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authorAndi Kleen <ak@linux.intel.com>2017-11-17 15:27:06 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-11-17 16:10:01 -0800
commitaaf5dcfb223617ac2d16113e4b500199c65689de (patch)
tree708dbc2baef2f18cfb368b2e785642f6a4ece283
parentb1fca27d384e8418aac84b39f6f5179aecc1b64f (diff)
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. [ak@linux.intel.com: add a missing ifdef CONFIG_MODULES] Link: http://lkml.kernel.org/r/20171020170633.9593-1-andi@firstfloor.org [akpm@linux-foundation.org: fix unused var warning] [akpm@linux-foundation.org: Use 0200 for clear_warn_once file, per mpe] [akpm@linux-foundation.org: clear BUGFLAG_DONE in clear_once_table(), per mpe] Link: http://lkml.kernel.org/r/20171019204642.7404-1-andi@firstfloor.org Signed-off-by: Andi Kleen <ak@linux.intel.com> Tested-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--include/linux/bug.h5
-rw-r--r--kernel/panic.c3
-rw-r--r--lib/bug.c23
3 files changed, 30 insertions, 1 deletions
diff --git a/include/linux/bug.h b/include/linux/bug.h
index da4231c905c8..fe5916550da8 100644
--- a/include/linux/bug.h
+++ b/include/linux/bug.h
@@ -43,6 +43,8 @@ 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,
@@ -51,6 +53,9 @@ 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 672a91dc20fe..67cebf2a3b67 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;
}
@@ -607,7 +608,7 @@ DEFINE_SIMPLE_ATTRIBUTE(clear_warn_once_fops,
static __init int register_warn_debugfs(void)
{
/* Don't care about failure */
- debugfs_create_file("clear_warn_once", 0644, NULL,
+ debugfs_create_file("clear_warn_once", 0200, NULL,
NULL, &clear_warn_once_fops);
return 0;
}
diff --git a/lib/bug.c b/lib/bug.c
index 1e094408c893..f66be6bf6206 100644
--- a/lib/bug.c
+++ b/lib/bug.c
@@ -196,3 +196,26 @@ 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_DONE;
+}
+
+void generic_bug_clear_once(void)
+{
+#ifdef CONFIG_MODULES
+ 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();
+#endif
+
+ clear_once_table(__start___bug_table, __stop___bug_table);
+}