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tracing, Text Edit Lock - kprobes architecture independent support

Browse source 
Use the mutual exclusion provided by the text edit lock in the kprobes code. It
allows coherent manipulation of the kernel code by other subsystems.

Changelog:

Move the kernel_text_lock/unlock out of the for loops.
Use text_mutex directly instead of a function.
Remove whitespace modifications.

(note : kprobes_mutex is always taken outside of text_mutex)

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Acked-by: Masami Hiramatsu <mhiramat@redhat.com>
LKML-Reference: <49B14306.2080202@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Mathieu Desnoyers 2009-03-06 10:36:38 -05:00 committed by Ingo Molnar
parent 0e39ac4446
commit 4460fdad85
1 changed files with 13 additions and 2 deletions
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15
kernel/kprobes.c
View file

@ -43,6 +43,7 @@
#include <linux/seq_file.h>
#include <linux/debugfs.h>
#include <linux/kdebug.h>
#include <linux/memory.h>
#include <asm-generic/sections.h>
#include <asm/cacheflush.h>
@ -699,9 +700,10 @@ int __kprobes register_kprobe(struct kprobe *p)
goto out;
}
mutex_lock(&text_mutex);
ret = arch_prepare_kprobe(p);
if (ret)
goto out;
goto out_unlock_text;
INIT_HLIST_NODE(&p->hlist);
hlist_add_head_rcu(&p->hlist,
@ -710,6 +712,8 @@ int __kprobes register_kprobe(struct kprobe *p)
if (kprobe_enabled)
arch_arm_kprobe(p);
out_unlock_text:
mutex_unlock(&text_mutex);
out:
mutex_unlock(&kprobe_mutex);
@ -746,8 +750,11 @@ valid_p:
* enabled and not gone - otherwise, the breakpoint would
* already have been removed. We save on flushing icache.
*/
if (kprobe_enabled && !kprobe_gone(old_p))
if (kprobe_enabled && !kprobe_gone(old_p)) {
mutex_lock(&text_mutex);
arch_disarm_kprobe(p);
mutex_unlock(&text_mutex);
}
hlist_del_rcu(&old_p->hlist);
} else {
if (p->break_handler && !kprobe_gone(p))
@ -1280,12 +1287,14 @@ static void __kprobes enable_all_kprobes(void)
if (kprobe_enabled)
goto already_enabled;
mutex_lock(&text_mutex);
for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
head = &kprobe_table[i];
hlist_for_each_entry_rcu(p, node, head, hlist)
if (!kprobe_gone(p))
arch_arm_kprobe(p);
}
mutex_unlock(&text_mutex);
kprobe_enabled = true;
printk(KERN_INFO "Kprobes globally enabled\n");
@ -1310,6 +1319,7 @@ static void __kprobes disable_all_kprobes(void)
kprobe_enabled = false;
printk(KERN_INFO "Kprobes globally disabled\n");
mutex_lock(&text_mutex);
for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
head = &kprobe_table[i];
hlist_for_each_entry_rcu(p, node, head, hlist) {
@ -1318,6 +1328,7 @@ static void __kprobes disable_all_kprobes(void)
}
}
mutex_unlock(&text_mutex);
mutex_unlock(&kprobe_mutex);
/* Allow all currently running kprobes to complete */
synchronize_sched();