Re: [PATCH v6 15/24] dyndbg: refactor param_set_dyndbg_classes and below
From: sashiko-bot@kernel.org
Date: 2026-07-08 02:29:18
Also in:
dri-devel
Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider: - [Medium] param_set_dyndbg_module_classes() fails to initialize debug queries for a newly probed module because it incorrectly uses the global class parameter state as the baseline (`old_bits`). --
--- Patch [15]: [PATCH v6 15/24] dyndbg: refactor param_set_dyndbg_classes and below ---commit 041ecc33e02248dbfd09801bededdf6047b80f6e Author: Jim Cromie [off-list ref] dyndbg: refactor param_set_dyndbg_classes and below This commit refactors the param_set_dyndbg_classes callchain to allow module-specific settings by passing a modname parameter down to ddebug_apply_class_bitmap and ddebug_exec_queries. It also adds a check to announce bit changes only when they actually change.
quoted hunk ↗ jump to hunk
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c index ce42e03f1600a..0fc9cd14e2d20 100644 --- a/lib/dynamic_debug.c +++ b/lib/dynamic_debug.c
[ ... ]
quoted hunk ↗ jump to hunk
@@ -682,8 +692,8 @@ int param_set_dyndbg_classes(const char *instr, const struct kernel_param *kp) KP_NAME(kp), inrep, CLASSMAP_BITMASK(map->length)); inrep &= CLASSMAP_BITMASK(map->length); } - v2pr_info("bits:%lx > %s\n", inrep, KP_NAME(kp)); - totct += ddebug_apply_class_bitmap(dcp, &inrep, dcp->bits); + v2pr_info("bits:0x%lx > %s.%s\n", inrep, mod_name ?: "*", KP_NAME(kp)); + totct += ddebug_apply_class_bitmap(dcp, &inrep, dcp->bits, mod_name); *dcp->bits = inrep; break; case DD_CLASS_TYPE_LEVEL_NUM:@@ -696,7 +706,7 @@ int param_set_dyndbg_classes(const char *instr, const struct kernel_param *kp) old_bits = CLASSMAP_BITMASK(*dcp->lvl); new_bits = CLASSMAP_BITMASK(inrep); v2pr_info("lvl:%ld bits:0x%lx > %s\n", inrep, new_bits, KP_NAME(kp)); - totct += ddebug_apply_class_bitmap(dcp, &new_bits, &old_bits); + totct += ddebug_apply_class_bitmap(dcp, &new_bits, &old_bits, mod_name);
[Severity: Medium]
Does this skip enabling debug queries for newly probed modules if the global
state already has those bits set?
When param_set_dyndbg_module_classes() is called for a newly probed module
(mod_name != NULL), it passes the global class parameter state as the old
state (dcp->bits and old_bits respectively) instead of 0.
If a global parameter was previously set (e.g., drm.debug=2), those bits are
already present in the global state. The optimization loop in
ddebug_apply_class_bitmap() checks this:
lib/dynamic_debug.c:ddebug_apply_class_bitmap() {
...
for (bi = 0; bi < map->length; bi++) {
if (test_bit(bi, new_bits) == test_bit(bi, old_bits))
continue;
...
}
Because the new module's target state matches the global state, it skips
executing the queries, even though the newly loaded module actually starts
with a default state of 0.
--
Sashiko AI review · https://sashiko.dev/#/patchset/20260707-dd-maint-2-v6-0-381f3edb0045@gmail.com?part=15