Hi everybody. Patch c5c34d4862e18ef07c1276d233507f540fb5a532 (tty: flush flip buffer on ldisc input queue flush) introduces a race condition which can lead to memory leaks.
The problem can be triggered when tcflush() is called when data are being pushed to the line discipline driver by flush_to_ldisc(). flush_to_ldisc() releases tty->buf.lock when calling the line discipline receive_buf function. At that poing tty_buffer_flush() kicks in and sets both tty->buf.head and tty->buf.tail to NULL. When flush_to_ldisc() finishes, it restores tty->buf.head but doesn't touch tty->buf.tail. This corrups the buffer queue, and the next call to tty_buffer_request_room() will allocate a new buffer and overwrite tty->buf.head. The previous buffer is then lost forever without being released. I'm not familiar enough with the tty code to decide what the proper fix should be. I'll try to write a patch if someone could point me in the right direction. Please CC me when answering, as I'm not subscribed to the list. Regards, -- Laurent Pinchart CSE Semaphore Belgium Chaussée de Bruxelles, 732A B-1410 Waterloo Belgium T +32 (2) 387 42 59 F +32 (2) 387 42 75 - 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/