tracing/ring-buffer: Have polling block on watermark
stable inclusion from stable-v5.10.156 commit 5d4cc7bc1a8d8b05b01800688f0e82781986b905 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I7MCG1 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=5d4cc7bc1a8d8b05b01800688f0e82781986b905 -------------------------------- commit 42fb0a1e upstream. Currently the way polling works on the ring buffer is broken. It will return immediately if there's any data in the ring buffer whereas a read will block until the watermark (defined by the tracefs buffer_percent file) is hit. That is, a select() or poll() will return as if there's data available, but then the following read will block. This is broken for the way select()s and poll()s are supposed to work. Have the polling on the ring buffer also block the same way reads and splice does on the ring buffer. Link: https://lkml.kernel.org/r/20221020231427.41be3f26@gandalf.local.home Cc: Linux Trace Kernel <linux-trace-kernel@vger.kernel.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Primiano Tucci <primiano@google.com> Cc: stable@vger.kernel.org Fixes: 1e0d6714 ("ring-buffer: Do not wake up a splice waiter when page is not full") Signed-off-by: NSteven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Nsanglipeng <sanglipeng1@jd.com> (cherry picked from commit 87f4ba53)
Showing
想要评论请 注册 或 登录