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authorSteven Rostedt (Google) <rostedt@goodmis.org>2022-09-28 01:15:27 +0200
committerSteven Rostedt (Google) <rostedt@goodmis.org>2022-09-29 02:28:13 +0200
commitf3ddb74ad0790030c9592229fb14d8c451f4e9a8 (patch)
tree1bca8a772c02e57ee8ca5db7f393ce5a6fabaea5 /kernel/trace
parentring-buffer: Add ring_buffer_wake_waiters() (diff)
downloadlinux-f3ddb74ad0790030c9592229fb14d8c451f4e9a8.tar.xz
linux-f3ddb74ad0790030c9592229fb14d8c451f4e9a8.zip
tracing: Wake up ring buffer waiters on closing of the file
When the file that represents the ring buffer is closed, there may be waiters waiting on more input from the ring buffer. Call ring_buffer_wake_waiters() to wake up any waiters when the file is closed. Link: https://lkml.kernel.org/r/20220927231825.182416969@goodmis.org Cc: stable@vger.kernel.org Cc: Ingo Molnar <mingo@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Fixes: e30f53aad2202 ("tracing: Do not busy wait in buffer splice") Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace')
-rw-r--r--kernel/trace/trace.c15
1 files changed, 15 insertions, 0 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index aed7ea6e6045..e101b0764b39 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -8160,6 +8160,12 @@ static int tracing_buffers_release(struct inode *inode, struct file *file)
__trace_array_put(iter->tr);
+ iter->wait_index++;
+ /* Make sure the waiters see the new wait_index */
+ smp_wmb();
+
+ ring_buffer_wake_waiters(iter->array_buffer->buffer, iter->cpu_file);
+
if (info->spare)
ring_buffer_free_read_page(iter->array_buffer->buffer,
info->spare_cpu, info->spare);
@@ -8313,6 +8319,8 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
/* did we read anything? */
if (!spd.nr_pages) {
+ long wait_index;
+
if (ret)
goto out;
@@ -8320,10 +8328,17 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
if ((file->f_flags & O_NONBLOCK) || (flags & SPLICE_F_NONBLOCK))
goto out;
+ wait_index = READ_ONCE(iter->wait_index);
+
ret = wait_on_pipe(iter, iter->tr->buffer_percent);
if (ret)
goto out;
+ /* Make sure we see the new wait_index */
+ smp_rmb();
+ if (wait_index != iter->wait_index)
+ goto out;
+
goto again;
}