diff mbox series

[net-next,06/15] net/mlx5: HWS, change error flow on matcher disconnect

Message ID 20250102181415.1477316-7-tariqt@nvidia.com (mailing list archive)
State New
Delegated to: Netdev Maintainers
Headers show
Series mlx5 Hardware Steering part 2 | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 1 this patch: 1
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers warning 1 maintainers not CCed: linux-rdma@vger.kernel.org
netdev/build_clang success Errors and warnings before: 2 this patch: 2
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 1 this patch: 1
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 49 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2025-01-04--18-00 (tests: 887)

Commit Message

Tariq Toukan Jan. 2, 2025, 6:14 p.m. UTC 
From: Yevgeny Kliteynik <kliteyn@nvidia.com>

Currently, when firmware failure occurs during matcher disconnect flow,
the error flow of the function reconnects the matcher back and returns
an error, which continues running the calling function and eventually
frees the matcher that is being disconnected.
This leads to a case where we have a freed matcher on the matchers list,
which in turn leads to use-after-free and eventual crash.

This patch fixes that by not trying to reconnect the matcher back when
some FW command fails during disconnect.

Note that we're dealing here with FW error. We can't overcome this
problem. This might lead to bad steering state (e.g. wrong connection
between matchers), and will also lead to resource leakage, as it is
the case with any other error handling during resource destruction.

However, the goal here is to allow the driver to continue and not crash
the machine with use-after-free error.

Signed-off-by: Yevgeny Kliteynik <kliteyn@nvidia.com>
Signed-off-by: Itamar Gozlan <igozlan@nvidia.com>
Reviewed-by: Mark Bloch <mbloch@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
---
 .../mellanox/mlx5/core/steering/hws/matcher.c | 24 +++++++------------
 1 file changed, 8 insertions(+), 16 deletions(-)
diff mbox series

Patch

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/steering/hws/matcher.c b/drivers/net/ethernet/mellanox/mlx5/core/steering/hws/matcher.c
index e40193f30c54..fea2a945b0db 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/steering/hws/matcher.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/steering/hws/matcher.c
@@ -165,14 +165,14 @@  static int hws_matcher_disconnect(struct mlx5hws_matcher *matcher)
 						    next->match_ste.rtc_0_id,
 						    next->match_ste.rtc_1_id);
 		if (ret) {
-			mlx5hws_err(tbl->ctx, "Failed to disconnect matcher\n");
-			goto matcher_reconnect;
+			mlx5hws_err(tbl->ctx, "Fatal error, failed to disconnect matcher\n");
+			return ret;
 		}
 	} else {
 		ret = mlx5hws_table_connect_to_miss_table(tbl, tbl->default_miss.miss_tbl);
 		if (ret) {
-			mlx5hws_err(tbl->ctx, "Failed to disconnect last matcher\n");
-			goto matcher_reconnect;
+			mlx5hws_err(tbl->ctx, "Fatal error, failed to disconnect last matcher\n");
+			return ret;
 		}
 	}
 
@@ -180,27 +180,19 @@  static int hws_matcher_disconnect(struct mlx5hws_matcher *matcher)
 	if (prev_ft_id == tbl->ft_id) {
 		ret = mlx5hws_table_update_connected_miss_tables(tbl);
 		if (ret) {
-			mlx5hws_err(tbl->ctx, "Fatal error, failed to update connected miss table\n");
-			goto matcher_reconnect;
+			mlx5hws_err(tbl->ctx,
+				    "Fatal error, failed to update connected miss table\n");
+			return ret;
 		}
 	}
 
 	ret = mlx5hws_table_ft_set_default_next_ft(tbl, prev_ft_id);
 	if (ret) {
 		mlx5hws_err(tbl->ctx, "Fatal error, failed to restore matcher ft default miss\n");
-		goto matcher_reconnect;
+		return ret;
 	}
 
 	return 0;
-
-matcher_reconnect:
-	if (list_empty(&tbl->matchers_list) || !prev)
-		list_add(&matcher->list_node, &tbl->matchers_list);
-	else
-		/* insert after prev matcher */
-		list_add(&matcher->list_node, &prev->list_node);
-
-	return ret;
 }
 
 static void hws_matcher_set_rtc_attr_sz(struct mlx5hws_matcher *matcher,