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Message-Id: <e0d275c30e97ddf943c2d797c4004673fbc82002.1711380724.git.jani.nikula@intel.com>
Date: Mon, 25 Mar 2024 17:36:35 +0200
From: Jani Nikula <jani.nikula@...el.com>
To: Andrew Morton <akpm@...ux-foundation.org>,
Greg KH <gregkh@...uxfoundation.org>,
linux-kernel@...r.kernel.org
Cc: jani.nikula@...el.com
Subject: [RFC 4/4] kernel/panic: add verbose logging of kernel taints in backtraces
With nearly 20 taint flags and respective characters, it's getting a bit
difficult to remember what each taint flag character means. Add verbose
logging of the set taints in the format:
Tainted: [P]=PROPRIETARY_MODULE, [W]=WARN
in dump_stack_print_info() when there are taints.
Note that the "negative flag" G is not included.
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Greg KH <gregkh@...uxfoundation.org>
Signed-off-by: Jani Nikula <jani.nikula@...el.com>
---
include/linux/panic.h | 8 +++++---
kernel/panic.c | 45 ++++++++++++++++++++++++++++++++-----------
lib/dump_stack.c | 3 +++
3 files changed, 42 insertions(+), 14 deletions(-)
diff --git a/include/linux/panic.h b/include/linux/panic.h
index 6717b15e798c..3130e0b5116b 100644
--- a/include/linux/panic.h
+++ b/include/linux/panic.h
@@ -77,9 +77,10 @@ static inline void set_arch_panic_timeout(int timeout, int arch_default_timeout)
#define TAINT_FLAGS_MAX ((1UL << TAINT_FLAGS_COUNT) - 1)
struct taint_flag {
- char c_true; /* character printed when tainted */
- char c_false; /* character printed when not tainted */
- bool module; /* also show as a per-module taint flag */
+ char c_true; /* character printed when tainted */
+ char c_false; /* character printed when not tainted */
+ bool module; /* also show as a per-module taint flag */
+ const char *desc; /* verbose description of the set taint flag */
};
extern const struct taint_flag taint_flags[TAINT_FLAGS_COUNT];
@@ -90,6 +91,7 @@ enum lockdep_ok {
};
extern const char *print_tainted(void);
+extern const char *print_tainted_verbose(void);
extern void add_taint(unsigned flag, enum lockdep_ok);
extern int test_taint(unsigned flag);
extern unsigned long get_taint(void);
diff --git a/kernel/panic.c b/kernel/panic.c
index e1f87ba51ba1..ed270d3b5f2b 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -477,6 +477,7 @@ EXPORT_SYMBOL(panic);
[ TAINT_##taint ] = { \
.c_true = _c_true, .c_false = _c_false, \
.module = _module, \
+ .desc = #taint, \
}
/*
@@ -507,8 +508,9 @@ const struct taint_flag taint_flags[TAINT_FLAGS_COUNT] = {
#undef TAINT_FLAG
-static void print_tainted_seq(struct seq_buf *s)
+static void print_tainted_seq(struct seq_buf *s, bool verbose)
{
+ const char *sep = "";
int i;
if (!tainted_mask) {
@@ -522,10 +524,32 @@ static void print_tainted_seq(struct seq_buf *s)
bool is_set = test_bit(i, &tainted_mask);
char c = is_set ? t->c_true : t->c_false;
- seq_buf_putc(s, c);
+ if (verbose) {
+ if (is_set) {
+ seq_buf_printf(s, "%s[%c]=%s", sep, c, t->desc);
+ sep = ", ";
+ }
+ } else {
+ seq_buf_putc(s, c);
+ }
}
}
+static const char *_print_tainted(bool verbose)
+{
+ /* FIXME: what should the size be? */
+ static char buf[sizeof(taint_flags)];
+ struct seq_buf s;
+
+ BUILD_BUG_ON(ARRAY_SIZE(taint_flags) != TAINT_FLAGS_COUNT);
+
+ seq_buf_init(&s, buf, sizeof(buf));
+
+ print_tainted_seq(&s, verbose);
+
+ return seq_buf_str(&s);
+}
+
/**
* print_tainted - return a string to represent the kernel taint state.
*
@@ -536,16 +560,15 @@ static void print_tainted_seq(struct seq_buf *s)
*/
const char *print_tainted(void)
{
- static char buf[TAINT_FLAGS_COUNT + sizeof("Tainted: ")];
- struct seq_buf s;
-
- BUILD_BUG_ON(ARRAY_SIZE(taint_flags) != TAINT_FLAGS_COUNT);
-
- seq_buf_init(&s, buf, sizeof(buf));
-
- print_tainted_seq(&s);
+ return _print_tainted(false);
+}
- return seq_buf_str(&s);
+/**
+ * print_tainted_verbose - A more verbose version of print_tainted()
+ */
+const char *print_tainted_verbose(void)
+{
+ return _print_tainted(true);
}
int test_taint(unsigned flag)
diff --git a/lib/dump_stack.c b/lib/dump_stack.c
index 222c6d6c8281..8b6b70eaf949 100644
--- a/lib/dump_stack.c
+++ b/lib/dump_stack.c
@@ -62,6 +62,9 @@ void dump_stack_print_info(const char *log_lvl)
(int)strcspn(init_utsname()->version, " "),
init_utsname()->version, BUILD_ID_VAL);
+ if (get_taint())
+ printk("%s%s\n", log_lvl, print_tainted_verbose());
+
if (dump_stack_arch_desc_str[0] != '\0')
printk("%sHardware name: %s\n",
log_lvl, dump_stack_arch_desc_str);
--
2.39.2
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