[PATCH 6.12 071/567] net/mlx5: fw_tracer, Handle escaped percent properly

Greg Kroah-Hartman
2026-01-06T17:19:58Z

From: Shay Drory <shayd@nvidia.com>

[ Upstream commit c0289f67f7d6a0dfba0e92cfe661a5c70c8c6e92 ]

The firmware tracer's format string validation and parameter counting
did not properly handle escaped percent signs (%%). This caused
fw_tracer to count more parameters when trace format strings contained
literal percent characters.

To fix it, allow %% to pass string validation and skip %% sequences when
counting parameters since they represent literal percent signs rather
than format specifiers.

Fixes: 70dd6fdb8987 ("net/mlx5: FW tracer, parse traces and kernel tracing support")
Signed-off-by: Shay Drory <shayd@nvidia.com>
Reported-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Moshe Shemesh <moshe@nvidia.com>
Closes: https://lore.kernel.org/netdev/hanz6rzrb2bqbplryjrakvkbmv4y5jlmtthnvi3thg5slqvelp@t3s3erottr6s/
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/1765284977-1363052-5-git-send-email-tariqt@nvidia.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
.../mellanox/mlx5/core/diag/fw_tracer.c | 20 +++++++++++++------
1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/diag/fw_tracer.c b/drivers/net/ethernet/mellanox/mlx5/core/diag/fw_tracer.c
index 9c86c8c72d049..0b82a6a133d6c 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/diag/fw_tracer.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/diag/fw_tracer.c
@@ -368,11 +368,11 @@ static bool mlx5_is_valid_spec(const char *str)
while (isdigit(*str) || *str == '#' || *str == '.' || *str == 'l')
str++;

- /* Check if it's a valid integer/hex specifier:
+ /* Check if it's a valid integer/hex specifier or %%:
* Valid formats: %x, %d, %i, %u, etc.
*/
if (*str != 'x' && *str != 'X' && *str != 'd' && *str != 'i' &&
- *str != 'u' && *str != 'c')
+ *str != 'u' && *str != 'c' && *str != '%')
return false;

return true;
@@ -390,7 +390,11 @@ static bool mlx5_tracer_validate_params(const char *str)
if (!mlx5_is_valid_spec(substr + 1))
return false;

- substr = strstr(substr + 1, PARAM_CHAR);
+ if (*(substr + 1) == '%')
+ substr = strstr(substr + 2, PARAM_CHAR);
+ else
+ substr = strstr(substr + 1, PARAM_CHAR);
+
}

return true;
@@ -469,11 +473,15 @@ static int mlx5_tracer_get_num_of_params(char *str)
substr = strstr(pstr, VAL_PARM);
}

- /* count all the % characters */
+ /* count all the % characters, but skip %% (escaped percent) */
substr = strstr(str, PARAM_CHAR);
while (substr) {
- num_of_params += 1;
- str = substr + 1;
+ if (*(substr + 1) != '%') {
+ num_of_params += 1;
+ str = substr + 1;
+ } else {
+ str = substr + 2;
+ }
substr = strstr(str, PARAM_CHAR);
}

--
2.51.0