lkml.org 
[lkml]   [2020]   [Sep]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[GIT PULL] tracing: A couple of fixes

Linus,

Two tracing fixes:

- Fix temp buffer accounting that caused a WARNING for
ftrace_dump_on_opps()

- Move the recursion check in one of the function callback helpers to the
beginning of the function, as if the rcu_is_watching() gets traced, it
will cause a recursive loop that will crash the kernel.


Please pull the latest trace-v5.9-rc6 tree, which can be found at:


git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
trace-v5.9-rc6

Tag SHA1: 87d55eca1585b1bd70fe7de33cd5ea2957628027
Head SHA1: b40341fad6cc2daa195f8090fd3348f18fff640a


Steven Rostedt (VMware) (2):
tracing: Fix trace_find_next_entry() accounting of temp buffer size
ftrace: Move RCU is watching check after recursion check

----
kernel/trace/ftrace.c | 6 ++----
kernel/trace/trace.c | 10 ++++++----
2 files changed, 8 insertions(+), 8 deletions(-)
---------------------------
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 603255f5f085..541453927c82 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -6993,16 +6993,14 @@ static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
{
int bit;

- if ((op->flags & FTRACE_OPS_FL_RCU) && !rcu_is_watching())
- return;
-
bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
if (bit < 0)
return;

preempt_disable_notrace();

- op->func(ip, parent_ip, op, regs);
+ if (!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching())
+ op->func(ip, parent_ip, op, regs);

preempt_enable_notrace();
trace_clear_recursion(bit);
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 2a7c26345e83..d3e5de717df2 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3546,13 +3546,15 @@ struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
if (iter->ent && iter->ent != iter->temp) {
if ((!iter->temp || iter->temp_size < iter->ent_size) &&
!WARN_ON_ONCE(iter->temp == static_temp_buf)) {
- kfree(iter->temp);
- iter->temp = kmalloc(iter->ent_size, GFP_KERNEL);
- if (!iter->temp)
+ void *temp;
+ temp = kmalloc(iter->ent_size, GFP_KERNEL);
+ if (!temp)
return NULL;
+ kfree(iter->temp);
+ iter->temp = temp;
+ iter->temp_size = iter->ent_size;
}
memcpy(iter->temp, iter->ent, iter->ent_size);
- iter->temp_size = iter->ent_size;
iter->ent = iter->temp;
}
entry = __find_next_entry(iter, ent_cpu, NULL, ent_ts);
\
 
 \ /
  Last update: 2020-10-01 01:54    [W:0.035 / U:4.724 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site