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Subject[PATCH] Support resetting WARN_ONCE for all architectures
Date
From: Andi Kleen <ak@linux.intel.com>

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.

Cc: mpe@ellerman.id.au
Signed-off-by: Andi Kleen <ak@linux.intel.com>
---
include/linux/bug.h | 5 +++++
kernel/panic.c | 1 +
lib/bug.c | 21 +++++++++++++++++++++
3 files changed, 27 insertions(+)

diff --git a/include/linux/bug.h b/include/linux/bug.h
index 5d5554c874fd..b8666ee88086 100644
--- a/include/linux/bug.h
+++ b/include/linux/bug.h
@@ -42,6 +42,8 @@ enum bug_trap_type report_bug(unsigned long bug_addr, struct pt_regs *regs);
/* 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_bug(unsigned long bug_addr,
return BUG_TRAP_TYPE_BUG;
}

+
+static inline void generic_bug_clear_once(void) {}
+
#endif /* CONFIG_GENERIC_BUG */

/*
diff --git a/kernel/panic.c b/kernel/panic.c
index 49dbdb231a77..840a98fa4963 100644
--- a/kernel/panic.c
+++ b/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 --git a/lib/bug.c b/lib/bug.c
index a6a1137d06db..7cb2d41845f7 100644
--- a/lib/bug.c
+++ b/lib/bug.c
@@ -195,3 +195,24 @@ enum bug_trap_type report_bug(unsigned long bugaddr, struct pt_regs *regs)

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);
+}
--
2.13.6
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