Once taint flag is set it's never cleared. Following taint could be detected
only via parsing kernel log messages which are different for each occasion.
For repeatable taints like TAINT_MACHINE_CHECK, TAINT_BAD_PAGE, TAINT_DIE,
TAINT_WARN, TAINT_LOCKUP it would be good to know count to see their rate.
This patch adds sysctl with vector of counters. One for each taint flag.
Counters are non-atomic in favor of simplicity. Exact count doesn't matter.
Writing vector of zeroes resets counters.
This is useful for detecting frequent problems with automatic monitoring.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx>
---
include/linux/kernel.h | 1 +
kernel/panic.c | 2 ++
kernel/sysctl.c | 9 +++++++++
3 files changed, 12 insertions(+)
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index e8a6808e4f2f..900d02167bbd 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -604,6 +604,7 @@ struct taint_flag {
};
extern const struct taint_flag taint_flags[TAINT_FLAGS_COUNT];
+extern int sysctl_nr_taints[TAINT_FLAGS_COUNT];
extern const char hex_asc[];
#define hex_asc_lo(x) hex_asc[((x) & 0x0f)]
diff --git a/kernel/panic.c b/kernel/panic.c
index d7750a45ca8d..a3df00ebcba2 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -39,6 +39,7 @@
int panic_on_oops = CONFIG_PANIC_ON_OOPS_VALUE;
static unsigned long tainted_mask =
IS_ENABLED(CONFIG_GCC_PLUGIN_RANDSTRUCT) ? (1 << TAINT_RANDSTRUCT) : 0;
+int sysctl_nr_taints[TAINT_FLAGS_COUNT];
static int pause_on_oops;
static int pause_on_oops_flag;
static DEFINE_SPINLOCK(pause_on_oops_lock);
@@ -434,6 +435,7 @@ void add_taint(unsigned flag, enum lockdep_ok lockdep_ok)
pr_warn("Disabling lock debugging due to kernel taint\n");
set_bit(flag, &tainted_mask);
+ sysctl_nr_taints[flag]++;
}
EXPORT_SYMBOL(add_taint);
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index b6f2f35d0bcf..5d9727556cef 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -553,6 +553,15 @@ static struct ctl_table kern_table[] = {
.mode = 0644,
.proc_handler = proc_taint,
},
+ {
+ .procname = "nr_taints",
+ .data = &sysctl_nr_taints,
+ .maxlen = sizeof(sysctl_nr_taints),
+ .mode = 0644,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = SYSCTL_ZERO,
+ .extra2 = SYSCTL_ZERO,
+ },
{
.procname = "sysctl_writes_strict",
.data = &sysctl_writes_strict,
