_raw_cksum(&psd_hdr, sizeof(psd_hdr)); } @@ -743,6 +744,7 @@ hinic_ipv6_phdr_cksum(const struct rte_ipv6_hdr *ipv6_hdr, uint64_t ol_flags) else psd_hdr.len = ipv6_hdr->payload_len; + RTE_FORCE_INIT_BARRIER(psd_hdr); sum = __rte_raw_cksum(&ipv6_hdr->src_addr, sizeof(ipv6_hdr->src_addr) + sizeof(ipv6_hdr->dst_addr), 0); sum = __rte_raw_cksum(&psd_hdr, sizeof(psd_hdr), sum); diff --git a/drivers/net/mlx5/mlx5_flow_dv.c b/drivers/net/mlx5/mlx5_flow_dv.c index 47f6d28410..1eeeb6747f 100644 --- a/drivers/net/mlx5/mlx5_flow_dv.c +++ b/drivers/net/mlx5/mlx5_flow_dv.c @@ -4445,6 +4445,8 @@ __flow_encap_decap_resource_register(struct rte_eth_dev *dev, .reserve = 0, } }; + RTE_FORCE_INIT_BARRIER(encap_decap_key); + struct mlx5_flow_cb_ctx ctx = { .error = error, .data = resource, diff --git a/lib/eal/include/rte_common.h b/lib/eal/include/rte_common.h index 00d428e295..d58e856d96 100644 --- a/lib/eal/include/rte_common.h +++ b/lib/eal/include/rte_common.h @@ -555,6 +555,20 @@ static void __attribute__((destructor(RTE_PRIO(prio)), used)) func(void) #define __rte_no_ubsan_alignment #endif +/** + * Force struct initialization to prevent GCC optimization bug. + * GCC has a bug where it incorrectly elides struct initialization in + * inline functions when strict aliasing is enabled, causing reads from + * uninitialized memory. This memory barrier prevents the misoptimization. + */ +#ifdef RTE_CC_GCC +#define RTE_FORCE_INIT_BARRIER(var) do { \ + asm volatile("" : "+m" (var)); \ +} while (0) +#else +#define RTE_FORCE_INIT_BARRIER(var) +#endif + /*********** Macros for pointer arithmetic ********/ /** diff --git a/lib/net/rte_ip4.h b/lib/net/rte_ip4.h index 822a660cfb..a0839c584e 100644 --- a/lib/net/rte_ip4.h +++ b/lib/net/rte_ip4.h @@ -238,6 +238,7 @@ rte_ipv4_phdr_cksum(const struct rte_ipv4_hdr *ipv4_hdr, uint64_t ol_flags) psd_hdr.len = rte_cpu_to_be_16((uint16_t)(l3_len - rte_ipv4_hdr_len(ipv4_hdr))); } + RTE_FORCE_INIT_BARRIER(psd_hdr); return rte_raw_cksum(&psd_hdr, sizeof(psd_hdr)); } diff --git a/lib/net/rte_ip6.h b/lib/net/rte_ip6.h index d1abf1f5d5..902f100a44 100644 --- a/lib/net/rte_ip6.h +++ b/lib/net/rte_ip6.h @@ -572,6 +572,7 @@ rte_ipv6_phdr_cksum(const struct rte_ipv6_hdr *ipv6_hdr, uint64_t ol_flags) else psd_hdr.len = ipv6_hdr->payload_len; + RTE_FORCE_INIT_BARRIER(psd_hdr); sum = __rte_raw_cksum(&ipv6_hdr->src_addr, sizeof(ipv6_hdr->src_addr) + sizeof(ipv6_hdr->dst_addr), 0); -- 2.39.5 (Apple Git-154)
