5.4-stable review patch. If anyone has any objections, please let me know.
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From: zhoumin teczm@foxmail.com
commit 42ea22e754ba4f2b86f8760ca27f6f71da2d982c upstream.
When the kernel contains a large number of functions that can be traced, the loop in ftrace_graph_set_hash() may take a lot of time to execute. This may trigger the softlockup watchdog.
Add cond_resched() within the loop to allow the kernel to remain responsive even when processing a large number of functions.
This matches the cond_resched() that is used in other locations of the code that iterates over all functions that can be traced.
Cc: stable@vger.kernel.org Fixes: b9b0c831bed26 ("ftrace: Convert graph filter to use hash tables") Link: https://lore.kernel.org/tencent_3E06CE338692017B5809534B9C5C03DA7705@qq.com Signed-off-by: zhoumin teczm@foxmail.com Signed-off-by: Steven Rostedt (Google) rostedt@goodmis.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/trace/ftrace.c | 1 + 1 file changed, 1 insertion(+)
--- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -5506,6 +5506,7 @@ ftrace_graph_set_hash(struct ftrace_hash } } } + cond_resched(); } while_for_each_ftrace_rec(); out: mutex_unlock(&ftrace_lock);