kernel/events/uprobes.c | 120 ++++++++++++++++++++++++++++++++++++---- 1 file changed, 109 insertions(+), 11 deletions(-)
From: Longjun Luo <luolongjun@huawei.com>
Since uprobes will replace instructions in the process
memory, it is necessary to provide one way to list
all active uprobes. One can access this file through
/sys/kernel/debug/uprobes/list.
Output looks like this
=====================
inode+offset/ref_ctr_offset 4160760670+0x30a10/0x0
ref 1
register_rwsem (unlocked)
consumer_rwsem (unlocked)
consumers-1
handler 0xffffffffc03ee02e(handler) uprobe
ret_handler 0x0000000000000000( )
filter 0xffffffffc03ee010(filter) uprobe
consumers-2
handler 0xffffffffc03e902e(handler_1) uprobe_1
ret_handler 0x0000000000000000( )
filter 0xffffffffc03e9010(filter_1) uprobe_1
Signed-off-by: Longjun Luo <luolongjun@huawei.com>
---
kernel/events/uprobes.c | 120 ++++++++++++++++++++++++++++++++++++----
1 file changed, 109 insertions(+), 11 deletions(-)
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index d9e357b7e17c..2fa9b910abc7 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -27,6 +27,9 @@
#include <linux/task_work.h>
#include <linux/shmem_fs.h>
#include <linux/khugepaged.h>
+#include <linux/rbtree.h>
+#include <linux/debugfs.h>
+#include <linux/kallsyms.h>
#include <linux/uprobes.h>
@@ -40,7 +43,7 @@ static struct rb_root uprobes_tree = RB_ROOT;
*/
#define no_uprobe_events() RB_EMPTY_ROOT(&uprobes_tree)
-static DEFINE_SPINLOCK(uprobes_treelock); /* serialize rbtree access */
+static DECLARE_RWSEM(uprobes_treelock); /* serialize rbtree access */
#define UPROBES_HASH_SZ 13
/* serialize uprobe->pending_list */
@@ -672,9 +675,9 @@ static struct uprobe *find_uprobe(struct inode *inode, loff_t offset)
{
struct uprobe *uprobe;
- spin_lock(&uprobes_treelock);
+ down_read(&uprobes_treelock);
uprobe = __find_uprobe(inode, offset);
- spin_unlock(&uprobes_treelock);
+ up_read(&uprobes_treelock);
return uprobe;
}
@@ -704,9 +707,9 @@ static struct uprobe *insert_uprobe(struct uprobe *uprobe)
{
struct uprobe *u;
- spin_lock(&uprobes_treelock);
+ down_write(&uprobes_treelock);
u = __insert_uprobe(uprobe);
- spin_unlock(&uprobes_treelock);
+ up_write(&uprobes_treelock);
return u;
}
@@ -938,9 +941,9 @@ static void delete_uprobe(struct uprobe *uprobe)
if (WARN_ON(!uprobe_is_active(uprobe)))
return;
- spin_lock(&uprobes_treelock);
+ down_write(&uprobes_treelock);
rb_erase(&uprobe->rb_node, &uprobes_tree);
- spin_unlock(&uprobes_treelock);
+ up_write(&uprobes_treelock);
RB_CLEAR_NODE(&uprobe->rb_node); /* for uprobe_is_active() */
put_uprobe(uprobe);
}
@@ -1301,7 +1304,7 @@ static void build_probe_list(struct inode *inode,
min = vaddr_to_offset(vma, start);
max = min + (end - start) - 1;
- spin_lock(&uprobes_treelock);
+ down_read(&uprobes_treelock);
n = find_node_in_range(inode, min, max);
if (n) {
for (t = n; t; t = rb_prev(t)) {
@@ -1319,7 +1322,7 @@ static void build_probe_list(struct inode *inode,
get_uprobe(u);
}
}
- spin_unlock(&uprobes_treelock);
+ up_read(&uprobes_treelock);
}
/* @vma contains reference counter, not the probed instruction. */
@@ -1410,9 +1413,9 @@ vma_has_uprobes(struct vm_area_struct *vma, unsigned long start, unsigned long e
min = vaddr_to_offset(vma, start);
max = min + (end - start) - 1;
- spin_lock(&uprobes_treelock);
+ down_read(&uprobes_treelock);
n = find_node_in_range(inode, min, max);
- spin_unlock(&uprobes_treelock);
+ up_read(&uprobes_treelock);
return !!n;
}
@@ -2357,3 +2360,98 @@ void __init uprobes_init(void)
BUG_ON(register_die_notifier(&uprobe_exception_nb));
}
+
+#ifdef CONFIG_DEBUG_FS
+
+static void *uprobe_seq_start(struct seq_file *m, loff_t *pos)
+{
+ loff_t num = *pos;
+ struct rb_node *rbp;
+
+ down_read(&uprobes_treelock);
+ for (rbp = rb_first(&uprobes_tree); rbp; rbp = rb_next(rbp)) {
+ if (num-- == 0)
+ return rbp;
+ }
+
+ return NULL;
+}
+
+static void *uprobe_seq_next(struct seq_file *f, void *v, loff_t *pos)
+{
+ ++*pos;
+ return (void *)rb_next(v);
+}
+
+static void uprobe_seq_stop(struct seq_file *f, void *v)
+{
+ up_read(&uprobes_treelock);
+}
+
+static int show_uprobe(struct seq_file *m, void *v)
+{
+ struct uprobe *uprobe = rb_entry_safe(v, struct uprobe, rb_node);
+ struct uprobe_consumer *con;
+ char *modname, namebuf[KSYM_NAME_LEN];
+ const char *sym;
+ unsigned int cnt = 1;
+
+ seq_printf(m, "inode+offset/ref_ctr_offset %lu+0x%llx/0x%llx\n",
+ uprobe->inode->i_ino, uprobe->offset, uprobe->ref_ctr_offset);
+ seq_printf(m, " ref %u\n",
+ refcount_read(&uprobe->ref));
+ seq_printf(m, " register_rwsem %s\n",
+ rwsem_is_locked(&uprobe->register_rwsem)?"(locked)":"(unlocked)");
+ seq_printf(m, " consumer_rwsem %s\n",
+ rwsem_is_locked(&uprobe->consumer_rwsem)?"(locked)":"(unlocked)");
+
+ /* lock consumer_rwsem when hold uprobes_treelock */
+ down_read(&uprobe->consumer_rwsem);
+ for (con = uprobe->consumers; con; con = con->next, cnt++) {
+ seq_printf(m, " consumers-%u\n", cnt);
+
+ modname = NULL;
+ sym = kallsyms_lookup((unsigned long)con->handler, NULL, NULL,
+ &modname, namebuf);
+ seq_printf(m, " handler 0x%px(%s) %s\n",
+ con->handler, (sym ? sym : " "), (modname ? modname : " "));
+
+ modname = NULL;
+ sym = kallsyms_lookup((unsigned long)con->ret_handler, NULL, NULL,
+ &modname, namebuf);
+ seq_printf(m, " ret_handler 0x%px(%s) %s\n",
+ con->ret_handler, (sym ? sym : " "), (modname ? modname : " "));
+
+ modname = NULL;
+ sym = kallsyms_lookup((unsigned long)con->filter, NULL, NULL,
+ &modname, namebuf);
+ seq_printf(m, " filter 0x%px(%s) %s\n",
+ con->filter, (sym ? sym : " "), (modname ? modname : " "));
+ }
+ up_read(&uprobe->consumer_rwsem);
+
+ return 0;
+}
+
+static const struct seq_operations uprobes_sops = {
+ .start = uprobe_seq_start,
+ .next = uprobe_seq_next,
+ .stop = uprobe_seq_stop,
+ .show = show_uprobe,
+};
+
+DEFINE_SEQ_ATTRIBUTE(uprobes);
+
+static int __init debugfs_uprobe_init(void)
+{
+ struct dentry *dir;
+
+ dir = debugfs_create_dir("uprobes", NULL);
+
+ debugfs_create_file("list", 0400, dir, NULL, &uprobes_fops);
+
+ return 0;
+}
+late_initcall(debugfs_uprobe_init);
+
+#endif /* CONFIG_DEBUG_FS */
--
2.38.1+cc: Steven, Oleg, Masami On 11-Jan-23 4:18 PM, luolongjun@huawei.com wrote: > From: Longjun Luo <luolongjun@huawei.com> > > Since uprobes will replace instructions in the process > memory, it is necessary to provide one way to list > all active uprobes. One can access this file through > /sys/kernel/debug/uprobes/list. > > Output looks like this > ===================== > inode+offset/ref_ctr_offset 4160760670+0x30a10/0x0 > ref 1 > register_rwsem (unlocked) > consumer_rwsem (unlocked) > consumers-1 > handler 0xffffffffc03ee02e(handler) uprobe > ret_handler 0x0000000000000000( ) > filter 0xffffffffc03ee010(filter) uprobe > consumers-2 > handler 0xffffffffc03e902e(handler_1) uprobe_1 > ret_handler 0x0000000000000000( ) > filter 0xffffffffc03e9010(filter_1) uprobe_1 You can list uprobes via /sys/kernel/tracing/uprobe_events. Any specific reason to introduce another way? Thanks, Ravi
On Fri, 13 Jan 2023 09:33:41 +0530 Ravi Bangoria <ravi.bangoria@amd.com> wrote: > +cc: Steven, Oleg, Masami > > On 11-Jan-23 4:18 PM, luolongjun@huawei.com wrote: > > From: Longjun Luo <luolongjun@huawei.com> > > > > Since uprobes will replace instructions in the process > > memory, it is necessary to provide one way to list > > all active uprobes. One can access this file through > > /sys/kernel/debug/uprobes/list. > > > > Output looks like this > > ===================== > > inode+offset/ref_ctr_offset 4160760670+0x30a10/0x0 > > ref 1 > > register_rwsem (unlocked) > > consumer_rwsem (unlocked) > > consumers-1 > > handler 0xffffffffc03ee02e(handler) uprobe > > ret_handler 0x0000000000000000( ) > > filter 0xffffffffc03ee010(filter) uprobe > > consumers-2 > > handler 0xffffffffc03e902e(handler_1) uprobe_1 > > ret_handler 0x0000000000000000( ) > > filter 0xffffffffc03e9010(filter_1) uprobe_1 > > You can list uprobes via /sys/kernel/tracing/uprobe_events. Any specific reason > to introduce another way? Note that /sys/kernel/tracing/uprobe_events is only for the uprobes defined by ftrace, it doesn't include the uprobes registered by out-of-tree modules. Thank you, > > Thanks, > Ravi -- Masami Hiramatsu (Google) <mhiramat@kernel.org>
在 1/13/2023 12:03 PM, Ravi Bangoria 写道: > +cc: Steven, Oleg, Masami > > On 11-Jan-23 4:18 PM, luolongjun@huawei.com wrote: >> From: Longjun Luo <luolongjun@huawei.com> >> >> Since uprobes will replace instructions in the process >> memory, it is necessary to provide one way to list >> all active uprobes. One can access this file through >> /sys/kernel/debug/uprobes/list. >> >> Output looks like this >> ===================== >> inode+offset/ref_ctr_offset 4160760670+0x30a10/0x0 >> ref 1 >> register_rwsem (unlocked) >> consumer_rwsem (unlocked) >> consumers-1 >> handler 0xffffffffc03ee02e(handler) uprobe >> ret_handler 0x0000000000000000( ) >> filter 0xffffffffc03ee010(filter) uprobe >> consumers-2 >> handler 0xffffffffc03e902e(handler_1) uprobe_1 >> ret_handler 0x0000000000000000( ) >> filter 0xffffffffc03e9010(filter_1) uprobe_1 > You can list uprobes via /sys/kernel/tracing/uprobe_events. Any specific reason > to introduce another way? > > Thanks, > Ravi /sys/kernel/tracing/uprobe_events only lists tracing events, not all uprobe events. For example, if I write a kernel module to call the uprobe_register to add a new uprobe event, it will not be listed by /sys/kernel/tracing/uprobe_events. Compare it with the kprobe is like: /sys/kernel/tracing/uprobe_events -> /sys/kernel/tracing/kprobe_events /sys/kernel/debug/uprobes/list -> /sys/kernel/debug/kprobes/list Nowadays, only the trace system uses the uprobe, so /sys/kernel/tracing/uprobe_events is enough. But we try to extend the usage of the uprobe, and we add many uprobe events by calling the uprobe_register. For this situation, we need a approach to see all the uprobe events in the kernel.
On Wed, Jan 11, 2023 at 2:49 AM <luolongjun@huawei.com> wrote:
>
> From: Longjun Luo <luolongjun@huawei.com>
>
> Since uprobes will replace instructions in the process
> memory, it is necessary to provide one way to list
> all active uprobes. One can access this file through
> /sys/kernel/debug/uprobes/list.
>
> Output looks like this
> =====================
> inode+offset/ref_ctr_offset 4160760670+0x30a10/0x0
> ref 1
> register_rwsem (unlocked)
> consumer_rwsem (unlocked)
> consumers-1
> handler 0xffffffffc03ee02e(handler) uprobe
> ret_handler 0x0000000000000000( )
> filter 0xffffffffc03ee010(filter) uprobe
> consumers-2
> handler 0xffffffffc03e902e(handler_1) uprobe_1
> ret_handler 0x0000000000000000( )
> filter 0xffffffffc03e9010(filter_1) uprobe_1
>
> Signed-off-by: Longjun Luo <luolongjun@huawei.com>
> ---
> kernel/events/uprobes.c | 120 ++++++++++++++++++++++++++++++++++++----
> 1 file changed, 109 insertions(+), 11 deletions(-)
>
> diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
> index d9e357b7e17c..2fa9b910abc7 100644
> --- a/kernel/events/uprobes.c
> +++ b/kernel/events/uprobes.c
> @@ -27,6 +27,9 @@
> #include <linux/task_work.h>
> #include <linux/shmem_fs.h>
> #include <linux/khugepaged.h>
> +#include <linux/rbtree.h>
> +#include <linux/debugfs.h>
> +#include <linux/kallsyms.h>
>
> #include <linux/uprobes.h>
>
> @@ -40,7 +43,7 @@ static struct rb_root uprobes_tree = RB_ROOT;
> */
> #define no_uprobe_events() RB_EMPTY_ROOT(&uprobes_tree)
>
> -static DEFINE_SPINLOCK(uprobes_treelock); /* serialize rbtree access */
> +static DECLARE_RWSEM(uprobes_treelock); /* serialize rbtree access */
>
> #define UPROBES_HASH_SZ 13
> /* serialize uprobe->pending_list */
> @@ -672,9 +675,9 @@ static struct uprobe *find_uprobe(struct inode *inode, loff_t offset)
> {
> struct uprobe *uprobe;
>
> - spin_lock(&uprobes_treelock);
> + down_read(&uprobes_treelock);
> uprobe = __find_uprobe(inode, offset);
> - spin_unlock(&uprobes_treelock);
> + up_read(&uprobes_treelock);
>
> return uprobe;
> }
> @@ -704,9 +707,9 @@ static struct uprobe *insert_uprobe(struct uprobe *uprobe)
> {
> struct uprobe *u;
>
> - spin_lock(&uprobes_treelock);
> + down_write(&uprobes_treelock);
> u = __insert_uprobe(uprobe);
> - spin_unlock(&uprobes_treelock);
> + up_write(&uprobes_treelock);
>
> return u;
> }
> @@ -938,9 +941,9 @@ static void delete_uprobe(struct uprobe *uprobe)
> if (WARN_ON(!uprobe_is_active(uprobe)))
> return;
>
> - spin_lock(&uprobes_treelock);
> + down_write(&uprobes_treelock);
> rb_erase(&uprobe->rb_node, &uprobes_tree);
> - spin_unlock(&uprobes_treelock);
> + up_write(&uprobes_treelock);
> RB_CLEAR_NODE(&uprobe->rb_node); /* for uprobe_is_active() */
> put_uprobe(uprobe);
> }
> @@ -1301,7 +1304,7 @@ static void build_probe_list(struct inode *inode,
> min = vaddr_to_offset(vma, start);
> max = min + (end - start) - 1;
>
> - spin_lock(&uprobes_treelock);
> + down_read(&uprobes_treelock);
> n = find_node_in_range(inode, min, max);
> if (n) {
> for (t = n; t; t = rb_prev(t)) {
> @@ -1319,7 +1322,7 @@ static void build_probe_list(struct inode *inode,
> get_uprobe(u);
> }
> }
> - spin_unlock(&uprobes_treelock);
> + up_read(&uprobes_treelock);
> }
>
> /* @vma contains reference counter, not the probed instruction. */
> @@ -1410,9 +1413,9 @@ vma_has_uprobes(struct vm_area_struct *vma, unsigned long start, unsigned long e
> min = vaddr_to_offset(vma, start);
> max = min + (end - start) - 1;
>
> - spin_lock(&uprobes_treelock);
> + down_read(&uprobes_treelock);
> n = find_node_in_range(inode, min, max);
> - spin_unlock(&uprobes_treelock);
> + up_read(&uprobes_treelock);
>
> return !!n;
> }
> @@ -2357,3 +2360,98 @@ void __init uprobes_init(void)
>
> BUG_ON(register_die_notifier(&uprobe_exception_nb));
> }
> +
> +#ifdef CONFIG_DEBUG_FS
> +
> +static void *uprobe_seq_start(struct seq_file *m, loff_t *pos)
> +{
> + loff_t num = *pos;
> + struct rb_node *rbp;
> +
> + down_read(&uprobes_treelock);
Is there a missing corresponding up_read?
Thanks,
Ian
> + for (rbp = rb_first(&uprobes_tree); rbp; rbp = rb_next(rbp)) {
> + if (num-- == 0)
> + return rbp;
> + }
> +
> + return NULL;
> +}
> +
> +static void *uprobe_seq_next(struct seq_file *f, void *v, loff_t *pos)
> +{
> + ++*pos;
> + return (void *)rb_next(v);
> +}
> +
> +static void uprobe_seq_stop(struct seq_file *f, void *v)
> +{
> + up_read(&uprobes_treelock);
> +}
> +
> +static int show_uprobe(struct seq_file *m, void *v)
> +{
> + struct uprobe *uprobe = rb_entry_safe(v, struct uprobe, rb_node);
> + struct uprobe_consumer *con;
> + char *modname, namebuf[KSYM_NAME_LEN];
> + const char *sym;
> + unsigned int cnt = 1;
> +
> + seq_printf(m, "inode+offset/ref_ctr_offset %lu+0x%llx/0x%llx\n",
> + uprobe->inode->i_ino, uprobe->offset, uprobe->ref_ctr_offset);
> + seq_printf(m, " ref %u\n",
> + refcount_read(&uprobe->ref));
> + seq_printf(m, " register_rwsem %s\n",
> + rwsem_is_locked(&uprobe->register_rwsem)?"(locked)":"(unlocked)");
> + seq_printf(m, " consumer_rwsem %s\n",
> + rwsem_is_locked(&uprobe->consumer_rwsem)?"(locked)":"(unlocked)");
> +
> + /* lock consumer_rwsem when hold uprobes_treelock */
> + down_read(&uprobe->consumer_rwsem);
> + for (con = uprobe->consumers; con; con = con->next, cnt++) {
> + seq_printf(m, " consumers-%u\n", cnt);
> +
> + modname = NULL;
> + sym = kallsyms_lookup((unsigned long)con->handler, NULL, NULL,
> + &modname, namebuf);
> + seq_printf(m, " handler 0x%px(%s) %s\n",
> + con->handler, (sym ? sym : " "), (modname ? modname : " "));
> +
> + modname = NULL;
> + sym = kallsyms_lookup((unsigned long)con->ret_handler, NULL, NULL,
> + &modname, namebuf);
> + seq_printf(m, " ret_handler 0x%px(%s) %s\n",
> + con->ret_handler, (sym ? sym : " "), (modname ? modname : " "));
> +
> + modname = NULL;
> + sym = kallsyms_lookup((unsigned long)con->filter, NULL, NULL,
> + &modname, namebuf);
> + seq_printf(m, " filter 0x%px(%s) %s\n",
> + con->filter, (sym ? sym : " "), (modname ? modname : " "));
> + }
> + up_read(&uprobe->consumer_rwsem);
> +
> + return 0;
> +}
> +
> +static const struct seq_operations uprobes_sops = {
> + .start = uprobe_seq_start,
> + .next = uprobe_seq_next,
> + .stop = uprobe_seq_stop,
> + .show = show_uprobe,
> +};
> +
> +DEFINE_SEQ_ATTRIBUTE(uprobes);
> +
> +static int __init debugfs_uprobe_init(void)
> +{
> + struct dentry *dir;
> +
> + dir = debugfs_create_dir("uprobes", NULL);
> +
> + debugfs_create_file("list", 0400, dir, NULL, &uprobes_fops);
> +
> + return 0;
> +}
> +late_initcall(debugfs_uprobe_init);
> +
> +#endif /* CONFIG_DEBUG_FS */
> --
> 2.38.1
>
在 1/12/2023 5:35 AM, Ian Rogers 写道:
> On Wed, Jan 11, 2023 at 2:49 AM <luolongjun@huawei.com> wrote:
>> From: Longjun Luo <luolongjun@huawei.com>
>>
>> Since uprobes will replace instructions in the process
>> memory, it is necessary to provide one way to list
>> all active uprobes. One can access this file through
>> /sys/kernel/debug/uprobes/list.
>>
>> Output looks like this
>> =====================
>> inode+offset/ref_ctr_offset 4160760670+0x30a10/0x0
>> ref 1
>> register_rwsem (unlocked)
>> consumer_rwsem (unlocked)
>> consumers-1
>> handler 0xffffffffc03ee02e(handler) uprobe
>> ret_handler 0x0000000000000000( )
>> filter 0xffffffffc03ee010(filter) uprobe
>> consumers-2
>> handler 0xffffffffc03e902e(handler_1) uprobe_1
>> ret_handler 0x0000000000000000( )
>> filter 0xffffffffc03e9010(filter_1) uprobe_1
>>
>> Signed-off-by: Longjun Luo <luolongjun@huawei.com>
>> ---
>> kernel/events/uprobes.c | 120 ++++++++++++++++++++++++++++++++++++----
>> 1 file changed, 109 insertions(+), 11 deletions(-)
>>
>> diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
>> index d9e357b7e17c..2fa9b910abc7 100644
>> --- a/kernel/events/uprobes.c
>> +++ b/kernel/events/uprobes.c
>> @@ -27,6 +27,9 @@
>> #include <linux/task_work.h>
>> #include <linux/shmem_fs.h>
>> #include <linux/khugepaged.h>
>> +#include <linux/rbtree.h>
>> +#include <linux/debugfs.h>
>> +#include <linux/kallsyms.h>
>>
>> #include <linux/uprobes.h>
>>
>> @@ -40,7 +43,7 @@ static struct rb_root uprobes_tree = RB_ROOT;
>> */
>> #define no_uprobe_events() RB_EMPTY_ROOT(&uprobes_tree)
>>
>> -static DEFINE_SPINLOCK(uprobes_treelock); /* serialize rbtree access */
>> +static DECLARE_RWSEM(uprobes_treelock); /* serialize rbtree access */
>>
>> #define UPROBES_HASH_SZ 13
>> /* serialize uprobe->pending_list */
>> @@ -672,9 +675,9 @@ static struct uprobe *find_uprobe(struct inode *inode, loff_t offset)
>> {
>> struct uprobe *uprobe;
>>
>> - spin_lock(&uprobes_treelock);
>> + down_read(&uprobes_treelock);
>> uprobe = __find_uprobe(inode, offset);
>> - spin_unlock(&uprobes_treelock);
>> + up_read(&uprobes_treelock);
>>
>> return uprobe;
>> }
>> @@ -704,9 +707,9 @@ static struct uprobe *insert_uprobe(struct uprobe *uprobe)
>> {
>> struct uprobe *u;
>>
>> - spin_lock(&uprobes_treelock);
>> + down_write(&uprobes_treelock);
>> u = __insert_uprobe(uprobe);
>> - spin_unlock(&uprobes_treelock);
>> + up_write(&uprobes_treelock);
>>
>> return u;
>> }
>> @@ -938,9 +941,9 @@ static void delete_uprobe(struct uprobe *uprobe)
>> if (WARN_ON(!uprobe_is_active(uprobe)))
>> return;
>>
>> - spin_lock(&uprobes_treelock);
>> + down_write(&uprobes_treelock);
>> rb_erase(&uprobe->rb_node, &uprobes_tree);
>> - spin_unlock(&uprobes_treelock);
>> + up_write(&uprobes_treelock);
>> RB_CLEAR_NODE(&uprobe->rb_node); /* for uprobe_is_active() */
>> put_uprobe(uprobe);
>> }
>> @@ -1301,7 +1304,7 @@ static void build_probe_list(struct inode *inode,
>> min = vaddr_to_offset(vma, start);
>> max = min + (end - start) - 1;
>>
>> - spin_lock(&uprobes_treelock);
>> + down_read(&uprobes_treelock);
>> n = find_node_in_range(inode, min, max);
>> if (n) {
>> for (t = n; t; t = rb_prev(t)) {
>> @@ -1319,7 +1322,7 @@ static void build_probe_list(struct inode *inode,
>> get_uprobe(u);
>> }
>> }
>> - spin_unlock(&uprobes_treelock);
>> + up_read(&uprobes_treelock);
>> }
>>
>> /* @vma contains reference counter, not the probed instruction. */
>> @@ -1410,9 +1413,9 @@ vma_has_uprobes(struct vm_area_struct *vma, unsigned long start, unsigned long e
>> min = vaddr_to_offset(vma, start);
>> max = min + (end - start) - 1;
>>
>> - spin_lock(&uprobes_treelock);
>> + down_read(&uprobes_treelock);
>> n = find_node_in_range(inode, min, max);
>> - spin_unlock(&uprobes_treelock);
>> + up_read(&uprobes_treelock);
>>
>> return !!n;
>> }
>> @@ -2357,3 +2360,98 @@ void __init uprobes_init(void)
>>
>> BUG_ON(register_die_notifier(&uprobe_exception_nb));
>> }
>> +
>> +#ifdef CONFIG_DEBUG_FS
>> +
>> +static void *uprobe_seq_start(struct seq_file *m, loff_t *pos)
>> +{
>> + loff_t num = *pos;
>> + struct rb_node *rbp;
>> +
>> + down_read(&uprobes_treelock);
> Is there a missing corresponding up_read?
>
> Thanks,
> Ian
This missing corresponding up_read is in the uprobe_seq_stop.
In my understanding, uprobe_seq_start and uprobe_seq_stop is one pair of
API.
uprobe_seq_start holds the lock and the uprobe_seq_stop releases it.
I am not sure if it is right.
By the way, may I ask if the community still plan to evolve the uprobe
since the uprobe hasn't changed for a long time.
>> + for (rbp = rb_first(&uprobes_tree); rbp; rbp = rb_next(rbp)) {
>> + if (num-- == 0)
>> + return rbp;
>> + }
>> +
>> + return NULL;
>> +}
>> +
>> +static void *uprobe_seq_next(struct seq_file *f, void *v, loff_t *pos)
>> +{
>> + ++*pos;
>> + return (void *)rb_next(v);
>> +}
>> +
>> +static void uprobe_seq_stop(struct seq_file *f, void *v)
>> +{
>> + up_read(&uprobes_treelock);
>> +}
>> +
>> +static int show_uprobe(struct seq_file *m, void *v)
>> +{
>> + struct uprobe *uprobe = rb_entry_safe(v, struct uprobe, rb_node);
>> + struct uprobe_consumer *con;
>> + char *modname, namebuf[KSYM_NAME_LEN];
>> + const char *sym;
>> + unsigned int cnt = 1;
>> +
>> + seq_printf(m, "inode+offset/ref_ctr_offset %lu+0x%llx/0x%llx\n",
>> + uprobe->inode->i_ino, uprobe->offset, uprobe->ref_ctr_offset);
>> + seq_printf(m, " ref %u\n",
>> + refcount_read(&uprobe->ref));
>> + seq_printf(m, " register_rwsem %s\n",
>> + rwsem_is_locked(&uprobe->register_rwsem)?"(locked)":"(unlocked)");
>> + seq_printf(m, " consumer_rwsem %s\n",
>> + rwsem_is_locked(&uprobe->consumer_rwsem)?"(locked)":"(unlocked)");
>> +
>> + /* lock consumer_rwsem when hold uprobes_treelock */
>> + down_read(&uprobe->consumer_rwsem);
>> + for (con = uprobe->consumers; con; con = con->next, cnt++) {
>> + seq_printf(m, " consumers-%u\n", cnt);
>> +
>> + modname = NULL;
>> + sym = kallsyms_lookup((unsigned long)con->handler, NULL, NULL,
>> + &modname, namebuf);
>> + seq_printf(m, " handler 0x%px(%s) %s\n",
>> + con->handler, (sym ? sym : " "), (modname ? modname : " "));
>> +
>> + modname = NULL;
>> + sym = kallsyms_lookup((unsigned long)con->ret_handler, NULL, NULL,
>> + &modname, namebuf);
>> + seq_printf(m, " ret_handler 0x%px(%s) %s\n",
>> + con->ret_handler, (sym ? sym : " "), (modname ? modname : " "));
>> +
>> + modname = NULL;
>> + sym = kallsyms_lookup((unsigned long)con->filter, NULL, NULL,
>> + &modname, namebuf);
>> + seq_printf(m, " filter 0x%px(%s) %s\n",
>> + con->filter, (sym ? sym : " "), (modname ? modname : " "));
>> + }
>> + up_read(&uprobe->consumer_rwsem);
>> +
>> + return 0;
>> +}
>> +
>> +static const struct seq_operations uprobes_sops = {
>> + .start = uprobe_seq_start,
>> + .next = uprobe_seq_next,
>> + .stop = uprobe_seq_stop,
>> + .show = show_uprobe,
>> +};
>> +
>> +DEFINE_SEQ_ATTRIBUTE(uprobes);
>> +
>> +static int __init debugfs_uprobe_init(void)
>> +{
>> + struct dentry *dir;
>> +
>> + dir = debugfs_create_dir("uprobes", NULL);
>> +
>> + debugfs_create_file("list", 0400, dir, NULL, &uprobes_fops);
>> +
>> + return 0;
>> +}
>> +late_initcall(debugfs_uprobe_init);
>> +
>> +#endif /* CONFIG_DEBUG_FS */
>> --
>> 2.38.1
>>
© 2016 - 2025 Red Hat, Inc.