net/mlx5: fix possible stack overflows

A couple of debug functions use a 512 byte temporary buffer and call another
function that has another buffer of the same size, which in turn exceeds the
usual warning limit for excessive stack usage:

drivers/net/ethernet/mellanox/mlx5/core/steering/dr_dbg.c:1073:1: error: stack frame size (1448) exceeds limit (1024) in 'dr_dump_start' [-Werror,-Wframe-larger-than]
dr_dump_start(struct seq_file *file, loff_t *pos)
drivers/net/ethernet/mellanox/mlx5/core/steering/dr_dbg.c:1009:1: error: stack frame size (1120) exceeds limit (1024) in 'dr_dump_domain' [-Werror,-Wframe-larger-than]
dr_dump_domain(struct seq_file *file, struct mlx5dr_domain *dmn)
drivers/net/ethernet/mellanox/mlx5/core/steering/dr_dbg.c:705:1: error: stack frame size (1104) exceeds limit (1024) in 'dr_dump_matcher_rx_tx' [-Werror,-Wframe-larger-than]
dr_dump_matcher_rx_tx(struct seq_file *file, bool is_rx,

Rework these so that each of the various code paths only ever has one of
these buffers in it, and exactly the functions that declare one have
the 'noinline_for_stack' annotation that prevents them from all being
inlined into the same caller.

Fixes: 917d1e799ddf ("net/mlx5: DR, Change SWS usage to debug fs seq_file interface")
Reviewed-by: Simon Horman <horms@kernel.org>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Link: https://lore.kernel.org/all/20240219100506.648089-1-arnd@kernel.org/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://lore.kernel.org/r/20240408074142.3007036-1-arnd@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/steering/dr_dbg.c b/drivers/net/ethernet/mellanox/mlx5/core/steering/dr_dbg.c
index 64f4cc284aea41715abecb1167439efe401951f8..030a5776c937406540645462b5950cd209c37974 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx5/core/steering/dr_dbg.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/steering/dr_dbg.c
@@ -205,12 +205,11 @@ dr_dump_hex_print(char hex[DR_HEX_SIZE], char *src, u32 size)
 }
 
 static int
-dr_dump_rule_action_mem(struct seq_file *file, const u64 rule_id,
+dr_dump_rule_action_mem(struct seq_file *file, char *buff, const u64 rule_id,
                        struct mlx5dr_rule_action_member *action_mem)
 {
        struct mlx5dr_action *action = action_mem->action;
        const u64 action_id = DR_DBG_PTR_TO_ID(action);
-       char buff[MLX5DR_DEBUG_DUMP_BUFF_LENGTH];
        u64 hit_tbl_ptr, miss_tbl_ptr;
        u32 hit_tbl_id, miss_tbl_id;
        int ret;
@@ -488,10 +487,9 @@ dr_dump_rule_action_mem(struct seq_file *file, const u64 rule_id,
 }
 
 static int
-dr_dump_rule_mem(struct seq_file *file, struct mlx5dr_ste *ste,
+dr_dump_rule_mem(struct seq_file *file, char *buff, struct mlx5dr_ste *ste,
                 bool is_rx, const u64 rule_id, u8 format_ver)
 {
-       char buff[MLX5DR_DEBUG_DUMP_BUFF_LENGTH];
        char hw_ste_dump[DR_HEX_SIZE];
        u32 mem_rec_type;
        int ret;
@@ -522,7 +520,8 @@ dr_dump_rule_mem(struct seq_file *file, struct mlx5dr_ste *ste,
 }
 
 static int
-dr_dump_rule_rx_tx(struct seq_file *file, struct mlx5dr_rule_rx_tx *rule_rx_tx,
+dr_dump_rule_rx_tx(struct seq_file *file, char *buff,
+                  struct mlx5dr_rule_rx_tx *rule_rx_tx,
                   bool is_rx, const u64 rule_id, u8 format_ver)
 {
        struct mlx5dr_ste *ste_arr[DR_RULE_MAX_STES + DR_ACTION_MAX_STES];
@@ -533,7 +532,7 @@ dr_dump_rule_rx_tx(struct seq_file *file, struct mlx5dr_rule_rx_tx *rule_rx_tx,
                return 0;
 
        while (i--) {
-               ret = dr_dump_rule_mem(file, ste_arr[i], is_rx, rule_id,
+               ret = dr_dump_rule_mem(file, buff, ste_arr[i], is_rx, rule_id,
                                       format_ver);
                if (ret < 0)
                        return ret;
@@ -542,7 +541,8 @@ dr_dump_rule_rx_tx(struct seq_file *file, struct mlx5dr_rule_rx_tx *rule_rx_tx,
        return 0;
 }
 
-static int dr_dump_rule(struct seq_file *file, struct mlx5dr_rule *rule)
+static noinline_for_stack int
+dr_dump_rule(struct seq_file *file, struct mlx5dr_rule *rule)
 {
        struct mlx5dr_rule_action_member *action_mem;
        const u64 rule_id = DR_DBG_PTR_TO_ID(rule);
@@ -565,19 +565,19 @@ static int dr_dump_rule(struct seq_file *file, struct mlx5dr_rule *rule)
                return ret;
 
        if (rx->nic_matcher) {
-               ret = dr_dump_rule_rx_tx(file, rx, true, rule_id, format_ver);
+               ret = dr_dump_rule_rx_tx(file, buff, rx, true, rule_id, format_ver);
                if (ret < 0)
                        return ret;
        }
 
        if (tx->nic_matcher) {
-               ret = dr_dump_rule_rx_tx(file, tx, false, rule_id, format_ver);
+               ret = dr_dump_rule_rx_tx(file, buff, tx, false, rule_id, format_ver);
                if (ret < 0)
                        return ret;
        }
 
        list_for_each_entry(action_mem, &rule->rule_actions_list, list) {
-               ret = dr_dump_rule_action_mem(file, rule_id, action_mem);
+               ret = dr_dump_rule_action_mem(file, buff, rule_id, action_mem);
                if (ret < 0)
                        return ret;
        }
@@ -586,10 +586,10 @@ static int dr_dump_rule(struct seq_file *file, struct mlx5dr_rule *rule)
 }
 
 static int
-dr_dump_matcher_mask(struct seq_file *file, struct mlx5dr_match_param *mask,
+dr_dump_matcher_mask(struct seq_file *file, char *buff,
+                    struct mlx5dr_match_param *mask,
                     u8 criteria, const u64 matcher_id)
 {
-       char buff[MLX5DR_DEBUG_DUMP_BUFF_LENGTH];
        char dump[DR_HEX_SIZE];
        int ret;
 
@@ -681,10 +681,10 @@ dr_dump_matcher_mask(struct seq_file *file, struct mlx5dr_match_param *mask,
 }
 
 static int
-dr_dump_matcher_builder(struct seq_file *file, struct mlx5dr_ste_build *builder,
+dr_dump_matcher_builder(struct seq_file *file, char *buff,
+                       struct mlx5dr_ste_build *builder,
                        u32 index, bool is_rx, const u64 matcher_id)
 {
-       char buff[MLX5DR_DEBUG_DUMP_BUFF_LENGTH];
        int ret;
 
        ret = snprintf(buff, MLX5DR_DEBUG_DUMP_BUFF_LENGTH,
@@ -702,11 +702,10 @@ dr_dump_matcher_builder(struct seq_file *file, struct mlx5dr_ste_build *builder,
 }
 
 static int
-dr_dump_matcher_rx_tx(struct seq_file *file, bool is_rx,
+dr_dump_matcher_rx_tx(struct seq_file *file, char *buff, bool is_rx,
                      struct mlx5dr_matcher_rx_tx *matcher_rx_tx,
                      const u64 matcher_id)
 {
-       char buff[MLX5DR_DEBUG_DUMP_BUFF_LENGTH];
        enum dr_dump_rec_type rec_type;
        u64 s_icm_addr, e_icm_addr;
        int i, ret;
@@ -731,7 +730,7 @@ dr_dump_matcher_rx_tx(struct seq_file *file, bool is_rx,
                return ret;
 
        for (i = 0; i < matcher_rx_tx->num_of_builders; i++) {
-               ret = dr_dump_matcher_builder(file,
+               ret = dr_dump_matcher_builder(file, buff,
                                              &matcher_rx_tx->ste_builder[i],
                                              i, is_rx, matcher_id);
                if (ret < 0)
@@ -741,7 +740,7 @@ dr_dump_matcher_rx_tx(struct seq_file *file, bool is_rx,
        return 0;
 }
 
-static int
+static noinline_for_stack int
 dr_dump_matcher(struct seq_file *file, struct mlx5dr_matcher *matcher)
 {
        struct mlx5dr_matcher_rx_tx *rx = &matcher->rx;
@@ -763,19 +762,19 @@ dr_dump_matcher(struct seq_file *file, struct mlx5dr_matcher *matcher)
        if (ret)
                return ret;
 
-       ret = dr_dump_matcher_mask(file, &matcher->mask,
+       ret = dr_dump_matcher_mask(file, buff, &matcher->mask,
                                   matcher->match_criteria, matcher_id);
        if (ret < 0)
                return ret;
 
        if (rx->nic_tbl) {
-               ret = dr_dump_matcher_rx_tx(file, true, rx, matcher_id);
+               ret = dr_dump_matcher_rx_tx(file, buff, true, rx, matcher_id);
                if (ret < 0)
                        return ret;
        }
 
        if (tx->nic_tbl) {
-               ret = dr_dump_matcher_rx_tx(file, false, tx, matcher_id);
+               ret = dr_dump_matcher_rx_tx(file, buff, false, tx, matcher_id);
                if (ret < 0)
                        return ret;
        }
@@ -803,11 +802,10 @@ dr_dump_matcher_all(struct seq_file *file, struct mlx5dr_matcher *matcher)
 }
 
 static int
-dr_dump_table_rx_tx(struct seq_file *file, bool is_rx,
+dr_dump_table_rx_tx(struct seq_file *file, char *buff, bool is_rx,
                    struct mlx5dr_table_rx_tx *table_rx_tx,
                    const u64 table_id)
 {
-       char buff[MLX5DR_DEBUG_DUMP_BUFF_LENGTH];
        enum dr_dump_rec_type rec_type;
        u64 s_icm_addr;
        int ret;
@@ -829,7 +827,8 @@ dr_dump_table_rx_tx(struct seq_file *file, bool is_rx,
        return 0;
 }
 
-static int dr_dump_table(struct seq_file *file, struct mlx5dr_table *table)
+static noinline_for_stack int
+dr_dump_table(struct seq_file *file, struct mlx5dr_table *table)
 {
        struct mlx5dr_table_rx_tx *rx = &table->rx;
        struct mlx5dr_table_rx_tx *tx = &table->tx;
@@ -848,14 +847,14 @@ static int dr_dump_table(struct seq_file *file, struct mlx5dr_table *table)
                return ret;
 
        if (rx->nic_dmn) {
-               ret = dr_dump_table_rx_tx(file, true, rx,
+               ret = dr_dump_table_rx_tx(file, buff, true, rx,
                                          DR_DBG_PTR_TO_ID(table));
                if (ret < 0)
                        return ret;
        }
 
        if (tx->nic_dmn) {
-               ret = dr_dump_table_rx_tx(file, false, tx,
+               ret = dr_dump_table_rx_tx(file, buff, false, tx,
                                          DR_DBG_PTR_TO_ID(table));
                if (ret < 0)
                        return ret;
@@ -881,10 +880,10 @@ static int dr_dump_table_all(struct seq_file *file, struct mlx5dr_table *tbl)
 }
 
 static int
-dr_dump_send_ring(struct seq_file *file, struct mlx5dr_send_ring *ring,
+dr_dump_send_ring(struct seq_file *file, char *buff,
+                 struct mlx5dr_send_ring *ring,
                  const u64 domain_id)
 {
-       char buff[MLX5DR_DEBUG_DUMP_BUFF_LENGTH];
        int ret;
 
        ret = snprintf(buff, MLX5DR_DEBUG_DUMP_BUFF_LENGTH,
@@ -902,13 +901,13 @@ dr_dump_send_ring(struct seq_file *file, struct mlx5dr_send_ring *ring,
        return 0;
 }
 
-static noinline_for_stack int
+static int
 dr_dump_domain_info_flex_parser(struct seq_file *file,
+                               char *buff,
                                const char *flex_parser_name,
                                const u8 flex_parser_value,
                                const u64 domain_id)
 {
-       char buff[MLX5DR_DEBUG_DUMP_BUFF_LENGTH];
        int ret;
 
        ret = snprintf(buff, MLX5DR_DEBUG_DUMP_BUFF_LENGTH,
@@ -925,11 +924,11 @@ dr_dump_domain_info_flex_parser(struct seq_file *file,
        return 0;
 }
 
-static noinline_for_stack int
-dr_dump_domain_info_caps(struct seq_file *file, struct mlx5dr_cmd_caps *caps,
+static int
+dr_dump_domain_info_caps(struct seq_file *file, char *buff,
+                        struct mlx5dr_cmd_caps *caps,
                         const u64 domain_id)
 {
-       char buff[MLX5DR_DEBUG_DUMP_BUFF_LENGTH];
        struct mlx5dr_cmd_vport_cap *vport_caps;
        unsigned long i, vports_num;
        int ret;
@@ -969,34 +968,35 @@ dr_dump_domain_info_caps(struct seq_file *file, struct mlx5dr_cmd_caps *caps,
 }
 
 static int
-dr_dump_domain_info(struct seq_file *file, struct mlx5dr_domain_info *info,
+dr_dump_domain_info(struct seq_file *file, char *buff,
+                   struct mlx5dr_domain_info *info,
                    const u64 domain_id)
 {
        int ret;
 
-       ret = dr_dump_domain_info_caps(file, &info->caps, domain_id);
+       ret = dr_dump_domain_info_caps(file, buff, &info->caps, domain_id);
        if (ret < 0)
                return ret;
 
-       ret = dr_dump_domain_info_flex_parser(file, "icmp_dw0",
+       ret = dr_dump_domain_info_flex_parser(file, buff, "icmp_dw0",
                                              info->caps.flex_parser_id_icmp_dw0,
                                              domain_id);
        if (ret < 0)
                return ret;
 
-       ret = dr_dump_domain_info_flex_parser(file, "icmp_dw1",
+       ret = dr_dump_domain_info_flex_parser(file, buff, "icmp_dw1",
                                              info->caps.flex_parser_id_icmp_dw1,
                                              domain_id);
        if (ret < 0)
                return ret;
 
-       ret = dr_dump_domain_info_flex_parser(file, "icmpv6_dw0",
+       ret = dr_dump_domain_info_flex_parser(file, buff, "icmpv6_dw0",
                                              info->caps.flex_parser_id_icmpv6_dw0,
                                              domain_id);
        if (ret < 0)
                return ret;
 
-       ret = dr_dump_domain_info_flex_parser(file, "icmpv6_dw1",
+       ret = dr_dump_domain_info_flex_parser(file, buff, "icmpv6_dw1",
                                              info->caps.flex_parser_id_icmpv6_dw1,
                                              domain_id);
        if (ret < 0)
@@ -1032,12 +1032,12 @@ dr_dump_domain(struct seq_file *file, struct mlx5dr_domain *dmn)
        if (ret)
                return ret;
 
-       ret = dr_dump_domain_info(file, &dmn->info, domain_id);
+       ret = dr_dump_domain_info(file, buff, &dmn->info, domain_id);
        if (ret < 0)
                return ret;
 
        if (dmn->info.supp_sw_steering) {
-               ret = dr_dump_send_ring(file, dmn->send_ring, domain_id);
+               ret = dr_dump_send_ring(file, buff, dmn->send_ring, domain_id);
                if (ret < 0)
                        return ret;
        }