ALSA: seq: Fix racy cell insertions during snd_seq_pool_done()
BugLink: http://bugs.launchpad.net/bugs/1677600 commit c520ff3d upstream. When snd_seq_pool_done() is called, it marks the closing flag to refuse the further cell insertions. But snd_seq_pool_done() itself doesn't clear the cells but just waits until all cells are cleared by the caller side. That is, it's racy, and this leads to the endless stall as syzkaller spotted. This patch addresses the racy by splitting the setup of pool->closing flag out of snd_seq_pool_done(), and calling it properly before snd_seq_pool_done(). BugLink: http://lkml.kernel.org/r/CACT4Y+aqqy8bZA1fFieifNxR2fAfFQQABcBHj801+u5ePV0URw@mail.gmail.comReported-and-tested-by:Dmitry Vyukov <dvyukov@google.com> Signed-off-by:
Takashi Iwai <tiwai@suse.de> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by:
Tim Gardner <tim.gardner@canonical.com> Signed-off-by:
Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
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