3a3567d337
Since commit bd5c51e (qemu-char: don't issue CHR_EVENT_OPEN in a BH), an infinite recursion occurs when putting the monitor on a pty (-monitor pty) and connecting a terminal to the slave port. This is because of the qemu_chr_be_event(s, CHR_EVENT_OPENED) added to qemu_chr_be_generic_open(). This event is captured by monitor_event() which prints a welcome message to the character device. The flush of that welcome message retriggers another open event in pty_chr_state() because it checks s->connected, but only sets it to 1 after calling qemu_chr_be_generic_open(). I've fixed this by setting s->connected = 1 before the call to qemu_chr_be_generic_open() instead of after, so that the recursive pty_chr_state() doesn't call it again. An example snippet of repeating backtrace: ... #107486 0x007aec58 in monitor_flush (mon=0xf418b0) at qemu/monitor.c:288 #107487 0x007aee7c in monitor_puts (mon=0xf418b0, str=0x1176d07 "") at qemu/monitor.c:322 #107488 0x007aef20 in monitor_vprintf (mon=0xf418b0, fmt=0x8d4820 "QEMU %s monitor - type 'help' for more information\n", ap=0x7f432be0) at qemu/monitor.c:339 #107489 0x007aefac in monitor_printf (mon=0xf418b0, fmt=0x8d4820 "QEMU %s monitor - type 'help' for more information\n") at qemu/monitor.c:347 #107490 0x007ba4bc in monitor_event (opaque=0xf418b0, event=2) at qemu/monitor.c:4699 #107491 0x00684c28 in qemu_chr_be_event (s=0xf37788, event=2) at qemu/qemu-char.c:108 #107492 0x00684c70 in qemu_chr_be_generic_open (s=0xf37788) at qemu/qemu-char.c:113 #107493 0x006880a4 in pty_chr_state (chr=0xf37788, connected=1) at qemu/qemu-char.c:1145 #107494 0x00687fa4 in pty_chr_update_read_handler (chr=0xf37788) at qemu/qemu-char.c:1121 #107495 0x00687c9c in pty_chr_write (chr=0xf37788, buf=0x70b3c008 <Address 0x70b3c008 out of bounds>, len=538720) at qemu/qemu-char.c:1063 #107496 0x00684cc4 in qemu_chr_fe_write (s=0xf37788, buf=0x70b3c008 <Address 0x70b3c008 out of bounds>, len=538720) at qemu/qemu-char.c:118 ... Signed-off-by: James Hogan <james.hogan@imgtec.com> Tested-by: Michael Roth <mdroth@linux.vnet.ibm.com> Message-id: 1375960178-10882-1-git-send-email-james.hogan@imgtec.com Cc: Michael Roth <mdroth@linux.vnet.ibm.com> Cc: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Read the documentation in qemu-doc.html or on http://wiki.qemu.org - QEMU team