[PATCH -tip V6 0/6] kprobes: Fixes mutex, rcu-list warnings and cleanups

[PATCH -tip V6 0/6] kprobes: Fixes mutex, rcu-list warnings and cleanups

[Masami Hiramatsu]

Hi Ingo,

Here is the 6th version of the series for kprobes. The previous
version is here.

 https://lore.kernel.org/lkml/158583483116.26060.10517933482238348979.stgit@devnote2/

In this version, I picked 2 patches[1][2] which has been reviewed
on LKML but not merged to tip tree yet.

[1] https://lore.kernel.org/lkml/20200408164641.3299633-1-jolsa@kernel.org/
[2] https://lore.kernel.org/lkml/20200507185733.GA14931@embeddedor/

You can also pull this series from kprobes/core branch from

 https://git.kernel.org/pub/scm/linux/kernel/git/mhiramat/linux.git/

Thank you,

---

Gustavo A. R. Silva (1):
      kprobes: Replace zero-length array with flexible-array

Jiri Olsa (1):
      kretprobe: Prevent triggering kretprobe from within kprobe_flush_task

Masami Hiramatsu (4):
      kprobes: Suppress the suspicious RCU warning on kprobes
      kprobes: Use non RCU traversal APIs on kprobe_tables if possible
      kprobes: Fix to protect kick_kprobe_optimizer() by kprobe_mutex
      kprobes: Remove redundant arch_disarm_kprobe() call


 arch/x86/kernel/kprobes/core.c |   16 ++--------
 include/linux/kprobes.h        |    6 +++-
 kernel/kprobes.c               |   61 +++++++++++++++++++++++++++++++---------
 3 files changed, 56 insertions(+), 27 deletions(-)

--
Masami Hiramatsu (Linaro) <mhiramat@kernel.org>

[PATCH -tip V6 1/6] kprobes: Suppress the suspicious RCU warning on kprobes

[Masami Hiramatsu]

Anders reported that the lockdep warns that suspicious
RCU list usage in register_kprobe() (detected by
CONFIG_PROVE_RCU_LIST.) This is because get_kprobe()
access kprobe_table[] by hlist_for_each_entry_rcu()
without rcu_read_lock.

If we call get_kprobe() from the breakpoint handler context,
it is run with preempt disabled, so this is not a problem.
But in other cases, instead of rcu_read_lock(), we locks
kprobe_mutex so that the kprobe_table[] is not updated.
So, current code is safe, but still not good from the view
point of RCU.

Joel suggested that we can silent that warning by passing
lockdep_is_held() to the last argument of
hlist_for_each_entry_rcu().

Add lockdep_is_held(&kprobe_mutex) at the end of the
hlist_for_each_entry_rcu() to suppress the warning.

Reported-by: Anders Roxell <anders.roxell@linaro.org>
Suggested-by: Joel Fernandes <joel@joelfernandes.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
---
 kernel/kprobes.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 2625c241ac00..bd484392d789 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -326,7 +326,8 @@ struct kprobe *get_kprobe(void *addr)
 	struct kprobe *p;
 
 	head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)];
-	hlist_for_each_entry_rcu(p, head, hlist) {
+	hlist_for_each_entry_rcu(p, head, hlist,
+				 lockdep_is_held(&kprobe_mutex)) {
 		if (p->addr == addr)
 			return p;
 	}

[PATCH -tip V6 2/6] kprobes: Use non RCU traversal APIs on kprobe_tables if possible

[Masami Hiramatsu]

Current kprobes uses RCU traversal APIs on kprobe_tables
even if it is safe because kprobe_mutex is locked.

Make those traversals to non-RCU APIs where the kprobe_mutex
is locked.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
---
 kernel/kprobes.c |   29 ++++++++++++++++++++---------
 1 file changed, 20 insertions(+), 9 deletions(-)

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index bd484392d789..38d9a5d7c8a4 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -46,6 +46,11 @@
 
 
 static int kprobes_initialized;
+/* kprobe_table can be accessed by
+ * - Normal hlist traversal and RCU add/del under kprobe_mutex is held.
+ * Or
+ * - RCU hlist traversal under disabling preempt (breakpoint handlers)
+ */
 static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
 static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];
 
@@ -850,7 +855,7 @@ static void optimize_all_kprobes(void)
 	kprobes_allow_optimization = true;
 	for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
 		head = &kprobe_table[i];
-		hlist_for_each_entry_rcu(p, head, hlist)
+		hlist_for_each_entry(p, head, hlist)
 			if (!kprobe_disabled(p))
 				optimize_kprobe(p);
 	}
@@ -877,7 +882,7 @@ static void unoptimize_all_kprobes(void)
 	kprobes_allow_optimization = false;
 	for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
 		head = &kprobe_table[i];
-		hlist_for_each_entry_rcu(p, head, hlist) {
+		hlist_for_each_entry(p, head, hlist) {
 			if (!kprobe_disabled(p))
 				unoptimize_kprobe(p, false);
 		}
@@ -1500,12 +1505,14 @@ static struct kprobe *__get_valid_kprobe(struct kprobe *p)
 {
 	struct kprobe *ap, *list_p;
 
+	lockdep_assert_held(&kprobe_mutex);
+
 	ap = get_kprobe(p->addr);
 	if (unlikely(!ap))
 		return NULL;
 
 	if (p != ap) {
-		list_for_each_entry_rcu(list_p, &ap->list, list)
+		list_for_each_entry(list_p, &ap->list, list)
 			if (list_p == p)
 			/* kprobe p is a valid probe */
 				goto valid;
@@ -1670,7 +1677,9 @@ static int aggr_kprobe_disabled(struct kprobe *ap)
 {
 	struct kprobe *kp;
 
-	list_for_each_entry_rcu(kp, &ap->list, list)
+	lockdep_assert_held(&kprobe_mutex);
+
+	list_for_each_entry(kp, &ap->list, list)
 		if (!kprobe_disabled(kp))
 			/*
 			 * There is an active probe on the list.
@@ -1749,7 +1758,7 @@ static int __unregister_kprobe_top(struct kprobe *p)
 	else {
 		/* If disabling probe has special handlers, update aggrprobe */
 		if (p->post_handler && !kprobe_gone(p)) {
-			list_for_each_entry_rcu(list_p, &ap->list, list) {
+			list_for_each_entry(list_p, &ap->list, list) {
 				if ((list_p != p) && (list_p->post_handler))
 					goto noclean;
 			}
@@ -2063,13 +2072,15 @@ static void kill_kprobe(struct kprobe *p)
 {
 	struct kprobe *kp;
 
+	lockdep_assert_held(&kprobe_mutex);
+
 	p->flags |= KPROBE_FLAG_GONE;
 	if (kprobe_aggrprobe(p)) {
 		/*
 		 * If this is an aggr_kprobe, we have to list all the
 		 * chained probes and mark them GONE.
 		 */
-		list_for_each_entry_rcu(kp, &p->list, list)
+		list_for_each_entry(kp, &p->list, list)
 			kp->flags |= KPROBE_FLAG_GONE;
 		p->post_handler = NULL;
 		kill_optimized_kprobe(p);
@@ -2238,7 +2249,7 @@ static int kprobes_module_callback(struct notifier_block *nb,
 	mutex_lock(&kprobe_mutex);
 	for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
 		head = &kprobe_table[i];
-		hlist_for_each_entry_rcu(p, head, hlist)
+		hlist_for_each_entry(p, head, hlist)
 			if (within_module_init((unsigned long)p->addr, mod) ||
 			    (checkcore &&
 			     within_module_core((unsigned long)p->addr, mod))) {
@@ -2489,7 +2500,7 @@ static int arm_all_kprobes(void)
 	for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
 		head = &kprobe_table[i];
 		/* Arm all kprobes on a best-effort basis */
-		hlist_for_each_entry_rcu(p, head, hlist) {
+		hlist_for_each_entry(p, head, hlist) {
 			if (!kprobe_disabled(p)) {
 				err = arm_kprobe(p);
 				if (err)  {
@@ -2532,7 +2543,7 @@ static int disarm_all_kprobes(void)
 	for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
 		head = &kprobe_table[i];
 		/* Disarm all kprobes on a best-effort basis */
-		hlist_for_each_entry_rcu(p, head, hlist) {
+		hlist_for_each_entry(p, head, hlist) {
 			if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p)) {
 				err = disarm_kprobe(p, false);
 				if (err) {

[PATCH -tip V6 3/6] kprobes: Fix to protect kick_kprobe_optimizer() by kprobe_mutex

[Masami Hiramatsu]

In kprobe_optimizer() kick_kprobe_optimizer() is called
without kprobe_mutex, but this can race with other caller
which is protected by kprobe_mutex.

To fix that, expand kprobe_mutex protected area to protect
kick_kprobe_optimizer() call.

Fixes: cd7ebe2298ff ("kprobes: Use text_poke_smp_batch for optimizing")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: stable@vger.kernel.org
---
  Changes in v5: Add Fixes and Cc:stable tags.
---
 kernel/kprobes.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 38d9a5d7c8a4..6d76a6e3e1a5 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -592,11 +592,12 @@ static void kprobe_optimizer(struct work_struct *work)
 	mutex_unlock(&module_mutex);
 	mutex_unlock(&text_mutex);
 	cpus_read_unlock();
-	mutex_unlock(&kprobe_mutex);
 
 	/* Step 5: Kick optimizer again if needed */
 	if (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list))
 		kick_kprobe_optimizer();
+
+	mutex_unlock(&kprobe_mutex);
 }
 
 /* Wait for completing optimization and unoptimization */

[PATCH -tip V6 4/6] kprobes: Remove redundant arch_disarm_kprobe() call

[Masami Hiramatsu]

Fix to remove redundant arch_disarm_kprobe() call in
force_unoptimize_kprobe(). This arch_disarm_kprobe()
will be invoked if the kprobe is optimized but disabled,
but that means the kprobe (optprobe) is unused (and
unoptimized) state.

In that case, unoptimize_kprobe() puts it in freeing_list
and kprobe_optimizer (do_unoptimize_kprobes()) automatically
disarm it. Thus this arch_disarm_kprobe() is redundant.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
 kernel/kprobes.c |    2 --
 1 file changed, 2 deletions(-)

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 6d76a6e3e1a5..627fc1b7011a 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -675,8 +675,6 @@ static void force_unoptimize_kprobe(struct optimized_kprobe *op)
 	lockdep_assert_cpus_held();
 	arch_unoptimize_kprobe(op);
 	op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
-	if (kprobe_disabled(&op->kp))
-		arch_disarm_kprobe(&op->kp);
 }
 
 /* Unoptimize a kprobe if p is optimized */

[PATCH -tip V6 5/6] kretprobe: Prevent triggering kretprobe from within kprobe_flush_task

[Masami Hiramatsu]

From: Jiri Olsa <jolsa@redhat.com>

Ziqian reported lockup when adding retprobe on _raw_spin_lock_irqsave.
My test was also able to trigger lockdep output:

 ============================================
 WARNING: possible recursive locking detected
 5.6.0-rc6+ #6 Not tainted
 --------------------------------------------
 sched-messaging/2767 is trying to acquire lock:
 ffffffff9a492798 (&(kretprobe_table_locks[i].lock)){-.-.}, at: kretprobe_hash_lock+0x52/0xa0

 but task is already holding lock:
 ffffffff9a491a18 (&(kretprobe_table_locks[i].lock)){-.-.}, at: kretprobe_trampoline+0x0/0x50

 other info that might help us debug this:
  Possible unsafe locking scenario:

        CPU0
        ----
   lock(&(kretprobe_table_locks[i].lock));
   lock(&(kretprobe_table_locks[i].lock));

  *** DEADLOCK ***

  May be due to missing lock nesting notation

 1 lock held by sched-messaging/2767:
  #0: ffffffff9a491a18 (&(kretprobe_table_locks[i].lock)){-.-.}, at: kretprobe_trampoline+0x0/0x50

 stack backtrace:
 CPU: 3 PID: 2767 Comm: sched-messaging Not tainted 5.6.0-rc6+ #6
 Call Trace:
  dump_stack+0x96/0xe0
  __lock_acquire.cold.57+0x173/0x2b7
  ? native_queued_spin_lock_slowpath+0x42b/0x9e0
  ? lockdep_hardirqs_on+0x590/0x590
  ? __lock_acquire+0xf63/0x4030
  lock_acquire+0x15a/0x3d0
  ? kretprobe_hash_lock+0x52/0xa0
  _raw_spin_lock_irqsave+0x36/0x70
  ? kretprobe_hash_lock+0x52/0xa0
  kretprobe_hash_lock+0x52/0xa0
  trampoline_handler+0xf8/0x940
  ? kprobe_fault_handler+0x380/0x380
  ? find_held_lock+0x3a/0x1c0
  kretprobe_trampoline+0x25/0x50
  ? lock_acquired+0x392/0xbc0
  ? _raw_spin_lock_irqsave+0x50/0x70
  ? __get_valid_kprobe+0x1f0/0x1f0
  ? _raw_spin_unlock_irqrestore+0x3b/0x40
  ? finish_task_switch+0x4b9/0x6d0
  ? __switch_to_asm+0x34/0x70
  ? __switch_to_asm+0x40/0x70

The code within the kretprobe handler checks for probe reentrancy,
so we won't trigger any _raw_spin_lock_irqsave probe in there.

The problem is in outside kprobe_flush_task, where we call:

  kprobe_flush_task
    kretprobe_table_lock
      raw_spin_lock_irqsave
        _raw_spin_lock_irqsave

where _raw_spin_lock_irqsave triggers the kretprobe and installs
kretprobe_trampoline handler on _raw_spin_lock_irqsave return.

The kretprobe_trampoline handler is then executed with already
locked kretprobe_table_locks, and first thing it does is to
lock kretprobe_table_locks ;-) the whole lockup path like:

  kprobe_flush_task
    kretprobe_table_lock
      raw_spin_lock_irqsave
        _raw_spin_lock_irqsave ---> probe triggered, kretprobe_trampoline installed

        ---> kretprobe_table_locks locked

        kretprobe_trampoline
          trampoline_handler
            kretprobe_hash_lock(current, &head, &flags);  <--- deadlock

Adding kprobe_busy_begin/end helpers that mark code with fake
probe installed to prevent triggering of another kprobe within
this code.

Using these helpers in kprobe_flush_task, so the probe recursion
protection check is hit and the probe is never set to prevent
above lockup.

Fixes: ef53d9c5e4da ("kprobes: improve kretprobe scalability with hashed locking")
Cc: stable@vger.kernel.org
Reported-by: "Ziqian SUN (Zamir)" <zsun@redhat.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 arch/x86/kernel/kprobes/core.c |   16 +++-------------
 include/linux/kprobes.h        |    4 ++++
 kernel/kprobes.c               |   24 ++++++++++++++++++++++++
 3 files changed, 31 insertions(+), 13 deletions(-)

diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index 4d7022a740ab..a12adbe1559d 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -753,16 +753,11 @@ asm(
 NOKPROBE_SYMBOL(kretprobe_trampoline);
 STACK_FRAME_NON_STANDARD(kretprobe_trampoline);
 
-static struct kprobe kretprobe_kprobe = {
-	.addr = (void *)kretprobe_trampoline,
-};
-
 /*
  * Called from kretprobe_trampoline
  */
 __used __visible void *trampoline_handler(struct pt_regs *regs)
 {
-	struct kprobe_ctlblk *kcb;
 	struct kretprobe_instance *ri = NULL;
 	struct hlist_head *head, empty_rp;
 	struct hlist_node *tmp;
@@ -772,16 +767,12 @@ __used __visible void *trampoline_handler(struct pt_regs *regs)
 	void *frame_pointer;
 	bool skipped = false;
 
-	preempt_disable();
-
 	/*
 	 * Set a dummy kprobe for avoiding kretprobe recursion.
 	 * Since kretprobe never run in kprobe handler, kprobe must not
 	 * be running at this point.
 	 */
-	kcb = get_kprobe_ctlblk();
-	__this_cpu_write(current_kprobe, &kretprobe_kprobe);
-	kcb->kprobe_status = KPROBE_HIT_ACTIVE;
+	kprobe_busy_begin();
 
 	INIT_HLIST_HEAD(&empty_rp);
 	kretprobe_hash_lock(current, &head, &flags);
@@ -857,7 +848,7 @@ __used __visible void *trampoline_handler(struct pt_regs *regs)
 			__this_cpu_write(current_kprobe, &ri->rp->kp);
 			ri->ret_addr = correct_ret_addr;
 			ri->rp->handler(ri, regs);
-			__this_cpu_write(current_kprobe, &kretprobe_kprobe);
+			__this_cpu_write(current_kprobe, &kprobe_busy);
 		}
 
 		recycle_rp_inst(ri, &empty_rp);
@@ -873,8 +864,7 @@ __used __visible void *trampoline_handler(struct pt_regs *regs)
 
 	kretprobe_hash_unlock(current, &flags);
 
-	__this_cpu_write(current_kprobe, NULL);
-	preempt_enable();
+	kprobe_busy_end();
 
 	hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) {
 		hlist_del(&ri->hlist);
diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
index 04bdaf01112c..645fd401c856 100644
--- a/include/linux/kprobes.h
+++ b/include/linux/kprobes.h
@@ -350,6 +350,10 @@ static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void)
 	return this_cpu_ptr(&kprobe_ctlblk);
 }
 
+extern struct kprobe kprobe_busy;
+void kprobe_busy_begin(void);
+void kprobe_busy_end(void);
+
 kprobe_opcode_t *kprobe_lookup_name(const char *name, unsigned int offset);
 int register_kprobe(struct kprobe *p);
 void unregister_kprobe(struct kprobe *p);
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 627fc1b7011a..3cb9e29908ed 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1241,6 +1241,26 @@ __releases(hlist_lock)
 }
 NOKPROBE_SYMBOL(kretprobe_table_unlock);
 
+struct kprobe kprobe_busy = {
+	.addr = (void *) get_kprobe,
+};
+
+void kprobe_busy_begin(void)
+{
+	struct kprobe_ctlblk *kcb;
+
+	preempt_disable();
+	__this_cpu_write(current_kprobe, &kprobe_busy);
+	kcb = get_kprobe_ctlblk();
+	kcb->kprobe_status = KPROBE_HIT_ACTIVE;
+}
+
+void kprobe_busy_end(void)
+{
+	__this_cpu_write(current_kprobe, NULL);
+	preempt_enable();
+}
+
 /*
  * This function is called from finish_task_switch when task tk becomes dead,
  * so that we can recycle any function-return probe instances associated
@@ -1258,6 +1278,8 @@ void kprobe_flush_task(struct task_struct *tk)
 		/* Early boot.  kretprobe_table_locks not yet initialized. */
 		return;
 
+	kprobe_busy_begin();
+
 	INIT_HLIST_HEAD(&empty_rp);
 	hash = hash_ptr(tk, KPROBE_HASH_BITS);
 	head = &kretprobe_inst_table[hash];
@@ -1271,6 +1293,8 @@ void kprobe_flush_task(struct task_struct *tk)
 		hlist_del(&ri->hlist);
 		kfree(ri);
 	}
+
+	kprobe_busy_end();
 }
 NOKPROBE_SYMBOL(kprobe_flush_task);
 

[PATCH -tip V6 6/6] kprobes: Replace zero-length array with flexible-array

[Masami Hiramatsu]

From: Gustavo A. R. Silva <gustavoars@kernel.org>

The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
---
 include/linux/kprobes.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
index 645fd401c856..53c4f2c1d658 100644
--- a/include/linux/kprobes.h
+++ b/include/linux/kprobes.h
@@ -161,7 +161,7 @@ struct kretprobe_instance {
 	kprobe_opcode_t *ret_addr;
 	struct task_struct *task;
 	void *fp;
-	char data[0];
+	char data[];
 };
 
 struct kretprobe_blackpoint {

Re: [PATCH -tip V6 0/6] kprobes: Fixes mutex, rcu-list warnings and cleanups

[Masami Hiramatsu]

(Oops, I missed Jiri in loop.)

Hi Ingo,

Could you take this series?
These are not adding any feature, but fixing real bugs.

Thank you,

On Tue, 12 May 2020 17:02:22 +0900
Masami Hiramatsu <mhiramat@kernel.org> wrote:

> Hi Ingo,
> 
> Here is the 6th version of the series for kprobes. The previous
> version is here.
> 
>  https://lore.kernel.org/lkml/158583483116.26060.10517933482238348979.stgit@devnote2/
> 
> In this version, I picked 2 patches[1][2] which has been reviewed
> on LKML but not merged to tip tree yet.
> 
> [1] https://lore.kernel.org/lkml/20200408164641.3299633-1-jolsa@kernel.org/
> [2] https://lore.kernel.org/lkml/20200507185733.GA14931@embeddedor/
> 
> You can also pull this series from kprobes/core branch from
> 
>  https://git.kernel.org/pub/scm/linux/kernel/git/mhiramat/linux.git/
> 
> Thank you,
> 
> ---
> 
> Gustavo A. R. Silva (1):
>       kprobes: Replace zero-length array with flexible-array
> 
> Jiri Olsa (1):
>       kretprobe: Prevent triggering kretprobe from within kprobe_flush_task
> 
> Masami Hiramatsu (4):
>       kprobes: Suppress the suspicious RCU warning on kprobes
>       kprobes: Use non RCU traversal APIs on kprobe_tables if possible
>       kprobes: Fix to protect kick_kprobe_optimizer() by kprobe_mutex
>       kprobes: Remove redundant arch_disarm_kprobe() call
> 
> 
>  arch/x86/kernel/kprobes/core.c |   16 ++--------
>  include/linux/kprobes.h        |    6 +++-
>  kernel/kprobes.c               |   61 +++++++++++++++++++++++++++++++---------
>  3 files changed, 56 insertions(+), 27 deletions(-)
> 
> --
> Masami Hiramatsu (Linaro) <mhiramat@kernel.org>


-- 
Masami Hiramatsu <mhiramat@kernel.org>

Re: [PATCH -tip V6 0/6] kprobes: Fixes mutex, rcu-list warnings and cleanups

[Jiri Olsa]

On Wed, May 27, 2020 at 11:49:41PM +0900, Masami Hiramatsu wrote:
> (Oops, I missed Jiri in loop.)
> 
> Hi Ingo,
> 
> Could you take this series?
> These are not adding any feature, but fixing real bugs.

Hi,
I still can't see this being pulled in, did I miss it?

thanks,
jirka

> 
> Thank you,
> 
> On Tue, 12 May 2020 17:02:22 +0900
> Masami Hiramatsu <mhiramat@kernel.org> wrote:
> 
> > Hi Ingo,
> > 
> > Here is the 6th version of the series for kprobes. The previous
> > version is here.
> > 
> >  https://lore.kernel.org/lkml/158583483116.26060.10517933482238348979.stgit@devnote2/
> > 
> > In this version, I picked 2 patches[1][2] which has been reviewed
> > on LKML but not merged to tip tree yet.
> > 
> > [1] https://lore.kernel.org/lkml/20200408164641.3299633-1-jolsa@kernel.org/
> > [2] https://lore.kernel.org/lkml/20200507185733.GA14931@embeddedor/
> > 
> > You can also pull this series from kprobes/core branch from
> > 
> >  https://git.kernel.org/pub/scm/linux/kernel/git/mhiramat/linux.git/
> > 
> > Thank you,
> > 
> > ---
> > 
> > Gustavo A. R. Silva (1):
> >       kprobes: Replace zero-length array with flexible-array
> > 
> > Jiri Olsa (1):
> >       kretprobe: Prevent triggering kretprobe from within kprobe_flush_task
> > 
> > Masami Hiramatsu (4):
> >       kprobes: Suppress the suspicious RCU warning on kprobes
> >       kprobes: Use non RCU traversal APIs on kprobe_tables if possible
> >       kprobes: Fix to protect kick_kprobe_optimizer() by kprobe_mutex
> >       kprobes: Remove redundant arch_disarm_kprobe() call
> > 
> > 
> >  arch/x86/kernel/kprobes/core.c |   16 ++--------
> >  include/linux/kprobes.h        |    6 +++-
> >  kernel/kprobes.c               |   61 +++++++++++++++++++++++++++++++---------
> >  3 files changed, 56 insertions(+), 27 deletions(-)
> > 
> > --
> > Masami Hiramatsu (Linaro) <mhiramat@kernel.org>
> 
> 
> -- 
> Masami Hiramatsu <mhiramat@kernel.org>
> 

Re: [PATCH -tip V6 0/6] kprobes: Fixes mutex, rcu-list warnings and cleanups

[Steven Rostedt]

On Sun, 14 Jun 2020 17:37:28 +0200
Jiri Olsa <jolsa@redhat.com> wrote:

> On Wed, May 27, 2020 at 11:49:41PM +0900, Masami Hiramatsu wrote:
> > (Oops, I missed Jiri in loop.)
> > 
> > Hi Ingo,
> > 
> > Could you take this series?
> > These are not adding any feature, but fixing real bugs.  
> 
> Hi,
> I still can't see this being pulled in, did I miss it?
> 

I'm getting a pull request ready for -rc2. I can pull these in with that.

-- Steve

Re: [PATCH -tip V6 0/6] kprobes: Fixes mutex, rcu-list warnings and cleanups

[Jiri Olsa]

On Tue, Jun 16, 2020 at 03:01:22PM -0400, Steven Rostedt wrote:
> On Sun, 14 Jun 2020 17:37:28 +0200
> Jiri Olsa <jolsa@redhat.com> wrote:
> 
> > On Wed, May 27, 2020 at 11:49:41PM +0900, Masami Hiramatsu wrote:
> > > (Oops, I missed Jiri in loop.)
> > > 
> > > Hi Ingo,
> > > 
> > > Could you take this series?
> > > These are not adding any feature, but fixing real bugs.  
> > 
> > Hi,
> > I still can't see this being pulled in, did I miss it?
> > 
> 
> I'm getting a pull request ready for -rc2. I can pull these in with that.

that'd be awesome, thanks!

jirka

Re: [PATCH -tip V6 0/6] kprobes: Fixes mutex, rcu-list warnings and cleanups

[Masami Hiramatsu]

On Tue, 16 Jun 2020 15:01:22 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:

> On Sun, 14 Jun 2020 17:37:28 +0200
> Jiri Olsa <jolsa@redhat.com> wrote:
> 
> > On Wed, May 27, 2020 at 11:49:41PM +0900, Masami Hiramatsu wrote:
> > > (Oops, I missed Jiri in loop.)
> > > 
> > > Hi Ingo,
> > > 
> > > Could you take this series?
> > > These are not adding any feature, but fixing real bugs.  
> > 
> > Hi,
> > I still can't see this being pulled in, did I miss it?
> > 
> 
> I'm getting a pull request ready for -rc2. I can pull these in with that.

Great! Thank you so much!


-- 
Masami Hiramatsu <mhiramat@kernel.org>