Messages in this thread | | | Date | Mon, 1 Apr 2024 11:39:15 +0200 | From | Greg KH <> | Subject | Re: [PATCH] tty: serial: fixed uart irq maybe cause irq storm |
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On Mon, Apr 01, 2024 at 05:30:01PM +0800, fengchunguo@126.com wrote: > From: "chunguo.feng" <chunguo.feng@semidrive.com>
Please use your name, which is not with a "." in it, right?
> if not disable uart irq before disable clk, uart irq maybe triggered after > disabled clk immediately, then maybe cause irq storm. > > Reproduced the below call trace, see i2c not be connected, but irq storm > was triggered. > > i2c_designware 30b70000.i2c: controller timed out > CPU: 2 PID: 2932 Comm: gnss@1.0-servic > Tainted: G O 5.14.61-00094-geaa0149416cc-dirty #8 > Hardware name: Semidrive kunlun x9 REF Board (DT) > Call trace: > [<ffff00000808a3cc>] dump_backtrace+0x0/0x3c0 > [<ffff00000808a7a0>] show_stack+0x14/0x1c > [<ffff000008cef43c>] dump_stack+0xc4/0xfc > [<ffff00000814eb80>] __report_bad_irq+0x50/0xe0 > [<ffff00000814eaec>] note_interrupt+0x248/0x28c > [<ffff00000814c0e8>] handle_irq_event+0x78/0xa4 > [<ffff00000814fcb8>] handle_fasteoi_irq+0xe4/0x1b4 > [<ffff00000814b060>] __handle_domain_irq+0x7c/0xbc > [<ffff00000808176c>] gic_handle_irq+0x4c/0xb8 > [<ffff000008083230>] el1_irq+0xb0/0x124 > [<ffff000008d09f5c>] _raw_spin_unlock_irqrestore+0x10/0x44 > [<ffff00000865b784>] dw8250_set_termios+0x48/0xf4 > [<ffff0000086545a4>] serial8250_set_termios+0x14/0x28 > [<ffff00000864c4f4>] uart_change_speed+0x38/0x10c > [<ffff00000864e458>] uart_set_termios+0xd0/0x17c > [<ffff000008630ad4>] tty_set_termios+0x160/0x1e4 > [<ffff00000863165c>] set_termios+0x32c/0x3bc > [<ffff000008631248>] tty_mode_ioctl+0x6f0/0x7d8 > [<ffff000008631a6c>] n_tty_ioctl_helper+0x10c/0x1e8 > [<ffff00000862d2c4>] n_tty_ioctl+0x120/0x194 > [<ffff00000862a724>] tty_ioctl+0x658/0xa34 > [<ffff0000082a8f40>] do_vfs_ioctl+0x554/0x810 > [<ffff0000082a9368>] SyS_ioctl+0x88/0x94 > Exception stack(0xffff00000ccf3ec0 to 0xffff00000ccf4000 > > Signed-off-by: chunguo.feng <chunguo.feng@semidrive.com> > --- > drivers/tty/serial/8250/8250_dw.c | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c > index c1d43f0..133c24e 100644 > --- a/drivers/tty/serial/8250/8250_dw.c > +++ b/drivers/tty/serial/8250/8250_dw.c > @@ -359,6 +359,12 @@ static void dw8250_set_termios(struct uart_port *p, struct ktermios *termios, > > rate = clk_round_rate(d->clk, newrate); > if (rate > 0 && p->uartclk != rate) { > + /*Need disable uart irq before disabled clk, because uart irq maybe triggered after
Space needed after '*', right?
> + * disabled clk immediately, then cause irq storm. > + */ > + if (p->irq) > + disabled_irq(p->irq);
This feels wrong, the irq should not be turned off here, what happens if some data comes in while this function is running? Will it be lost?
thanks,
greg k-h
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