From 2e211723953f7740e54b53f3d3a0d5e351a5e223 Mon Sep 17 00:00:00 2001 From: Jacques Nilo Date: Wed, 13 May 2026 15:30:25 +0200 Subject: [PATCH] serial: 8250_dw: dispatch SysRq character in dw8250_handle_irq() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit dw8250_handle_irq() calls serial8250_handle_irq_locked() with the port lock held via guard(uart_port_lock_irqsave). The guard destructor is plain uart_port_unlock_irqrestore(), so a SysRq character captured into port->sysrq_ch by uart_prepare_sysrq_char() is dropped without ever being dispatched to handle_sysrq(). This is the same regression pattern as in serial8250_handle_irq(), introduced when 883c5a2bc934 ("serial: 8250_dw: Rework dw8250_handle_irq() locking and IIR handling") moved the function to the guard()-based locking scheme without using the sysrq-aware unlock helper. Switch to guard(uart_port_lock_check_sysrq_irqsave) so that captured sysrq_ch is dispatched on scope exit, matching the fix in serial8250_handle_irq(). Fixes: 883c5a2bc934 ("serial: 8250_dw: Rework dw8250_handle_irq() locking and IIR handling") Cc: stable@vger.kernel.org Reviewed-by: Ilpo Järvinen Signed-off-by: Jacques Nilo Link: https://patch.msgid.link/ed56fcaf4af24e4ed011a7bce206e0182acb761c.1778675349.git.jnilo@free.fr Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_dw.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c index 94beadb4024d..2af0c4d0ad82 100644 --- a/drivers/tty/serial/8250/8250_dw.c +++ b/drivers/tty/serial/8250/8250_dw.c @@ -427,7 +427,7 @@ static int dw8250_handle_irq(struct uart_port *p) unsigned int quirks = d->pdata->quirks; unsigned int status; - guard(uart_port_lock_irqsave)(p); + guard(uart_port_lock_check_sysrq_irqsave)(p); switch (FIELD_GET(DW_UART_IIR_IID, iir)) { case UART_IIR_NO_INT: