| Message ID | 20171103131959.73560-1-kirill.shutemov@linux.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi On Fri, Nov 3, 2017 at 2:19 PM, Kirill A. Shutemov <kirill.shutemov@linux.intel.com> wrote: > I noticied that on recent versions on QEMU I was not able to trigger > SysRq to invoke debug capabilites of Linux Kernel. > > I've tracked it down to qemu_chr_be_event() ignoring CHR_EVENT_BREAK due > s->be being NULL. > > Looks like the bug was introduced in a4afa548fc6d ("char: move front end > handlers in CharBackend"). Since the commit the qemu_chr_be_event() > failed to deliver CHR_EVENT_BREAK due to qemu_chr_fe_init() forgot to > get s->be initialized in case of mux. > > Let's fix this. > > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> > Fixes: a4afa548fc6d ("char: move front end handlers in CharBackend") > --- > chardev/char-fe.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/chardev/char-fe.c b/chardev/char-fe.c > index ee6d59610031..d4a54947a567 100644 > --- a/chardev/char-fe.c > +++ b/chardev/char-fe.c > @@ -209,9 +209,8 @@ bool qemu_chr_fe_init(CharBackend *b, Chardev *s, Error **errp) > tag = d->mux_cnt++; > } else if (s->be) { > goto unavailable; > - } else { > - s->be = b; > } > + s->be = b; This will send the event to the last frontend that called chr_fe_init(). Instead, it should probably send it to the one with focus. I am sending an alternative patch. thanks > > b->fe_open = false; > b->tag = tag; > -- > 2.14.2 > >
diff --git a/chardev/char-fe.c b/chardev/char-fe.c index ee6d59610031..d4a54947a567 100644 --- a/chardev/char-fe.c +++ b/chardev/char-fe.c @@ -209,9 +209,8 @@ bool qemu_chr_fe_init(CharBackend *b, Chardev *s, Error **errp) tag = d->mux_cnt++; } else if (s->be) { goto unavailable; - } else { - s->be = b; } + s->be = b; b->fe_open = false; b->tag = tag;
I noticied that on recent versions on QEMU I was not able to trigger SysRq to invoke debug capabilites of Linux Kernel. I've tracked it down to qemu_chr_be_event() ignoring CHR_EVENT_BREAK due s->be being NULL. Looks like the bug was introduced in a4afa548fc6d ("char: move front end handlers in CharBackend"). Since the commit the qemu_chr_be_event() failed to deliver CHR_EVENT_BREAK due to qemu_chr_fe_init() forgot to get s->be initialized in case of mux. Let's fix this. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Fixes: a4afa548fc6d ("char: move front end handlers in CharBackend") --- chardev/char-fe.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)