The patch titled
Subject: kernel debug: support resetting WARN_ONCE for all architectures
has been added to the -mm tree. Its filename is
support-resetting-warn_once-for-all-architectures.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/support-resetting-warn_once-for-all-architectures.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/support-resetting-warn_once-for-all-architectures.patch
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------------------------------------------------------
From: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Subject: kernel debug: support resetting WARN_ONCE for all architectures
Some architectures store the WARN_ONCE state in the flags field of the
bug_entry. Clear that one too when resetting once state through
/sys/kernel/debug/clear_warn_once
Pointed out by Michael Ellerman
Improves the earlier patch that add clear_warn_once.
Link: http://lkml.kernel.org/r/20171019204642.7404-1-andi@xxxxxxxxxxxxxx
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/bug.h | 5 +++++
kernel/panic.c | 1 +
lib/bug.c | 21 +++++++++++++++++++++
3 files changed, 27 insertions(+)
diff -puN include/linux/bug.h~support-resetting-warn_once-for-all-architectures include/linux/bug.h
--- a/include/linux/bug.h~support-resetting-warn_once-for-all-architectures
+++ a/include/linux/bug.h
@@ -42,6 +42,8 @@ enum bug_trap_type report_bug(unsigned l
/* These are defined by the architecture */
int is_valid_bugaddr(unsigned long addr);
+void generic_bug_clear_once(void);
+
#else /* !CONFIG_GENERIC_BUG */
static inline enum bug_trap_type report_bug(unsigned long bug_addr,
@@ -50,6 +52,9 @@ static inline enum bug_trap_type report_
return BUG_TRAP_TYPE_BUG;
}
+
+static inline void generic_bug_clear_once(void) {}
+
#endif /* CONFIG_GENERIC_BUG */
/*
diff -puN kernel/panic.c~support-resetting-warn_once-for-all-architectures kernel/panic.c
--- a/kernel/panic.c~support-resetting-warn_once-for-all-architectures
+++ a/kernel/panic.c
@@ -595,6 +595,7 @@ EXPORT_SYMBOL(warn_slowpath_null);
static int clear_warn_once_set(void *data, u64 val)
{
+ generic_bug_clear_once();
memset(__start_once, 0, __end_once - __start_once);
return 0;
}
diff -puN lib/bug.c~support-resetting-warn_once-for-all-architectures lib/bug.c
--- a/lib/bug.c~support-resetting-warn_once-for-all-architectures
+++ a/lib/bug.c
@@ -195,3 +195,24 @@ enum bug_trap_type report_bug(unsigned l
return BUG_TRAP_TYPE_BUG;
}
+
+static void clear_once_table(struct bug_entry *start, struct bug_entry *end)
+{
+ struct bug_entry *bug;
+
+ for (bug = start; bug < end; bug++)
+ bug->flags &= ~BUGFLAG_ONCE;
+}
+
+void generic_bug_clear_once(void)
+{
+ struct module *mod;
+
+ rcu_read_lock_sched();
+ list_for_each_entry_rcu(mod, &module_bug_list, bug_list)
+ clear_once_table(mod->bug_table,
+ mod->bug_table + mod->num_bugs);
+ rcu_read_unlock_sched();
+
+ clear_once_table(__start___bug_table, __stop___bug_table);
+}
_
Patches currently in -mm which might be from ak@xxxxxxxxxxxxxxx are
support-resetting-warn_once.patch
support-resetting-warn_once-for-all-architectures.patch
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