Although the tty core maintains a pid reference for the foreground process group, if the foreground process group is changed that pid reference is dropped. Thus, the pid reference used for signalling could become stale.
Safely obtain a pid reference to the foreground process group and release the reference after signalling is complete. cc: Jeff Dike <[email protected]> cc: Richard Weinberger <[email protected]> cc: [email protected] Signed-off-by: Peter Hurley <[email protected]> --- arch/um/drivers/line.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/arch/um/drivers/line.c b/arch/um/drivers/line.c index 8035145..6208702 100644 --- a/arch/um/drivers/line.c +++ b/arch/um/drivers/line.c @@ -632,6 +632,7 @@ static irqreturn_t winch_interrupt(int irq, void *data) int fd = winch->fd; int err; char c; + struct pid *pgrp; if (fd != -1) { err = generic_read(fd, &c, NULL); @@ -657,7 +658,10 @@ static irqreturn_t winch_interrupt(int irq, void *data) if (line != NULL) { chan_window_size(line, &tty->winsize.ws_row, &tty->winsize.ws_col); - kill_pgrp(tty->pgrp, SIGWINCH, 1); + pgrp = tty_get_pgrp(tty); + if (pgrp) + kill_pgrp(pgrp, SIGWINCH, 1); + put_pid(pgrp); } tty_kref_put(tty); } -- 2.1.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
