From: Johan Hovold <johan@kernel.org> stable inclusion from stable-5.10.71 commit 67d1df661088b70382cd2499945ad80333c16ba1 bugzilla: 182981 https://gitee.com/openeuler/kernel/issues/I4I3KD Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit cd20d59291d1790dc74248476e928f57fc455189 upstream. Registration of the ipoctal tty devices is unlikely to fail, but if it ever does, make sure not to deregister a never registered tty device (and dereference a NULL pointer) when the driver is later unbound. Fixes: 2afb41d9d30d ("Staging: ipack/devices/ipoctal: Check tty_register_device return value.") Cc: stable@vger.kernel.org # 3.7 Acked-by: Samuel Iglesias Gonsalvez <siglesias@igalia.com> Signed-off-by: Johan Hovold <johan@kernel.org> Link: https://lore.kernel.org/r/20210917114622.5412-4-johan@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Chen Jun <chenjun102@huawei.com> Acked-by: Weilong Chen <chenweilong@huawei.com> Signed-off-by: Chen Jun <chenjun102@huawei.com> --- drivers/ipack/devices/ipoctal.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/ipack/devices/ipoctal.c b/drivers/ipack/devices/ipoctal.c index 84488dc34942..4dd924994bb9 100644 --- a/drivers/ipack/devices/ipoctal.c +++ b/drivers/ipack/devices/ipoctal.c @@ -35,6 +35,7 @@ struct ipoctal_channel { unsigned int pointer_read; unsigned int pointer_write; struct tty_port tty_port; + bool tty_registered; union scc2698_channel __iomem *regs; union scc2698_block __iomem *block_regs; unsigned int board_id; @@ -399,9 +400,11 @@ static int ipoctal_inst_slot(struct ipoctal *ipoctal, unsigned int bus_nr, i, NULL, channel, NULL); if (IS_ERR(tty_dev)) { dev_err(&ipoctal->dev->dev, "Failed to register tty device.\n"); + tty_port_free_xmit_buf(&channel->tty_port); tty_port_destroy(&channel->tty_port); continue; } + channel->tty_registered = true; } /* @@ -702,6 +705,10 @@ static void __ipoctal_remove(struct ipoctal *ipoctal) for (i = 0; i < NR_CHANNELS; i++) { struct ipoctal_channel *channel = &ipoctal->channel[i]; + + if (!channel->tty_registered) + continue; + tty_unregister_device(ipoctal->tty_drv, i); tty_port_free_xmit_buf(&channel->tty_port); tty_port_destroy(&channel->tty_port); -- 2.20.1