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jump label: Fix deadlock b/w jump_label_mutex vs. text_mutex

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register_kprobe() downs the 'text_mutex' and then calls
jump_label_text_reserved(), which downs the 'jump_label_mutex'.
However, the jump label code takes those mutexes in the reverse
order.

Fix by requiring the caller of jump_label_text_reserved() to do
the jump label locking via the newly added: jump_label_lock(),
jump_label_unlock(). Currently, kprobes is the only user
of jump_label_text_reserved().

Reported-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Jason Baron <jbaron@redhat.com>
LKML-Reference: <759032c48d5e30c27f0bba003d09bffa8e9f28bb.1285965957.git.jbaron@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Jason Baron
2010-10-28 09:17:40 -04:00
committed by Steven Rostedt
parent b842f8faf6
commit 91bad2f8d3
3 changed files with 32 additions and 12 deletions
Download Patch File Download Diff File Expand all files Collapse all files
include/linux/jump_label.h
+5
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@@ -18,6 +18,8 @@ struct module;
extern struct jump_entry __start___jump_table[];
extern struct jump_entry __stop___jump_table[];
extern void jump_label_lock(void);
extern void jump_label_unlock(void);
extern void arch_jump_label_transform(struct jump_entry *entry,
enum jump_label_type type);
extern void arch_jump_label_text_poke_early(jump_label_t addr);
@@ -59,6 +61,9 @@ static inline int jump_label_text_reserved(void *start, void *end)
return 0;
}
static inline void jump_label_lock(void) {}
static inline void jump_label_unlock(void) {}
#endif
#define COND_STMT(key, stmt) \