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.
Signed-off-by: Mathieu Desnoyers <[EMAIL PROTECTED]>
Acked-by: Ananth N Mavinakayanahalli <[EMAIL PROTECTED]>
CC: [EMAIL PROTECTED]
CC: [EMAIL PROTECTED]
CC: [EMAIL PROTECTED]
CC: [EMAIL PROTECTED]
CC: Roel Kluin <[EMAIL PROTECTED]>
---
kernel/kprobes.c | 19 +++++++++++++------
1 file changed, 13 insertions(+), 6 deletions(-)
Index: linux-2.6-lttng/kernel/kprobes.c
===================================================================
--- linux-2.6-lttng.orig/kernel/kprobes.c 2007-11-16 13:40:06.000000000
-0500
+++ linux-2.6-lttng/kernel/kprobes.c 2007-11-17 10:00:23.000000000 -0500
@@ -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>
@@ -568,9 +569,10 @@ static int __kprobes __register_kprobe(s
goto out;
}
+ kernel_text_lock();
ret = arch_prepare_kprobe(p);
if (ret)
- goto out;
+ goto out_unlock_text;
INIT_HLIST_NODE(&p->hlist);
hlist_add_head_rcu(&p->hlist,
@@ -578,7 +580,8 @@ static int __kprobes __register_kprobe(s
if (kprobe_enabled)
arch_arm_kprobe(p);
-
+out_unlock_text:
+ kernel_text_unlock();
out:
mutex_unlock(&kprobe_mutex);
@@ -621,8 +624,11 @@ valid_p:
* enabled - otherwise, the breakpoint would already have
* been removed. We save on flushing icache.
*/
- if (kprobe_enabled)
+ if (kprobe_enabled) {
+ kernel_text_lock();
arch_disarm_kprobe(p);
+ kernel_text_unlock();
+ }
hlist_del_rcu(&old_p->hlist);
cleanup_p = 1;
} else {
@@ -644,9 +650,7 @@ valid_p:
list_del_rcu(&p->list);
kfree(old_p);
}
- mutex_lock(&kprobe_mutex);
arch_remove_kprobe(p);
- mutex_unlock(&kprobe_mutex);
} else {
mutex_lock(&kprobe_mutex);
if (p->break_handler)
@@ -717,7 +721,6 @@ static int __kprobes pre_handler_kretpro
ri->rp = rp;
ri->task = current;
arch_prepare_kretprobe(ri, regs);
-
/* XXX(hch): why is there no hlist_move_head? */
hlist_del(&ri->uflist);
hlist_add_head(&ri->uflist, &ri->rp->used_instances);
@@ -938,11 +941,13 @@ static void __kprobes enable_all_kprobes
if (kprobe_enabled)
goto already_enabled;
+ kernel_text_lock();
for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
head = &kprobe_table[i];
hlist_for_each_entry_rcu(p, node, head, hlist)
arch_arm_kprobe(p);
}
+ kernel_text_unlock();
kprobe_enabled = true;
printk(KERN_INFO "Kprobes globally enabled\n");
@@ -967,6 +972,7 @@ static void __kprobes disable_all_kprobe
kprobe_enabled = false;
printk(KERN_INFO "Kprobes globally disabled\n");
+ kernel_text_lock();
for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
head = &kprobe_table[i];
hlist_for_each_entry_rcu(p, node, head, hlist) {
@@ -974,6 +980,7 @@ static void __kprobes disable_all_kprobe
arch_disarm_kprobe(p);
}
}
+ kernel_text_unlock();
mutex_unlock(&kprobe_mutex);
/* Allow all currently running kprobes to complete */
--
Mathieu Desnoyers
Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
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